Add Unit Test in SUSI.AI Android App

Unit testing is an integral part of software development. Hence, this blog focuses on adding unit tests to SUSI.AI Android app. To keep things simple, take a very basic example of anonymize feedback section. In this section the email of the user is truncated after ‘@’ symbol in order to maintain the anonymity of the user. Here is the function that takes ‘email’ as a parameter and returns the truncated email that had to be displayed in the feedback section :

fun truncateEmailAtEnd(email: String?): String? {
   if (!email.isNullOrEmpty()) {
       val truncateAt = email?.indexOf('@')
       if (truncateAt is Int && truncateAt != -1) {
           return email.substring(0, truncateAt.plus(1)) + " ..."
       }
   }
   return null
}

 

The unit test has to be written for the above function.

Step – 1 : Add the following dependencies to your build.gradle file.

//unit test
testImplementation "junit:junit:4.12"
testImplementation "org.mockito:mockito-core:1.10.19"

 

Step – 2 : Add a file in the correct package (same as the file to be tested) in the test package. The function above is present in the Utils.kt file. Thus create a file, called UtilsTest.kt, in the test folder in the package org.fossasia.susi.ai.helper’.

Step – 3 : Add a method, called testTruncateEmailAtEnd(), to the UtilsTest.kt and add ‘@Test’ annotation to before this method.

Step – 4 : Now add tests for various cases, including all possible corner cases that might occur. This can be using assertEquals() which takes in two paramters – expected value and actual value.

For example, consider an email ‘[email protected]’. This email is passed as a parameter to the truncateAtEnd() method. The expected returned string would be ‘[email protected] …’. So, add a test for this case using assertEquals() as :

assertEquals("[email protected] ...", Utils.truncateEmailAtEnd("[email protected]"))

 

Similary, add other cases, like empty email string, null string, email with numbers and symbols and so on.

Here is how the UtilsTest.kt class looks like.

package org.fossasia.susi.ai.helper

import junit.framework.Assert.assertEquals
import org.junit.Test

class UtilsTest {
   @Test
   fun testTruncateEmailAtEnd() {
       assertEquals("[email protected] ...", Utils.truncateEmailAtEnd("[email protected]"))
       assertEquals(null, Utils.truncateEmailAtEnd("testuser"))
       assertEquals(null, Utils.truncateEmailAtEnd(""))
       assertEquals(null, Utils.truncateEmailAtEnd(" "))
       assertEquals(null, Utils.truncateEmailAtEnd(null))
       assertEquals("[email protected] ...", Utils.truncateEmailAtEnd("[email protected]"))
       assertEquals("[email protected] ...", Utils.truncateEmailAtEnd("[email protected]"))
       assertEquals("[email protected] ...", Utils.truncateEmailAtEnd("[email protected]"))
       assertEquals(null, Utils.truncateEmailAtEnd("test [email protected]xample.com"))
   }
}

 

Note: You can add more tests to check for other general and corner cases.

Step – 5 : Run the tests in UtilsTest.kt.

If all the test cases pass, then the tests pass. But, if the tests fail, try to figure out the cause of failure of the tests and add/modify the code in the Utils.kt accordingly. This approach helps recognize flaws in the existing code thereby reducing the risk of bugs and failures.

Resources

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Using RealmRecyclerView Adapter to show list of recorded sensor data from Realm Database

In previous blog Storing Recorded Sensor Data in Realm Database we have stored the data fetched from sensors into the Realm Database by defining model classes.

In this blog, we will use the data stored in the Realm to display a list of recorded experiments in the form of well defining card view items so that it is easier for the user to understand.

For showing the list we will make use of RecyclerView  widget provided by Android which is a more advanced version of the List view and is used to display large data sets in a vertical list, horizontal list, grid, staggered grid etc.

RecyclerView  works in accordance with RecyclerView Adapter which is core engine that is responsible of inflating the layout of list items, populating the items with data, recycling of list item views when they go out of viewing screen and much more.

For this blog, we are going to use a special RecyclerView Adapter provided by Realm itself because it integrates properly with the Realm Database and handles modifying, addition, deletion or updating of Realm data automatically and efficiently.   

