A mobile application for weather and pollen statistics

A mobile application for weather and pollen statistics industriële wetenschappen en technologie bachelor in de elektronica-ICT Eindwerk aangeboden tot het behalen van het diploma van bachelor in de elektronica-ICT door Milan Lamote Campus Oostende Academiejaar 2016 - 2017 o.l.v. Tom Cordemans, Vives Luc Vanhee, Vives Quiliano Isaac Moro Sancho, E. Ingeniería Informática de Valladolid Javier Bastida Ibáñez, E. Ingeniería Informática de Valladolid A mobile application for weather and pollen statistics industriële wetenschappen en technologie bachelor in de elektronica-ICT Eindwerk aangeboden tot het behalen van het diploma van bachelor in de elektronica-ICT door Milan Lamote Campus Oostende Academiejaar 2016 - 2017 o.l.v. Tom Cordemans, Vives Luc Vanhee, Vives Quiliano Isaac Moro Sancho, E. Ingeniería Informática de Valladolid Javier Bastida Ibáñez, E. Ingeniería Informática de Valladolid Announcement This final project was an exam. The questions formulated during the defense presentation are not included. Deze eindverhandeling was een examen. De tijdens de verdediging geformuleerde opmerkingen werden niet opgenomen. Abstract in English This bachelor’s thesis was given to me by the ‘Universidad de Valladolid’, it is about an Android application for collecting and showing weather statistics. These statistics concern things like temperature, wind, rainfall and pollen information from the current day as well as the next few days. The goal is to be able to download the needed information, save it and show it to the user in a way he or she can read it. This book will cover the whole process from scratch to how to install. The interface will be explained using a graphical user manual. Abstract in Dutch Dit eindwerk werd mij aangeboden door de ‘Universidad de Valladolid’, het betreft een Android applicatie voor het verzamelen en tentoonstellen van weerstatistieken. Deze statistieken betreffen informatie zoals de temperatuur, de wind, de neerslag en stuifmeelconcentratie van de huidige dag zowel als enkele komende dagen. Het doel is om deze informatie te downloaden, op te slaan en in een leesbaar formaat aan de gebruiker te tonen. Dit boek omvat het hele proces van nul tot hoe te installeren. Het gebruikersscherm wordt toegelicht aan de hand van een gebruikershandleiding. Abstract in Spanish Esta tesis de licenciatura ha sido realizada en la Universidad de Valladolid, se trata de una aplicación de Android para recopilar y mostrar estadísticas del tiempo. Estas estadísticas se refieren a cosas como la temperatura, el viento, la lluvia y la información sobre el polen del día actual, así como los próximos días. El objetivo es poder descargar la información necesaria, guardarla y mostrarla al usuario de manera que pueda leerla. Este documento cubrirá todo el proceso desde cero, hasta cómo instalarlo. La interfaz se explicará mediante un manual de usuario gráfico. Dedication in English I would like to thank ‘VIVES University College’ for giving me the opportunity of completing my studies abroad with an Erasmus+ program. By this, I’d like to personally thank my internal promotors Cordemans Tom and Vanhee Luc. They’ve prepared me in any way possible for this experience. Although quite the distance they were always prepared to answer any questions I had via mail. Secondly, I’d like to thank the ‘Universidad de Valladolid’ for accepting and helping me through this journey. By this, I’d like to thank my external promotor Quilano Isaac Moro Sancho and supervising professor Javier Bastida Ibáñez. I was always welcome at their offices for any questions or further ideas concerning my project. Thirdly, I’d like to thank my local student mentor and friend Tamara Alonso Bernal. She has helped me a lot getting settled in and giving me opportunities to get to know the city and meeting new friends. Lastly, I’d like to thank my family for supporting me in taking on this project abroad. I wouldn’t have been able to enjoy this experience as much as I did without their support. This project has taught me a lot on how to take on a big project by myself even in an unknown environment, an environment most likely different than the one I will be spending my career in. During the process, I’ve made a lot of friends and memories, things I will never forget and will be able to use in my further life. Dedication in Dutch Ik wil graag ‘Hogeschool VIVES’ bedanken om mij de gelegenheid te geven mijn studies in het buitenland te voltooien met een Erasmus+ programma. Hierbij wil ik persoonlijk mijn interne promotors Cordemans Tom en Vanhee Luc bedanken. Zij waren een grote hulp bij mijn voorbereiding op dit avontuur. Alhoewel ze niet nabij waren, waren ze steeds bereid om vragen via mail te beantwoorden. Ten tweede wil ik de 'Universidad de Valladolid' bedanken om mij als student te accepteren en mij te helpen doorheen dit avontuur. Hierbij bedank ik mijn externe promotor Quilano Isaac Moro Sancho en begeleidende professor Javier Bastida Ibáñez. Ik was altijd welkom bij hun op kantoor voor vragen of verdere ideeën in verband met mijn project. Ten derde wil ik mijn lokale student-mentor en vriend Tamara Alonso Bernal bedanken. Zij heeft mij vooral geholpen me te vestigen daarnaast gaf ze mij kansen de stad te leren kennen en nieuwe vrienden te ontmoeten. Tenslotte wil ik mijn familie bedanken voor de steun bij mijn keuze om dit project in het buitenland uit te voeren. Ik had nooit zoveel van deze ervaring kunnen genieten zonder hun hulp. Dit project heeft mij vooral veel geleerd over hoe ik een groot project dien aan te pakken. Zelf in een onbekende omgeving, een omgeving die waarschijnlijk anders is dan die waar ik de rest van mijn carrière zal doorbrengen. Tijdens dit proces heb ik veel vrienden en herinneringen gemaakt dingen die ik nooit zal vergeten en ik in mijn verdere leven zal kunnen gebruiken. 4 Table of contents Announcement ................................................................................................................................... 4 Abstract in English............................................................................................................................ 4 Abstract in Dutch .............................................................................................................................. 4 Abstract in Spanish .......................................................................................................................... 4 Dedication in English ....................................................................................................................... 5 Dedication in Dutch .......................................................................................................................... 5 Table of contents .............................................................................................................................. 4 List of figures ...................................................................................................................................... 6 Objectives ............................................................................................................................................ 7 Introduction ........................................................................................................................................ 8 Planning .............................................................................................................................................. 10 February ......................................................................................................................................... 10 March ............................................................................................................................................... 10 April .................................................................................................................................................. 11 May ................................................................................................................................................... 11 1 Project’s logic ........................................................................................................................... 