Christa Stehr

Christa Stehr

1593330480

How to Test Android Activities

When I started developing Android apps, I didn’t write any tests. Of course not — I was just mucking about, making things for my own enjoyment. Then, I decided to be a professional. I started small, with the simplest possible app, and the simplest possible test, and was immediately stumped. For anyone in the same boat, this article is for you!

Say you have an activity with a button. When you press the button, you want to open a different activity.

Your source code might look something like this:

class ExampleActivity : AppCompatActivity() {
	    fun openOtherActivity() {
	        val intent = Intent(this, OtherActivity::class.java)
	        startActivity(intent)
	   }
	}

Somewhere, in a layout file, you set the onClickof a button to openOtherActivity. But let’s just focus on the Kotlin code. No need to aim too high, right?

Then (or preferably beforehand, if you are diligently applying TDD) you try to write a test. To start with, you might not even check that it behaves as you expect. The simplest possible test is just “When you call the function, nothing explodes.”

It might look something like this:

class ExampleActivityTest {
	    @Test
	    fun breaks() {
	        val exampleActivity = ExampleActivity()
	        exampleActivity.openOtherActivity()
	    }
	}

Even this very simple test, however, results in an error:

java.lang.RuntimeException: Method startActivity in android.app.Activity not mocked.

This is because in test environments, Android-specific stuff doesn’t exist. This was a deliberate design choice by Android, and it has its pros and cons. One outcome of this decision for unit testing is that we have to mock Android-specific components.

One mocking library for Kotlin is MockK, which I will use for this example. Any other similar mocking library should do the trick.

So, back to our test. We can mock the startActivity method (and keep everything else as the real thing) using spykfrom MockK:

class ExampleActivityTest {
	    @Test
	    fun does_not_break() {
	        val exampleActivity = spyk(ExampleActivity())
	        every { exampleActivity.startActivity(any()) } returns Unit
	        exampleActivity.openOtherActivity()
	    }
	}

And now the test passes!

From there, we could extend the test to more thoroughly check the actual behaviour of the function. For example, whether it calls startActivitywith the right kind of intent.

For the next example, suppose we want to add some extras to the intent before opening the activity:

class ExampleActivity : AppCompatActivity() {
	    fun openOtherActivityWithExtras() {
	        val intent = Intent(this, OtherActivity::class.java)
	        intent.putExtra("name", "value")
	        startActivity(intent)
	    }
	}

We try running a similar simple test, just checking that nothing explodes:

class ExampleActivityTest {
	    @Test
	    fun breaks_again() {
	        val exampleActivity = spyk(ExampleActivity())
	        every { exampleActivity.startActivity(any()) } returns Unit
	        exampleActivity.openOtherActivityWithExtras()
	    }
	}

We’ve used the same mocking trick as last time, but now we get another error:

java.lang.RuntimeException: Method putExtra in android.content.Intent not mocked.

#andoid #dependency-injection #kotlin #programming #mobile #app

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How to Test Android Activities
Autumn Blick

Autumn Blick

1593867420

Top Android Projects with Source Code

Android Projects with Source Code – Your entry pass into the world of Android

Hello Everyone, welcome to this article, which is going to be really important to all those who’re in dilemma for their projects and the project submissions. This article is also going to help you if you’re an enthusiast looking forward to explore and enhance your Android skills. The reason is that we’re here to provide you the best ideas of Android Project with source code that you can choose as per your choice.

These project ideas are simple suggestions to help you deal with the difficulty of choosing the correct projects. In this article, we’ll see the project ideas from beginners level and later we’ll move on to intermediate to advance.

top android projects with source code

Android Projects with Source Code

Before working on real-time projects, it is recommended to create a sample hello world project in android studio and get a flavor of project creation as well as execution: Create your first android project

Android Projects for beginners

1. Calculator

build a simple calculator app in android studio source code

Android Project: A calculator will be an easy application if you have just learned Android and coding for Java. This Application will simply take the input values and the operation to be performed from the users. After taking the input it’ll return the results to them on the screen. This is a really easy application and doesn’t need use of any particular package.

