Ball Animation Example In Android

This example shows create bouncing animation effect in android.

Algorithm:

1.) Create a new project by File-> New -> Android Project name it BallAnimationExample.

2.) Write following into main.xml:

<!–?xml version="1.0" encoding="utf-8"?–>

3.) Create and write following into src/ShapeHolder.java:

package com.example.BallAnimationExample;

import android.graphics.Paint;

import android.graphics.RadialGradient;

import android.graphics.drawable.ShapeDrawable;

import android.graphics.drawable.shapes.Shape;

/**

* A data structure that holds a Shape and various properties that can be used to define

* how the shape is drawn.

*/

public class ShapeHolder {

private float x = 0, y = 0;

private ShapeDrawable shape;

private int color;

private RadialGradient gradient;

private float alpha = 1f;

private Paint paint;

public void setPaint(Paint value) {

paint = value;

}

public Paint getPaint() {

return paint;

}

public void setX(float value) {

x = value;

}

public float getX() {

return x;

}

public void setY(float value) {

y = value;

}

public float getY() {

return y;

}

public void setShape(ShapeDrawable value) {

shape = value;

}

public ShapeDrawable getShape() {

return shape;

}

public int getColor() {

return color;

}

public void setColor(int value) {

shape.getPaint().setColor(value);

color = value;

}

public void setGradient(RadialGradient value) {

gradient = value;

}

public RadialGradient getGradient() {

return gradient;

}

public void setAlpha(float alpha) {

this.alpha = alpha;

shape.setAlpha((int)((alpha * 255f) + .5f));

}

public float getWidth() {

return shape.getShape().getWidth();

}

public void setWidth(float width) {

Shape s = shape.getShape();

s.resize(width, s.getHeight());

}

public float getHeight() {

return shape.getShape().getHeight();

}

public void setHeight(float height) {

Shape s = shape.getShape();

s.resize(s.getWidth(), height);

}

public ShapeHolder(ShapeDrawable s) {

shape = s;

}

}

4.) Run for output.

Steps:

1.) Create a project named BallAnimationExample and set the information as stated in the image.

Build Target: Android 4.0

Application Name: BallAnimationExample

Package Name: com. example. BallAnimationExample

Activity Name: BallAnimationExample

Min SDK Version: 14

2.) Open BallAnimationExample.java file and write following code there:

package com.example.BallAnimationExample;

import java.util.ArrayList;

import android.animation.Animator;

import android.animation.AnimatorListenerAdapter;

import android.animation.AnimatorSet;

import android.animation.ArgbEvaluator;

import android.animation.ObjectAnimator;

import android.animation.ValueAnimator;

import android.app.Activity;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Paint;

import android.graphics.RadialGradient;

import android.graphics.Shader;

import android.graphics.drawable.ShapeDrawable;

import android.graphics.drawable.shapes.OvalShape;

import android.os.Bundle;

import android.view.MotionEvent;

import android.view.View;

import android.view.animation.AccelerateInterpolator;

import android.view.animation.DecelerateInterpolator;

import android.widget.LinearLayout;

public class BallAnimationExample extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

LinearLayout container = (LinearLayout) findViewById(R.id.container);

container.addView(new MyAnimationView(this));

}

public class MyAnimationView extends View {

private static final int RED = 0xffFF8080;

private static final int BLUE = 0xff8080FF;

private static final int CYAN = 0xff80ffff;

private static final int GREEN = 0xff80ff80;

public final ArrayList balls = new ArrayList();

AnimatorSet animation = null;

public MyAnimationView(Context context) {

super(context);

// Animate background color

// Note that setting the background color will automatically invalidate the

// view, so that the animated color, and the bouncing balls, get redisplayed on

// every frame of the animation.

ValueAnimator colorAnim = ObjectAnimator.ofInt(this, "backgroundColor", RED, BLUE);

colorAnim.setDuration(3000);

colorAnim.setEvaluator(new ArgbEvaluator());

colorAnim.setRepeatCount(ValueAnimator.INFINITE);

colorAnim.setRepeatMode(ValueAnimator.REVERSE);

colorAnim.start();

}

@Override

public boolean onTouchEvent(MotionEvent event) {

if (event.getAction() != MotionEvent.ACTION_DOWN &amp;&amp;

event.getAction() != MotionEvent.ACTION_MOVE) {

return false;

}

ShapeHolder newBall = addBall(event.getX(), event.getY());

// Bouncing animation with squash and stretch

float startY = newBall.getY();

float endY = getHeight() - 50f;

float h = (float)getHeight();

float eventY = event.getY();

int duration = (int)(500 * ((h - eventY)/h));

