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.animation.ObjectAnimator;
22 import android.animation.ValueAnimator;
23 import com.example.android.apis.R;
24 
25 import java.util.ArrayList;
26 
27 import android.app.Activity;
28 import android.content.Context;
29 import android.graphics.Canvas;
30 import android.graphics.Paint;
31 import android.graphics.RadialGradient;
32 import android.graphics.Shader;
33 import android.graphics.drawable.ShapeDrawable;
34 import android.graphics.drawable.shapes.OvalShape;
35 import android.os.Bundle;
36 import android.view.View;
37 import android.view.animation.AccelerateInterpolator;
38 import android.widget.Button;
39 import android.widget.LinearLayout;
40 
41 public class ReversingAnimation extends Activity {
42 
43     @Override
onCreate(Bundle savedInstanceState)44     public void onCreate(Bundle savedInstanceState) {
45         super.onCreate(savedInstanceState);
46         setContentView(R.layout.animation_reversing);
47         LinearLayout container = (LinearLayout) findViewById(R.id.container);
48         final MyAnimationView animView = new MyAnimationView(this);
49         container.addView(animView);
50 
51         Button starter = (Button) findViewById(R.id.startButton);
52         starter.setOnClickListener(new View.OnClickListener() {
53             public void onClick(View v) {
54                 animView.startAnimation();
55             }
56         });
57 
58         Button reverser = (Button) findViewById(R.id.reverseButton);
59         reverser.setOnClickListener(new View.OnClickListener() {
60             public void onClick(View v) {
61                 animView.reverseAnimation();
62             }
63         });
64 
65     }
66 
67     public class MyAnimationView extends View implements ValueAnimator.AnimatorUpdateListener {
68 
69         public final ArrayList<ShapeHolder> balls = new ArrayList<ShapeHolder>();
70         ValueAnimator bounceAnim = null;
71         ShapeHolder ball = null;
72 
MyAnimationView(Context context)73         public MyAnimationView(Context context) {
74             super(context);
75             ball = createBall(25, 25);
76         }
77 
createAnimation()78         private void createAnimation() {
79             if (bounceAnim == null) {
80                 bounceAnim = ObjectAnimator.ofFloat(ball, "y", ball.getY(), getHeight() - 50f).
81                         setDuration(1500);
82                 bounceAnim.setInterpolator(new AccelerateInterpolator(2f));
83                 bounceAnim.addUpdateListener(this);
84             }
85         }
86 
startAnimation()87         public void startAnimation() {
88             createAnimation();
89             bounceAnim.start();
90         }
91 
reverseAnimation()92         public void reverseAnimation() {
93             createAnimation();
94             bounceAnim.reverse();
95         }
96 
seek(long seekTime)97         public void seek(long seekTime) {
98             createAnimation();
99             bounceAnim.setCurrentPlayTime(seekTime);
100         }
101 
createBall(float x, float y)102         private ShapeHolder createBall(float x, float y) {
103             OvalShape circle = new OvalShape();
104             circle.resize(50f, 50f);
105             ShapeDrawable drawable = new ShapeDrawable(circle);
106             ShapeHolder shapeHolder = new ShapeHolder(drawable);
107             shapeHolder.setX(x - 25f);
108             shapeHolder.setY(y - 25f);
109             int red = (int)(Math.random() * 255);
110             int green = (int)(Math.random() * 255);
111             int blue = (int)(Math.random() * 255);
112             int color = 0xff000000 | red << 16 | green << 8 | blue;
113             Paint paint = drawable.getPaint(); //new Paint(Paint.ANTI_ALIAS_FLAG);
114             int darkColor = 0xff000000 | red/4 << 16 | green/4 << 8 | blue/4;
115             RadialGradient gradient = new RadialGradient(37.5f, 12.5f,
116                     50f, color, darkColor, Shader.TileMode.CLAMP);
117             paint.setShader(gradient);
118             shapeHolder.setPaint(paint);
119             return shapeHolder;
120         }
121 
122         @Override
onDraw(Canvas canvas)123         protected void onDraw(Canvas canvas) {
124             canvas.save();
125             canvas.translate(ball.getX(), ball.getY());
126             ball.getShape().draw(canvas);
127             canvas.restore();
128         }
129 
onAnimationUpdate(ValueAnimator animation)130         public void onAnimationUpdate(ValueAnimator animation) {
131             invalidate();
132         }
133 
134     }
135 }