Creating Settings Screen in SUSI Android Using PreferenceActivity and Kotlin

An Android application often includes settings that allow the user to modify features of the app. For example, SUSI Android app allows users to specify whether they want to use in built mic to give speech input or not. Different settings in SUSI Android app and their purpose are given below

Setting                                        Purpose
Enter As Send It allows users to specify whether they want to use enter key to send message or to add new line.
Mic Input It allows users to specify whether they want to use in built mic to give speech input or not.
Speech Always It allows users to specify whether they want voice output in case of speech input or not.
Speech Output It allows users to specify whether they want speech output irrespective of input type or not.
Language It allows users to set different query language.
Reset Password It allows users to change password.
Select Server It allows users to specify whether they want to use custom server or not.

Android provides a powerful framework, Preference framework, that allows us to define the way we want preferences. In this blog post, I will show you how Settings UI is created using Preference framework and Kotlin in SUSI Android.

Advantages of using Preference are:

  • It has own UI so we don‘t have to develop our own UI for it
  • It stores the string into the SharedPreferences so we don’t need to manage the values in SharedPreference.

First, we will add the dependency in build.gradle(project) file as shown below.

compile ‘com.takisoft.fix:preference-v7:’

To create the custom style for our Settings Activity screen we can set


as the base theme and can apply various other modifications and colour over this. By default, it has the usual Day and Night theme with NoActionBar extension.

Layout Design

I used PreferenceScreen as the main container to create UI of Settings and filled it with the other components. Different components used are following:

  • SwitchPreferenceCompat: This gives us the Switch Preference which we can use to toggle between two different modes in the setting.


  • PreferenceCategory: It is used for grouping the preference. For example, Chat Settings, Mic Settings, Speech Settings etc are different groups in settings.

  • ListPreference: This preference display list of values and help in selecting one. For example in setLanguage option ListPreference is used to show a list of query language. List of query language is provided via xml file array.xml (res/values). Attribute android:entries point to arrays languagentries and android:entryValue holds the corresponding value defined for each of the languages.





Implementation in SUSI Android

All the logic related to Preferences and their action is written in ChatSettingsFragment class. ChatSettingsFragment extends PreferenceFragmentCompat class.

class ChatSettingsFragment : PreferenceFragmentCompat()

Fragment populate the preferences when created. addPreferencesFromResource method is used to inflate view from xml.



Restoring State after Orientation Change in Loklak Wok Android

During orientation change i.e. from portrait to landscape mode in Android, the current activity restarts again. As the activity restarts again, all the defined variables loose their previous value, for example the scroll position of a RecyclerView, or the data in the rows of RecyclerView etc. Just imagine a user searched some tweets in Loklak Wok Android, and as the user’s phone is in “Auto rotation” mode, the orientation changes from portrait to landscape. As a result of this, the user loses the search result and has to do the search again. This leads to a bad UX.

Saving state in onSavedInstanceState

The state of the app can be saved by inserting values in a Bundle object in onSavedInstanceState callback. Inserting values is same as adding elements to a Map in Java. Methods like putDouble, putFloat, putChar etc. are used where the first parameter is a key and the second parameter is the value we want to insert.

public void onSaveInstanceState(Bundle outState) {
   if (mLatitude != null && mLongitude != null) {
       outState.putDouble(PARCELABLE_LATITUDE, mLatitude);
       outState.putDouble(PARCELABLE_LONGITUDE, mLongitude);


The values can be retrieved back when onCreate or onCreateView of the Activity or Fragment is called. Bundle object in the callback parameter is checked, whether it is null or not, if not the values are retrieved back using the keys provided at the time of inserting. The latitude and longitude of a location in TweetPostingFragment are retrieved in the same fashion

public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
   if (savedInstanceState != null) { // checking if bundle is null
       // extracting from bundle
       mLatitude = savedInstanceState.getDouble(PARCELABLE_LATITUDE);
       mLongitude = savedInstanceState.getDouble(PARCELABLE_LONGITUDE);
       // use extracted value

Restoring Custom Objects, using Parcelable

But what if we want to restore custom object(s). A simple option can be serializing the objects using the native Java Serialization or libraries like Gson. The problem in these cases is performance, they are quite slow. Parcelable can be used, which leads the pack in performance and moreover it is provided by Android SDK, on top of that, it is simple to use.

