samples/ApiDemos/src/com/example/android/apis/animation/BouncingBalls.java

   1 /*
   2  * Copyright (C) 2010 The Android Open Source Project
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 package com.example.android.apis.animation;
  18
  19 // Need the following import to get access to the app resources, since this
  20 // class is in a sub-package.
  21 import android.graphics.drawable.ColorDrawable;
  22 import com.example.android.apis.R;
  23
  24 import android.animation.*;
  25 import android.app.Activity;
  26 import android.content.Context;
  27 import android.graphics.Canvas;
  28 import android.graphics.Paint;
  29 import android.graphics.RadialGradient;
  30 import android.graphics.Shader;
  31 import android.graphics.drawable.ShapeDrawable;
  32 import android.graphics.drawable.shapes.OvalShape;
  33 import android.graphics.drawable.shapes.RectShape;
  34 import android.os.Bundle;
  35 import android.view.MotionEvent;
  36 import android.view.View;
  37 import android.view.animation.AccelerateInterpolator;
  38 import android.view.animation.DecelerateInterpolator;
  39 import android.widget.LinearLayout;
  40
  41 import java.util.ArrayList;
  42
  43
  44 public class BouncingBalls extends Activity {
  45     /** Called when the activity is first created. */
  46     @Override
  47     public void onCreate(Bundle savedInstanceState) {
  48         super.onCreate(savedInstanceState);
  49         setContentView(R.layout.bouncing_balls);
  50         LinearLayout container = (LinearLayout) findViewById(R.id.container);
  51         container.addView(new MyAnimationView(this));
  52     }
  53
  54     public class MyAnimationView extends View implements ValueAnimator.AnimatorUpdateListener,
  55             Animator.AnimatorListener {
  56
  57         private static final int RED = 0xffFF8080;
  58         private static final int BLUE = 0xff8080FF;
  59         private static final int CYAN = 0xff80ffff;
  60         private static final int GREEN = 0xff80ff80;
  61
  62         public final ArrayList<ShapeHolder> balls = new ArrayList<ShapeHolder>();
  63         AnimatorSet animation = null;
  64
  65         public MyAnimationView(Context context) {
  66             super(context);
  67
  68             // Create a colored background
  69             ColorDrawable background = new ColorDrawable(RED);
  70             setBackgroundDrawable(background);
  71
  72             // Animate background color
  73             ValueAnimator colorAnim = ObjectAnimator.ofInt(background, "color", BLUE);
  74             colorAnim.setDuration(3000);
  75             colorAnim.setEvaluator(new RGBEvaluator());
  76             colorAnim.setRepeatCount(ValueAnimator.INFINITE);
  77             colorAnim.setRepeatMode(ValueAnimator.REVERSE);
  78             colorAnim.addUpdateListener(this); // forces invalidation to get the redraw
  79             colorAnim.start();
  80         }
  81
  82         @Override
  83         public boolean onTouchEvent(MotionEvent event) {
  84             if (event.getAction() != MotionEvent.ACTION_DOWN &&
  85                     event.getAction() != MotionEvent.ACTION_MOVE) {
  86                 return false;
  87             }
  88             ShapeHolder newBall = addBall(event.getX(), event.getY());
  89
  90             // Bouncing animation with squash and stretch
  91             float startY = newBall.getY();
  92             float endY = getHeight() - 50f;
  93             float h = (float)getHeight();
  94             float eventY = event.getY();
  95             int duration = (int)(500 * ((h - eventY)/h));
  96             ValueAnimator bounceAnim = ObjectAnimator.ofFloat(newBall, "y", startY, endY);
  97             bounceAnim.setDuration(duration);
  98             bounceAnim.setInterpolator(new AccelerateInterpolator());
  99             ValueAnimator squashAnim1 = ObjectAnimator.ofFloat(newBall, "x", newBall.getX(),
 100                     newBall.getX() - 25f);
 101             squashAnim1.setDuration(duration/4);
 102             squashAnim1.setRepeatCount(1);
 103             squashAnim1.setRepeatMode(ValueAnimator.REVERSE);
 104             squashAnim1.setInterpolator(new DecelerateInterpolator());
 105             ValueAnimator squashAnim2 = ObjectAnimator.ofFloat(newBall, "width", newBall.getWidth(),
 106                     newBall.getWidth() + 50);
 107             squashAnim2.setDuration(duration/4);
 108             squashAnim2.setRepeatCount(1);