To make a calculator you’d need Android IDE, Kotlin/Java for coding, and for layout of your application, you’d need XML or JSON. For this, coding would be the same as that in any language, but in the form of an application. Not to forget creating a calculator initially will increase your logical thinking.

Once the user installs the calculator, they’re ready to use it even without the internet. They’ll enter the values, and the application will show them the value after performing the given operations on the entered operands.

Source Code: Simple Calculator Project

2. A Reminder App

Android Project: This is a good project for beginners. A Reminder App can help you set reminders for different events that you have throughout the day. It’ll help you stay updated with all your tasks for the day. It can be useful for all those who are not so good at organizing their plans and forget easily. This would be a simple application just whose task would be just to remind you of something at a particular time.

To make a Reminder App you need to code in Kotlin/Java and design the layout using XML or JSON. For the functionality of the app, you’d need to make use of AlarmManager Class and Notifications in Android.

In this, the user would be able to set reminders and time in the application. Users can schedule reminders that would remind them to drink water again and again throughout the day. Or to remind them of their medications.

3. Quiz Application

Android Project: Another beginner’s level project Idea can be a Quiz Application in android. Here you can provide the users with Quiz on various general knowledge topics. These practices will ensure that you’re able to set the layouts properly and slowly increase your pace of learning the Android application development. In this you’ll learn to use various Layout components at the same time understanding them better.

To make a quiz application you’ll need to code in Java and set layouts using xml or java whichever you prefer. You can also use JSON for the layouts whichever preferable.

In the app, questions would be asked and answers would be shown as multiple choices. The user selects the answer and gets shown on the screen if the answers are correct. In the end the final marks would be shown to the users.

4. Simple Tic-Tac-Toe

android project tic tac toe game app

Android Project: Tic-Tac-Toe is a nice game, I guess most of you all are well aware of it. This will be a game for two players. In this android game, users would be putting X and O in the given 9 parts of a box one by one. The first player to arrange X or O in an adjacent line of three wins.

To build this game, you’d need Java and XML for Android Studio. And simply apply the logic on that. This game will have a set of three matches. So, it’ll also have a scoreboard. This scoreboard will show the final result at the end of one complete set.

Upon entering the game they’ll enter their names. And that’s when the game begins. They’ll touch one of the empty boxes present there and get their turn one by one. At the end of the game, there would be a winner declared.

Source Code: Tic Tac Toe Game Project

5. Stopwatch

Android Project: A stopwatch is another simple android project idea that will work the same as a normal handheld timepiece that measures the time elapsed between its activation and deactivation. This application will have three buttons that are: start, stop, and hold.

This application would need to use Java and XML. For this application, we need to set the timer properly as it is initially set to milliseconds, and that should be converted to minutes and then hours properly. The users can use this application and all they’d need to do is, start the stopwatch and then stop it when they are done. They can also pause the timer and continue it again when they like.

6. To Do App

Android Project: This is another very simple project idea for you as a beginner. This application as the name suggests will be a To-Do list holding app. It’ll store the users schedules and their upcoming meetings or events. In this application, users will be enabled to write their important notes as well. To make it safe, provide a login page before the user can access it.

So, this app will have a login page, sign-up page, logout system, and the area to write their tasks, events, or important notes. You can build it in android studio using Java and XML at ease. Using XML you can build the user interface as user-friendly as you can. And to store the users’ data, you can use SQLite enabling the users to even delete the data permanently.

Now for users, they will sign up and get access to the write section. Here the users can note down the things and store them permanently. Users can also alter the data or delete them. Finally, they can logout and also, login again and again whenever they like.

7. Roman to decimal converter

Android Project: This app is aimed at the conversion of Roman numbers to their significant decimal number. It’ll help to check the meaning of the roman numbers. Moreover, it will be easy to develop and will help you get your hands on coding and Android.

You need to use Android Studio, Java for coding and XML for interface. The application will take input from the users and convert them to decimal. Once it converts the Roman no. into decimal, it will show the results on the screen.

The users are supposed to just enter the Roman Number and they’ll get the decimal values on the screen. This can be a good android project for final year students.

