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.os.Bundle;
34 import android.view.MotionEvent;
35 import android.view.View;
36 import android.view.animation.AccelerateInterpolator;
37 import android.view.animation.DecelerateInterpolator;
38 import android.widget.LinearLayout;
39 
40 import java.util.ArrayList;
41 
42 
43 public class BouncingBalls extends Activity {
44     /** Called when the activity is first created. */
45     @Override
onCreate(Bundle savedInstanceState)46     public void onCreate(Bundle savedInstanceState) {
47         super.onCreate(savedInstanceState);
48         setContentView(R.layout.bouncing_balls);
49         LinearLayout container = (LinearLayout) findViewById(R.id.container);
50         container.addView(new MyAnimationView(this));
51     }
52 
53     public class MyAnimationView extends View {
54 
55         private static final int RED = 0xffFF8080;
56         private static final int BLUE = 0xff8080FF;
57         private static final int CYAN = 0xff80ffff;
58         private static final int GREEN = 0xff80ff80;
59 
60         public final ArrayList<ShapeHolder> balls = new ArrayList<ShapeHolder>();
61         AnimatorSet animation = null;
62 
MyAnimationView(Context context)63         public MyAnimationView(Context context) {
64             super(context);
65 
66             // Animate background color
67             // Note that setting the background color will automatically invalidate the
68             // view, so that the animated color, and the bouncing balls, get redisplayed on
69             // every frame of the animation.
70             ValueAnimator colorAnim = ObjectAnimator.ofInt(this, "backgroundColor", RED, BLUE);
71             colorAnim.setDuration(3000);
72             colorAnim.setEvaluator(new ArgbEvaluator());
73             colorAnim.setRepeatCount(ValueAnimator.INFINITE);
74             colorAnim.setRepeatMode(ValueAnimator.REVERSE);
75             colorAnim.start();
76         }
77 
78         @Override
onTouchEvent(MotionEvent event)79         public boolean onTouchEvent(MotionEvent event) {
80             if (event.getAction() != MotionEvent.ACTION_DOWN &&
81                     event.getAction() != MotionEvent.ACTION_MOVE) {
82                 return false;
83             }
84             ShapeHolder newBall = addBall(event.getX(), event.getY());
85 
86             // Bouncing animation with squash and stretch
87             float startY = newBall.getY();
88             float endY = getHeight() - 50f;
89             float h = (float)getHeight();
90             float eventY = event.getY();
91             int duration = (int)(500 * ((h - eventY)/h));
92             ValueAnimator bounceAnim = ObjectAnimator.ofFloat(newBall, "y", startY, endY);
93             bounceAnim.setDuration(duration);
94             bounceAnim.setInterpolator(new AccelerateInterpolator());
95             ValueAnimator squashAnim1 = ObjectAnimator.ofFloat(newBall, "x", newBall.getX(),
96                     newBall.getX() - 25f);
97             squashAnim1.setDuration(duration/4);
98             squashAnim1.setRepeatCount(1);
99             squashAnim1.setRepeatMode(ValueAnimator.REVERSE);
100             squashAnim1.setInterpolator(new DecelerateInterpolator());
101             ValueAnimator squashAnim2 = ObjectAnimator.ofFloat(newBall, "width", newBall.getWidth(),
102                     newBall.getWidth() + 50);
103             squashAnim2.setDuration(duration/4);
104             squashAnim2.setRepeatCount(1);
105             squashAnim2.setRepeatMode(ValueAnimator.REVERSE);
106             squashAnim2.setInterpolator(new DecelerateInterpolator());
107             ValueAnimator stretchAnim1 = ObjectAnimator.ofFloat(newBall, "y", endY,
108                     endY + 25f);
109             stretchAnim1.setDuration(duration/4);
110             stretchAnim1.setRepeatCount(1);
111             stretchAnim1.setInterpolator(new DecelerateInterpolator());
112             stretchAnim1.setRepeatMode(ValueAnimator.REVERSE);
113             ValueAnimator stretchAnim2 = ObjectAnimator.ofFloat(newBall, "height",
114                     newBall.getHeight(), newBall.getHeight() - 25);
115             stretchAnim2.setDuration(duration/4);
116             stretchAnim2.setRepeatCount(1);
117             stretchAnim2.setInterpolator(new DecelerateInterpolator());
118             stretchAnim2.setRepeatMode(ValueAnimator.REVERSE);
119             ValueAnimator bounceBackAnim = ObjectAnimator.ofFloat(newBall, "y", endY,
120                     startY);
121             bounceBackAnim.setDuration(duration);
122             bounceBackAnim.setInterpolator(new DecelerateInterpolator());
123             // Sequence the down/squash&stretch/up animations
124             AnimatorSet bouncer = new AnimatorSet();
125             bouncer.play(bounceAnim).before(squashAnim1);
126             bouncer.play(squashAnim1).with(squashAnim2);
127             bouncer.play(squashAnim1).with(stretchAnim1);
128             bouncer.play(squashAnim1).with(stretchAnim2);
129             bouncer.play(bounceBackAnim).after(stretchAnim2);
130 
131             // Fading animation - remove the ball when the animation is done
132             ValueAnimator fadeAnim = ObjectAnimator.ofFloat(newBall, "alpha", 1f, 0f);
133             fadeAnim.setDuration(250);
134             fadeAnim.addListener(new AnimatorListenerAdapter() {
135                 @Override
136                 public void onAnimationEnd(Animator animation) {
137                     balls.remove(((ObjectAnimator)animation).getTarget());
138 
139                 }
140             });
141 
142             // Sequence the two animations to play one after the other
143             AnimatorSet animatorSet = new AnimatorSet();
144             animatorSet.play(bouncer).before(fadeAnim);
145 
146             // Start the animation
147             animatorSet.start();
148 
149             return true;
150         }
151 
addBall(float x, float y)152         private ShapeHolder addBall(float x, float y) {
153             OvalShape circle = new OvalShape();
154             circle.resize(50f, 50f);
155             ShapeDrawable drawable = new ShapeDrawable(circle);
156             ShapeHolder shapeHolder = new ShapeHolder(drawable);
157             shapeHolder.setX(x - 25f);
158             shapeHolder.setY(y - 25f);
159             int red = (int)(Math.random() * 255);
160             int green = (int)(Math.random() * 255);
161             int blue = (int)(Math.random() * 255);
162             int color = 0xff000000 | red << 16 | green << 8 | blue;
163             Paint paint = drawable.getPaint(); //new Paint(Paint.ANTI_ALIAS_FLAG);
164             int darkColor = 0xff000000 | red/4 << 16 | green/4 << 8 | blue/4;
165             RadialGradient gradient = new RadialGradient(37.5f, 12.5f,
166                     50f, color, darkColor, Shader.TileMode.CLAMP);
167             paint.setShader(gradient);
168             shapeHolder.setPaint(paint);
169             balls.add(shapeHolder);
170             return shapeHolder;
171         }
172 
173         @Override
onDraw(Canvas canvas)174         protected void onDraw(Canvas canvas) {
175             for (int i = 0; i < balls.size(); ++i) {
176                 ShapeHolder shapeHolder = balls.get(i);
177                 canvas.save();
178                 canvas.translate(shapeHolder.getX(), shapeHolder.getY());
179                 shapeHolder.getShape().draw(canvas);
180                 canvas.restore();
181             }
182         }
183     }
184 }