The objects of class which needs to be restored implements Parcelable interface and the class must provide a static final object called CREATOR which implements Parcelable.Creator interface.

writeToParcel and describeContents method need to be override to implement Parcelable interface. In writeToParcel method the member variables are put inside the parcel, in our case describeContents method is not used, so, simply 0 is returned. Status class which stores the data of a searched tweet implements parcelable.

public int describeContents() {
   return 0;

public void writeToParcel(Parcel dest, int flags) {
   dest.writeParcelable(mUser, flags);


NOTE: The order in which variables are pushed into Parcel needs to be maintained while variables are extracted from the parcel to recreate the object. This is the reason why no “key” is required to push data into a parcel as we do in bundle.

The CREATOR object implements the creation of object from a Parcel. The CREATOR object overrides two methods createFromParcel and newArray. createFromParcel is the method in which we implement the way an object is created from a parcel.

public static final Parcelable.Creator<Status> CREATOR = new Creator<Status>() {
   public Status createFromParcel(Parcel source) {
       return new Status(source); // a private constructor to create object from parcel

   public Status[] newArray(int size) {
       return new Status[size];


The private constructor, note that the order in which variables were pushed is maintained while retrieving the values.

private Status(Parcel source) {
   mText = source.readString();
   mRetweetCount = source.readInt();
   mFavouritesCount = source.readInt();
   mImages = source.createStringArrayList();
   mUser = source.readParcelable(User.class.getClassLoader());


The status objects are restored the same way, latitude and longitude were restored. putParcelableArrayList in onSaveInstaceState and getParcelableArrayList in onCreateView methods are used to push into Bundle object and retrieve from Bundle object respectively.

public void onSaveInstanceState(Bundle outState) {
   ArrayList<Status> searchedTweets = mSearchCategoryAdapter.getStatuses();
   outState.putParcelableArrayList(PARCELABLE_SEARCHED_TWEETS, searchedTweets);

// retrieval of the pushed values in bundle
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                            Bundle savedInstanceState) {
   if (savedInstanceState != null) {
       List<Status> searchedTweets =
   return view;


Testing Presenter of MVP in Loklak Wok Android

Imagine working on a large source code, and as a new developer you are not sure whether the available source code works properly or not, you are surrounded by questions like, Are all these methods invoked properly or the number of times they need to be invoked? Being new to source code and checking manually already written code is a pain. For cases like these unit-tests are written. Unit-tests check whether the implemented code works as expected or not. This blog post explains about implementation of unit-tests of Presenter in a Model-View-Presenter (MVP) architecture in Loklak Wok Android.

Adding Dependencies to project

In app/build.gradle file

defaultConfig {
   testInstrumentationRunner ""

dependencies {
   androidTestCompile 'org.mockito:mockito-android:2.8.47'
   androidTestCompile ''
   androidTestCompile ''

Setup for Unit-Tests

The presenter needs a realm database and an implementation of LoklakAPI interface. Along with that a mock of the View is required, so as to check whether the methods of View are called or not.

The LoklakAPI interface can be mocked easily using Mockito, but the realm database can’t be mocked. For this reason an in-memory realm database is created, which will be destroyed once all unit-test are executed. As the presenter is required for each unit-test method we instantiate the in-memory database before all the tests start i.e. by annotating a public static method with @BeforeClass, e.g. setDb method.

public static void setDb() {
   RealmConfiguration testConfig = new RealmConfiguration.Builder()
   mDb = Realm.getInstance(testConfig);


NOTE: The in-memory database should be closed once all unit-tests are executed. So, for closing the databasse we create a public static method annotated with @AfterClass, e.g. closeDb method.

public static void closeDb() {


Now, before each unit-test is executed we need to do some setup work like instantiating the presenter, a mock instance of API interface generated  by using mock static method and pushing in some sample data into the database. Our presenter uses RxJava and RxAndroid which depend on IO scheduler and MainThread scheduler to perform tasks asynchronously and these schedulers are not present in testing environment. So, we override RxJava and RxAndroid to use trampoline scheduler in place of IO and MainThread so that our test don’t encounter NullPointerException. All this is done in a public method annotated with @Before e.g. setUp.

public void setUp() throws Exception {
   // mocking view and api
   mMockView = mock(SuggestContract.View.class);
   mApi = mock(LoklakAPI.class);

   mPresenter = new SuggestPresenter(mApi, mDb);

   queries = getFakeQueries();
   // overriding rxjava and rxandroid
   RxJavaPlugins.setIoSchedulerHandler(scheduler -> Schedulers.trampoline());
   RxAndroidPlugins.setMainThreadSchedulerHandler(scheduler -> Schedulers.trampoline());



Some fake suggestion queries are created which will be returned as observable when API interface is mocked. For this, simply two query objects are created and added to a List after their query parameter is set. This is implemented in getFakeQueries method.

private List<Query> getFakeQueries() {
   List<Query> queryList = new ArrayList<>();

   Query linux = new Query();

   Query india = new Query();

   return queryList;


After that, a method is created which provides the created fake data wrapped inside an Observable as implemented in getFakeSuggestionsMethod method.

private Observable<SuggestData> getFakeSuggestions() {
   SuggestData suggestData = new SuggestData();
   return Observable.just(suggestData);


Lastly, the mocking part is implemented using Mockito. This is really simple, when and thenReturn static methods of mockito are used for this. The method which would provide the fake data is invoked inside when and the fake data is passed as a parameter to thenReturn. For example, stubSuggestionsFromApi method

private void stubSuggestionsFromApi(Observable observable) {

Finally, Unit-Tests

All the tests methods must be annotated with @Test.

Firstly, we test for a successful API request i.e. we get some suggestions from the Loklak Server. For this, getSuggestions method of LoklakAPI is mocked using stubSuggestionFromApi method and the observable to be returned is obtained using getFakeSuggestions method. Then, loadSuggestionFromAPI method is called, the one that we need to test. Once loadSuggestionFromAPI method is invoked, we then check whether the method of the View are invoked inside loadSuggestionFromAPI method, this is done using verify static method. The unit-test is implemented in testLoadSuggestionsFromApi method.

public void testLoadSuggestionsFromApi() {

   mPresenter.loadSuggestionsFromAPI("", true);



Similarly, a failed network request for obtaining is suggestions is tested using testLoadSuggestionsFromApiFail method. Here, we pass an IOException throwable – wrapped inside an Observable – as parameter to stubSuggestionsFromApi.

public void testLoadSuggestionsFromApiFail() {
   Throwable throwable = new IOException();

   mPresenter.loadSuggestionsFromAPI("", true);


Lastly, we test if our suggestions are saved in the database by counting the number of saved suggestions and asserting that, in testSaveSuggestions method.

public void testSaveSuggestions() {
   int count = mDb.where(Query.class).findAll().size();
  // queries is the List that contains the fake suggestions
   assertEquals(queries.size(), count);


Handling Data Requests in Open Event Organizer Android App

Open Event Organizer is a client side application of Open Event API Server created for event organizers and entry managers. The app maintains a local database and syncs it with the server when required. I will be talking about handling data requests in the app in this blog.

The app uses ReactiveX for all the background tasks including data accessing. When a user requests any data, there are two possible ways the app can perform. The one where app fetches the data directly from the local database maintained and another where it requests data from the server. The app has to decide one of the ways. In the Organizer app, AbstractObservableBuilder class takes care of this. The relevant code is:

final class AbstractObservableBuilder<T> {

   private final IUtilModel utilModel;
   private boolean reload;
   private Observable<T> diskObservable;
   private Observable<T> networkObservable;


   private Callable<Observable<T>> getReloadCallable() {
       return () -> {
           if (reload)
               return Observable.empty();
               return diskObservable
                   .doOnNext(item -> Timber.d("Loaded %s From Disk on Thread %s",
                       item.getClass(), Thread.currentThread().getName()));

   private Observable<T> getConnectionObservable() {
       if (utilModel.isConnected())
           return networkObservable
               .doOnNext(item -> Timber.d("Loaded %s From Network on Thread %s",
                   item.getClass(), Thread.currentThread().getName()));
           return Observable.error(new Throwable(Constants.NO_NETWORK));

   private <V> ObservableTransformer<V, V> applySchedulers() {
       return observable -> observable

   public Observable<T> build() {
       if (diskObservable == null || networkObservable == null)
           throw new IllegalStateException("Network or Disk observable not provided");

       return Observable
               .flatMap(items -> diskObservable.toList())
               .flattenAsObservable(items -> items)