12 1.1 Gather sources ................................................................................................................. 12 1.1.1 Past and current data ............................................................................................ 13 1.1.2 Predictions ................................................................................................................. 14 1.1.3 Pollen ........................................................................................................................... 14 1.2 Download data ................................................................................................................. 16 1.2.1 Connection ................................................................................................................. 16 1.2.2 DownloadManager .................................................................................................. 16 1.2.3 BroadcastReceiver .................................................................................................. 17 1.3 Read data ........................................................................................................................... 19 1.3.1 CSVReader ................................................................................................................. 19 1.3.2 xmlParser ................................................................................................................... 20 1.4 Show data .......................................................................................................................... 23 1.4.1 Swipe pages .............................................................................................................. 23 1.4.2 TextView, ImageView ............................................................................................ 23 1.4.3 PopupWindow, Radio buttons ............................................................................ 23 1.4.4 ScrollView .................................................................................................................. 24 5 1.4.5 GraphView ................................................................................................................. 24 2 Logic’s implementation ......................................................................................................... 25 Manifest ...................................................................................................................................... 25 2.1 Sources ............................................................................................................................... 26 Selecting location .................................................................................................................... 27 URLs ............................................................................................................................................. 29 2.2 Downloading ..................................................................................................................... 30 2.2.1 Connection ................................................................................................................. 32 2.2.2 DownloadManager .................................................................................................. 32 2.2.3 BroadcastReceiver .................................................................................................. 34 2.3 Read data ........................................................................................................................... 35 Weather class ........................................................................................................................... 35 Pollen class ................................................................................................................................ 37 2.3.1 CSV reader ................................................................................................................ 38 2.3.2 Xmlparser................................................................................................................... 40 2.4 Show data .......................................................................................................................... 43 2.4.1 Swipe pages .............................................................................................................. 45 2.4.2 ScrollView .................................................................................................................. 51 2.4.3 GraphView ................................................................................................................. 52 3 Tests ............................................................................................................................................ 53 3.1 Finished downloads ........................................................................................................ 53 3.2 Reading the files ............................................................................................................. 53 3.3 Background image .......................................................................................................... 54 3.4 X-axis labels...................................................................................................................... 54 4 Conclusion ................................................................................................................................. 55 5 Appendix .................................................................................................................................... 56 5.1 Manual ................................................................................................................................. 56 Installation ................................................................................................................................ 56 How to use ................................................................................................................................ 58 5.2 Bibliography ...................................................................................................................... 62 6 List of figures Figure 1: Smartphone OS market share ................................................................................. 8 Figure 2: Historic data, website ................................................................................................ 13 Figure 3: Predictions, website ................................................................................................... 14 Figure 4: XmlPullParser explanation ....................................................................................... 20 Figure 5: GraphView XML layout .............................................................................................. 24 Figure 6: GraphView code snippet ........................................................................................... 24 Figure 7: GraphView example ................................................................................................... 24 Figure 8: Sources flowchart........................................................................................................ 26 Figure 9: Edit location screenshots ......................................................................................... 27 Figure 10: Edit location snippet ................................................................................................ 28 Figure 11: Constant UML ............................................................................................................. 29 Figure 12: MainActivity UML ....................................................................................................... 30 Figure 13: Downloading flowchart ........................................................................................... 31 Figure 14: Network state manifest .......................................................................................... 32 Figure 15: Access Shared Preferences snippet ................................................................... 