学步园

/*
 * 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.graphics.drawable.ColorDrawable;
import com.example.android.apis.R;

import android.animation.*;
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.MotionEvent;
import android.view.View;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.DecelerateInterpolator;
import android.widget.LinearLayout;

import java.util.ArrayList;


public class BouncingBalls extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.bouncing_balls);
        LinearLayout container = (LinearLayout) findViewById(R.id.container);
        container.addView(new MyAnimationView(this));
    }

    public class MyAnimationView extends View {

        private static final int RED = 0xffFF8080;
        private static final int BLUE = 0xff8080FF;
        private static final int CYAN = 0xff80ffff;
        private static final int GREEN = 0xff80ff80;

        public final ArrayList<ShapeHolder> balls = new ArrayList<ShapeHolder>();
        AnimatorSet animation = null;

        public MyAnimationView(Context context) {
            super(context);
//start{
            ValueAnimator colorAnim = ObjectAnimator.ofInt(this, "backgroundColor", RED, BLUE);//创建一个动画器；"backgroundColor"是属性的名称；[RED, BLUE]是属性取值区间
            colorAnim.setDuration(3000);//设置动画持续时间
            colorAnim.setEvaluator(new ArgbEvaluator());//类型评估器，有了和前面指定的属性相对应的类型的评估器，动画器才能理解这个属性；
            colorAnim.setRepeatCount(ValueAnimator.INFINITE);//设置重复次数
            colorAnim.setRepeatMode(ValueAnimator.REVERSE);//设置重复模式
            colorAnim.start();//启动动画
//end}      //这断代码是绘制属性动画的基本动作//还有一个setInterpolator()函数设置时间插值，默认没有设置的话是线性插值器


} @Override public boolean onTouchEvent(MotionEvent event) { if (event.getAction() != MotionEvent.ACTION_DOWN && event.getAction() != MotionEvent.ACTION_MOVE) { return false; } ShapeHolder newBall = addBall(event.getX(), event.getY()); // Bouncing animation

 with squash and stretch float startY = newBall.getY(); float endY = getHeight() - 50f; float h = (float)getHeight(); float eventY = event.getY(); int duration = (int)(500 * ((h - eventY)/h)); ValueAnimator bounceAnim = ObjectAnimator.ofFloat(newBall, "y",

 startY, endY); bounceAnim.setDuration(duration); bounceAnim.setInterpolator(new AccelerateInterpolator()); ValueAnimator squashAnim1 = ObjectAnimator.ofFloat(newBall, "x", newBall.getX(), newBall.getX() - 25f); squashAnim1.setDuration(duration/4); squashAnim1.setRepeatCount(1);

 squashAnim1.setRepeatMode(ValueAnimator.REVERSE); squashAnim1.setInterpolator(new DecelerateInterpolator()); ValueAnimator squashAnim2 = ObjectAnimator.ofFloat(newBall, "width", newBall.getWidth(), newBall.getWidth() + 50); squashAnim2.setDuration(duration/4);

 squashAnim2.setRepeatCount(1); squashAnim2.setRepeatMode(ValueAnimator.REVERSE); squashAnim2.setInterpolator(new DecelerateInterpolator()); ValueAnimator stretchAnim1 = ObjectAnimator.ofFloat(newBall, "y", endY, endY + 25f); stretchAnim1.setDuration(duration/4);

 stretchAnim1.setRepeatCount(1); stretchAnim1.setInterpolator(new DecelerateInterpolator()); stretchAnim1.setRepeatMode(ValueAnimator.REVERSE); ValueAnimator stretchAnim2 = ObjectAnimator.ofFloat(newBall, "height", newBall.getHeight(), newBall.getHeight() -

 25); stretchAnim2.setDuration(duration/4); stretchAnim2.setRepeatCount(1); stretchAnim2.setInterpolator(new DecelerateInterpolator()); stretchAnim2.setRepeatMode(ValueAnimator.REVERSE); ValueAnimator bounceBackAnim = ObjectAnimator.ofFloat(newBall, "y", endY,

 startY); bounceBackAnim.setDuration(duration); bounceBackAnim.setInterpolator(new DecelerateInterpolator()); // Sequence the down/squash&stretch/up animations AnimatorSet bouncer = new AnimatorSet();//可以定义一套动画器在一起，并设置他们的播放顺序 bouncer.play(bounceAnim).before(squashAnim1);

 bouncer.play(squashAnim1).with(squashAnim2); bouncer.play(squashAnim1).with(stretchAnim1); bouncer.play(squashAnim1).with(stretchAnim2); bouncer.play(bounceBackAnim).after(stretchAnim2); // Fading animation - remove the ball when the animation is done ValueAnimator

 fadeAnim = ObjectAnimator.ofFloat(newBall, "alpha", 1f, 0f); fadeAnim.setDuration(250); fadeAnim.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { balls.remove(((ObjectAnimator)animation).getTarget()); }

 }); // Sequence the two animations to play one after the other AnimatorSet animatorSet = new AnimatorSet(); animatorSet.play(bouncer).before(fadeAnim); // Start the animation animatorSet.start(); return true; } private ShapeHolder addBall(float x, float y)

 { OvalShape circle = new OvalShape(); circle.resize(50f, 50f); ShapeDrawable drawable = new ShapeDrawable(circle); ShapeHolder shapeHolder = new ShapeHolder(drawable); shapeHolder.setX(x - 25f); shapeHolder.setY(y - 25f); int red = (int)(Math.random() * 255);

 int green = (int)(Math.random() * 255); int blue = (int)(Math.random() * 255); int color = 0xff000000 | red << 16 | green << 8 | blue;//这四行代码定义了一个随机颜色，这是可以学习的方式 Paint paint = drawable.getPaint(); //new Paint(Paint.ANTI_ALIAS_FLAG); 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);//定义着色器，使得画笔颜色是渐变的 paint.setShader(gradient); shapeHolder.setPaint(paint); balls.add(shapeHolder); return shapeHolder;

 } @Override protected void onDraw(Canvas canvas) {//这个函数的内容是MyAnimationView所呈现出来的视图的最终样子 for (int i = 0; i < balls.size(); ++i) { ShapeHolder shapeHolder = balls.get(i); canvas.save(); canvas.translate(shapeHolder.getX(), shapeHolder.getY()); shapeHolder.getShape().draw(canvas);//本质上是shapeDrawable的绘制

 canvas.restore(); } } }}