DiskObservable is a data request to the local database and networkObservable is a data request to the server. The build function decides which one to use and returns a correct observable accordingly. The class object takes a boolean field reload which is used to decide which observable to subscribe. If reload is true, that means the user wants data from the server, hence networkObservable is returned to subscribe. Also switchIfEmpty in the build method checks whether the data fetched using diskObservable is empty, if found empty it switches the observable to the networkObservable to subscribe.

This class object is used for every data access in the app. For example, this is a code snippet of the gettEvents method in EventRepository class.

public Observable<Event> getEvents(boolean reload) {
   Observable<Event> diskObservable = Observable.defer(() ->

   Observable<Event> networkObservable = Observable.defer(() ->
           .flatMapIterable(events -> events));

   return new AbstractObservableBuilder<Event>(utilModel)


1. Documentation of ReactiveX API
2. Github repository link of RxJava – Reactive Extension for JVM

Implement Internationalization in SUSI Android With Weblate

When you build an Android app, you must consider about users for whom you are building an app. It may be possible that you users are from the different region. To support the most users your app should show text in locale language so that user can use your app easily. Our app SUSI Android is also targeting users from different regions. Internationalization is a way that ensures our app can be adapted to various languages without requiring any change to source code. This also allows projects to collaborate with non-coders more easily and plugin translation tools like Weblate.

Benefits of using Internationalization are:

  • It reduces the time for localization i.e it will localize your app automatically.
  • It helps us to keep and maintain only single source code for different regions.

To achieve Internationalization in Android app you must follow below steps:

  • Move all the required contents of your app’s user interface into the resource file.
  • Create new directories inside res to add support for Internationalization. Each directory’s name should follow rule <resource type>-(language code). For example values-es contains string resource for es language code i.e Spanish.
  • Now add different locale content in the respective folder.

We need to create separate directories for different locale because to show locale specific content, Android check specific folder i.e res/<resource type>-(language code) like res/values-de and show content from that folder. That’s why we need to move all the required content into resource file so that each required content can be shown in the specific locale.

How Internationalization is implemented in SUSI Android

In SUSI Android there is not any locale specific image but only string. So I created only locale specific value resource folder to add locale specific strings. To create locale specific values folder I follow the above-mentioned rule i.e <resource type>-(language code).

After that, I added specific language string in the respective folder.

Instead of hard-coded strings, we used strings from string.xml file so that it will change automatically according to the region.




In absence of resource directory for any specific locale, Android use default resource directory.

Integrate Weblate in SUSI Android

Weblate is a web based translation tool. The best part of Weblate is its tight version control integration which makes it easy for translators to contribute because translator does not need to fork your repo and send pull request for each change but Weblate handle this part i.e translator translate strings of the project in Weblate site and Weblate will send pull request for those changes.

Weblate can host your free software projects for free but it depends on them. Here is the link of SUSI Android project hosted on Weblate. If your project is good then they can host your project for free. But for that, you have to apply from this link and select ask for hosting. Now fill up form as shown in below picture.

Once your project is hosted on Weblate, they will email you about it. After that, you have to integrate Weblate in your project so that Weblate can automatically push translated strings to your project and also Weblate get notify about changes in your repository. Here is the link on how to add Weblate service and Weblate user to your project.