32 Figure 16: File location snippet ................................................................................................. 33 Figure 17: Weather UML .............................................................................................................. 35 Figure 18: Pollen UML ................................................................................................................... 37 Figure 19: CSV file example ....................................................................................................... 38 Figure 20: csvParser UML ............................................................................................................ 39 Figure 21: XML file example ....................................................................................................... 40 Figure 22: xmlParser UML ........................................................................................................... 41 Figure 23: XML tags snippet ...................................................................................................... 41 Figure 24: KEY_PROBPRECI snippet ....................................................................................... 42 Figure 25: MainActivity UML ....................................................................................................... 43 Figure 26: Data showing flowchart .......................................................................................... 44 Figure 27: Fragment instances snippet ................................................................................. 45 Figure 28: Fragment class 1, layout 1 ................................................................................... 46 Figure 29: Fragment class 2, layout 1 ................................................................................... 47 Figure 30: Fragment class 3, layout 2 ................................................................................... 47 Figure 31: FirstFragment UML ................................................................................................... 48 Figure 32: Set fragment arguments snippet ....................................................................... 48 Figure 33: Get fragment arguments snippet ....................................................................... 49 Figure 34: Resize background image ..................................................................................... 49 Figure 35: ScrollView screenshots ........................................................................................... 51 Figure 36: graphActivity UML .................................................................................................... 52 Figure 37: Device usage screenshot ....................................................................................... 56 Figure 38: Installation screenshots ......................................................................................... 57 Figure 39: Open application screenshot ................................................................................ 58 Figure 40: Swipe screenshots .................................................................................................... 59 Figure 41: Select location screenshots .................................................................................. 60 Figure 42: Pollen screenshot ...................................................................................................... 60 Figure 43: Charts screenshots .................................................................................................. 61 7 Objectives Before we begin, it’s important to know what this project is about and what its objectives are. This project is in fact a mobile application which gathers and displays information about weather and pollen statistics. In order to do so we have some objectives we need to fulfill. The following list summarizes these objectives. Objectives Gathering the right sources where to obtain the necessary data. This data contains information concerning: • Past 24 hour weather statistics • Current weather status • Weather predictions • Pollen status Downloading this data to the user’s device in order to be able to let the application handle this data. Read the data collected from the internet and contain it within the application. Present this data to the user in an easy to read manner. 14 1.1.2 Predictions Next, we have information about weather predictions which we can also find on this website. We find information about temperature, precipitation, wind and the state of the sky. This information is also available for multiple Spanish cities. For example, the data for Valladolid can be found at: http://www.aemet.es/es/eltiempo/prediccion/municipios/valladolid-id47186 Figure 3: Predictions, website This information can be downloaded as a file with an XML-format. This format is also a plain text file readable by a human being with possibilities to read and process in our application. 1.1.3 Pollen Last but not least, we need some information about pollen. Pollen consist of male cells that fertilize plants, these are richly present during some periods. Pollen are often a big cause for allergic reactions. We want to provide the user with information concerning the concentration of pollen present. The data provided is available for download in two different formats, CSV or XML. We choose the XML-format because this makes it easier for us to read the data; this will be clarified in another chapter. This file provides us with data from 13 different cities and 36 different types of pollen. The specific link is http://www.datosabiertos.jcyl.es/web/jcyl/set/es/mediciones/niveles_de_polen/1 284208096554 15 We do now have all the sources we need in order to retrieve the necessary information. We can update our objectives as follows: Objective Completed Gathering the right sources where to obtain the necessary data. This data contains information concerning: • Past 24 hour weather statistics • Current weather status • Weather predictions • Pollen status Downloading this data to the user’s device in order to be able to let the application handle this data. Read the data collected from the internet and contain it within the application. Present this data to the user in an easy to read manner. The next step is to make our application download this information. 16 1.2 Download data This part will cover the downloading of the files needed in order to access the data required. In addition, it is very important to know when the downloads are finished before we are able to show the information to the user. 1.2.1 Connection Before we can actually start downloading, we have to check if there is a valid internet connection on the user’s device. If so, we can go on to the next step and actually download the requested files. (5) If there is no valid internet connection, the program will use previously downloaded data if these are available. If there is no previous data available, the application won’t be able to reach its goal of showing the user actual weather information. 1.2.2 DownloadManager “The download manager is a system service that handles long-running HTTP downloads. Clients may request that a URI be downloaded to a particular destination file. The download manager will conduct the download in the background, taking care of HTTP interactions and retrying downloads after failures or across connectivity changes and system reboots.” (6) With the manager concerning all the network operations required for downloading a file, we can fill in a request for each file we want the manager to download. With this request, we can specify some information. Here are some common examples: • Network type: define which connections can be used in order to download the requested file (wifi or/and mobile connection). • Description and title: define the information shown in the notifications while the file is being downloaded. • Destination: where should the file be placed once the download has finished. • Notifications visibility: define if you want to show a notification at start, during and after the download. 