Question

我花了一整天的时间试图找出，如何用随机颜色绘制正方形，填满整个屏幕。我认为发生的是，当调用drawRect（）时，它会重绘先前的绘制，这没有任何意义，但它是我得到的全部。这是代码，我不知道还能做什么，解决这个问题，这是结果。 http://i.imgur.com/a083U0a.png

public class MyView extends View {
    public MyView(Context context) {
        super(context);
    }

    @Override
    protected void onDraw(Canvas canvas) {

        super.onDraw(canvas);
        int numberPerRow = 10;
        int x = getWidth()/numberPerRow;
        int y = getHeight();



        for(int i = 0; i < 50; i++){
            for (int j = 0; i <= numberPerRow; j++){
                Paint paintTopRight = new Paint();
                int randColor = randomColor();
                paintTopRight.setColor(randColor);
                canvas.drawRect(j*x,i*x,x,x,paintTopRight);
            }
        }
    }


    public int randomColor() {

        int r = (int) (0xff * Math.random());
        int g = (int) (0xff * Math.random());
        int b = (int) (0xff * Math.random());

        return Color.rgb(r, g, b);
    }
}

Answer 1

您的for循环似乎有拼写错误;你应该使用`j。

时使用i

将新的onDraw(Canvas canvas)方法更改为

@Override
protected void onDraw(Canvas canvas) {

    super.onDraw(canvas);
    int numberPerRow = 10;
    int x = getWidth()/numberPerRow;
    int y = getHeight();



    for(int i = 0; i < 50; i++){
        for (int j = 0; j <= numberPerRow; j++){
            Paint paintTopRight = new Paint();
            int randColor = randomColor();
            paintTopRight.setColor(randColor);
            canvas.drawRect(j*x,i*x,x,x,paintTopRight);
        }
    }
}

Android canvas drawRect（）也重绘了以前的绘制

1 个答案: