[Android实例] 水下气泡上升界面效果

该篇文章从eoeAndroid搬迁过来的，原文地址：[Android实例] 水下气泡上升界面效果

首先声明，该效果并不是用动画实现的，而是用自定义View实现的，在onDraw方法里面调用invalidate()函数，实现气泡上升效果

气泡类：

private class Bubble {
/** 气泡半径 */
private int 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;
}

另起线程生成气泡：

if (!starting) {
starting = true;
new Thread() {
public void run() {
while (true) {
if(isPause){
continue;
}
try {
Thread.sleep(random.nextInt(3) * 300);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
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();
}

绘制渐变背景和气泡：

Paint paint = new Paint();
// 绘制渐变正方形
Shader shader = new LinearGradient(0, 0, 0, height, new int[] {
getResources().getColor(R.color.blue_bright),
getResources().getColor(R.color.blue_light),
getResources().getColor(R.color.blue_dark) },
null, Shader.TileMode.REPEAT);
paint.setShader(shader);
canvas.drawRect(0, 0, width, height, paint);
paint.reset();
paint.setColor(Color.WHITE);
paint.setAlpha(200);
List<Bubble> list = new ArrayList<Bubble>(bubbles);
for (Bubble bubble : list) {
if (bubble.getY() - bubble.getSpeedY() <= 0) {
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());
bubbles.set(i, bubble);
canvas.drawCircle(bubble.getX(), bubble.getY(),
bubble.getRadius(), paint);
}
}

下载地址：项目代码