17 In my case, I’m not using all of these examples. I’ve decided not to show any notifications at the start or during the download because the files are very small and I don’t want to overload the user with additional unnecessary information. With the files being very small I’ve neither chosen to set a limit on the network type, any internet connection is valid. What I have specified is the destination, this is very important because you always want to know where to find your files once they are downloaded. The files in this application are saved within the application’s external files. This way the user doesn’t regularly encounter these files on their device but they can find it if necessary. Before actually downloading the file, we look if there are previous files like this one available on the device. If so, we delete them in order not to stack up too much place on the device. At the end, we can finally enqueue the file to the manager, who will decide when the device is ready to download. Each of these enqueues are given a unique id which we need in the next step. 1.2.3 BroadcastReceiver In order to decide whether the download has finished downloading we need to listen to some broadcasts being sent from the manager. There are constantly broadcast sent in the device by different applications or by the system itself. (7) The manager itself has 2 different broadcasts as well: • ACTION_DOWNOAD_COMPLETE: sent when a download completes. • ACTION_NOTIFICATION_CLICKED: sent when the user clicks on a running download either from a system notification or from the downloads UI. We’re not using any notifications so we have no need for the second broadcast. We do need the first broadcast because we can’t start reading the data and filling our screen before the data is actually downloaded. Very important in this description is the ‘a’, when we have multiple files to download each of these downloads will send a broadcast when finished. In order to know which download the broadcast is from we use the enqueue id we talked about earlier. Besides from debugging issues it’s not very important to know which specific file has finished downloading and which hasn’t. More importantly we need to be sure that all files are finished before we start reading the data. In order to check this, whenever a download has finished it increments a counter. We know in this application we need three different files so when the counter reaches 2 the next finished download broadcast can trigger the start of the data reading. 18 We do now have all of the data downloaded to the device so we can update our objectives as follows: Objective Completed Gathering the right sources where to obtain the necessary data. This data contains information concerning: • Past 24 hour weather statistics • Current weather status • Weather predictions • Pollen status Downloading this data to the user’s device in order to be able to let the application handle this data. Read the data collected from the internet and contain it within the application. Present this data to the user in an easy to read manner. The next step is to make our application read or parse the data. 19 1.3 Read data Once we’ve downloaded the necessary files we can start reading, or using the right terminology, parsing these files. We have two types of files, one is CSV the other one is XML. For both these layouts we need a separate parser. We use these to read out the files containing information about past weather statistics, current weather, predictions and pollen. All of this information is put into neatly organized classes so we can easily access it in the next chapter. 1.3.1 CSVReader “In computing, a comma-separated values (CSV) file stores tabular data (numbers and text) in plain text. Each line of the file is a data record. Each record consists of one or more fields, separated by commas. The use of the comma as a field separator is the source of the name for this file format.” (8) In order to parse CSV files, I went looking online for a solution. After some research, most of the problems I’ve encountered were solved with the help of a library called ‘opencsv’. Looking further into this library, I came to the conclusion that it was easy to use and exactly what I was looking for. “Opencsv is a very simple CSV (comma-separated values) parser library for Java. It was developed because all of current CSV parsers I've come across don't have commercial-friendly licenses.” (9) This library contains a class called ‘CSVReader’, which is essentially a CSV- parser. With this class’s constructor, we can give along some information: • Filereader with specific file: we define a reader along with the CSV-file to be read. • Separator: the default separator in a CSV-file is the comma ‘,’. Although we can define another separator if necessary. • Quote character: the default quote character in a CSV-file is the double quote ‘ ” ’. Although we can define another separator if necessary. • Skip lines: define the number of lines to be skipped before actually parsing the file. In my case, we define the correct file the download manager saved for us earlier. The separator and quote characters are the default characters so no need to change anything there. But, at the start of our CSV there is some information we don’t need and cannot accept as values otherwise our system would crash. Therefore, we skip the first 4 lines of the CSV file in order not to run into trouble reading the data and in order to collect the correct information. The information derived from the CSV files is information concerning the current state and the past 24 hours. Values such as temperature, humidity, rainfall, air pressure and wind. This information is put into a class called the ‘Weather’ class. This class contains all of the information and can be called upon when we need it. Because the information we derive from this CSV contains values for each of the past 24 hours we immediately use this information after one of the lines is read. In this case we use it to build up a graph (more on this in the next chapter). 20 1.3.2 xmlParser The second type of file we want to parse is an XML-file. “In computing, Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format that is both humanreadable and machine-readable.” (10) In order to do this we use an Android interface called ‘XmlPullParser’, this interface intercepts different kinds of events occurring while reading the xml. These events are: • START_TAG: an XML start tag was read “<…>”. • TEXT: text content was read, a certain string. • END_TAG: an XML end tag was read “</…>” • END_DOCUMENT: no more events are available. In order to explain how does goes to work, I’m using an example I found online. (11) Figure 4: XmlPullParser explanation The first event we use is the END_DOCUMENT, we use this do decide when our document is fully read and we can exit our while-loop. As long as this event does not occur, we keep reading the xml file. Inside the while-loop we have a switch-case statement do decide which event has occurred. The reader continues to read the document and looks for any events to occur. 21 The first event who occurs is a START_TAG, of course we’re not interested in all the tags inside of the XML. So, we decide what to do when a START_TAG occurs by different if-statements. In this case, we are interested in the tags with values ‘book’ and ‘name’. So, we declare an if-statement where we check if the name who goes along with this START_TAG is equal to “book” and another if-statement where to name goes along with “name”. If not, we just skip the line as is done with the first two lines inside this example XML. The third START_TAG we encounter has the value ‘book’. In this tag we are interested in its attribute ‘ISBN’ so we save this into a String called isbn using the function getAttributeValue(). This function requires two parameters: the first one being a namespace, if there is one, and the second one being the name of the attribute we’re looking for. This XML does not use any namespaces so we pass along the NO_NAMESPACE value, the name of the attribute we need is “ISBN”. The value of the String isbn is now equal to “ISBN-001”. The next tag we are interested in has the value ‘name’. We declare another ifstatement which looks for a START_TAG with the value ‘name’. We encounter it on the 4th line of the XML file. Now we need the text next to this tag so, we save this text into a String called name using the function nextText(). The value of the String name is now equal to “How To Be A Cat”. At the end of line 4 we encounter an END_TAG with the value ‘name’, we have no interest in this tag so we move on. The next interesting event occurs at line 7 where we encounter an END_TAG with the value ‘book’. In human language, this means we have finished reading all the values of one certain book. It is not described in this example but we could save the variables we’ve noted like the strings ‘isbn’ and ‘name’ into a different class so we don’t lose this information when we overwrite these variables with information about the next book. After we’ve checked all possible tags inside the switch-case statement or did not encounter any interesting events, we call next() to go to the next parsing event. When we reach the end of the document the END_DOCUMENT tag becomes the current eventType and we quit the while loop, the document has been fully read. In the case of the project concerning this book, all of the necessary information is saved into weather classes so we can use this information for displaying the information on the screen. 