If it is not possible to host your project on Weblate for free then you can host it by own. You can follow below steps:

  • First, we deploy Weblate on our localhost using the installation guide given on Weblate site. I install Weblate from git. I cloned latest source code using Git
git clone
  • Now change directory to where you cloned weblate source code and install all the required dependencies and optional dependencies using code
pip install -r requirements.txt


pip install -r requirements-optional.txt
  • After doing that we copy weblate/ to weblate/ Then we configure and use the following command to migrate the settings.
./ migrate
  • Now create an admin using following command.
./ createadmin
  • After that add a project from your Admin dashboard (Web translations-> Projects-> Add Project) by filling all details.
  • Once the project is added, we add the component (Web translations-> Components-> Add Component) to link our Translation files.
  • To change any translation we make changes and push it to the repository where our SSH key generated from Weblate is added. A full guide to do that is mentioned in this link.


How to use Realm in SUSI Android to Save Data

Sometimes we need to store information on the device locally so that we can use information offline and also query data faster. Initially, SQLite was only option to store information on the device. But working with SQLite is difficult sometimes and also it makes code difficult to understand. Also, SQL queries take a long time. But now we have realm a better alternative of SQLite. The Realm is a lightweight mobile database and better substitute of SQLite. The Realm has own C++ core and store data in a universal, table-based format by a C++ core. This allows Realm to allow data access from multiple languages as well as a range of queries. In this blog post, I will show you why we used Realm and how we save data in SUSI Android using Realm.

“How about performance? Well, we’re glad you asked 🙂 For all the API goodness & development productivity we give you, we’re still up to 100x faster than some SQLite ORMs and on average ~10x faster than raw SQLite and common ORMs for typical operations.” (compare:

Advantages of Realm over SQLite are following:

  • It is faster than SQLite as explained on the Realm blog. One of the reasons realm is faster than SQLite is, the traditional SQLite + ORM abstraction is leaky because ORM simply converts  Objects and their methods into SQL statements. Realm, on the other hand, is an object database, meaning your objects directly reflect your database.
  • It is easier to use as it uses objects for storing data. When we use SQLite we need boilerplate code to convert values to and from the database, setting up mappings between classes and tables, fields and columns, foreign keys, etc. Whereas in Realm data is directly exposed as objects and can be queried without any conversion.


To include this library in your project you need

  • Android studio version 1.5.1 or higher.
  • JDK version 7.0 or higher.
  • Android API level 9 or higher.

How to use realm in Android

To use Realm in your project we must add the dependency of the library in build.gradle(project) file 

 dependencies {
       classpath “io.realm:realm-gradle-plugin:3.3.1”

and build.gradle(module) file.

apply plugin: realm-android
dependencies {
compile io.realm:android-adapters:1.3.0

Now you have to instantiate Realm in your application class. Setting a default configuration in your Application class, will ensure that it is available in the rest of your code.

RealmConfiguration realmConfiguration = new RealmConfiguration.Builder(this)

Now we need to create a model class. A model class is use to save data in Realm and retrieve saved data and it must extend RealmObject class. For eg.

public class Person extends RealmObject {
   private String name;
   public String getName() {
       return name;
   public void setName(String name) { = name;

Field in the model class uses to define columns. For eg. ‘name’ is a column name. Method like setName() use to save data  and getName() use to retrieve saved data.

Now create an instance of the Realm in the activity where you want to use it. It will be used to read data from the Realm and write data to the Realm.

Realm realm = Realm.getInstance(this);

Before you start a new transaction you must call beginTransaction(). It will open database.


To write data to the Realm you need to create an instance of the model class. createObject used to create an instance of RealmObject class. Our model class is RealmObject type so we use createObject() to create an instance of the model class.

Person person = realm.createObject(Person.class);

Write data to realm.


And after it you must call commitTransaction(). commitTransaction() use to end transaction.


Reading data from Realm is easier than writing data to it. You need to create an instance of the Realm.

Realm realm = Realm.getInstance(this);

To create query use where the method and pass the class of object you want to query. After creating query you can fetch all data using findAll() method.



Showing only Logged-in Accounts in the Sharing Page of Phimpme Android

In Phimpme Android application, users can edit their pictures and share them to a number of platforms ranging from social networking sites like Facebook, Twitter etc to cloud storage and image hosting sites like Box, Dropbox, Imgur etc.

Desired flow of the application

According to the flow of the application, the user has to add an account first i.e. log in to the particular account that needs to be connected to the application. After that when the user enters the share page for sharing the image, a button corresponding to the connected account is visible in that page which on clicking will share the image to that platform directly.