8. Virtual Dice Roller

Android Project: Well, coming to this part that is Virtual Dice or a random no. generator. It is another simple but interesting app for computer science students. The only task that it would need to do would be to generate a number randomly. This can help people who’re often confused between two or more things.

Using a simple random number generator you can actually create something as good as this. All you’d need to do is get you hands-on OnClick listeners. And a good layout would be cherry on the cake.

The user’s task would be to set the range of the numbers and then click on the roll button. And the app will show them a randomly generated number. Isn’t it interesting ? Try soon!

9. A Scientific Calculator App

Android Project: This application is very important for you as a beginner as it will let you use your logical thinking and improve your programming skills. This is a scientific calculator that will help the users to do various calculations at ease.

To make this application you’d need to use Android Studio. Here you’d need to use arithmetic logics for the calculations. The user would need to give input to the application that will be in terms of numbers. After that, the user will give the operator as an input. Then the Application will calculate and generate the result on the user screen.

10. SMS App

Android Project: An SMS app is another easy but effective idea. It will let you send the SMS to various no. just in the same way as you use the default messaging application in your phone. This project will help you with better understanding of SMSManager in Android.

For this application, you would need to implement Java class SMSManager in Android. For the Layout you can use XML or JSON. Implementing SMSManager into the app is an easy task, so you would love this.

The user would be provided with the facility to text to whichever number they wish also, they’d be able to choose the numbers from the contact list. Another thing would be the Textbox, where they’ll enter their message. Once the message is entered they can happily click on the send button.

#android tutorials #android application final year project #android mini projects #android project for beginners #android project ideas #android project ideas for beginners #android projects #android projects for students #android projects with source code #android topics list #intermediate android projects #real-time android projects

Chaz Homenick

Chaz Homenick

1596459153

Building Dark Mode Theme in Android

Hello World, today we are going to see how we can implement a dark theme or night mode in our android application. This tutorial is going to be very simple and easy to understand. The dark theme is attractive to users and it is comfortable for low light conditions.

Recently many apps adapt dark mode in their app and the output of the night mode is amazing as many users love dark mode for their app. An example of a dark theme is Whatsapp dark mode in android see the below image.

Let’s look at how our app will look like, see the below gif for our end result app.

Let’s see how we can implement dark theme in our app.

Make layout for dark theme

First, we need to make our layout so that we can apply our dark theme to it.

If you see the above gif we used cardview to make our layout.

See the below code for layout.

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:padding="10sp"
    >

    <androidx.cardview.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:cardCornerRadius="10sp"
        android:id="@+id/post"
        >
        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="10sp"
            >
            <androidx.cardview.widget.CardView
                android:layout_width="70sp"
                android:layout_height="70sp"
                android:id="@+id/profilePicContainer"
                app:cardCornerRadius="100sp"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintTop_toTopOf="parent"
                >
                <ImageView
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"

                    android:src="@drawable/user1"
                    />
            </androidx.cardview.widget.CardView>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/username"
                android:text="John Doe"
                android:textAppearance="@style/TextAppearance.AppCompat.Large"
                app:layout_constraintLeft_toRightOf="@id/profilePicContainer"
                android:layout_marginStart="10sp"
                app:layout_constraintTop_toTopOf="@id/profilePicContainer"
                />
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/time"
                android:text="Just now"
                android:textAppearance="@style/TextAppearance.AppCompat.Caption"
                app:layout_constraintLeft_toRightOf="@id/profilePicContainer"
                android:layout_marginStart="10sp"
                app:layout_constraintTop_toBottomOf="@id/username"
                />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="35sp"
                android:id="@+id/caption"
                android:text="Lorem Ipsum is simply dummy text of the printing and typesetting industry."
                app:layout_constraintTop_toBottomOf="@id/profilePicContainer"
                android:textAppearance="@style/TextAppearance.AppCompat.Body2"
                android:layout_marginTop="10sp"
                />

