着色矩形问题

Question

我正在尝试开发我的第一个Android游戏。我的问题是，无论我为CharSprite矩形设置什么颜色，它始终显示为黑色。我尝试将绘制样式更改为FILL或FILL和STROKE或使用RGB值设置绘制。我不知道问题是什么。 canvas.drawColor方法调用非常有效。

    import android.graphics.Canvas;
    import android.graphics.Color;
    import android.graphics.Paint;
    import android.graphics.Rect;

    public class CharSprite {

    private Paint paint;
    private int xPos;
    private int yPos;
    private boolean goingDown;

    public CharSprite(int xPos, int yPos) {

        this.paint = new Paint(Color.RED);
        this.goingDown = true;
        this.xPos = xPos;
        this.yPos = yPos;

    }

    public void draw(Canvas canvas) {

       Rect rect = new Rect(xPos - 50, yPos -50, xPos+50, yPos+50);
       canvas.drawRect(rect, this.paint);

    }
}




    import android.content.Context;
      import android.graphics.Canvas;
      import android.graphics.Color;
      import android.graphics.Paint;
      import android.text.method.Touch;
      import android.view.MotionEvent;
      import android.view.SurfaceView;
      import android.view.SurfaceHolder;

     public class GameView extends SurfaceView implements SurfaceHolder.Callback {

    private MainThread thread;
    private CharSprite charSprite;

    public GameView(Context context) {
        super(context);
        getHolder().addCallback(this);
        thread = new MainThread(getHolder(), this);
        setFocusable(true);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        charSprite = new CharSprite(300, 300);
        thread.setRunning(true);
        thread.start();
    }

    @Override
    public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        boolean retry = true;
        while (retry) {
            try {
                thread.setRunning(false);
                thread.join();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            retry = false;
        }
    }

    public void update() {

    }

    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);

            canvas.drawColor(Color.WHITE);
            charSprite.draw(canvas);

    }
}