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.



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.



Implementation of Set Different Language for Query in SUSI Android

SUSI.AI has many skills. Some of which are displaying web search of a certain query, provide a list of relevant information of a topic, displaying a map of the certain position and simple text message of any query. Previously SUSI.AI reply all query in English language but now one important feature is added in SUSI.AI and that feature is, reply query of the user in the language that user wants. But to get the reply in different language user has to send language code of that language along with query to SUSI Server. In this blog post, I will show you how it is implemented in SUSI Android app.

Different language supported in SUSI Android

Currently, different languages added in option in SUSI Android and their language code are:

Language Language Code
English en
German de
Spanish es
French fr
Italian it
Default Default language of the device.

Layout design

I added an option for choosing the different language in settings. When the user clicks on Language option a dialog box pops up. I used listpreference to show the list of different languages.







“title” is used to show the title of setting, “entries” is used to show the list of entry to the user and “entryValue” is the value corresponding to each entry. I used listpreference because it has own UI so we don‘t have to develop our own UI for it and also it stores the string into the SharedPreferences so we don’t need to manage the values in SharedPreference. SharedPreference needed to set value in Language in settings so that once user close app and again open it setting will show same value otherwise it will show default value. We used an array of string to show the list of languages.

<string-array name=“languagentries”>








SetLanguage implementation

To set language user must choose Language option in setting.

On clicking Language option a dialog box pop up with the list of different languages. When the user chooses a language then we save corresponding language code in preference with key “prefLanguage” so that we can use it later to send it to the server along with the query. It also uses to send language to the server to store user language on the server, so that user can use the same language in the different client.

querylanguage.setOnPreferenceChangeListener { _, newValue ->

  PrefManager.putString(Constant.LANGUAGE, newValue.toString())

  if(!settingsPresenter.getAnonymity()) {

      settingsPresenter.sendSetting(Constant.LANGUAGE, newValue.toString(), 1)



newValue.toString() is the value i.e language code of corresponding language.

Now when we query anything from SUSI.AI we send language code along with query to the server. Default language is default language of the device. Before sending language to the server we check language is default language or any specific language.

val language = if (PrefManager.getString(Constant.LANGUAGE, Constant.DEFAULT).equals(Constant.DEFAULT))


else PrefManager.getString(Constant.LANGUAGE, Constant.DEFAULT)

And after that, we send the corresponding language along with query to the server.

clientBuilder.susiApi.getSusiResponse(timezoneOffset, longitude, latitude, source, language, query)


Using Vector Images in SUSI Android

Android designed to run across many devices with different screen sizes and display resolutions. One of the things that confuse many new Android developers is how to support multiple screen sizes. For making  SUSI Android app more user-friendly and interactive we used a lot of images in the form of drawable resources. Most of these drawables are in the form of PNG (Portable Network Graphic) and to support multiple screen size we have to include separate images of varied dimensions because we can’t scale PNG images without losing quality.

Other disadvantages of using PNG images are

  • PNG images take large disk space.
  • PNG images have fixed colour and dimensions which cannot be changed.

To overcome these shortcomings of PNG image we decided to use vector images in SUSI Android.

Advantages of using vector image are

  • It is smaller in size as compared to PNG i.e it takes less disk space than PNG.
  • It can be scaled without losing quality. So we need to include only a single image for all screen size.

Disadvantages of using vector image are

  • Reconstruction of vector data may take considerably longer than that contained in a bitmap file of equivalent complexity because each image element must be drawn individually and in sequence.
  • Vector image can’t be used to display complex photographs.
  • If the object consists of a large number of small elements then file size grow very fast.

Vector produce smaller size file than bitmap only for simple stuff. When it comes to creating a photographic quality vector where colour information is paramount and may vary on a pixel-by-pixel basis, the file can be much larger than its bitmap version, that’s why vector image is only suitable for small images like logo designs, icons etc.

In this blog post, I will show you how we used vector images in SUSI Android.

How to create vector image using Asset Studio tool

Asset Studio is inbuilt Android Studio tool which we use to create a vector image from default material icon or local SVG images. To use vector asset in Android Studio

  • Go to File> New > Vector Asset
  • Vector Asset Studio Tool Window is prompted

  • Create vector image from default material icon or local SVG image.