22 We do now have all the data from the downloaded files read and organized into classes so it is contained into the application. We can update our objective list as follows: Objective Completed Gathering the right sources where to obtain the necessary data. This data contains information concerning: • Past 24 hour weather statistics • Current weather status • Weather predictions • Pollen status Downloading this data to the user’s device in order to be able to let the application handle this data. Read the data collected from the internet and contain it within the application. Present this data to the user in an easy to read manner. The next step is the most important one, use this data and finally present it on the user’s device. 23 1.4 Show data Now that we have all the data at our disposal, we only need to show it in an easy-to-read manner to the user. The idea I’ve come up with consists of 7 different pages through which you can swipe. The first one containing information for today, the second one for tomorrow and so on. In order to do that I needed a couple of classes and methods. 1.4.1 Swipe pages I wanted to have the application’s swiping go smoothly and not needing any loading time. So we could only use one activity for these 7 pages because loading an activity takes some time, although only milliseconds it doesn’t look smooth. (12) (13) (14) First we need the activity. “The Activity class serves as the entry point for an app’s interaction with the user, providing the window in which the app draws its UI.” (15) In other words an activity is the base of what your application does. Linked to this activity we have a layout file which determines what the user gets to see on the screen. We make use of one base on which we build our 7 pages. Each page is a fragment. A fragment is a portion of a user interface, in one activity you can have multiple fragments. You can arrange them neatly on one screen or you can specify that the fragment uses the whole screen. We use a fragment for each page so 7 fragments and manage them using a ViewPager. The viewpager is a layout manager which allows the user to swipe left and right through pages of data. In order to generate all these pages we need a PagerAdapter in our case we use the FragmentStatePagerAdapter. 1.4.2 TextView, ImageView TextViews and ImageView are widgets from Android itself. TextView which displays text to the user and optionally allows them to edit. ImageView shows an image instead of text. These views are easily added to the layout in the graphical design or straight into the layout XML. The text and images can be logically set or fixed from the start. They can also be made clickable so when the user pushes them a certain action can be programmed. 1.4.3 PopupWindow, Radio buttons The PopupWindow class speaks for itself. We can use this class in order to create a popup window. It’s a floating container that appears on top of the current activity. (16) (17) Radio buttons allow the user to select one option from a set. Only one option can be chosen each time. We’ll use both if these for the selection of the location. 30 2.2 Downloading The downloading happens automatically when the application is booted, so all of this is done in the MainActivity. This activity is also responsible for generating the ViewPager which generates our 7 swipeable pages, but this will be explained in the next chapter. MainActivity -downloadsDone: int -defaultCsv: String -startUp( onComplete: BroadcastReceiver): void -mainPath: String -sharedPref: SharedPreferences -pager: ViewPager -pollenReference: long -predReference: long -csvReference: long -defaultLocation: String -defaultXml: String -pollenUrl: String -onComplete: BroadcastReceiver #onCreate(): void -downloader(mainPath: String, URL: String, fileName: String, fileType: String): void -checkConnection(): boolean Figure 12: MainActivity UML In order to be able to download files from the internet, the application needs the permission to use an internet connection. Therefore, we need to add another permission into the manifest. <uses-permission android:name="android.permission.INTERNET" /> 31 Flowchart Open application Connection? Yes Load URLs from shared preferences Download files All downloads done? No Generate fragments using PagerAdapter Yes Use old files No Shared Preferences Read Figure 13: Downloading flowchart 32 2.2.1 Connection Before downloading, we have to check if there is a valid internet connection. The method checkConnection returns a Boolean, either true or false depending on the fact that there is a connection or not. This Boolean is then used to depend if we can start downloading or not. In order to do so we use the class ConnectivityManager; this is a class that answers queries about the state of network connectivity. From this class we use the function getActiveNetworkInfo() which returns the currently active default data network. If there is none, it returns null. Therefore, we check whether this functions returns null. If not, it means there’s currently an active internet connection so we return true and are able to start downloading. In order for the application to access information about networks, we need to add a permission into the manifest. <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> Figure 14: Network state manifest We are now able to check for a valid connectivity to the internet. 2.2.2 DownloadManager So, first we check whether there is an internet connection available. If not, a message pops up notifying the user there is no valid internet connection and we use the known data. The adapter is added to the view pager and the fragments are produced which we will explain later on. If we do have a valid internet connection, the checkConnection() method returns true as seen before. We decide which URLs to use based on the URLs stored in the shared preferences. This also requires a default value in case the required value is not found, we’ve chosen to add the URLs for Valladolid. sharedPref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext()); String csvURL = sharedPref.getString("csvURL", defaultCsv); String xmlURL = sharedPref.getString("xmlURL", defaultXml); Figure 15: Access Shared Preferences snippet These URLs can now be used in order to download the correct information related to the users’ requested location. 