Android Property Animation API. This tutorial describes how to use the animation API in Android.

1. Android Animations

1.1. Using animations

Android allows changing object properties over a certain time interval via the properties animation API.

The superclass of the animation API is the Animator class. The ObjectAnimator class can be used to modify attributes of an object.

You can also add an AnimatorListener class to your Animator class. This listener is called in the different phases of the animation. You can use this listener to perform actions before or after a certain animation, e.g. add or remove a View from a ViewGroup.

The animate() method on a View object returns an ViewPropertyAnimator object for the view. It provides a fluent API to typical animations which can be performed on views.

The following code shows an example.

myView.animate().translationX(400);

// if an animation is slow you can try to activate a hardware layer which
// uses a cache
// watch-out: this might not always result in a correct animation

myView.animate().translationX(400).withLayer();

You can also register action, which are executed before the start or after the end of the animation.

// StartAction
myView.animate().translationX(100).withStartAction(new Runnable(){
    public void run(){
        viewer.setTranslationX(100-myView.getWidth());
        // do something
    }
});

// EndAction
myView.animate().alpha(0).withEndAction(new Runnable(){
    public void run(){
        // rRemove the view from the parent layout
        parent.removeView(myView);
    }
});

1.2. Define the rate of change for an animation

Via the setInterpolator() method you register an TimeInterpolator object with an animation. It defines the rate of change for an animation.

The standard is linear. The Android platform defines a few default ones. For example, the AccelerateDecelerateInterpolator class defines that the animation starts and ends slowly but accelerates through the middle.

1.3. Using animations with arbitrary properties

The animation system cannot automatically understand every type. Via the setEvaluator method you can set an object of type TypeEvaluator. It allows creating animations for arbitrary types, by providing custom evaluators for these types.

1.4. Layout animations

The LayoutTransition class allows setting animations on a layout container and a change on the view hierarchy of this container will be animated.

package com.example.android.layoutanimation;

import android.animation.LayoutTransition;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

public class MainActivity extends Activity {

    private ViewGroup viewGroup;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        LayoutTransition l = new LayoutTransition();
        l.enableTransitionType(LayoutTransition.CHANGING);
        viewGroup = (ViewGroup) findViewById(R.id.container);
        viewGroup.setLayoutTransition(l);

    }

    public void onClick(View view) {
        viewGroup.addView(new Button(this));
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
}

1.5. Animations for Activity transition

Animations can be applied to Views but it is also possible to apply them on the transition between activities.

The ActivityOptions class allows defining defaults or customer animations.

public void onClick(View view) {
    Intent intent = new Intent(this, SecondActivity.class);
    ActivityOptions options = ActivityOptions.makeScaleUpAnimation(view, 0,
            0, view.getWidth(), view.getHeight());
    startActivity(intent, options.toBundle());
}

2. Android Basics

The following description assumes that you have already basic knowledge in Android development.

Please check https://www.vogella.com/tutorials/Android/article.html - Android development tutorial, to learn the basics. Also see https://www.vogella.com/android.html - Android development tutorials, for more information about Android development.

3. Exercise: Using the properties animations API

This exercise demonstrates the usage of the Properties animation API.

Create a new Android project with the top level package name com.vogella.android.animation.views and an activity called AnimationExampleActivity. The layout file should be called activity_main.xml.

Change your layout file to the following code.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:id="@+id/test"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >

        <Button
            android:id="@+id/Button01"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="startAnimation"
            android:text="Rotate" />

        <Button
            android:id="@+id/Button04"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="startAnimation"
            android:text="Group" >
        </Button>

        <Button
            android:id="@+id/Button03"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="startAnimation"
            android:text="Fade" />

        <Button
            android:id="@+id/Button02"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="startAnimation"
            android:text="Animate" />

    </LinearLayout>

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:src="@drawable/icon" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/imageView1"
        android:layout_alignRight="@+id/imageView1"
        android:layout_marginBottom="30dp"
        android:text="Large Text"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</RelativeLayout>

Create the following menu resource.

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:id="@+id/item1"
        android:showAsAction="ifRoom"
        android:title="Game">
    </item>

</menu>

Change your activity similar to the following listing.

package com.vogella.android.animation.views;

import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

public class AnimationExampleActivity extends Activity {

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

    }

    public void startAnimation(View view) {
        float dest = 0;
        ImageView aniView = (ImageView) findViewById(R.id.imageView1);
        switch (view.getId()) {

        case R.id.Button01:
            dest = 360;
            if (aniView.getRotation() == 360) {
                System.out.println(aniView.getAlpha());
                dest = 0;
            }
            ObjectAnimator animation1 = ObjectAnimator.ofFloat(aniView,
                    "rotation", dest);
            animation1.setDuration(2000);
            animation1.start();
            // Show how to load an animation from XML
            // Animation animation1 = AnimationUtils.loadAnimation(this,
            // R.anim.myanimation);
            // animation1.setAnimationListener(this);
            // animatedView1.startAnimation(animation1);
            break;

        case R.id.Button02:
            // shows how to define a animation via code
            // also use an Interpolator (BounceInterpolator)
            Paint paint = new Paint();
            TextView aniTextView = (TextView) findViewById(R.id.textView1);
            float measureTextCenter = paint.measureText(aniTextView.getText()
                    .toString());
            dest = 0 - measureTextCenter;
            if (aniTextView.getX() < 0) {
                dest = 0;
            }
            ObjectAnimator animation2 = ObjectAnimator.ofFloat(aniTextView,
                    "x", dest);
            animation2.setDuration(2000);
            animation2.start();
            break;

        case R.id.Button03:
            // demonstrate fading and adding an AnimationListener

            dest = 1;
            if (aniView.getAlpha() > 0) {
                dest = 0;
            }
            ObjectAnimator animation3 = ObjectAnimator.ofFloat(aniView,
                    "alpha", dest);
            animation3.setDuration(2000);
            animation3.start();
            break;

        case R.id.Button04:

            ObjectAnimator fadeOut = ObjectAnimator.ofFloat(aniView, "alpha",
                    0f);
            fadeOut.setDuration(2000);
            ObjectAnimator mover = ObjectAnimator.ofFloat(aniView,
                    "translationX", -500f, 0f);
            mover.setDuration(2000);
            ObjectAnimator fadeIn = ObjectAnimator.ofFloat(aniView, "alpha",
                    0f, 1f);
            fadeIn.setDuration(2000);
            AnimatorSet animatorSet = new AnimatorSet();

            animatorSet.play(mover).with(fadeIn).after(fadeOut);
            animatorSet.start();
            break;

        default:
            break;
        }

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.mymenu, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        Intent intent = new Intent(this, HitActivity.class);
        startActivity(intent);
        return true;
    }
}

Create a new xml layout file called target like the following.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/button1"/>

</LinearLayout>

Create a new HitActivity activity.

package com.vogella.android.animation.views;

import java.util.Random;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class HitActivity extends Activity {
    private ObjectAnimator animation1;
    private ObjectAnimator animation2;
    private Button button;
    private Random randon;
    private int width;
    private int height;
    private AnimatorSet set;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.target);
        width = getWindowManager().getDefaultDisplay().getWidth();
        height = getWindowManager().getDefaultDisplay().getHeight();
        randon = new Random();

        set = createAnimation();
        set.start();
        set.addListener(new AnimatorListenerAdapter() {

            @Override
            public void onAnimationEnd(Animator animation) {
                int nextX = randon.nextInt(width);
                int nextY = randon.nextInt(height);
                animation1 = ObjectAnimator.ofFloat(button, "x", button.getX(),
                        nextX);
                animation1.setDuration(1400);
                animation2 = ObjectAnimator.ofFloat(button, "y", button.getY(),
                        nextY);
                animation2.setDuration(1400);
                set.playTogether(animation1, animation2);
                set.start();
            }
        });
    }

    public void onClick(View view) {
        String string = button.getText().toString();
        int hitTarget = Integer.valueOf(string) + 1;
        button.setText(String.valueOf(hitTarget));
    }

    private AnimatorSet createAnimation() {
        int nextX = randon.nextInt(width);
        int nextY = randon.nextInt(height);
        button = (Button) findViewById(R.id.button1);
        animation1 = ObjectAnimator.ofFloat(button, "x", nextX);
        animation1.setDuration(1400);
        animation2 = ObjectAnimator.ofFloat(button, "y", nextY);
        animation2.setDuration(1400);
        AnimatorSet set = new AnimatorSet();
        set.playTogether(animation1, animation2);
        return set;
    }
}

If you run this example and press the different buttons, the animation should start. Via the toolbar, you can start your HitActivity.

4. Activity animations in Android with shared views

Android 5.0 adds the capability to animate between activities and to have shared views between these activity. If you define a shared part the old view with be animating into the position and size of the new view.

To test this create a project with the top level package called com.vogella.android.activityanimationwithsharedviews.

Create two activity with two different layout, both containing a ImageView with the same android:transitionName property.

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/sharedimage"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scaleType="centerCrop"
        android:src="@drawable/ic_sharedimage"
        />

</LinearLayout>

activity_second.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.vogella.android.activityanimationwithsharedviews.SecondActivity">

    <ImageView
        android:id="@+id/sharedimage"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_sharedimage"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world"
        android:id="@+id/textView" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Button"
        android:id="@+id/button"
        android:transitionName="sharedImage"
        android:layout_below="@+id/textView"
        android:layout_alignParentStart="true"
        android:layout_marginTop="54dp" />

</RelativeLayout>

Adjust your activity code.

package com.vogella.android.activityanimationwithsharedviews;

import android.app.Activity;
import android.app.ActivityOptions;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final ImageView sharedImage = (ImageView) findViewById(R.id.sharedimage);
        sharedImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //This is where the magic happens.
                // makeSceneTransitionAnimation takes a context, view,
                // a name for the target view.
                ActivityOptions options =
                        ActivityOptions.
                        makeSceneTransitionAnimation(MainActivity.this, sharedImage, "sharedImage");
                Intent intent = new Intent(MainActivity.this, SecondActivity.class);
                startActivity(intent, options.toBundle());
            }
        });

    }

}
package com.vogella.android.activityanimationwithsharedviews;

import android.app.Activity;
import android.os.Bundle;

public class SecondActivity extends Activity {

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

If you run your application and click on the image view, it is animated to the view with the same android:transitionName property, in our case the button.

5. Android Animation Resources