            <ImageView
                android:layout_width="match_parent"
                android:layout_height="250sp"
                android:id="@+id/photoPost"
                android:scaleType="centerCrop"
                app:layout_constraintTop_toBottomOf="@id/caption"
                android:src="@drawable/post"
                android:layout_marginTop="10sp"
                />

            <ImageView
                android:layout_width="30sp"
                android:layout_height="30sp"
                android:id="@+id/likeBtn"
                android:src="@drawable/ic_like"
                app:layout_constraintLeft_toLeftOf="@id/photoPost"
                app:layout_constraintTop_toBottomOf="@id/photoPost"
                android:layout_marginTop="15sp"
                />

            <ImageView
                android:layout_width="30sp"
                android:layout_height="30sp"
                android:id="@+id/shareBtn"
                android:src="@drawable/ic_share"
                app:layout_constraintLeft_toRightOf="@id/likeBtn"
                app:layout_constraintTop_toBottomOf="@id/photoPost"
                app:layout_constraintTop_toTopOf="@id/likeBtn"
                android:layout_marginLeft="15sp"
                />

        </androidx.constraintlayout.widget.ConstraintLayout>
    </androidx.cardview.widget.CardView>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/changeThemeBtn"
        android:text="Change Theme"
        app:layout_constraintTop_toBottomOf="@id/post"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        android:layout_marginTop="20sp"
        android:paddingHorizontal="10sp"

        />

</androidx.constraintlayout.widget.ConstraintLayout>

#android-app-development #android-development #android-studio #android #android-tutorial #android-dark-mode #android-mobile-app #mobile

Alayna Rippin

Alayna Rippin

1597708800

How to Write Good Tests - Android Testing - Part 2

In this important video you will learn what makes a test case a good test case and which factors we need to consider when testing our code. I also cover the main principles of test driven development.

00:00 - Test Driven Development
03:12 - What makes a good test?
05:04 - How many test cases should you write?

#testing #good tests #android testing #android

Marielle Rippin

Marielle Rippin

1595098800

Top 130 Android Interview Questions - Crack Technical Interview Now!

Android Interview Questions and Answers from Beginner to Advanced level

DataFlair is committed to provide you all the resources to make you an android professional. We started with android tutorials along with practicals, then we published Real-time android projects along with source code. Now, we come up with frequently asked android interview questions, which will help you in showing expertise in your next interview.

android interview questions

Android Interview Questions – Get ready for your next interview

Android – one of the hottest technologies, which is having a bright future. Get ready to crack your next interview with the following android interview questions. These interview questions start with basic and cover deep concepts along with advanced topics.

Android Interview Questions for Freshers

1. What is Android?

Android is an open-source mobile operating system that is based on the modified versions of Linux kernel. Though it was mainly designed for smartphones, now it is being used for Tablets, Televisions, Smartwatches, and other Android wearables.

2. Who is the inventor of Android Technology?

The inventors of Android Technology are- Andry Rubin, Nick Sears, and Rich Miner.

3. What is the latest version of Android?

The latest version of Android is Android 10.0, known as Android Q. The upcoming major Android release is Android 11, which is the 18th version of Android. [Note: Keep checking the versions, it is as of June 2020.]

4. How many Android versions can you recall right now?

Till now, there are 17 versions of Android, which have their names in alphabetical order. The 18th version of Android is also going to come later this year. The versions of Android are here:

  • Android 1.0 – Its release is 23 September 2008.
  • Android 1.1 – Its release date is 9 February 2009.
  • Android 1.5 – Its name is Cupcake, Released on 27 April 2009.
  • Android 1.6 – Its name is Donut, Released on 15 September 2009.
  • Android 2.0 – Its name is Eclair, Released on 26 October 2009
  • Android 2.2 – Its name is Froyo, Released on 20 May 2010.
  • Android 2.3 – Its name is Gingerbread, Released on 06 December 2010.
  • Android 3.0 – Its name is Honeycomb, Released on 22 February 2011.
  • Android 4.0 – Its name is Ice Cream Sandwich, Released on 18 October 2011.
  • Android 4.1 – Its name is Jelly Bean, Released on 9 July 2012.
  • Android 4.4 – Its name is KitKat, Released on 31 October 2013.
  • Android 5.0 – Its name is Lollipop, Released on 12 November 2014.
  • Android 6.0 – Its name is Marshmallow, Released on 5 October 2015.
  • Android 7.0 – Its name is Nougat, Released on 22 August 2016.
  • Android 8.0 – Its name is Oreo, Released on 21 August 2017.
  • Android 9.0 – Its name is Pie, Released on 6 August 2018.
  • Android 10.0 – Its name is Android Q, Released on 3 September 2019.
  • Android 11.0 – As of now, it is Android 11.