Asset Studio will add icon in drawable. It can be used anywhere in the project.

Vector images in SUSI Android

In SUSI Android all drawable images like search, mic, arrow, check etc are vector images,  even the logo of the app is a vector image.

This vector image is the result of code you can find here.

Now I will describe some special attributes used here

  • fillColor: It defines the colour of the image. So the colour of your image depends on the colour you provide in fillColor. We used white color(#ffffff) as fillColor that’s why the image is white in colour.
  • strokeColour: It defines the colour of boundary of the image.
  • pathData: Shape of your image depends on pathData. Different commands used in pathData are
  1. M: It is used to define the starting point. For example, M10,10 means starting     Coordinate of the image will be (10,10). M used for absolute position and m   for relative position.
  2. L: L means to draw a line from the current position to given position. For example, M10,10 L20,20 means a straight line will be drawn from coordinate (10,10) to coordinate (20,20. L Use for absolute position and l for relative position.
  3. C: C means to draw an arc. For example, Cx1,x2 x3,x4 x5,x6 means draw a curve  (cubic Bezier curve) from coordinate  (x1,x2) using (x3,x4) as control point at the beginning and (x5,x6) as control point at the end.
  4. Z: Z means to close the path using the straight line between the current position and starting position.


Let’s consider a curve

M9,16.17L4.83,12l-1.42,1.41L9,19 21,7l-1.41,-1.41z

It starts from point (9,16.17). From (9,16.17) to (4.83,12) a straight line will be drawn. Now again a straight will be drawn from point (4.83,12) to the relative point (-1.42,1.41). After that from point (-1.42, 1.41) it will draw a polyline like an upward arrow(^) with the end point at (21,7). Again it will draw a straight line between point (21,7) and relative point (-1.41, -1.41). At the last z will close curve using the straight line between current point and starting point).




Shift from Java to Kotlin in SUSI Android

Previously SUSI Android was written in JAVA. But recently Google announced that it will officially support Kotlin on Android as a first class language so we decided to shift from Java to Kotlin. Kotlin runs on Java Virtual Machine and hence we can use Kotlin for Android app development. Kotlin is new programming language developed by JetBrains, which also developed IntelliJ-the IDE that Android Studio is based on. So Android Studio has excellent support for Kotlin.

Advantages of Kotlin over Java

  • Kotlin is a null safe language. It changes all the instances used in the code to non nullable type thus it ensures that the developers don’t get any nullPointerException.
  • Good Android Studio support. Kotlin tool is included with Android Studio 3.0 by default. But for Android Studio 2.x we need to install the required plugin for Kotlin.
  • Kotlin also provides support for Lambda function and other high order functions.
  • One of Kotlin’s greatest strengths as a potential alternative to Java is interoperability between Java and Kotlin. You can even have Java and Kotlin code existing side by side in the same project.
  • Kotlin provides the way to declare Extension function similar to that of C# and Gosu. We can use this function in the same way as we use the member functions of our class.

After seeing the above points it is now clear that Kotlin is much more effective than Java. In this blog post, I will show you how ForgotPasswordActivity is shifted from JAVA to Kotlin in SUSI Android.

How to install Kotlin plugin in Android Studio 2.x

We are using Android Studio 2.3.0 in our android project. To use Kotlin in Android Studio 2.x we need to install Kotlin plugin.

Steps to include Kotlin plugin in Android Studio 2.x are:

  • Go to File
  • After that select Settings
  • Then select Plugin Option from the left sidebar.
  • After that click on Browse repositories.
  • Search for Kotlin and install it.

Once it is installed successfully, restart Android Studio. Now configure Kotlin in Android Studio.

Shift  SUSI Android from JAVA to Kotlin

Kotlin is compatible with JAVA. Thus it allows us to change the code bit by bit instead of all at once. In SUSI Android app we implemented MVP architecture with Kotlin. We converted the code by one activity each time from JAVA to Kotlin. I converted the ForgotPassword of SUSI Android from JAVA to Kotlin with MVP architecture. I will discuss only shifting of SUSI Android from JAVA to Kotlin and not about MVP architecture implementation.