What was happening previously?

The list of accounts which is present in the account manager of Phimpme Android application is also getting displayed in the share image page. As the list is large, it is difficult for the user to find the connected account from the list. There is not even an indicator whether a particular account is connected or not. On clicking the button corresponding to the non-connected account, an error dialog instructing the user to log in from the account manager first, will get displayed.

How we solved it?

We first thought of just adding an indicator on the buttons in the accounts page to show whether it is connected or not. But this fix solves only a single issue. Find the connected account in that large list will be difficult for the user even then. So we decided to remove the whole list and show only the accounts which are connected previously in account manager. This cleans the flow of the accounts and share in  Phimpme Android application

When a user logins from the account manager, the credentials, tokens and other details corresponding to that accounts gets saved in database. We used realm database for saving the details in our application. As the details are present in this database, the list can be dynamically generated when the user opens share image page. We implemented a function in Utils class for getting the list of logged in accounts. Its implementation is shown below.

public static boolean checkAlreadyExist(AccountDatabase.AccountName s) {

   Realm realm = Realm.getDefaultInstance();

   RealmQuery<AccountDatabase> query = realm.where(AccountDatabase.class);

   query.equalTo("name", s.toString());

   RealmResults<AccountDatabase> result1 = query.findAll();

   return (result1.size() > 0);


public static ArrayList<AccountDatabase.AccountName> getLoggedInAccountsList(){

   ArrayList<AccountDatabase.AccountName> list = new ArrayList<>();

   for (AccountDatabase.AccountName account : AccountDatabase.AccountName.values()){

       if (checkAlreadyExist(account))



   return list;


Additional changes

There are few accounts which don’t need authentication. Those accounts need their respective application to be installed in the user’s device. So for adding those accounts to the list, we added another function which checks whether a particular package is installed in user’s device or not. Using that it adds the account to the list. The implementation for checking whether a package is installed or not is shown below.

public static boolean isAppInstalled(String packageName, PackageManager pm) {

   boolean installed;

   try {

       pm.getPackageInfo(packageName, PackageManager.GET_ACTIVITIES);

       installed = true;

   } catch (PackageManager.NameNotFoundException e) {

       installed = false;


   return installed;




Animations in Loklak Wok Android

Imagine an Activity popping out of nowhere suddenly in front of the user. And even more irritating, the user doesn’t even know whether a button was clicked. Though these are very small animation implementations but these animations enhance the user experience to a new level. This blog deals with the animations in Loklak Wok Android, a peer message harvester of Loklak Server.

Activity transition animation

Activity transition is applied when we move from a current activity to a new activity or just go back to an old activity by pressing back button.

In Loklak Wok Android, when user navigates for search suggestions from TweetHarvestingActivity to SuggestActivity, the new activity i.e. SuggestActivity comes from right side of the screen and the old one i.e. TweetHarvestingActivity leaves the screen through the left side. This is an example of left-right activity transition. For implementing this, two xml files which define the animations are created, enter.xml and exit.xml are created.




NOTE: The entering activity comes from right side, that’s why android:fromXDelta parameter is set to 100% and as the activity finally stays at extreme left, android:toXDelta parameter is set to 0%.

As the current activity, in this case TweetHarvestingActivity, leaves the screen from left to the negative of left. So, in exit.xml the android:fromXDelta parameter is set to 0% and android:toXDelta parameter is set to -100%.

Now, that we are done with defining the animations in xml, it’s time we apply the animations, which is really easy. The animations are applied by invoking Activity.overridePendingTransition(enterAnim, exitAnim) just after the startActivity method. For example, in openSuggestActivity

private void openSuggestActivity() {
   Intent intent = new Intent(getActivity(), SuggestActivity.class);
   getActivity().overridePendingTransition(R.anim.enter, R.anim.exit);


Touch Selectors

Using touch selectors background color of a button or any clickable can be changed, this way a user can see that the clickable responded to the click. The background is usually light accent color or a lighter shade of the icon present in button.

