How can I make animation like whatsapp call screen?

I am trying to write an animation like in WhatsApp Call screen. But I don't know what is the true way to achieve this.

To achieve this animation I am starting trying with fadein and fadeout animation. These are my set methods for fade in and out animations.

private Animation setAnimFadeOut(int startOff,int duration){
    Animation animFadeOut;
    animFadeOut = new AlphaAnimation(1, 0);
    animFadeOut.setInterpolator(new AccelerateInterpolator());
    animFadeOut.setStartOffset(startOff);
    animFadeOut.setDuration(duration);
    return  animFadeOut;
}

private Animation setAnimFadeIn(int startOff,int duration){
    Animation animFadeIn;
    animFadeIn = new AlphaAnimation(0, 1);
    animFadeIn.setInterpolator(new AccelerateInterpolator());
    animFadeIn.setStartOffset(startOff);
    animFadeIn.setDuration(duration);
    return  animFadeIn;
}

and for every animations animationlisteners onAnimationEnd method triggers animation for restart. fadeIn animation starts fadeOut animation and fadeOut starts fadeIn animation.

    right1FadeOut.setAnimationListener(new Animation.AnimationListener() {
        @Override
        public void onAnimationEnd(Animation animation) {
            right1.startAnimation(right1FadeIn);
            Log.i(TAG, "onAnimationEnd: 1 outEnd");
        }
    });
    right1FadeIn.setAnimationListener(new Animation.AnimationListener() {
        Override
        public void onAnimationEnd(Animation animation) {
            right1.startAnimation(right1FadeOut);
            Log.i(TAG, "onAnimationEnd: 1 inEnd");
        }
    });

Initialization

int startOff = 0;
int diff = 100;
int duration = 600;

final Animation right1FadeOut = setAnimFadeOut(startOff,duration);
final Animation right1FadeIn  = setAnimFadeIn(0,duration);
final Animation right2FadeOut = setAnimFadeOut(startOff+diff,duration+diff);
final Animation right2FadeIn  = setAnimFadeIn(0,duration);
final Animation right3FadeOut = setAnimFadeOut(startOff+diff*2,duration+diff*2);
final Animation right3FadeIn  = setAnimFadeIn(0,duration);

I am starting animation calling fadeout for every button and it did not work as I expected. How can I achieve animation like WhatsApp?

right1.startAnimation(right1FadeOut);
right2.startAnimation(right2FadeOut);          
right3.startAnimation(right3FadeOut);

this is the result.

Solution

I would first use Animator objects instead of Animation, then i can use AnimatorSet to control all animators as a group. (aka: order)

For example:

activity XML:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/txt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:clickable="true"
        android:focusable="true"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/img1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:alpha="0"
            android:src="@drawable/ic_launcher_foreground" />

        <ImageView
            android:id="@+id/img2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:alpha="0"
            android:src="@drawable/ic_launcher_foreground" />

        <ImageView
            android:id="@+id/img3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:alpha="0"
            android:src="@drawable/ic_launcher_foreground" />

        <ImageView
            android:id="@+id/img4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:alpha="0"
            android:src="@drawable/ic_launcher_foreground" />
    </LinearLayout>

</android.support.constraint.ConstraintLayout>

Activity Class:

Java:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        View[] images = {findViewById(R.id.img1), findViewById(R.id.img2), findViewById(R.id.img3), findViewById(R.id.img4),}; //array of views that we want to animate

        //we will have 2 animator foreach view, fade in & fade out
        //prepare animators - creating array of animators & instantiating Object animators
        ArrayList<ObjectAnimator> anims = new ArrayList<>(images.length * 2);
        for (View v : images) anims.add(ObjectAnimator.ofFloat(v, View.ALPHA, 0f, 1f).setDuration(80)); //fade in animator
        for (View v : images) anims.add(ObjectAnimator.ofFloat(v, View.ALPHA, 1f, 0f).setDuration(80)); //fade out animator

        final AnimatorSet set = new AnimatorSet(); //create Animator set object
        //if we want to repeat the animations then we set listener to start again in 'onAnimationEnd' method
        set.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                set.start(); //repeat animator set indefinitely
            }
        });

        set.setStartDelay(600); //set delay every time we start the chain of animations

        for (int i = 0; i < anims.size() - 1; i++) set.play(anims.get(i)).before(anims.get(i + 1)); //put all animations in set by order (from first to last)

        findViewById(R.id.txt).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) { //start the animations on click
                set.start();
            }
        });
    }
}

Kotlin:

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val images = arrayOf(img1, img2, img3, img4) //array of views that we want to animate

        //we will have 2 animator foreach view, fade in & fade out
        //prepare animators - creating array of animators & instantiating Object animators
        val anims = ArrayList<ObjectAnimator>(images.size * 2)
        for (v in images) anims.add(ObjectAnimator.ofFloat(v, View.ALPHA, 0f, 1f).setDuration(80)) //fade in animator
        for (v in images) anims.add(ObjectAnimator.ofFloat(v, View.ALPHA, 1f, 0f).setDuration(80)) //fade out animator

        val set = AnimatorSet() //create Animator set object
        //if we want to repeat the animations then we set listener to start again in 'onAnimationEnd' method
        set.addListener(object : AnimatorListenerAdapter() {
            override fun onAnimationEnd(animation: Animator?) = set.start() //repeat animator set indefinitely
        })

        set.startDelay = 600 //set delay every time we start the chain of animations

        for (i in 0 until anims.size - 1) set.play(anims[i]).before(anims[i + 1]) //put all animations in set by order (from first to last)

        txt.setOnClickListener { set.start() } //start the animations on click
    }
}