Step 1 Adding the dependencies

As always first we need to add the following code in our build.gradle file to add the dependency of Realm database and RealmRecyclerViewAdapter.

dependencies {
   implementation"com.android.support:recyclerview-v7:27.1.1 "
   implementation 'io.realm:android-adapters:2.1.1'
}

Step 2 Adding RecyclerView widget in our Activity layout file

First, we need to create an activity and name it as “DataLoggerActivity”, inside the layout of the Activity add the <RecyclerView> widget. This RecyclerView will act as a container of our list item.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    tools:context=".activity.DataLoggerActivity">

    <android.support.v7.widget.RecyclerView
        android:layout_below="@id/top_app_bar_layout"
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</RelativeLayout>

Step 3 Creating the layout and View holder for the list item

We have to create the layout of the list item which will be inflated by the Adapter. So for this create an XML file in res folder and name it “data_list_item.xml”. For the list of the experiments, we want to show Name of the experiment, recording time, recording date for every list item. For this we will make use of <CardView> and <TextView>. This gist shows the code of xml file.

The layout of the list item created is shown in Figure 2

Figure 1 Layout of list item showing mock information

Now we need to create a view holder for this layout which we need to pass to the Adapter, the following code shows the implementation of View Holder for above list item layout.

public class ViewHolder extends RecyclerView.ViewHolder {
   private TextView sensor, dateTime;
   ImageView deleteIcon;
   private CardView cardView;

   public ViewHolder(View itemView) {
       super(itemView);
       dateTime = itemView.findViewById(R.id.date_time);
       sensor = itemView.findViewById(R.id.sensor_name);
       deleteIcon = itemView.findViewById(R.id.delete_item);
       cardView = itemView.findViewById(R.id.data_item_card);
   }
}

Step 4 Creating the adapter for RecyclerView  

In this step, we will start by creating a class called “SensorLoggedListAdpater” and for using use the RecyclerView adapter provided by Realm we need to make this class extend the RealmRecyclerViewAdpater class.

But for that we need to pass two generic parameter:

  1. Model Class : This is class which define a Realm model, for this, we will pass a reference of “SensorLogged.class” which is defined in the previous blog as we want to show the list experiments which are stored using “SensorLogged” model class.
  2. ViewHolder : For this, we will pass the ViewHolder that we have created in Step 3.

As every RecyclerView Adapter needs a arraylist which contains the list of object containing information which we have to populate on the list item, the RealmRecyclerViewAdpater needs data in form of RealmResult to operate on, so we will create a constructor and pass in the RealmResult list in the super() method which we need to provide when we initialize this adapter in our “DataLoggerActivity” class.

public SensorLoggerListAdapter(RealmResults<SensorLogged> list, Activity context) {
   super(list, true, true);
   this.context = context;
   realm = Realm.getDefaultInstance();
}

Now we need to override two methods provided by RealmRecyclerViewAdapter class that are:

  1. public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType): In which we will inflate the layout of list item “dta_list_tem.xml” which we have created in Step 3.
  2. public void onBindViewHolder(@NonNull final ViewHolder holder, int position): In which we will populate the list item view using references stored in the ViewHolder with the data which we have provided while initializing the adapter.
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
   View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.logger_data_item, parent, false);
   return new ViewHolder(itemView);
}

@Override
public void onBindViewHolder(@NonNull final ViewHolder holder, int position) {
   SensorLogged temp = getItem(position);
   holder.sensor.setText(temp.getSensor());
   Date date = new Date(temp.getDateTimeStart());
   holder.dateTime.setText(String.valueOf(sdf.format(date)));
}

Step 5 Initializing the Adapter in Data Logger Activity and connecting with RecyclerView

Now we head to our Data Logger Activity, here in OnCreate() method first we will create a object of RecyclerView, then we will initialize our adapter by passing the RealmResult<SensorLogged> list which we have queried from the Realm Database.

Then we will set the LinearLayoutManager and finally, we will connect the the Adapter with the RecyclerView.

@Override
protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_data_logger);
   ButterKnife.bind(this);

   Realm realm = Realm.getDefaultInstance();

   RealmResults<SensorLogged> results;
   String title;
  
   results = realm.where(SensorLogged.class)
           .findAll()
           .sort("dateTimeStart", Sort.DESCENDING);

   SensorLoggerListAdapter adapter = new SensorLoggerListAdapter(results, this);
   LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);

   recyclerView.setLayoutManager(linearLayoutManager);

   recyclerView.setAdapter(adapter);
}

After following all the above steps we have finally a activity as shown in Figure 4.

Figure 2 showing a list of recorded experiments with the instrument
name and date time of an experiment

Thus we have successfully displayed a list of the experiments from the data stored in the Realm Database using RealmRecyclerViewAdapter.