There are three states involved while a clickable is touched, pressed, activated and selected. And a default state, i.e. the clickable is not clicked. The background color of each state is defined in a xml file like media_button_selector, which is present in drawable directory.

<selector xmlns:android="">

   <item android:drawable="@color/media_button_touch_selector_backgroud" android:state_pressed="true"/>
   <item android:drawable="@color/media_button_touch_selector_backgroud" android:state_activated="true"/>
   <item android:drawable="@color/media_button_touch_selector_backgroud" android:state_selected="true"/>

   <item android:drawable="@android:color/transparent"/>


The selector is applied by setting it as the background of a clickable, for example, touch selector applied on Location image button present in fragment_tweet_posting.xml .

   android:background="@drawable/media_button_selector" />


Notice the change in the background color of the buttons when clicked.


Some youtube videos for getting started:

Automatic Signing and Publishing of Android Apps from Travis

As I discussed about preparing the apps in Play Store for automatic deployment and Google App Signing in previous blogs, in this blog, I’ll talk about how to use Travis Ci to automatically sign and publish the apps using fastlane, as well as how to upload sensitive information like signing keys and publishing JSON to the Open Source repository. This method will be used to publish the following Android Apps:

Current Project Structure

The example project I have used to set up the process has the following structure:

It’s a normal Android Project with some .travis.yml and some additional bash scripts in scripts folder. The file is standard app build and repo push file found in FOSSASIA projects. The process used to develop it is documented in previous blogs. First, we’ll see how to upload our keys to the repo after encrypting them.

Encrypting keys using Travis

Travis provides a very nice documentation on encrypting files containing sensitive information, but a crucial information is buried below the page. As you’d normally want to upload two things to the repo – the app signing key, and API JSON file for release manager API of Google Play for Fastlane, you can’t do it separately by using standard file encryption command for travis as it will override the previous encrypted file’s secret. In order to do so, you need to create a tarball of all the files that need to be encrypted and encrypt that tar instead. Along with this, before you need to use the file, you’ll have to decrypt in in the travis build and also uncompress it for use.

So, first install Travis CLI tool and login using travis login (You should have right access to the repo and Travis CI in order to encrypt the files for it)

Then add the signing key and fastlane json in the scripts folder. Let’s assume the names of the files are key.jks and fastlane.json

Then, go to scripts folder and run this command to create a tar of these files:

tar cvf secrets.tar fastlane.json key.jks


secrets.tar will be created in the folder. Now, run this command to encrypt the file

travis encrypt-file secrets.tar


A new file secrets.tar.enc will be created in the folder. Now delete the original files and secrets tar so they do not get added to the repo by mistake. The output log will show the the command for decryption of the file to be added to the .travis.yml file.

Decrypting keys using Travis

But if we add it there, the keys will be decrypted for each commit on each branch. We want it to happen only for master branch as we only require publishing from that branch. So, we’ll create a bash script for the task with following content

set -e


if [ "$TRAVIS_PULL_REQUEST" != "false" -o "$TRAVIS_REPO_SLUG" != "iamareebjamal/android-test-fastlane" -o "$TRAVIS_BRANCH" != "$DEPLOY_BRANCH" ]; then
    echo "We decrypt key only for pushes to the master branch and not PRs. So, skip."
    exit 0

openssl aes-256-cbc -K $encrypted_4dd7_key -iv $encrypted_4dd7_iv -in ./scripts/secrets.tar.enc -out ./scripts/secrets.tar -d
tar xvf ./scripts/secrets.tar -C scripts/


Of course, you’ll have to change the commands and arguments according to your need and repo. Specially, the decryption command keys ID

The script checks if the repo and branch are correct, and the commit is not of a PR, then decrypts the file and extracts them in appropriate directory

Before signing the app, you’ll need to store the keystore password, alias and key password in Travis Environment Variables. Once you have done that, you can proceed to signing the app. I’ll assume the variable names to be $STORE_PASS, $ALIAS and $KEY_PASS respectively

Signing App

Now, come to the part in script where you have the unsigned release app built. Let’s assume its name is app-release-unsigned.apk.Then run this command to sign it

cp app-release-unsigned.apk app-release-unaligned.apk
jarsigner -verbose -tsa -sigalg SHA1withRSA -digestalg SHA1 -keystore ../scripts/key.jks -storepass $STORE_PASS -keypass $KEY_PASS app-release-unaligned.apk $ALIAS