First thing is how to extend parent class. In JAVA we need to use extend keyword

public class ForgotPasswordActivity extends AppCompatActivity

but in Kotlin parent class is extended like

class ForgotPasswordActivity : AppCompatActivity ()

Second is no need to bind view in Kotlin. In JAVA we bind view using Butter Knife.


protected TextInputLayout email;



but in Kotlin we can directly use view using id.

forgot_email.error = getString(R.string.email_invalid_title)

Another important thing is that instead of using setError and getError we can use only error for both purposes.


It can be used to get error in TextInputLayout ‘forgot_email’ and

forgot_email.error = getString(R.string.email_invalid_title)

can be use to set error in TextInputLayout ‘forgot_email’.

Third one is in Kotlin we don’t need to define variable type always

val notSuccessAlertboxHelper = AlertboxHelper(this@ForgotPasswordActivity, title, message, null, null, button, null, color)

but in JAVA we need to define it always.

AlertboxHelper notSuccessAlertboxHelper = new AlertboxHelper(ForgotPasswordActivity.this, title, message, null, null, positiveButtonText, null, colour);

And one of the most important feature of Kotlin null safety. So you don’t need to worry about NullPointerException. In java we need to check for null otherwise our app crash

if (url.getEditText() == null)

      throw new IllegalArgumentException(“No Edittext hosted!”);

But in Kotlin there is no need to check for null. You need to use ’?’ and Kotlin will handle it itself.  


You can find the previous ForgotPasswordActivity here. You can compare it with new ForgotPaswordActivity.


Full-Screen Speech Input Implementation in SUSI Android App

SUSI Android has some very good features and one of them is, it can take input in speech format from user i.e if the user says anything then it can detect it and convert it to text. This feature is implemented in SUSI Android app using Android’s built-in speech-to-text functionality. You can implement Android’s built-in speech-to-text functionality using either only RecognizerIntent class or SpeechRecognizerIntent class, RecognitionListner interface and RecognizerIntent class. Using former method has some disadvantages:

  • During speech input, it shows a dialog box (as shown here) and it breaks the connection between user and app.
  • We can’t show partial result i.e text to the user but using the later method we can show it.

We used  SpeechRecognizerIntent class, RecognitionListner interface and RecognizerIntent class to implement Android’s built-in speech-to-text functionality in SUSI Android and you know the reason for that. In this blog post, I will show you how I implemented this feature in SUSI Android with new UI.

Layout design

You can give speech input to SUSI Android either by clicking mic button

or using ‘Hi SUSI’ hotword. When you click on mic button or use ‘Hi SUSI’ hotword, you can see a screen where you will give speech input.

Two important part of this layout are:







  • TextView: It used to show the partial result of speech input i.e it will show converted text (partial) of your speech.






  • SpeechProgressView: It is a custom view which use to show the animation when the user gives speech input. When the user starts speaking, the animation starts. This custom view contains five bars and these five bars animate according to user input.

Full-screen speech input implementation

When the user clicks on mic button or uses ‘Hi SUSI’ hotword, a screen comes where the user can give speech input. As already mentioned I used SpeechRecognizerIntent class, RecognitionListner interface and RecognizerIntent class to implement speech-to-text functionality in SUSI Android. RecognizerIntent class starts an intent and asks for speech input

val intent = Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH)



intent.putExtra(RecognizerIntent.EXTRA_CALLING_PACKAGE, “”)

intent.putExtra(RecognizerIntent.EXTRA_PARTIAL_RESULTS, true)

and send it through the speech recognizer. It does it through ACTION_RECOGNIZE_SPEECH. SpeechRecognizer class provides access to the speech recognition service. This service allows access to the speech recognizer and recognition related event occurs RecognitionListner receive notification from SpeechRecognizer class.

recognizer = SpeechRecognizer


val listener = object : RecognitionListener {

 //implement all override methods


When the user starts speaking, the height of bars changes according to change in sound level. When sound level changes, onRmsChanged method get called where we are calling onRmsChanged method of SpeechProgressView class which is responsible for animating bars according to change in sound level.

override fun onRmsChanged(rmsdB: Float) {

  if (speechprogress != null)



When user finished speaking onEndOfSpeech method get called where we call onEndOfSpeech method of SpeechProgressView class which is responsible for rotating animation. Rotation is used to show that SUSI Android has finished listening and now it is processing your input.