Resources

  1. https://academy.realm.io/posts/android-realm-listview/ – Blog on creating a To-do list on Realm official website
  2. https://gist.github.com/Avjeet/2f350feeafff17ec855a39891d8c2d66  Gist of layout of list item used
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Use objects to pass multiple query parameters when making a request using Retrofit

There are multiple instances where there is a need to make an API call to the SUSI.AI server to send or fetch data. The Android client uses Retrofit to make this process easier and more convenient.
While making a GET or POST request, there are often multiple query parameters that need to sent along with the base url. Here is an example how this is done:

@GET("/cms/getSkillFeedback.json")
Call<GetSkillFeedbackResponse> fetchFeedback(
                          @Query("model") String model,
                          @Query("group") String group,
                          @Query("language") String language,
                          @Query("skill") String skill);

 

It can be seen that the list of params can be very long indeed. A long list of params would lead to more risks of incorrect key value pairs and typos.

This blog would talk about replacing such multiple params with objects. The entire process would be explained with the help of an example of the API call being made to the getSkillFeedback.json API.

Step – 1 : Replace multiple params with a query map.

@GET("/cms/getSkillFeedback.json")
Call<GetSkillFeedbackResponse> fetchFeedback(@QueryMap Map<String, String> query);

 

Step – 2 : Make a data class to hold query param values.

data class FetchFeedbackQuery(
       val model: String,
       val group: String,
       val language: String,
       val skill: String
)

 

Step – 3 : Instead of passing all different strings for different query params, pass an object of the data class. Hence, add the following code to the ISkillDetailsModel.kt interface.

...

fun fetchFeedback(query: FetchFeedbackQuery, listener: OnFetchFeedbackFinishedListener)
...

 

Step – 4 : Add a function in the singleton file (ClientBuilder.java) to get SUSI client. This method should return a call.

...

public static Call<GetSkillFeedbackResponse> fetchFeedbackCall(FetchFeedbackQuery queryObject){
   Map<String, String> queryMap = new HashMap<String, String>();
   queryMap.put("model", queryObject.getModel());
   queryMap.put("group", queryObject.getGroup());
   queryMap.put("language", queryObject.getLanguage());
   queryMap.put("skill", queryObject.getSkill());
   //Similarly add other params that might be needed
   return susiService.fetchFeedback(queryMap);
}
...

 

Step – 5 : Send a request to the getSkillFeedback.json API by passing an object of FetchFeedbackQuery data class to the fetchFeedbackCall method of the ClientBuilder.java file which in turn would return a call to the aforementioned API.

...

override fun fetchFeedback(query: FetchFeedbackQuery, listener:  
                                   ISkillDetailsModel.OnFetchFeedbackFinishedListener) {

   fetchFeedbackResponseCall = ClientBuilder.fetchFeedbackCall(query)
   ...
}

 

No other major changes are needed except that instead of passing individual strings for each query param as params to different methods and creating maps at different places like in a view, create an object of FetchFeedbackQuery class and use it to pass data throughout the project. This ensures type safety. Also, data classes reduce the code length significantly and hence are more convenient to use in practice.

Resources

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Create Call for Speakers with Open Event Organizer Android App

In The Open Event Organizer Android app, we were providing variety of features to the user but the functionality to create call for speakers for an Event was missing. This feature was required to attract speakers from all over the world to participate in the event and make it a success. Theis blog explains how we added this feature to the project us following MVVM Architecture and using libraries like Retrofit, RxJava, Db Flow etc.

Objective

The goal will be to provide an option to the organizer to create Call for Speakers for an Event (if it doesn’t exist already). We will provide the organizer a Floating Action Button in Speakers Call detail layout which will open a fragment which contain all the relevant fields provided by Open Event Server. The organizer can fill up all the fields as per requirement and create the call for speakers.

Specifications

Let’s move on to the implementation details.

First, we will create the model which will contain all the fields offered by server. We are using Lombok library to reduce boilerplate code using annotations. For example, @Data annotation is used to generate getters and setters. @NoArgsConstructor to generate no arguments constructor as the name suggests. Along with that we are using @JonNaming annotation provided by Jackson library to serialize the model using KebabCaseStrategy. Also, the Table annotation provided by Raziz DbFlow library to make a table in database for this model.