Then run this command to zipalign the app

${ANDROID_HOME}/build-tools/25.0.2/zipalign -v -p 4 app-release-unaligned.apk app-release.apk


Remember that the build tools version should be the same as the one specified in .travis.yml

This will create an apk named app-release.apk

Publishing App

This is the easiest step. First install fastlane using this command

gem install fastlane


Then run this command to publish the app to alpha channel on Play Store

fastlane supply --apk app-release.apk --track alpha --json_key ../scripts/fastlane.json --package_name com.iamareebjamal.fastlane


You can always configure the arguments according to your need. Also notice that you have to provide the package name for Fastlane to know which app to update. This can also be stored as an environment variable.

This is all for this blog, you can read more about travis CLI, fastlane features and signing process in these links below:

Using Universal Image Loader to Display Image on Phimpme Android Application

In Phimpme Android application we needed to load image on the sharing Activity fast so that there won’t be any delay that is visible by a user in the loading of any activity. We used Universal Image Loader to load the image on the sharing Activity to load Image faster.

Getting Universal Image Loader

To get Universal Image Loader in your application go to Gradle(app)-> and then add the following line of code inside dependencies:


compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.4'


Initialising Universal Image Loader and Displaying Image

To display image on using Universal Image Loader we need to convert the image into a URI from a file path:

saveFilePath = getIntent().getStringExtra(EXTRA_OUTPUT);
Uri uri = Uri.fromFile(new File(saveFilePath));

How an image should be displayed

We need to display the image in such a way that it covers the whole image view in the sharing Activity. The image should be zoomed out. The quality of the image should not be distorted or reduced. The image should look as it is. The image should be zoomable so that the user can pinch to zoom in and zoom out. For the image to adjust the whole Image View we set ImageScaleType.EXACTLY_STRETCHED. We will also set cacheInMemory to true and cacheOnDisc to true.  

private void initView() {
   saveFilePath = getIntent().getStringExtra(EXTRA_OUTPUT);
   Uri uri = Uri.fromFile(new File(saveFilePath));
   ImageLoader imageLoader = ((MyApplication)getApplicationContext()).getImageLoader();
   DisplayImageOptions options = new DisplayImageOptions.Builder()
   imageLoader.displayImage(uri.toString(), shareImage, options);

Image Loader function in MyApplication class:

private void initImageLoader() {
   File cacheDir = com.nostra13.universalimageloader.utils.StorageUtils.getCacheDirectory(this);
   int MAXMEMONRY = (int) (Runtime.getRuntime().maxMemory());
   // System.out.println("dsa-->"+MAXMEMONRY+"   "+(MAXMEMONRY/5));//.memoryCache(new
   // LruMemoryCache(50 * 1024 * 1024))
   DisplayImageOptions defaultOptions = new DisplayImageOptions.Builder()

   ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(
           this).memoryCacheExtraOptions(480, 800).defaultDisplayImageOptions(defaultOptions)
           .diskCacheExtraOptions(480, 800, null).threadPoolSize(3)
           .threadPriority(Thread.NORM_PRIORITY - 2)
           .memoryCache(new LruMemoryCache(MAXMEMONRY / 5))
           .diskCache(new UnlimitedDiskCache(cacheDir))
           .diskCacheFileNameGenerator(new HashCodeFileNameGenerator()) // default
           .imageDownloader(new BaseImageDownloader(this)) // default
           .imageDecoder(new BaseImageDecoder(false)) // default

   this.imageLoader = ImageLoader.getInstance();

Image View in Sharing Activity XML file:

In the Sharing Activity Xml resource, we need to specify the width of the image view and the height of the image view. In Phimpme Android application we are using ImageViewTouch so that we have features like touch to zoom in zoom out. The scale type of the imageView is centerCrop so that image which is loaded is zoomed out and focus is in the center of the image.  



To load image faster on any ImageView we should use Universal Image Loader. It helps load the activity faster and allows many features as discussed in the blog.