5. Explain the Android Architecture with its components.

This is a popular android developer interview question

Android Architecture consists of 5 components that are-

a. Linux Kernel: It is the foundation of the Android Architecture that resides at the lowest level. It provides the level of abstraction for hardware devices and upper layer components. Linux Kernel also provides various important hardware drivers that act as software interfaces for hardwares like camera, bluetooth, etc.

b. Native Libraries: These are the libraries for Android that are written in C/C++. These libraries are useful to build many core services like ART and HAL. It provides support for core features.

c. Android Runtime: It is an Android Runtime Environment. Android Operating System uses it during the execution of the app. It performs the translation of the application bytecode into the native instructions. The runtime environment of the device then executes these native instructions.

d. Application Framework: Application Framework provides many java classes and interfaces for app development. And it also provides various high-level services. This complete Application framework makes use of Java.

e. Applications: This is the topmost layer of Android Architecture. It provides applications for the end-user, so they can use the android device and compute the tasks.

6. What are the services that the Application framework provides?

The Android application framework has the following key services-

a. Activity Manager: It uses testing and debugging methods.

b. Content provider: It provides the data from application to other layers.

c. Resource Manager: This provides users access to resources.

d. Notification Manager: This gives notification to the users regarding actions taking place in the background.

e. View System: It is the base class for widgets, and it is also responsible for event handling.

7. What are the important features of Linux Kernel?

The important features of the Linux Kernel are as follows:

a. Power Management: Linux Kernel does power management to enhance and improve the battery life of the device.

b. Memory Management: It is useful for the maximum utilization of the available memory of the device.

c. Device Management: It includes managing all the hardware device drivers. It maximizes the utilization of the available resources.

d. Security: It ensures that no application has any such permission that it affects any other application in order to maintain security.

e. Multi-tasking: Multi-tasking provides the users the ease of doing multiple tasks at the same time.

8. What are the building blocks of an Android Application?

This is a popular android interview question for freshers.

The main components of any Android application are- Activity, Services, Content Provider, and Broadcast Receiver. You can understand them as follows:

a. Activity- It is a class that acts as the entry point representing a single screen to the user. It is like a window to show the user interface.

b. Services- Services are the longest-running component that runs in the background.

c. Content Provider- The content provider is an essential component that allows apps to share data between themselves.

d. Broadcast receivers- Broadcast receiver is another most crucial application component. It helps the apps to receive and respond to broadcast messages from the system or some other application.

9. What are the important components of Android Application?

The Components of Android application are listed below:

  1. Widgets
  2. Intents
  3. Views
  4. Notification
  5. Fragments
  6. Layout XML files
  7. Resources

10. What are the widgets?

Widgets are the variations of Broadcast receivers. They are an important part of home screen customization. They often display some data and also allow users to perform actions on them. Mostly they display the app icon on the screen.

11. Can you name some types of widgets?

Mentioned below are the types of widgets-

a. Informative Widgets: These widgets show some important information. Like, the clock widget or a weather widget.

b. Collective Widgets: They are the collection of some types of elements. For example, a music widget that lets us change, skip, or forward the song.

c. Control Widgets: These widgets help us control the actions within the application through it. Like an email widget that helps check the recent mails.

d. Hybrid Widgets: Hybrid widgets are those that consist of at least two or more types of widgets.

12. What are Intents?

Intents are an important part of Android Applications. They enable communication between components of the same application as well as separate applications. The Intent signals the Android system about a certain event that has occurred.