@Data
@Type(“speakers-call”)
@NoArgsConstructor
@JsonNaming(PropertyNamingStrategy.KebabCaseStrategy.class)
@Table(database = OrgaDatabase.class, allFields = true)
public class SpeakersCall {@Id(LongIdHandler.class)
@PrimaryKey
public Long id;@Relationship(“event”)
@ForeignKey(onDelete = ForeignKeyAction.CASCADE)
public Event event;

public String announcement;
public String hash;
public String privacy;
public String startsAt;
public String endsAt;
}

To handle this problem we will be using Retrofit 2.3.0 to make Network Requests, which is a REST client for Android and Java by Square Inc. It makes it relatively easy to retrieve and upload JSON (or other structured data) via a REST based Web Service. Also we will be using other awesome libraries like RxJava 2.1.10 (by ReactiveX) to handle tasks asynchronously, Jackson, Jasminb-Json-Api in an MVVM architecture.

We will make a POST request to the server . So we specify the declaration in SpeakersCallApi.java

@POST(“speakers-calls”)
Observable<SpeakersCall> postSpeakersCall(@Body SpeakersCall speakersCall);

We will use the method createSpeakersCall(SpeakersCall speakersCall) in SpeakersCallRepositoryImpl.java to interact with the SpeakersCallApi and make the network request for us. The response will be passed on to the SpeakersCallViewModel method which calls it.

@Override
public Observable<SpeakersCall> createSpeakersCall(SpeakersCall speakersCall) {
if (!repository.isConnected()) {
return Observable.error(new Throwable(Constants.NO_NETWORK));
}return speakersCallApi
.postSpeakersCall(speakersCall)
.doOnNext(created -> {
created.setEvent(speakersCall.getEvent());
repository
.save(SpeakersCall.class, created)
.subscribe();
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread());
}

Next, we will see the code for SpeakersCallViewModel which is using MVVM ViewModel to handle the processing logic for SpeakesCallFragment. Here we are passing SpeakersCallRepository instance in constructor. Methods like getProgress, getError and getSuccess pass on a LiveData Object from ViewModel to Fragment and the latter observes the changes on the object and show these in UI. CreateSpeakersCall method is used to call speakersCallRepository to send a POST request to server asynchronously using Retrofit and RxJava. Further, initialize method is used to set initial values of time and date to SpeakersCall object.

public class CreateSpeakersCallViewModel extends ViewModel {
public void createSpeakersCall(long eventId) {
if (!verify())
return;Event event = new Event();event.setId(eventId);
speakersCallLive.getValue().setEvent(event);

compositeDisposable.add(speakersCallRepository.createSpeakersCall(speakersCallLive.getValue())
.doOnSubscribe(disposable -> progress.setValue(true))
.doFinally(() -> progress.setValue(false))
.subscribe(var -> success.setValue(“Speakers Call Created Successfully”),
throwable -> error.setValue(ErrorUtils.getMessage(throwable))));
}
}

We will create a Fragment class to bind the UI elements to the Model class so that they can be processed by ViewModel. The creation form contains less fields therefore BaseBottomSheetFragment is used. In the onStart method, we are binding several LiveData objects like SpeakersCall, Progress, Error, Success to the UI and then observe changes in them. Using LiveData we don’t have to write extra code to handle screen rotation and to update UI when the binded object is modified.

public class CreateSpeakersCallFragment extends BaseBottomSheetFragment implements CreateSpeakersCallView {
@Override
public void onStart() {
super.onStart();
createSpeakersCallViewModel.getSpeakersCall().observe(this, this::showSpeakersCall);
createSpeakersCallViewModel.getProgress().observe(this, this::showProgress);
createSpeakersCallViewModel.getError().observe(this, this::showError);
createSpeakersCallViewModel.getSuccess().observe(this, this::onSuccess);
createSpeakersCallViewModel.initialize();
}
}

We will design the speaker create form using Two Way Data Binding to bind SpeakersCall object to the UI and use TextInputEditText to take user Input. Along with that we have used Time and Date pickers to make it easier to select Date and Time. For viewing the complete code, please refer here.

Thus, we are able to build a responsive, reactive UI using Android Architectural Components.

References

  1. Official documentation of Retrofit 2.x http://square.github.io/retrofit/
  2. Official documentation for RxJava 2.x https://github.com/ReactiveX/RxJava
  3. Official documentation for ViewModel https://developer.android.com/topic/libraries/architecture/viewmodel
  4. Codebase for Open Event Orga App https://github.com/fossasia/open-event-orga-app
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Correct the API for Downloading GitHub Content in SUSI.AI android app

The content from github in the SUSI.AI android app is downloaded through simple links and the data is parsed through them and is used in the app depending upon what needs to be done with that data at that time.