 109             squashAnim2.setRepeatMode(ValueAnimator.REVERSE);
 110             squashAnim2.setInterpolator(new DecelerateInterpolator());
 111             ValueAnimator stretchAnim1 = ObjectAnimator.ofFloat(newBall, "y", endY,
 112                     endY + 25f);
 113             stretchAnim1.setDuration(duration/4);
 114             stretchAnim1.setRepeatCount(1);
 115             stretchAnim1.setInterpolator(new DecelerateInterpolator());
 116             stretchAnim1.setRepeatMode(ValueAnimator.REVERSE);
 117             ValueAnimator stretchAnim2 = ObjectAnimator.ofFloat(newBall, "height",
 118                     newBall.getHeight(), newBall.getHeight() - 25);
 119             stretchAnim2.setDuration(duration/4);
 120             stretchAnim2.setRepeatCount(1);
 121             stretchAnim2.setInterpolator(new DecelerateInterpolator());
 122             stretchAnim2.setRepeatMode(ValueAnimator.REVERSE);
 123             ValueAnimator bounceBackAnim = ObjectAnimator.ofFloat(newBall, "y", endY,
 124                     startY);
 125             bounceBackAnim.setDuration(duration);
 126             bounceBackAnim.setInterpolator(new DecelerateInterpolator());
 127             // Sequence the down/squash&stretch/up animations
 128             AnimatorSet bouncer = new AnimatorSet();
 129             bouncer.play(bounceAnim).before(squashAnim1);
 130             bouncer.play(squashAnim1).with(squashAnim2);
 131             bouncer.play(squashAnim1).with(stretchAnim1);
 132             bouncer.play(squashAnim1).with(stretchAnim2);
 133             bouncer.play(bounceBackAnim).after(stretchAnim2);
 134
 135             // Fading animation - remove the ball when the animation is done
 136             ValueAnimator fadeAnim = ObjectAnimator.ofFloat(newBall, "alpha", 1f, 0f);
 137             fadeAnim.setDuration(250);
 138             fadeAnim.addListener(this);
 139
 140             // Sequence the two animations to play one after the other
 141             AnimatorSet animatorSet = new AnimatorSet();
 142             animatorSet.play(bouncer).before(fadeAnim);
 143
 144             // Start the animation
 145             animatorSet.start();
 146
 147             return true;
 148         }
 149
 150         private ShapeHolder addBall(float x, float y) {
 151             OvalShape circle = new OvalShape();
 152             circle.resize(50f, 50f);
 153             ShapeDrawable drawable = new ShapeDrawable(circle);
 154             ShapeHolder shapeHolder = new ShapeHolder(drawable);
 155             shapeHolder.setX(x - 25f);
 156             shapeHolder.setY(y - 25f);
 157             int red = (int)(Math.random() * 255);
 158             int green = (int)(Math.random() * 255);
 159             int blue = (int)(Math.random() * 255);
 160             int color = 0xff000000 | red << 16 | green << 8 | blue;
 161             Paint paint = drawable.getPaint(); //new Paint(Paint.ANTI_ALIAS_FLAG);
 162             int darkColor = 0xff000000 | red/4 << 16 | green/4 << 8 | blue/4;
 163             RadialGradient gradient = new RadialGradient(37.5f, 12.5f,
 164                     50f, color, darkColor, Shader.TileMode.CLAMP);
 165             paint.setShader(gradient);
 166             shapeHolder.setPaint(paint);
 167             balls.add(shapeHolder);
 168             return shapeHolder;
 169         }
 170
 171         @Override
 172         protected void onDraw(Canvas canvas) {
 173             for (int i = 0; i < balls.size(); ++i) {
 174                 ShapeHolder shapeHolder = balls.get(i);
 175                 canvas.save();
 176                 canvas.translate(shapeHolder.getX(), shapeHolder.getY());
 177                 shapeHolder.getShape().draw(canvas);
 178                 canvas.restore();
 179             }
 180         }
 181
 182         public void onAnimationUpdate(ValueAnimator animation) {
 183             invalidate();
 184         }
 185
 186         @Override
 187         public void onAnimationCancel(Animator animation) {
 188         }
 189
 190         @Override
 191         public void onAnimationEnd(Animator animation) {
 192             balls.remove(((ObjectAnimator)animation).getTarget());
 193
 194         }
 195
 196         @Override
 197         public void onAnimationRepeat(Animator animation) {
 198         }
 199
 200         @Override
 201         public void onAnimationStart(Animator animation) {
 202         }
 203     }
 204 }