ValueAnimator bounceAnim = ObjectAnimator.ofFloat(newBall, "y", startY, endY);

bounceAnim.setDuration(duration);

bounceAnim.setInterpolator(new AccelerateInterpolator());

ValueAnimator squashAnim1 = ObjectAnimator.ofFloat(newBall, "x", newBall.getX(),

newBall.getX() - 25f);

squashAnim1.setDuration(duration/4);

squashAnim1.setRepeatCount(1);

squashAnim1.setRepeatMode(ValueAnimator.REVERSE);

squashAnim1.setInterpolator(new DecelerateInterpolator());

ValueAnimator squashAnim2 = ObjectAnimator.ofFloat(newBall, "width", newBall.getWidth(),

newBall.getWidth() + 50);

squashAnim2.setDuration(duration/4);

squashAnim2.setRepeatCount(1);

squashAnim2.setRepeatMode(ValueAnimator.REVERSE);

squashAnim2.setInterpolator(new DecelerateInterpolator());

ValueAnimator stretchAnim1 = ObjectAnimator.ofFloat(newBall, "y", endY,

endY + 25f);

stretchAnim1.setDuration(duration/4);

stretchAnim1.setRepeatCount(1);

stretchAnim1.setInterpolator(new DecelerateInterpolator());

stretchAnim1.setRepeatMode(ValueAnimator.REVERSE);

ValueAnimator stretchAnim2 = ObjectAnimator.ofFloat(newBall, "height",

newBall.getHeight(), newBall.getHeight() - 25);

stretchAnim2.setDuration(duration/4);

stretchAnim2.setRepeatCount(1);

stretchAnim2.setInterpolator(new DecelerateInterpolator());

stretchAnim2.setRepeatMode(ValueAnimator.REVERSE);

ValueAnimator bounceBackAnim = ObjectAnimator.ofFloat(newBall, "y", endY,

startY);

bounceBackAnim.setDuration(duration);

bounceBackAnim.setInterpolator(new DecelerateInterpolator());

// Sequence the down/squash&amp;stretch/up animations

AnimatorSet bouncer = new AnimatorSet();

bouncer.play(bounceAnim).before(squashAnim1);

bouncer.play(squashAnim1).with(squashAnim2);

bouncer.play(squashAnim1).with(stretchAnim1);

bouncer.play(squashAnim1).with(stretchAnim2);

bouncer.play(bounceBackAnim).after(stretchAnim2);

// Fading animation – remove the ball when the animation is done

ValueAnimator fadeAnim = ObjectAnimator.ofFloat(newBall, "alpha", 1f, 0f);

fadeAnim.setDuration(250);

fadeAnim.addListener(new AnimatorListenerAdapter() {

@Override

public void onAnimationEnd(Animator animation) {

balls.remove(((ObjectAnimator)animation).getTarget());

}

});

// Sequence the two animations to play one after the other

AnimatorSet animatorSet = new AnimatorSet();

animatorSet.play(bouncer).before(fadeAnim);

// Start the animation

animatorSet.start();

return true;

}

private ShapeHolder addBall(float x, float y) {

OvalShape circle = new OvalShape();

circle.resize(50f, 50f);

ShapeDrawable drawable = new ShapeDrawable(circle);

ShapeHolder shapeHolder = new ShapeHolder(drawable);

shapeHolder.setX(x - 25f);

shapeHolder.setY(y - 25f);

int red = (int)(Math.random() * 255);

int green = (int)(Math.random() * 255);

int blue = (int)(Math.random() * 255);

int color = 0xff000000 | red &lt;&lt; 16 | green &lt;&lt; 8 | blue;

Paint paint = drawable.getPaint(); //new Paint(Paint.ANTI_ALIAS_FLAG);

int darkColor = 0xff000000 | red/4 &lt;&lt; 16 | green/4 &lt;&lt; 8 | blue/4;

RadialGradient gradient = new RadialGradient(37.5f, 12.5f,

50f, color, darkColor, Shader.TileMode.CLAMP);

paint.setShader(gradient);

shapeHolder.setPaint(paint);

balls.add(shapeHolder);

return shapeHolder;

}

@Override

protected void onDraw(Canvas canvas) {

for (int i = 0; i &lt; balls.size(); ++i) {

ShapeHolder shapeHolder = balls.get(i);

canvas.save();

canvas.translate(shapeHolder.getX(), shapeHolder.getY());

shapeHolder.getShape().draw(canvas);

canvas.restore();

}

}

}

}

3.) Compile and build the project.

Output