A simple example for this that was used in the app was  :

private val imageLink = “https://raw.githubusercontent.com/fossasia/susi_skill_data/master/models/general/”

Above is the link that is used to download and display the images of the skills in the app. All the api calls that generally take place in SUSI are through the SUSI server, and making the call to display the images for the skills which takes place through the github links should be replaced by making the calls to the SUSI server instead, as this is a terrible programming style, with this style the project cannot be cloned from other developers and it cannot be moved to other repositories.

We see that there was a huge programming style issue present in the android app and hence, it was fixed by adding the API that calls the SUSI server for external source images and removing the existing implementation that downloads the image from github directly.

Below is an example of the link to the API call made in the app that was needed for the request to be made to the SUSI server :

${BaseUrl.SUSI_DEFAULT_BASE_URL}/cms/getImage.png?model=${skillData.model}&language=${skillData.language}&group=${skillData.group}&image=${skillData.image}

The link is displayed in the kotlin string interpolation manner, here is what the actual URL would look like :

https://api.susi.ai/cms/getImage.pngmodel=${skillData.model}&language=${skillData.language}&group=${skillData.group}&image=${skillData.image}

Here the values with ‘$’ symbol are the parameters for the API taken from the SkillData.kt file and are put inside the link so that the image needed can be extracted.

Now, since we use this link to set the images, to avoid the duplicate code, an Object class was made for this purpose. The object class contained two functions, one for setting the image and one for parsing the skilldata object and forming a URL out of it. Here is the code for the object class :

object Utils {

  fun setSkillsImage(skillData: SkillData, imageView: ImageView) {
      Picasso.with(imageView.context)
              .load(getImageLink(skillData))
              .error(R.drawable.ic_susi)
              .fit()
              .centerCrop()
              .into(imageView)
  }

  fun getImageLink(skillData: SkillData): String {
      val link = “${BaseUrl.SUSI_DEFAULT_BASE_URL}/cms/getImage.png?model=${skillData.model}&language=${skillData.language}&group=${skillData.group}&image=${skillData.image}”
              .replace(” “,“%20”)
      Timber.d(“SUSI URI” + link)
      return link
  }
}

setSkillsImage() method sets the image in the ImageView and the getImageLink() method returns the image formed out of the SkillData object.

References

 

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Building SUSI.AI Android App with FDroid

Fdroid is an app store for Free and Open Source Software (FOSS). Building and hosting an app on Fdroid is not an easy process compared to when we host one on Google Play. A certain set of build checks are required to be done prior to making a merge request (which is similar to a pull request in GitHub) in the fdroid-data GitLab repository. SUSI.AI Android app has undergone through all these checks and tests and is now ready for the merge request to be made.

Setting up the fdroid-server and fdroid-data repositories is a separate thing and is fairly easy. Building the app using the tools provided by fdroid is another thing and is the one that causes the most problems. It will involve quite a few steps to get started. Fdroid requires all the apps need to be built using:

$ fdroid build -v -l ai.susi

This will output a set of logs which tell us what went wrong in the builds. The usual one in a first time app is obviously the build is not taking place at all. The reason is our metadata file needs to be changed to initiate a build.

The metadata file is used for the build process and contains all the information about the app. The metadata file for a.susi package was a .yaml file.

Builds:

 – versionName: 1.0.10

   versionCode: 11

   commit: 1ad2fd0e858b1256617e652c6c8ce1b8372473e6

   subdir: app

   gradle:

     – fdroid

This is the metadata reference file’s build section that is used for the build process using the command that was mentioned above.The versionName a nd versionCode is found in the build.gradle file in the app and commit denotes the commit-id of the latest commit that will be checked out and built, subdir shows the subdirectory of the app, here the subdirectory is the app file.

Next is the interesting stuff, since we are using flavors in the app, we have to mention in the gradle the flavor which we are using, in our case we are using the flavor by the name of “fdroid” and by mentioning this we can build only the “fdroid” flavor in the app.