override fun onEndOfSpeech() {

  if (speechprogress != null)



In case of any error, onError method get called and in case of successful speech input, onResults method get called. In both cases, we reset bars to their initial position and show chat activity user. The user can again give speech input either by clicking on mic or using ‘Hi SUSI’ hotword.

override fun onResults(results: Bundle) {

  if (speechprogress != null)





How to Parse HTML Tags and Anchor Clickable Links in SUSI Android App

Html tags are used to define how contents of a webpage should be formatted and displayed. Sometimes the SUSI answer type response contains some html tags but showing these html tags without parsing would distort the normal text flow in SUSI Android.

For the query ‘Ask me something’ SUSI’s reply is

“data”: [
      “question”: “Which soccer team won the Copa Am&eacute;rica 2015 Championship ? “,                                          

In SUSI Android this message looks like

As you can see that showing html tags without parsing distort the normal text flow. So we need to parse html tags properly. We use Html class for this purpose. Html class is present in android.text package and you can import it in the class where you want to use it.

import android.text.Html

fromHtml method of Html class is used to parse html tags. But for API level less than 24 and equal to or greater than 24 we use different parameters in fromHtml method.

For API level less than 24 we used


But for API level equal to or greater than 24 we have to use

Html.fromHtml(model.getContent(), Html.FROM_HTML_MODE_COMPACT)

Here the second parameter is legacy flags which decides how text inside a tag will be shown after parsing.

In case of Html.fromHtml(String string) legacy flag is by default FROM_HTML_MODE_LEGACY. It indicates that separate block-level elements with blank lines.

So after parsing html tags using fromHtml

But return type of fromHtml method is Spanned so if you need String then you have to convert it into string using toString() method.

Anchor action type in susi response contains link and text.

       “link”: “”,
       “text”: “Link to Openstreetmap: Singapore”

Here the text is the text we show in textview and link is used to show web content in the browser when user click on text. So first link and text are attached together like

“<a href=\”” +susiResponse.getAnswers().get(0).getActions().get(i).getAnchorLink() + “\”>”
+ susiResponse.getAnswers().get(0).getActions().get(1).getAnchorText() + “</a>”

Here text between the tag is description of link and after parsing we show this text in textview. It can be parsed using fromHtml method of Html class and textview is made clickable by



Reset Password Option in SUSI Android App

Login and signup are an important feature for some android apps like chat apps because the user will want to save and secure personal messages from others. In SUSI Android app we provide a token to a logged-in user for a limit period of time so that once the user logs in and someone else gets access to the device, then he/she can’t use the user account for a long period of time. It is a security provided from our side but the user also has to maintain some security. Cyber security risks have increased and hacking technologies have improved a lot in the past 10 years. So, using the same password for a long period of time absolutely puts your account security at risk. So to keep your account secure you should change/reset your password regularly. In this blog post, I will show you how reset password option is implemented in SUSI Android app.

Layout design for reset password

Reset password option is added in the setting. When the user clicks on reset password option a dialog box pops up. There are three textinputlayout boxes – each for the current password, new password and confirm password. I have used textinputlayout instead of simple edittext box because it helps user to show first “hint” and when user taps on, hint will come up with text over it as floating label so that the user can understand what to add in that box and also in case of error we can show that error to user.

Reset Password implementation

On clicking reset password option a dialog box appears in which user inserts the current password, new password and confirm password to confirm the new password. Before sending new password to the server we perform two checks

  1. New password should not be empty and length of new password should be at least six.
  2. New password and confirm password must be same.
if (!CredentialHelper.isPasswordValid(newPassword)) {




if (newPassword != conPassword) {

settingView?.invalidCredentials(false, Constant.NEW_PASSWORD)



And when these two checks are passed we send “new password” to server.

Endpoint use to reset password is mail id&password=current password&newpassword=newpassword

As you can see it needed three parameters

  • changepassword: Your email id
  • password : Your current password
  • newpassword: Your new password

When user logs in, we save user’s email id so that the user doesn’t have to provide it again and again when the user wants to change the password.