33 Next, we call the downloader method. We call this method 3 times, once for each file to be downloaded. We pass along some arguments with this function. • mainPath: this is the path to the application’s external files directory where we will save our downloaded files. We use this to determine the download destination. This has been declared as follows. final String mainPath = getExternalFilesDir(null) + "/"; Figure 16: File location snippet • URL: previously defined URL who leads to the file you want to download. • fileName: define a name for the file. • fileType: describe the type of the file, we need this in order to give the download a unique id so we can then check when the download is finished. As noted before we first build up a request to pass along to the manager. This request contains the URL. With this request, we can specify some properties but with the choice of not showing any download notifications, we only need to adjust the notification visibility and set it to hidden. We then declare a file with the mainPath and fileName. This is in fact the file we are downloading, but we need to declare it before the download to check if the file does not already exist. If so, we delete the file before downloading it again in order to save up space on the device. We set the destination for the file, as discussed before we save the files into the applications external files directory. At last, we can enqueue the download to the manager. While doing this, each enqueue generates a unique id, we need this id for the BroadcastReceiver in order to know which download was finished. So, we save the id based on which fileType we are downloading. We have 3 different references: csvReference for the CSV file containing the historic and current information, predRefernce for the XML file containing the predictions and pollenReference for the XML file containing information about the pollen. 34 2.2.3 BroadcastReceiver We need to check whether the downloads are finished in order to start filling the screen. In order to use a receiver, you need to register it. With this registration we declare the name of the receiver as well what kind of broadcasts this receiver’s interests are, in this case we want to know when a download has completed. Therefore, we use the ACTION_DOWNLOAD_COMPLETE constant which checks broadcasts concerning downloads which have been completed. We declare the BroadcastReceiver with the name onComplete. Every time this receiver receives a broadcast, this broadcast comes along with a unique id which is linked to the id given by the downloader. We then compare this id with the id’s we’ve filled in earlier to know which download has completed. Once we receive a broadcast with an id we recongize, we call the startUp method. This method checks the downloadsDone variable, this variable is in fact a counter. For each download who has been completed this counter goes up, once we reach 3 which means all of the necessary files are done downloading the receiver is unregistered since we don’t need it anymore and an adapter is set for the ViewPager. This causes the creation of our 7 pages which we’ll cover in the next chapter. The files are now downloaded to the device and available for reading. 35 2.3 Read data We can now start reading the downloaded data which was saved on the device. As mentioned before in order to contain this data and be able to use it throughout the application we save it inside Weather classes and Pollen classes. Weather class The weather class will contain our information about the weather statistics and make it easy for us to obtain it wherever necessary. The next figure shows a shortened version of the UML from this class. I’ve shortened the method’s because they are all just getters and setters for each attribute in order to be able edit and read them. Weather +getHour (): int -hour: int -temperature: float ... -temp12: String -maxTemp: String -temp18: String -minTemp: String -windSpeedCsv: int -windDirDay: String -windDir1824: String -rainProb0006: String -windSpeed0612: String -temp00: String -temp06: String -windDirectionCsv: String -windDir0612: String -windSpeed0006: String -windSpeed1824: String -rainProb1218: float -windSpeedDay: String -windDir0006: String -windDir1218: String -windSpeed1218: String -rainProbDay: String -humidity: int +setHour (hour: int) -rainProb0612: String -precipitation: float -airPressure: float -sky1824: String -sky1218: String -sky0612: String -sky0006: String -skyDay: String -rainProb1824: String Figure 17: Weather UML 36 As you can see, it has the ability to hold a lot of information. Although we don’t always need all of this information. Concerning the CSV file where we find information about the current weather situation and the past 24 hours we only need certain values: • temperature • windSpeedCsv • windDirectionCsv • precipitation • humidity • airPressure These are the values we can derive from the CSV file. We are able to fill up to 24 of these classes, one for each passed hour including the current hour. The other values are used when reading the XML file where we have information concerning weather predictions which are available per six hours. 37 Pollen class The Pollen class will contain our information about the pollen statistics and make it easy for us to obtain it wherever necessary. The next figure shows a shortened version of the UML from this class. I’ve shortened the method’s because they are all just getters and setters for each attribute in order to be able edit and read them. Pollen +getLocation (): String -location: String -acer: String ... -asteraceae: String -aesculus: String -betula: String -alnus: String -chenopodiaceae: String -cyperaceae: String -fagus: String -taraxacum: String -myrtaceae: String -juglans: String -brassicaceae: String -apiaceae: String -cupressaceae: String -ercaceae: String -galium: String -mercurialis: String -pinus: float -fraxinus: String -echium: String -fabaceae: String -juncaceae: String -morus: String -salix: String +setLocation (location: String) -olea: String -rumex: String -sambucus: String -rosaceae: String -quercus: String -populus: String -poaceae: String -platanus: String -plantago: String -urticaceae: String -ulmus: String -tilia: String Figure 18: Pollen UML 38 As you can see, there are a lot of different types of pollen for which we can acquire information. Each class concerns one location; we have 13 locations in total so in the end there will be 13 objects of this class. Although not every location contains all of these different types of pollen. Some locations don’t supply information about a certain type of pollen because they do not measure it or simply because this type is not common in that area. This data is updated on the website once every week with data for the current status and a prediction for the whole week. We only make use of the prediction to supply a clear view for the whole week to come. 2.3.1 CSV reader Before explaining how we derive the data from the CSV file, let me first give you an example of what one of these CSV files might look like. The next figure shows a part of such a file. "Valladolid" Actualizado: martes, 14 marzo 2017 a las 12:22 hora official "Fecha y hora oficial","Temperatura (ºC)","Velocidad del viento (km/h)","Dirección del viento","Racha (km/h)","Dirección de racha","Precipitación (mm)","Presión (hPa)","Tendencia (hPa)","Humedad (%)" "14/03/2017 12:00","13.4","13","Nordeste","37","Nordeste","0.0","942.3","0.3","56" "14/03/2017 11:00","11.9","9","Nordeste","39","Nordeste","0.0","941.9","0.1","61" "14/03/2017 10:00","10.0","9","Nordeste","35","Norte","0.0","942.0","-0.3","69" "14/03/2017 09:00","7.7","10","Nordeste","33","Nordeste","0.0","942.0","0.3","76" "14/03/2017 08:00","6.2","10","Nordeste","33","Norte","0.0","941.8","0.5","81" … Figure 19: CSV file example As we’ve mentioned before, the first 4 lines (“Fecha hora… is one line) are information we don’t need so we can safely skip these 4 lines. Starting from the fifth line we can see the different values each surrounded by “” and separated by a comma. We have date and hour, temperature, windspeed, wind direction, gust speed, gust direction, rainfall, air pressure, air pressure trend and air humidity. Each of these for each of the past 24 hours. Now that we know what we want to read, we can start reading. And saving the information into a Weather class(es). 