Also when building the app there were many blockers that were faced, the reason for the usual build fails were :

1 actionable task: 1 executed
INFO: Scanning source for common problems…
ERROR: Found usual suspect ‘youtube.*android.*player.*api’ at app/libs/YouTubeAndroidPlayerApi.jar
WARNING: Found JAR file at app/libs/YouTubeAndroidPlayerApi.jar
WARNING: Found possible binary at app/src/main/assets/snowboy/alexa_02092017.umdl
WARNING: Found possible binary at app/src/main/assets/snowboy/common.res
ERROR: Found shared library at app/src/main/jniLibs/arm64-v8a/libsnowboy-detect-android.so
ERROR: Found shared library at app/src/main/jniLibs/armeabi-v7a/libsnowboy-detect-android.so
INFO: Removing gradle-wrapper.jar at gradle/wrapper/gradle-wrapper.jar
ERROR: Could not build app ai.susi: Can‘t build due to 3 errors while scanning
INFO: Finished
INFO: 1 build failed

The reason for these build fails were that fdroid does not allow us to use prebuilt files and any proprietary software if present, the above log indicates the two prebuilt files which should be removed and also the YouTubeAndroidPlayerApi.jar which is proprietary software and hence needs to removed. So, to remove the files that are not used in the fdroid flavor and exclude them in the build process, we have to include the following statements in the build section of the metadata reference file :

   rm:
     – app/src/main/jniLibs/arm64-v8a/libsnowboy-detect-android.so
     – app/src/main/jniLibs/armeabi-v7a/libsnowboy-detect-android.so
     – app/libs/YouTubeAndroidPlayerApi.jar

Once the metadata file is complete we are ready to run the build command once again. If you have properly set the environment in your local PC, build will end successfully assuming there were no Java or any other language syntax errors.

It is worth to mention few other facts which are common to Android software projects. Usually the source code is packed in a folder named “app” inside the repository and this is the common scenario if Android Studio builds up the project from scratch. If this “app” folder is one level below the root, that is “android/app”, the build instructions shown above will throw an error as it cannot find the project files.

The reason for this is as it is mentioned “subdir=app” in the metadata file. Change this to “subdir=android/app” and run the build again. The idea is to direct the build to find where the project files are.

Reference:

  1. Metadata : https://f-droid.org/docs/Build_Metadata_Reference/#Build
  2. Publish an app on fdroid: https://blog.fossasia.org/publish-an-open-source-app-on-fdroid/
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Ticket Details in the Open Event Android App

After entering all the attendee details and buying a ticket for an event the user expects to see the ticket so that he can use it later. This is why ticket details are shown in a separate fragment in the Open Event Android App. Let’s see how the tickets fragment was made in the Open Event Android App.

Two things that we require from the previous fragment are the event id and the order identifier so that we show the information related to the event as well as the order.

if (bundle != null) {
id = bundle.getLong(EVENT_ID, -1)
orderId = bundle.getString(ORDERS)
}

 

We are requesting data from the following two endpoints. In the first GET request we are passing the order identifier in the URL and we get the list of attendees from the server. In the second endpoint we simply pass the event identifier and get the event details from the server.

 

@GET("/v1/orders/{orderIdentifier}/attendees")
fun attendeesUnderOrder(@Path("orderIdentifier") orderIdentifier: String): Single<List<Attendee>>

@GET("/v1/events/{eventIdentifier}")
fun getEventFromApi(@Path("eventIdentifier") eventIdentifier: Long): Single<Event>

 

Here we are observing the attendees live data and adding the list of attendees returned from the server to the recyclerview so that we can show the user all the details of the attendees like the first name, last name etc. We then notify the adapter that the list of attendees have been added. In the end we log the number of attendees so that it is easier to debug in case there are any bugs.

orderDetailsViewModel.attendees.observe(this, Observer {
it?.let {
ordersRecyclerAdapter.addAll(it)
ordersRecyclerAdapter.notifyDataSetChanged()
}
Timber.d("Fetched attendees of size %s", ordersRecyclerAdapter.itemCount)
})

 

As mentioned earlier we need the event id and order identifier to show event and attendee related information to the user so here we are using the event id and appending it to the url. We are sending a GET request in a background thread and storing the list of events returned from the server in a mutable live data. In case of any errors we log it and show the error message to the user. Similarly we will use the order identifier to get the list of orders from the server and show it to the user.

compositeDisposable.add(eventService.getEventFromApi(id)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe({
event.value = it
}, {
Timber.e(it, "Error fetching event %d", id)
message.value = "Error fetching event"
}))

 

After fetching the list of attendees and event details, the only thing that we need to do is extract the important information and show it to the user so we pass the order and event objects to the ViewHolder. This can be done simply by using the attendee and event objects and accessing the fields required.

itemView.name.text = "${attendee.firstname} ${attendee.lastname}"
itemView.eventName.text = event?.name
itemView.date.text = "$formattedDate\n$formattedTime $timezone"