The user provides current password and new password through dialog box. We used resetPassword method to reset the password. We send these three parameters to the server using resetPassword method and if the password changed successfully then server sends a message.

override fun resetPassword(password: String, newPassword: String, listener: ISettingModel.onSettingFinishListener) {

  val email = PrefManager.getString(Constant.SAVE_EMAIL, null)

  resetPasswordResponseCall = ClientBuilder().susiApi


  resetPasswordResponseCall.enqueue(object : Callback<ResetPasswordResponse> {

  } )


We used retrofit library for network call and resetPasswordResponse is a model class using which we are retrieving server response.


Updating Settings Activity With MVP Architecture in SUSI Android

SUSI Android app includes settings that allow users to modify app features and behaviours. For example, SUSI Android allows users to specify whether they want voice output i.e text to speech irrespective of input type.

Currently different settings available in SUSI Android are:

Settings                                          Use
Enter As Send It allows users to specify whether they want to use action button of soft keyboard as carriage return or send message
Mic Input It allows users to specify whether they want to use speech for input type or not. User can also use keyboard to provide input.
Speech Always It allows users to specify whether they want speech output i.e text to speech irrespective of input type
Speech Output It allows users to specify whether they want speech output in case of speech input or not.
Select Server It allows user to specify whether they want to use default susi_server or their own server.
Language It allows users to select text to speech engine language.

Android’s standard architecture isn’t always sufficient, especially in the case of complex applications that need to be tested regularly. So we need an architecture that can improve the app’s testability and MVP(Model View Presenter) architecture is one of the best options for that.

Working with MVP architecture to show settings

MVP architecture creates three layers: Model, View and Presenter. Use of each layer is described below

  • Model: The Model holds the business logic of the application. It controls how data can be created, stored, and modified.
  • View: The View is a UI that displays data and routes user actions to the Presenter.
  • Presenter: Presenter is a mediator between View and Model. It retrieves data from the Model and shows it in the View. It also processes user actions forwarded to it by the View.

Steps followed to implement MVP architecture are:

1. I first created three interfaces: ISettingsView, ISettingModel and  ISettingsPresenter. These classes contain all the important functions we needed in model, presenter and view. Presenter’s interaction with model is handled by  ISettingModel and presenter’s interaction with view is handled by ISettingsPresenter and ISettingView.

  1. I created model, view and presenter class i.e SettingModel, SettingsPresenter and SettingsActivity and implemented ISettingModel, ISettingsPresenter and ISettingsView in SettingModel, SettingPresenter and SettingsActivity respectively so that presenter can communicate with both model and view.
class SettingsPresenter(fragmentActivity: FragmentActivity): ISettingsPresenter, ISettingModel.onSettingFinishListener
class SettingsActivity : AppCompatActivity(), ISettingsView
class SettingModel: ISettingModel
  1. After that, I created ChatSettingsFragment class. It is a PreferenceFragment class which resides in SettingsActivity and contains all settings.
class ChatSettingsFragment : PreferenceFragmentCompat() 

How Presenter communicates with Model and View

As already mentioned presenter’s interaction with view is handled by ISettingsView and ISettingsPresenter. So first I created object of ISettingsPresenter in ChatSettingsFragment, which is part of view, as shown below

lateinit var settingsPresenter: ISettingsPresenter
settingsPresenter = SettingsPresenter(activity)

And used it to call method of presenter, SettingsPresenter

settingsPresenter.sendSetting(Constant.ENTER_SEND, newValue.toString())

After that, I created an object of ISettingsView in SettingsPresenter, so that it can communicate with view, SettingsActivity.

Presenter’s interaction with model is handled by ISettingModel. So first I created an object of SettingModel class which implemented ISettingModel and then used it to call methods of SettingModel.

var settingModel: SettingModel = SettingModel()
settingModel.sendSetting(key, value, this)

Here the third parameter in the sendSetting method is ISettingModel.onSettingFinishListener which is part of ISettingModel. SettingModel used it to communicate with SettingsPresenter as shown below

override fun sendSetting(key: String, value: String, listener: ISettingModel.onSettingFinishListener) {

settingResponseCall.enqueue(object : Callback<ChangeSettingResponse> {

 override fun onResponse(call: Call<ChangeSettingResponse>?, response:

Response<ChangeSettingResponse>) {





onSuccess method present in SettingsPresenter.