Android 绘制气泡

效果图

思想

1.绘制气泡

随机xy轴，r半径，速度，随机xy方向(方向就是x和y加减同一个随机偏移量)，随机透明度

2.气泡移动和复用气泡

 在原来的xy+=或者-=偏移量，每一次便宜判断xy是否超过屏幕宽度和高度，超过就重新随机生成

3.代码实现

制气泡效果
public class QiPao extends View {
    public Paint paint;
    public DisplayMetrics displayMetrics;
    public QiPao(Context context) {
        this(context,null);
    }

    public QiPao(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs,0);
        displayMetrics = context.getResources().getDisplayMetrics();
        init();
    }

    public QiPao(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }
    Timer timer;
    @SuppressLint("ResourceAsColor")
    public void init(){
        paint = new Paint();
        paint.setAntiAlias(true);
        timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                postInvalidate();//在子线程中执行  postInvalidate()会使onDrow()方法得到执行
            }
        }, 300, 10);
        for (int i = 0; i <100 ; i++) {
            QiPaoPoin qiPaoPoin = new QiPaoPoin();
            //点的位置
            qiPaoPoin.setX(random.nextFloat()*displayMetrics.widthPixels);
            qiPaoPoin.setY(random.nextFloat()*displayMetrics.heightPixels);
            int v = random.nextInt(2)+1;
            qiPaoPoin.setxSke(random.nextFloat()*((v==1)?2:-2));
            v = random.nextInt(2)+1;
            qiPaoPoin.setySke(random.nextFloat()*((v==1)?2:-2));
            qiPaoPoin.setDiaph(random.nextInt(100)+100);
            qiPaoPoin.setSpeet(random.nextFloat());
            //圆的半径
            qiPaoPoin.setRadius(random.nextInt(170)+30);
            list.add(qiPaoPoin);
        }
    }

    @SuppressLint("NewApi")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        aaa();
        list.forEach((element)->{
            paint.setARGB(element.getDiaph(),255,255,255);
                canvas.drawCircle(element.getX(),element.getY(),element.getRadius(),paint);
        });
    }

    List<QiPaoPoin> list =new ArrayList<>();
    Random random = new Random();
    float yske,xske;//xy轴偏移量
    int radius;//半径
    public void aaa(){
        for (int i = 0; i <list.size() ; i++) {
            yske = list.get(i).getySke();//y偏移
            xske = list.get(i).getxSke();//x偏移
            radius = list.get(i).getRadius();//半径
            //如果不是按住就解锁
            if(!isDown){
                list.get(i).setLock(false);
            }
            if(list.get(i).isLock()){
                if(isMove){//跟随鼠标移动
                    list.get(i).setY(lastY);
                    list.get(i).setX(lastX);
                }
            }else {
                //点击不动
                if(isDown&&(lastX<=list.get(i).getX()+list.get(i).getRadius()&&lastX>=list.get(i).getX()-list.get(i).getRadius())&&(lastY<=list.get(i).getY()+list.get(i).getRadius()&&lastY>=list.get(i).getY()-list.get(i).getRadius())){
                    if(isMove){//跟随鼠标移动
                        list.get(i).setY(lastY);
                        list.get(i).setX(lastX);
                        list.get(i).setLock(true);
                    }
                }else {
                    //这里才是真正的复用 和实现移动气泡
                    if(list.get(i).getY()-(yske+radius)<displayMetrics.heightPixels&&list.get(i).getY()-(yske+radius)>-radius*2){
                        list.get(i).setY(list.get(i).getY()+yske);
                    }else {//结束完随机y轴出现 和任意方向飘动
                        list.get(i).setY(random.nextFloat()*displayMetrics.heightPixels);
//                int v = random.nextInt(2)+1;
//                list.get(i).setxSke(random.nextFloat()*((v==1)?3:-3));
//                v = random.nextInt(2)+1;
//                list.get(i).setySke(random.nextFloat()*((v==1)?3:-3));
                    }
                    if(list.get(i).getX()-(xske+radius)<displayMetrics.widthPixels&&list.get(i).getX()-(xske+radius)>-radius*2){
                        list.get(i).setX(list.get(i).getX()+xske);
                    }else{//结束完随机x轴出现  和任意方向飘动
                        list.get(i).setX(random.nextFloat()*displayMetrics.widthPixels);
                        int v = random.nextInt(2)+1;
                        list.get(i).setxSke(random.nextFloat()*((v==1)?2:-2));
                        v = random.nextInt(2)+1;
                        list.get(i).setySke(random.nextFloat()*((v==1)?2:-2));
                    }
                }
            }

        }
    }

    public int lastX,lastY;
    public boolean isDown,isMove;
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        int x = (int) event.getX();
        int y = (int) event.getY();
        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN:
                // 记录触摸点坐标
                lastX = x;
                lastY = y;
                isDown = true;
                break;
            case MotionEvent.ACTION_MOVE:
                lastX = x;
                lastY = y;
                isMove = true;
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
                isDown = false;
                isMove = false;
                break;
        }
        return true;
    }

    public void dis(){
        timer.cancel();
    }