 

Resources

  1. ReactiveX official documentation: http://reactivex.io/
  2. Retrofit Android: http://square.github.io/retrofit/
  3. Google Android Developers Recycler View: https://developer.android.com/guide/topics/ui/layout/recyclerview
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Show Option to choose WiFi for Smart Speaker Connection in SUSI.AI Android APP

SUSI.AI android app has the functionality to detect the available WiFi networks and among them check for the hotspot named “SUSI.AI”. Now, this process is required so that the app can connect to the smart speaker and send the WiFi credentials, the authentication credentials and the configuration data to the smart speaker.

After on clicking the “SET UP” button on the available SUSI.AI hotspot as shown in the image below,

The app needs to make API requests where the app will send the data to the speaker, the first API that needs to be hit is for the WiFi credentials. Once the “SET UP” button is clicked the app shows a message “Connecting to your device” with a loader as in the image below :

Now during this step the code to detect the available WiFi networks is run again and the list of the available networks is sent from the DeviceConnectPresenter.kt to the DeviceConnectFragment.kt from the function defined in the presenter as follows :

override fun availableWifi(list: List<ScanResult>) {
  connections = ArrayList<String>()
  for (i in list.indices) {
      connections.add(list[i].SSID)
  }
  if (!list.isEmpty()) {
      deviceConnectView?.setupWiFiAdapter(connections)
  } else {
      deviceConnectView?.onDeviceConnectionError(utilModel.getString(R.string.no_device_found), utilModel.getString(R.string.setup_tut))
  }
}

Now to show the list of available WiFi networks a new ViewHolder had to made which contained a textview and an imageview. The viewholder file named WifiViewHolder.java is responsible for this and is used along with the DeviceAdapter only.

The interesting thing to see is that the DeviceAdapter already inflates the ViewItems of the type DeviceViewHolder. Instead of making a new adapter for the WifiViewHolder view item, I wrote some smart code that handles both the viewholders with the same adapter i.e DeviceAdapter. Let’s now see how this was handled,

In the DeviceAdapter a private variable named viewCode of type integer was made and it would be responsible to segregate the two viewholders using an if command. Here is code below that shows how using viewcode variable allows us to choose and inflate a viewholder among the two we have in onCreateViewHolder() method :

if (viewCode == 1) {
  View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.device_layout, parent, false);
  return new DeviceViewHolder(v, (DeviceConnectPresenter) devicePresenter);
} else {
  View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_wifi_item, parent, false);
  return new WifiViewHolder(v, (DeviceConnectPresenter) devicePresenter);
}

Now, when the viewholder of type WifiViewHolder is inflated the app displays a list of available wifi networks and on clicking any of the Wifi items the app asks the user to enter the credentials of the WiFi network. Below is how the app looks when the available wifi networks are loaded and displayed and also when we click on any of the item in the list.

References :

  1. Android manipulating Wifi networks using WiFiManager : https://medium.com/@josiassena/android-manipulating-wifi-using-the-wifimanager-9af77cb04c6a
  2. Kotlin broadcast intents and receivers : https://www.techotopia.com/index.php/Kotlin_Android_Broadcast_Intents_and_Broadcast_Receivers
  3. Android Viewholder pattern : https://www.javacodegeeks.com/2013/09/android-viewholder-pattern-example.html
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Option to Rename an Image in Phimpme Android Application

In the Phimpme Android application, users can perform various operations on images such as editing an image, sharing an image, moving the image to another folder, printing a pdf version of the image and many more. However, another important functionality that has been implemented is the option to rename an image. So in this blog post, I will be discussing how we achieved the functionality to rename an image.

Step 1

First, we need to add an option in the overflow menu to rename the image being viewed. The option to rename an image has been added by implementing the following lines of code in the  menu_view_pager.xml file.

<item
  android:id=“@+id/rename_photo”
  app:showAsAction=“never”
  android:title=“@string/Rename”/>

Step 2

Now after the user chooses the option to rename any image from the overflow menu, an alert dialog with an edittext would be displayed to the user with the old name and provide the user to add a new name for the photo. The dialog box with edittext has been implemented with the following lines of XML code.

