Home | History | Annotate | Download | only in animation 
      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.TypeEvaluator;
     23 import android.animation.ValueAnimator;
     24 import com.example.android.apis.R;
     25 
     26 import java.util.ArrayList;
     27 
     28 import android.app.Activity;
     29 import android.content.Context;
     30 import android.graphics.Canvas;
     31 import android.graphics.Paint;
     32 import android.graphics.RadialGradient;
     33 import android.graphics.Shader;
     34 import android.graphics.drawable.ShapeDrawable;
     35 import android.graphics.drawable.shapes.OvalShape;
     36 import android.os.Bundle;
     37 import android.view.View;
     38 import android.widget.Button;
     39 import android.widget.LinearLayout;
     40 
     41 public class CustomEvaluator extends Activity {
     42 
     43     @Override
     44     public void onCreate(Bundle savedInstanceState) {
     45         super.onCreate(savedInstanceState);
     46         setContentView(R.layout.animator_custom_evaluator);
     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 
     59     public class XYHolder {
     60         private float mX;
     61         private float mY;
     62 
     63         public XYHolder(float x, float y) {
     64             mX = x;
     65             mY = y;
     66         }
     67 
     68         public float getX() {
     69             return mX;
     70         }
     71 
     72         public void setX(float x) {
     73             mX = x;
     74         }
     75 
     76         public float getY() {
     77             return mY;
     78         }
     79 
     80         public void setY(float y) {
     81             mY = y;
     82         }
     83     }
     84 
     85     public class XYEvaluator implements TypeEvaluator {
     86         public Object evaluate(float fraction, Object startValue, Object endValue) {
     87             XYHolder startXY = (XYHolder) startValue;
     88             XYHolder endXY = (XYHolder) endValue;
     89             return new XYHolder(startXY.getX() + fraction * (endXY.getX() - startXY.getX()),
     90                     startXY.getY() + fraction * (endXY.getY() - startXY.getY()));
     91         }
     92     }
     93 
     94     public class BallXYHolder {
     95 
     96         private ShapeHolder mBall;
     97 
     98         public BallXYHolder(ShapeHolder ball) {
     99             mBall = ball;
    100         }
    101 
    102         public void setXY(XYHolder xyHolder) {
    103             mBall.setX(xyHolder.getX());
    104             mBall.setY(xyHolder.getY());
    105         }
    106 
    107         public XYHolder getXY() {
    108             return new XYHolder(mBall.getX(), mBall.getY());
    109         }
    110     }
    111 
    112     public class MyAnimationView extends View implements ValueAnimator.AnimatorUpdateListener {
    113 
    114         public final ArrayList<ShapeHolder> balls = new ArrayList<ShapeHolder>();
    115         ValueAnimator bounceAnim = null;
    116         ShapeHolder ball = null;
    117         BallXYHolder ballHolder = null;
    118 
    119         public MyAnimationView(Context context) {
    120             super(context);
    121             ball = createBall(25, 25);
    122             ballHolder = new BallXYHolder(ball);
    123         }
    124 
    125         private void createAnimation() {
    126             if (bounceAnim == null) {
    127                 XYHolder startXY = new XYHolder(0f, 0f);
    128                 XYHolder endXY = new XYHolder(300f, 500f);
    129                 bounceAnim = ObjectAnimator.ofObject(ballHolder, "xY",
    130                         new XYEvaluator(), endXY);
    131                 bounceAnim.setDuration(1500);
    132                 bounceAnim.addUpdateListener(this);
    133             }
    134         }
    135 
    136         public void startAnimation() {
    137             createAnimation();
    138             bounceAnim.start();
    139         }
    140 
    141         private ShapeHolder createBall(float x, float y) {
    142             OvalShape circle = new OvalShape();
    143             circle.resize(50f, 50f);
    144             ShapeDrawable drawable = new ShapeDrawable(circle);
    145             ShapeHolder shapeHolder = new ShapeHolder(drawable);
    146             shapeHolder.setX(x - 25f);
    147             shapeHolder.setY(y - 25f);
    148             int red = (int)(Math.random() * 255);
    149             int green = (int)(Math.random() * 255);
    150             int blue = (int)(Math.random() * 255);
    151             int color = 0xff000000 | red << 16 | green << 8 | blue;
    152             Paint paint = drawable.getPaint(); //new Paint(Paint.ANTI_ALIAS_FLAG);
    153             int darkColor = 0xff000000 | red/4 << 16 | green/4 << 8 | blue/4;
    154             RadialGradient gradient = new RadialGradient(37.5f, 12.5f,
    155                     50f, color, darkColor, Shader.TileMode.CLAMP);
    156             paint.setShader(gradient);
    157             shapeHolder.setPaint(paint);
    158             return shapeHolder;
    159         }
    160 
    161         @Override
    162         protected void onDraw(Canvas canvas) {
    163             canvas.save();
    164             canvas.translate(ball.getX(), ball.getY());
    165             ball.getShape().draw(canvas);
    166             canvas.restore();
    167         }
    168 
    169         public void onAnimationUpdate(ValueAnimator animation) {
    170             invalidate();
    171         }
    172 
    173     }
    174 }