39 UML csvParser -reader: CSVReader +getWeatherHistory(path: String): List<Weather> +getWeatherFromFile(path: String): Weather -line: String[] -historyList: List<Weather> -cur: Weather Figure 20: csvParser UML First, we collect information about the current status. In order to put the CSV data into a Weather class I’ve made a csvParser class with a method called getWeatherFromFile which returns a Weather object containing the data. With this function we pass along the location of where the file is supposed to be. There is some safety built in to cover that by any chance the file is not there using some exception handlers. We start by initiating a CSVReader, which reads a stream of data coming from the CSV-file. This stream contains each of the characters in the file one by one. We also initiate a Weather object in which we will store our data. We then specify the reader using the stream of data, which separator to look for (here it’s just the default comma), which quote character to look for (also default) and the 4 decides we skip the first 4 lines. Each line is now transformed to a String array with each element being a value. We can then fill our Weather object using the corresponding value in this String array. At the end, we return the Weather object which can then be used to obtain this information. On the other hand, we also need information about the past 24 hours. We use the getWeatherHistory method which works more or less the same as the previous method with the only difference being it returns a list of Weather objects for each hour instead of just one. 46 Fragment class 1, layout 1 The next figure shows an example of what this one might look like. Figure 28: Fragment class 1, layout 1 As we can see, there’s a lot going on. First of all, we can see that the background is filled with an image. This image is related to the current weather state. So, when it would be raining, there would be rain in the background. Next, we have a lot of textViews, all of the red noted views are textViews. They are very important in giving information to the user. Some of them have fixed text, while others are based on the data we’ve assembled. Then we have the green ones, these are imageViews, they are in fact just images on the screen. Also here some are fixed while others depend on the predictions. The upper part consists of information obtained from the CSV file, that is, the current status. While the bottom half shows the predictions. 47 Fragment class 2, layout 1 The next figure shows an example of what this one might look like. Figure 29: Fragment class 2, layout 1 Fragment class 3, layout 2 The next figure shows an example of what this one might look like. Figure 30: Fragment class 3, layout 2 If the previous one was for today, then this one is information about tomorrow. As you can see, we’ve used the same layout. But the big difference is that here the upper part also consists of predictions. So both, the upper and the bottom half, are based upon predictions. Same for the background, it looks like they’re predicting some rain. For the remaining fragments we use a different layout. This one contains less information for the simple reason that the data we download doesn’t contain as much information for days as far ahead. We’ve got predictions for the temperatures, the state of the sky (looks like it’ll be sunny), the chance for rainfall and the wind. 48 Now we know what the different types of fragments look like, it’s time to look at how we’ve managed to make them look like they do. Let’s take a look at the logic behind each of the 3 types of fragment classes. FirstFragment This one is responsible for solely the first day, so in fact the current day. FirstFragment -c: Calendar +newInstance (predWeather: Weather, csvWeather: Weather, location: String): FirstFragment -radioGroup: RadioGroup +onCreateView(inflater: LayoutInflater, container: ViewGroup, savedInstanceState: Bundle): View -selectWindDir (direction: String): Drawable -selectIcon (sky: String): Drawable -setBackground (v: View, sky: String): void +showPopup (anchorView: View): void Figure 31: FirstFragment UML We use a Calendar instance to acquire today’s date and add it to the screen, and to decide the current hour in order to set the correct background image depending on the prediction for the current time. The radioGroup is for when the user selects a location. When the PageAdapter generates these fragments, the first method that is called is the newInstance. As seen before we pass along all the information necessary in order to fill the screen. Inside this method we make a Bundle object who concerns about the arguments of this fragment. We take all the information given by the PageAdapters’ arguments and set them as arguments from this fragment. args.putFloat("curTemp", csvWeather.getTemperature()); args.putInt("curSpeed", csvWeather.getWindSpeedCsv()); args.putString("curDirection", csvWeather.getWindDirectionCsv()); Figure 32: Set fragment arguments snippet These are some examples of how to put the information in the Bundle object which describes the fragments’ arguments. It’s, like the shared preferences, with a key-value pair. For example, in the last shown line we put the given location 49 String into an argument with the name location. We do this for all of the necessary values. When this method finishes it returns the fragment and the onCreateView method is called. This is where we produce the actual view and give all the layout elements their values. The views must first be associated with a view in the layout file. Now each of these views can be modified as desired. The text views are filled with the correct data. This data is fetched from the arguments we formed when creating the instance. We can now call on them by using the getArguments() method. (22) tempView.setText(getArguments().getFloat("curTemp") + "°C"); speedView.setText(getArguments().getInt("curSpeed") + " km/h"); directionImage.setImageDrawable(selectWindDir( getArguments().getString("curDirection"))); Figure 33: Get fragment arguments snippet In order for the sky icons to show the correct icon linked to the weather state we made a method that returns the correct drawable based on the given sky state selectIcon. Next, we have the wind icons which show the direction of the wind. We do the same as with the sky icons, we give the method selectWindDir a wind direction as a String and it returns the correct drawable. At last, we decide the correct background for this fragment using the setBackground method. This does not only decide the background but sets it as well. But very important here was that not every user is using the same device, and not all the devices have the same screen size. Therefor the image has to be scaled correctly before adding as background. Display display = getActivity().getWindowManager().getDefaultDisplay(); Point size = new Point(); display.getSize(size); Bitmap bmp; bmp = Bitmap.createScaledBitmap(BitmapFactory.decodeResource( getResources(),R.drawable.clear_sky),size.x,size.y,true); LinearLayout ly = (LinearLayout) v.findViewById(R.id.first_frag); Drawable dr = new BitmapDrawable(getResources(), bmp); (ly).setBackground(dr); Figure 34: Resize background image Therefore, we first determine which display is being used, along with that we can decide the size. We then select the correct image based on the sky state and we rescale it. This is only possible if the image has a bitmap or .bmp type. But we cannot set the background with a bitmap type so at the end we convert the converted bitmap, which now has the correct size along with the screen size, to a drawable which we then use to set the background. (23) 50 Second and third fragment classes The seconds’ class only difference with the first fragment class is the data used to fill the layout elements. For tomorrow we can only use predictions, there is no current data available. The thirds’ class just has a lot fewer layout elements since there isn’t a lot of information available from two days in the future. 51 2.4.2 ScrollView The scrollView allows us to expand our layout on a single view. We are not limited to the boundaries of the screen itself. We can make a view which is bigger than the screen and scroll through it all on one screen. In this project we use it to display a detailed list of different types of pollen and their status. Figure 35: ScrollView screenshots As you can see on the second screenshot there’s a scrollbar present. 