13. Explain the types of intents briefly?

Intent is of three types that are-

a. Implicit Intents: Implicit intents are those in which there is no description of the component name but only the action.

b. Explicit Intents: In explicit intents, the target component is present by declaring the name of the component.

c. Pending Intents: These are those intents that act as a shield over the Intent objects. It covers the intent objects and grants permission to the external app components to access them.

14. What is a View?

A view is an important building block that helps in designing the user interface of the application. It can be a rectangular box or a circular shape, for example, Text View, Edit Text, Buttons, etc. Views occupy a certain area of the screen, and it is also responsible for event handling. A view is the superclass of all the graphical user interface components.

15. What do you understand by View Group?

It is the subclass of the ViewClass. It gives an invisible container to hold layouts or views. You can understand view groups as special views that are capable of holding other views, that are Child View.

16. What do you understand about Shared Preferences?

It is a simple mechanism for data storage in Android. In this, there is no need to create files, and using APIs, it stores the data in XML files. It stores the data in the pair of key-values. SharedPreferences class lets the user save the values and retrieve them when required. Using SharedPreferences we can save primitive data like- boolean, float, integer, string and long.

17. What is a Notification?

A notification is just like a message that shows up outside the Application UI to provide reminders to the users. They remind the user about a message received, or some other timely information from the app.

18. Give names of Notification types.

There are three types of notifications namely-

a. Toast Notification- This notification is the one that fades away sometime after it pops up.

b. Status Notification- This notification stays till the user takes some action on it.

c. Dialog Notification- This notification is the result of an Active Activity.

19. What are fragments?

A fragment is a part of the complete user interface. These are present in Activity, and an activity can have one or more fragments at the same time. We can reuse a fragment in multiple activities as well.

20. What are the types of fragments?

There are three types of fragments that are: Single Fragment, List Fragment, Fragment Transactions.

  1. Single Transactions can only show a single view for the user.
  2. List Fragments have a special list view feature that provides a list from which the user can select one.
  3. Fragment Transactions are helpful for the transition between one fragment to the other.

Frequently asked Android Interview Questions and Answers

21. What are Layout XML files?

Layout XML files contain the structure for the user interface of the application. The XML file also contains various different layouts and views, and they also specify various GUI components that are there in Activity or fragments.

22. What are Resources in Android Application?

The resources in Android Apps defines images, texts, strings, colors, etc. Everything in resources directory is referenced in the source code of the app so that we can use them.

23. Can you develop Android Apps with languages other than Java? If so, name some.

Yes, there are many languages that we can work with, for the development of Android Applications. To name some, I would say Java, Python, C, C++, Kotlin, C#, Corona/LUA.

24. What are the states of the Activity Lifecycle?

Activity lifecycle has the following four stages-

a. Running State: As soon as the activity starts, it is the first state.

b. Paused State: When some other activity starts without closing the previous one, the running activity turns into the Paused state.

c. Resume State: When the activity opens again after being in pause state, it comes into the Resume State.

d. Stopped State: When the user closes the application or stops using it, the activity goes to the Stopped state.

25. What are some methods of Activity?

The methods of Activity are as follows:

  • onCreate()
  • onStart()
  • onPause()
  • onRestart()
  • onResume()
  • onStop()
  • onDestroy()

26. How can you launch an activity in Android?

We launch an activity using Intents. For this we need to use intent as follows:

  1. ntent intent_name= new Intent(this, Activity_name.class);
  2. startActivity(intent_name);

27. What is the service lifecycle?

There are two states of a service that are-

a. Started State: This is when the service starts its execution. A Services come in start state only through the startService() method.

b. Bounded State: A service is in the bounded state when it calls the method bindService().

28. What are some methods of Services?

The methods of service are as follows-

  • onStartCommand()
  • onBind()
  • onCreate()
  • onUnbind()
  • onDestroy()
  • onRebind()

29. What are the types of Broadcast?

Broadcasts are of two types that are-

a. Ordered Broadcast: Ordered broadcasts are Synchronous and work in a proper order. It decides the order by using the priority assigned to the broadcasts.

b. Normal Broadcast: These are asynchronous and unordered. They are more efficient as they run unorderly and all at once. But, they lack full utilization of the results.

