java - 为什么我的矩形没有在我的 Canvas 方法中更新？(android java)

Question

所以我制作了一个绘画类，它有一个 ontouchevent 方法，我将矩形的 xpos 设置为触摸事件的 xpos，但矩形没有移动!我该如何纠正？矩形类:

public class myRectangle{
public int xpos;
public int ypos;
public int size;
private Paint paint;
public myRectangle(){
    size = 40;
    paint = new Paint();
    paint.setStyle(Paint.Style.FILL);
    paint.setColor(Color.BLUE);
}
public void drawRectangle(Canvas c,int  x, int y){
    c.drawRect(x, y, size, size, paint);
}

和我的绘画 View :

public class Painting extends View {
myRectangle player;
float x;
float y;
public Painting(Context context) {
    super(context);
    player = new myRectangle();
    // TODO Auto-generated constructor stub
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    // TODO Auto-generated method stub
    x = event.getX();
    y = event.getY();
    String s = Float.toString(event.getX());
    String c = Float.toString(event.getX());

    Log.d(c, s);
    return super.onTouchEvent(event);
}

@Override
protected void onDraw(Canvas canvas) {
    // TODO Auto-generated method stub
    super.onDraw(canvas);
    player.drawRectangle(canvas, (int)x, (int)y);

}

}如果需要，我也可以发布主要 Activity

Answer 1

唯一缺少的是 onTouchEvent 中的 invalidate() 调用。 invalidate() 安排抽签