The file containing the source code shown below is located in the corresponding directory in <sdk>/samples/android-<version>/...
/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.apis.animation;
// Need the following import to get access to the app resources, since this
// class is in a sub-package.
import android.animation.*;
import android.view.animation.AccelerateInterpolator;
import com.example.android.apis.R;
import java.util.ArrayList;
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.View;
import android.view.animation.BounceInterpolator;
import android.widget.Button;
import android.widget.LinearLayout;
/**
* This application demonstrates the seeking capability of ValueAnimator. The SeekBar in the
* UI allows you to set the position of the animation. Pressing the Run button will play from
* the current position of the animation.
*/
public class MultiPropertyAnimation extends Activity {
private static final int DURATION = 1500;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.animation_multi_property);
LinearLayout container = (LinearLayout) findViewById(R.id.container);
final MyAnimationView animView = new MyAnimationView(this);
container.addView(animView);
Button starter = (Button) findViewById(R.id.startButton);
starter.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
animView.startAnimation();
}
});
}
public class MyAnimationView extends View implements ValueAnimator.AnimatorUpdateListener {
private static final float BALL_SIZE = 100f;
public final ArrayList<ShapeHolder> balls = new ArrayList<ShapeHolder>();
AnimatorSet animation = null;
Animator bounceAnim = null;
ShapeHolder ball = null;
public MyAnimationView(Context context) {
super(context);
addBall(50, 0);
addBall(150, 0);
addBall(250, 0);
addBall(350, 0);
}
private void createAnimation() {
if (bounceAnim == null) {
ShapeHolder ball;
ball = balls.get(0);
ObjectAnimator yBouncer = ObjectAnimator.ofFloat(ball, "y",
ball.getY(), getHeight() - BALL_SIZE).setDuration(DURATION);
yBouncer.setInterpolator(new BounceInterpolator());
yBouncer.addUpdateListener(this);
ball = balls.get(1);
PropertyValuesHolder pvhY = PropertyValuesHolder.ofFloat("y", ball.getY(),
getHeight() - BALL_SIZE);
PropertyValuesHolder pvhAlpha = PropertyValuesHolder.ofFloat("alpha", 1.0f, 0f);
ObjectAnimator yAlphaBouncer = ObjectAnimator.ofPropertyValuesHolder(ball,
pvhY, pvhAlpha).setDuration(DURATION/2);
yAlphaBouncer.setInterpolator(new AccelerateInterpolator());
yAlphaBouncer.setRepeatCount(1);
yAlphaBouncer.setRepeatMode(ValueAnimator.REVERSE);
ball = balls.get(2);
PropertyValuesHolder pvhW = PropertyValuesHolder.ofFloat("width", ball.getWidth(),
ball.getWidth() * 2);
PropertyValuesHolder pvhH = PropertyValuesHolder.ofFloat("height", ball.getHeight(),
ball.getHeight() * 2);
PropertyValuesHolder pvTX = PropertyValuesHolder.ofFloat("x", ball.getX(),
ball.getX() - BALL_SIZE/2f);
PropertyValuesHolder pvTY = PropertyValuesHolder.ofFloat("y", ball.getY(),
ball.getY() - BALL_SIZE/2f);
ObjectAnimator whxyBouncer = ObjectAnimator.ofPropertyValuesHolder(ball, pvhW, pvhH,
pvTX, pvTY).setDuration(DURATION/2);
whxyBouncer.setRepeatCount(1);
whxyBouncer.setRepeatMode(ValueAnimator.REVERSE);
ball = balls.get(3);
pvhY = PropertyValuesHolder.ofFloat("y", ball.getY(), getHeight() - BALL_SIZE);
float ballX = ball.getX();
Keyframe kf0 = Keyframe.ofFloat(0f, ballX);
Keyframe kf1 = Keyframe.ofFloat(.5f, ballX + 100f);
Keyframe kf2 = Keyframe.ofFloat(1f, ballX + 50f);
PropertyValuesHolder pvhX = PropertyValuesHolder.ofKeyframe("x", kf0, kf1, kf2);
ObjectAnimator yxBouncer = ObjectAnimator.ofPropertyValuesHolder(ball, pvhY,
pvhX).setDuration(DURATION/2);
yxBouncer.setRepeatCount(1);
yxBouncer.setRepeatMode(ValueAnimator.REVERSE);
bounceAnim = new AnimatorSet();
((AnimatorSet)bounceAnim).playTogether(yBouncer, yAlphaBouncer, whxyBouncer,
yxBouncer);
}
}
public void startAnimation() {
createAnimation();
bounceAnim.start();
}
private ShapeHolder addBall(float x, float y) {
OvalShape circle = new OvalShape();
circle.resize(BALL_SIZE, BALL_SIZE);
ShapeDrawable drawable = new ShapeDrawable(circle);
ShapeHolder shapeHolder = new ShapeHolder(drawable);
shapeHolder.setX(x);
shapeHolder.setY(y);
int red = (int)(100 + Math.random() * 155);
int green = (int)(100 + Math.random() * 155);
int blue = (int)(100 + Math.random() * 155);
int color = 0xff000000 | red << 16 | green << 8 | blue;
Paint paint = drawable.getPaint();
int darkColor = 0xff000000 | red/4 << 16 | green/4 << 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 (ShapeHolder ball : balls) {
canvas.translate(ball.getX(), ball.getY());
ball.getShape().draw(canvas);
canvas.translate(-ball.getX(), -ball.getY());
}
}
public void onAnimationUpdate(ValueAnimator animation) {
invalidate();
}
}
}