<android.support.v7.widget.CardView
  android:layout_width=“match_parent”
  android:layout_height=“wrap_content”
  app:cardCornerRadius=“2dp”
  android:id=“@+id/description_dialog_card”>
  <ScrollView
      android:layout_width=“match_parent”
      android:layout_height=“match_parent”>
      <LinearLayout
          android:layout_width=“match_parent”
          android:layout_height=“wrap_content”
          android:orientation=“vertical”>
          <TextView
              android:id=“@+id/description_dialog_title”
              android:layout_width=“match_parent”
              android:textColor=“@color/md_dark_primary_text”
              android:layout_height=“wrap_content”
              android:background=“@color/md_dark_appbar”
              android:padding=“24dp”
              android:text=“@string/type_description”
              android:textSize=“18sp”
              android:textStyle=“bold” />
          <LinearLayout
              android:id=“@+id/rl_description_dialog”
              android:layout_width=“match_parent”
              android:layout_height=“wrap_content”
              android:orientation=“horizontal”
              android:padding=“15dp”>
              <EditText
                  android:id=“@+id/description_edittxt”
                  android:layout_width=“fill_parent”
                  android:layout_height=“wrap_content”
                  android:padding=“15dp”
                  android:hint=“@string/description_hint”
                  android:textColorHint=“@color/grey”
                  android:layout_margin=“20dp”
                  android:gravity=“top|left”
                  android:inputType=“textCapSentences|textMultiLine”
                  android:maxLength=“2000”
                  android:maxLines=“4”
                  android:selectAllOnFocus=“true”/>
              <ImageButton
                  android:layout_width=“@dimen/mic_image”
                  android:layout_height=“@dimen/mic_image”
                  android:layout_alignRight=“@+id/description_edittxt”
                  app2:srcCompat=“@drawable/ic_mic_black”
                  android:layout_gravity=“center”
                  android:background=“@color/transparent”
                  android:paddingEnd=“10dp”
                  android:paddingTop=“12dp”
                  android:id=“@+id/voice_input”/>
          </LinearLayout>
      </LinearLayout>
  </ScrollView>
</android.support.v7.widget.CardView>

The screenshot displaying the dialog with edittext is provided below.

Step 3

Now after retrieving the new name entered by the user for the photo we would extract the extension of the old name which can be .jpg, .png etc. Thereafter we’d need to create a new File object passing in the new path of the image(the path folder remains the same only the image name gets changed to a new one) as the constructor parameter. Now using the renameTo method of the File class the old image file can be renamed. However, with this rename operation the image reference would not be automatically updated in the MediaStore database. So we’d need to delete the old file path from the Android system MediaStore database which keeps a URI reference to all the media files present on the device. At last, we’d need to invoke the MediaScanner class to scan all the media files so that the new file path of the renamed image is scanned and is picked up by the MediaStore database. This can be done with the help of an action intent to initiate the media scan action. The code changes implemented to perform the above-mentioned operation is given below.

public void onClick(View dialog) {
      if (editTextNewName.length() != 0) {
          int index = file.getPath().lastIndexOf(“/”);
          String path = file.getPath().substring(0, index);
          File newname = new File(path + “/” + editTextNewName.getText().toString() + “.” +
                  imageextension);
          if(file.renameTo(newname)){
              ContentResolver resolver = getApplicationContext().getContentResolver();
              resolver.delete(
                      MediaStore.Images.Media.EXTERNAL_CONTENT_URI, MediaStore.Images.Media.DATA +
                              “=?”, new String[] { file.getAbsolutePath() });
              Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
              intent.setData(Uri.fromFile(newname));
              getApplicationContext().sendBroadcast(intent);
          }
          if(!allPhotoMode){
              int a = getAlbum().getCurrentMediaIndex();
              getAlbum().getMedia(a).setPath(newname.getPath());
          }else {
              listAll.get(current_image_pos).setPath(newname.getPath());
          }
          renameDialog.dismiss();
          SnackBarHandler.showWithBottomMargin(parentView, getString(R.string.rename_succes), navigationView
                  .getHeight());
      } else {
          SnackBarHandler.showWithBottomMargin(parentView, getString(R.string.insert_something),
                  navigationView.getHeight());
          editTextNewName.requestFocus();
      }
  }
});

This is how we have implemented the functionality to rename an image in the Phimpme Android application. To get the full source code, please refer to the Phimpme Android Github repository listed in the resource section below.

Resources

1.Android Developer documentation-https://developer.android.com/reference/java/io/File

2.Github-Phimpme Android Repository – https://github.com/fossasia/phimpme-android/

3.Renaming a file in java – http://stacktips.com/tutorials/java/how-to-delete-and-rename-a-file-in-java

 

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