Android_实现水滴效果

最新推荐文章于 2021-05-26 07:12:57 发布

原创最新推荐文章于 2021-05-26 07:12:57 发布 · 1.6k 阅读

CC 4.0 BY-SA版权

该博客介绍了如何在Android中实现水滴效果。通过创建`Cricle`和`Point`实体类来存储圆的位置和属性，然后在自定义`MyView`视图中绘制这些圆，并使用线程`ViewThread3`改变圆的半径和透明度，模拟水滴动态效果。同时，`createCircle`线程用于创建新的圆，而`MainActivity`负责处理触摸事件，动态添加和移除点及圆。

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编写实体类：
public class Cricle {
    float x;
    float y;
    int pointIndex;
    float r=0;//初始半径
    int alpha=255;//初始透明度
    public Cricle(float x,float y,int pointIndex){
        this.x=x;
        this.y=y;
        this.pointIndex=pointIndex;
    }

}
public class Point {
    float pointx;
    float pointy;
    int pointIndex;
    public Point(float pointx, float pointy, int pointIndex) {
        super();
        this.pointx = pointx;
        this.pointy = pointy;
        this.pointIndex = pointIndex;
    }

}
编写控件：
public class MyView extends View {
    public List<Cricle> cs=new ArrayList<Cricle>();
    public List<Point> ps=new ArrayList<Point>();
    Context context;
    Thread thread=new Thread();
    ViewThread3 thread3=new ViewThread3();
    createCircle thread4=new createCircle();
    float x=100;
    float y=100;
    float x2=80;
    float y2=80;
    int i=0;

    public MyView(Context context) {
        super(context);
        this.context=context;
        thread.start();
        thread4.start();
        thread3.start();


    }

    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);
        Paint paint=new Paint();
        paint.setColor(Color.GREEN);
        paint.setStyle(Paint.Style.STROKE);
        //从list中拿到圆并画出来
        for (int i = 0; i < cs.size(); i++) {
            paint.setStyle(Paint.Style.STROKE);
            paint.setAntiAlias(true);
            paint.setStrokeWidth(3);
            paint.setColor(Color.argb(cs.get(i).alpha, 0, 0, 255));
            canvas.drawCircle(cs.get(i).x, cs.get(i).y, cs.get(i).r, paint);
        }

    }

    //线程改变圆的半径和透明度和移除圆
    public class ViewThread3 extends Thread {
        @Override
        public void run() {
            super.run();
            while(true){
                try {
                    thread.sleep(300);
                    for(int i = 0; i < cs.size(); i++){
                        cs.get(i).r+=3;
                        cs.get(i).alpha-=8;
                        if(cs.get(i).alpha<0){
                            cs.remove(cs.get(i));
                        }
                        postInvalidate();
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }

    }
    //线程创建圆
    public class createCircle extends Thread {
        @SuppressWarnings("static-access")
        @Override
        public void run() {
            super.run();
            while(true){
                try {
                    thread.sleep(200);
                    for(int i = 0; i < ps.size(); i++){
                        Cricle c=new Cricle(ps.get(i).pointx, ps.get(i).pointy, ps.get(i).pointIndex);
                        cs.add(c);
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();

                }
            }
        }
    }
}
编写Activity:
public class MainActivity extends Activity {
    MyView view;
    GestureDetector gs=null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        view=new MyView(MainActivity.this);

        setContentView(view);


    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        int action=event.getAction();
        int actionCode=(action&0x000000ff)>=5?(action&0x000000ff)-5:(action&0x000000ff);
        int pointIndex=action>>8;
        int pointId=event.getPointerId(pointIndex);
        switch(actionCode){
            case MotionEvent.ACTION_DOWN:
                Point cp=new Point(event.getX(pointIndex), event.getY(pointIndex), pointIndex);
                addPoint(cp);
                break;
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_OUTSIDE:
            case MotionEvent.ACTION_UP:
                removePoint(pointId);
                break;
            case MotionEvent.ACTION_MOVE:
                for(int i=0;i<event.getPointerCount();i++){
                    int id=event.getPointerId(i);
                    Point p=getPoint(id);
                    if(null!=p){
                        p.pointx=event.getX(i);
                        p.pointy=event.getY(i);
                    }
                }
                break;
        }

        return true;
    }
    public void addCircle(Cricle circle){
        view.cs.add(circle);
    }
    public void addPoint(Point p){
        view.ps.add(p);
    }
    public void removePoint(int id){
        Iterator<Point> it= view.ps.iterator();
        while(it.hasNext()){
            Point p=it.next();
            if(p.pointIndex==id){
                it.remove();
            }
        }
    }
    public void removeCircle(int id){
        Iterator<Cricle> it= view.cs.iterator();
        while(it.hasNext()){
            Cricle c=it.next();
            if(c.pointIndex==id){
                it.remove();
            }
        }
    }
    public Cricle getCircle(int id){
        for(int i=0;i<view.cs.size();i++){
            if(view.cs.get(i).pointIndex==id){
                return view.cs.get(i);
            }
        }
        return null;
    }
    public Point getPoint(int id){
        for(int i=0;i<view.ps.size();i++){
            if(view.ps.get(i).pointIndex==id){
                return view.ps.get(i);
            }
        }
        return null;
    }
}