52 2.4.3 GraphView In order to represent the historic data I’ve opted to use some charts. In order to build these charts I’ve used a library called GraphView. The activity where I make use of this is the graphActivity, which represents the historic data. graphActivity #onCreate (): void -c: Calendar -getPoints (historyList: List<Weather>, size: int, hlabels: String []): List<DataPoint[]> -mainPath: String -hLabels: String[] -historyList: List<Weather> -collection: List<DataPoint[]> -size: int -humidSeries: LineGraphSeries<DataPoint> -tempSeries: LineGraphSeries<DataPoint> -rainSeries: BarGraphSeries<DataPoint> -pressSeries: LineGraphSeries<DataPoint> Figure 36: graphActivity UML This class creates three charts. In order to do so it locates the XML file, containing information about the pollen, using the mainPath string which describes this location. It then passes this location to the xmlParser (using the getPollenListFromFile method) which parses the file and returns a list of Weather objects containing the information from the file. This list is saved as the historyList, the size refers to the size of this list which we’ll need to transform this list into a set of DataPoint collections. In order to fill the charts we need LineGraphSeries for line graph and BarGraphSeries for bar charts. These series are lists of DataPoint objects. A DataPoint contains 2 numbers which describe a point on the chart. The getPoints method converts this historyList into a list of collections of DataPoint objects, one collection for each chart or graph we want to draw. We then define each collection based on which series they describe: temperature, rainfall, humidity or air pressure. The hLabels is also produced in the getPoints method, this describes the x-axis’ labels which are timestamps. While the y-axis’ labels are linked to the values displayed and are automatically generated. 53 3 Tests This chapter will cover some of the problems I ran into and how I’ve solved them. The method of solving these problems involved some debugging by using tags or console lines which returned certain information wherever these were placed. This way I could read out what the application was doing step by step and intervene where necessary. 3.1 Finished downloads The main problem I’ve encountered when downloading the files was finding out when the downloads are finished. When I ran the application, it didn’t find any information to fill the pages with information. The cause was that it tried filling the page before the files were finished downloading which caused the page to be empty because no information was available yet. Solution I’ve solved this by implementing the broadcast receiver which looked for broadcasts sent by the downloader notifying a file has finished downloading. Only once this occurred the application could start filling the page with information. The problem returned when I needed more than one file; I needed multiple files to obtain all the information necessary. The broadcast receiver activated for whichever file had finished downloading first. Therefor I saved the id’s given to the download, one unique id for each download. Now I could identify each broadcast with a certain file. Once all of the necessary files were downloaded the application could start filling the page with information. 3.2 Reading the files When trying to implement a parser for the XML files I ran into quite some troubles. Most of these troubles were in fact just typo’s. I defined some tags with faulty information which caused the parser to not find the wanted tags. Another big problem was the separation between the START_TAG’s and the END_TAG’s. At first the parser only returned END_TAG’s which caused it to return faulty information or even no information. The problem was in my switch case where I forgot to add the break; statement at the end of the START_TAG case. Therefor the parser just skipped these tags and only looked for END_TAG’s. Solution The solution was quite simple, once I found out. I corrected the faulty defined tags and added a break; statement at the end of each case. This resulted in the parser returning the correct information when asked for. 54 A second problem which occurred while trying to read the files was with the CSV type of file. The first couple of lines in these files contained for the application unnecessary information. So the first parts of information this parser returned was unusable. Solution In order to solve this I first implemented a for loop which does nothing the first lines where this faulty information was defined. After these lines it started reading and returning the correct information. But, this method wasn’t really clean and I went to look for a better solution. I found out that in the constructer of the CsvReader you can add an argument which defines the number of lines to skip before actually starting to read. This made my previous solution with the for loop unnecessary and still returned the correct information. I opted for this solution as it was the cleaner solution. 3.3 Background image The applications background is an image which differs depending on the current or predicted weather state. I used some pictures and cut them to a ratio which is most common with Android devices. But when I used this image on a different device it was stretched messed up. Solution In order to solve this I used a scaler. First I measured the user’s screen, then the image is rescaled to fit the screen perfectly and in a good state. Now whichever device is used the image should be properly scaled to its screen size. (24) 3.4 X-axis labels When generating the charts the graphView class looks at each of the DataPoint objects and use them as coordinates. So I had to decide a way to generate the x-coordinates in order for the charts to represent correct information. Since the x-axis is about time, one DataPoint for each hour, I tried using a Date objects because the graphView knew how to handle these. This resulted in the graph itself being correct but the x-labels were unreadable. When I tried to format these Date objects the graph didn’t represent the correct data because the graphView saw these formats as simple strings which messed up the order. Solution The solution was to set up a custom list of strings which represented the xlabels, they were yet again formatted Date objects but they have no relation to the building of the chart. This caused the charts to be correct and the labels as well. 55 4 Conclusion This application provides an easy way to access the current weather status as well as predictions as well as some statistics. It’s an easy tool to check whether you’ll need a jacket when going outside or deciding when to do a barbecue in your garden. The application has met all of the required objectives. It gathers the right sources for information and it provides the user with this information in a way where it doesn’t take a lot of effort to find the information required. This project has improved my knowledge and interests of the Android environment not only by knowing how to implement certain functionalities but mostly by solving the problems I’ve encountered. I’ve found a lot of information and help online, the Android community is a very open community. You can implement certain solutions but they don’t always fit your needs. By adapting these solutions to my problems I came to understand them thoroughly. I came to recognize some things I’ve been learning the previous years at college but came to expand this knowledge by creating this application. Nonetheless, this application is far from finished. Future improvements could involve expanding the different locations, this will require valuable sources of information. All of the data acquired at this point is data straight from an online source, a possible improvement could be to save some of this data on the device in order to expand the information known about previous weather statistics as for now you can only go back 24 hours. Another useful improvement is a widget, a widget is a miniature version of the application which can be embedded on the home screen. This way the user wouldn’t have to open the application in order to receive some information nonetheless. 62 5.2 Bibliography 1. Apple Vs Android - A comparative study. AndroidPub. [Online] [Cited: May 25, 2017.] https://android.jlelse.eu/apple-vs-android-a-comparative-study-2017- c5799a0a1683. 2. Choosing a membership. Apple Developer. [Online] [Cited: May 25, 2017.] https://developer.apple.com/support/compare-memberships/. 3. Android (operating system). Wikipedia. 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