冒泡动画的实现

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package us.eiyou.bubblelayout;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

//模拟海底气泡上升的自定义控件
//修改了一些细节

public class BubbleLayout extends View {

private List<Bubble> bubbles = new ArrayList<Bubble>();
private Random random = new Random();//生成随机数
private int width, height;
private boolean starting = false;

public BubbleLayout(Context context) {
super(context);
}

public BubbleLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}

public BubbleLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
width = getWidth();
height = getHeight();
if (!starting) {
starting = true;
new Thread() {
public void run() {
while (true) {
try {
Thread.sleep(random.nextInt(3) * 300);
} catch (InterruptedException e) {
e.printStackTrace();
}
Bubble bubble = new Bubble();
int radius = random.nextInt(30);
while (radius == 0) {
radius = random.nextInt(30);
}
float speedY = random.nextFloat()*5;
while (speedY < 1) {
speedY = random.nextFloat()*5;
}
bubble.setRadius(radius);
bubble.setSpeedY(speedY);
bubble.setX(width / 2);
bubble.setY(height);
float speedX = random.nextFloat()-0.5f;
while (speedX == 0) {
speedX = random.nextFloat()-0.5f;
}
bubble.setSpeedX(speedX*2);
bubbles.add(bubble);
}
};
}.start();
}
Paint paint = new Paint();
// 绘制渐变正方形作为背景
// 我更倾向于用图片做背景
/*
Shader shader = new LinearGradient(0, 0, 0, height, new int[] {
getResources().getColor(android.R.color.holo_blue_bright),
getResources().getColor(android.R.color.holo_blue_light),
getResources().getColor(android.R.color.holo_blue_dark) },
null, Shader.TileMode.REPEAT);
paint.setShader(shader);
canvas.drawRect(0, 0, width, height, paint);
*/
//绘制气泡
paint.reset();
paint.setColor(0X669999);//灰白色
paint.setAlpha(45);//设置不透明度：透明为0，完全不透明为255
List<Bubble> list = new ArrayList<Bubble>(bubbles);
//依次绘制气泡
for (Bubble bubble : list)
{
//碰到上边界从数组中移除
if (bubble.getY() - bubble.getSpeedY() <= 0)
{
bubbles.remove(bubble);
}
//碰到左边界从数组中移除
else if(bubble.getX() - bubble.getRadius() <= 0)
{
bubbles.remove(bubble);
}
//碰到右边界从数组中移除
else if(bubble.getX() + bubble.getRadius() >= width)
{
bubbles.remove(bubble);
}
else
{
int i = bubbles.indexOf(bubble);
if (bubble.getX() + bubble.getSpeedX() <= bubble.getRadius()) {
bubble.setX(bubble.getRadius());
} else if (bubble.getX() + bubble.getSpeedX() >= width
- bubble.getRadius()) {
bubble.setX(width - bubble.getRadius());
} else {
bubble.setX(bubble.getX() + bubble.getSpeedX());
}
bubble.setY(bubble.getY() - bubble.getSpeedY());

//海底溢出的甲烷上升过程越来越大（气压减小）
//鱼类和潜水员吐出的气体却会越变越小（被海水和藻类吸收）
//如果考虑太多现实情景的话，代码量就会变得很大，也容易出现bug
//感兴趣的读者可以自行添加
//bubble.setRadius(bubble.getRadius());

bubbles.set(i, bubble);
canvas.drawCircle(bubble.getX(), bubble.getY(),
bubble.getRadius(), paint);
}
}
//刷新屏幕
invalidate();
}

//内部VO，不需要太多注释吧？
private class Bubble {
//气泡半径
private float radius;
//上升速度
private float speedY;
//平移速度
private float speedX;
//气泡x坐标
private float x;
// 气泡y坐标
private float y;

public float getRadius() {
return radius;
}

public void setRadius(float radius) {
this.radius = radius;
}

public float getX() {
return x;
}

public void setX(float x) {
this.x = x;
}

public float getY() {
return y;
}

public void setY(float y) {
this.y = y;
}

public float getSpeedY() {
return speedY;
}

public void setSpeedY(float speedY) {
this.speedY = speedY;
}

public float getSpeedX() {
return speedX;
}

public void setSpeedX(float speedX) {
this.speedX = speedX;
}

}
}

冒泡动画的实现

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原文地址：http://www.cnblogs.com/jetereting/p/4414804.html