30. What are useful impotent folders in Android?

The impotent folders in an Android application are-

  1. build.xml- It is responsible for the build of Android applications.
  2. bin/ – The bin folder works as a staging area to wrap the files packages into the APK.
  3. src/ – The src is a folder where all the source files of the project are present.
  4. res/ – The res is the resource folder that stores values of the resources that are used in the application. These resources can be colors, styles, strings, dimensions, etc.
  5. assets/ – It provides a facility to include files like text, XML, fonts, music, and video in the Android application.

31. What are the important files for Android Application when working on Android Studio?

This is an important android studio interview question

There are following three files that we need to work on for an application to work-

a. The AndroidManifest.xml file: It has all the information about the application.

b. The MainActivity.java file: It is the app file that actually gets converted to the dalvik executable and runs the application. It is written in java.

c. The Activity_main.xml file: It is the layout file that is available in the res/layout directory. It is another mostly used file while developing the application.

32. Which database do you use for Android Application development?

The database that we use for Android Applications is SQLite. It is because SQLite is lightweight and specially developed for Android Apps. SQLite works the same way as SQL using the same commands.

33. Tell us some features of Android OS.

The best features of Android include-

  1. Multi-tasking
  2. Support for a great range of languages
  3. Support for split-screen
  4. High connectivity with 5G support
  5. Motion Control

34. Why did you learn Android development?

Learning Android Studio is a good idea because of the following-

  1. It has a low application development cost.
  2. It is an open-source platform.
  3. It has multi-platform support as well as Multi-carrier support.
  4. It is open for customizations.
  5. Android is a largely used operating system throughout the world.

35. What are the different ways of storage supported in Android?

The various storage ways supported in Android are as follows:

  1. Shared Preference
  2. Internal Storage
  3. External Storage
  4. SQLite Databases
  5. Network Connection

36. What are layouts?

Layout is nothing but arrangements of elements on the device screen. These elements can be images, tests, videos, anything. They basically define the structure of the Android user interface to make it user friendly.

37. How many layout types are there?

The type of layouts used in Android Apps are as follows:

  1. Linear Layout
  2. Relative Layout
  3. Constraint Layout
  4. Table Layout
  5. Frame Layout
  6. Absolute Layout
  7. Scrollview layout

38. What is an APK?

An APK stands for Android Package that is a file format of Android Applications. Android OS uses this package for the distribution and installation of the Android Application.

39. What is an Android Manifest file?

The manifest file describes all the essential information about the project application for build tools, Android operating system, and google play. This file is a must for every Android project that we develop, and it is present in the root of the project source set.

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Domingo Jakubowski

Domingo Jakubowski

1602784800

A Guide to Building Custom Switches in Android

Hello World, today we are going to make a custom switch. Why? Because the default one looks so boring and ugly. Why we use a switch? As the name suggests, the switch is used to trigger the value either it is on, or it is off. Let’s see, how our custom switch will look at the end of the tutorial.

In the above gif, there are 3 switches. The First one is the default one and the second and third are our custom switches. To make these custom switches we need to follow certain steps are as follows:

Step 1. Add Switch to Activity Layout

First, we need to add the switch to our layout XML file. We will add SwitchCompat to the layout.

Look at the below code for better understanding.

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    >
    <androidx.appcompat.widget.SwitchCompat
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/customSwitch"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"

        app:track="@drawable/track"
        android:thumb="@drawable/thumb"

        android:text="Custom switch  "

        />
</androidx.constraintlayout.widget.ConstraintLayout>

In the above code, things to be noticed are app:track and android:thumb attributes.

The track is the horizontal container where our thumb or round shape view is placed and the thumb is, as I told you before, is the round shape where we will add an image on top of it.

Step 2. Make Custom Track for Switch

To make our custom track we need to make a drawable file and set the root element as a selector. So click on the drawable folder and make a new file and name it as track.

In our track.xml we write this code for making the custom track.

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