Android 自定义View画圆环统计图

public class MyView extends View {

    public MyView(Context context) {
        super(context);
    }

    public MyView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public void setData() {
        //设置数据
        invalidate();//用它来刷新view，显示设置数据后的图
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // 获取控件的高度和宽度
        int width = getWidth();
        int height = getHeight();
        
        Log.e("MyView", "width:" + width);
        Log.e("MyView", "height:" + height);

        Paint paint_bg = new Paint();
        paint_bg.setStrokeWidth(100);
        paint_bg.setStyle(Paint.Style.FILL);
        paint_bg.setColor(Color.parseColor("#FF0000"));

        int banjing_bg;
        if (width > height) {
            banjing_bg = height / 2 - 100;
        } else {
            banjing_bg = width / 2 - 100;
        }
        Log.e("MyView", "banjing:" + banjing_bg);
        RectF oval = new RectF(width / 2 - banjing_bg, height / 2 - banjing_bg, width / 2 + banjing_bg, height / 2 + banjing_bg);
        canvas.drawArc(oval, 0, 270, true, paint_bg);


        Paint paint = new Paint();
        paint.setStrokeWidth(100);
        paint.setStyle(Paint.Style.FILL);
        paint.setColor(Color.parseColor("#FFFFFF"));
        int banjing;
        if (width > height) {
            banjing = height / 2 - 200;
        } else {
            banjing = width / 2 - 200;
        }
        Log.e("MyView", "banjing:" + banjing);
        RectF oval1 = new RectF(width / 2 - banjing, height / 2 - banjing, width / 2 + banjing, height / 2 + banjing);
        canvas.drawArc(oval1, 0, 360, true, paint);

    }

}

刚开始宽高一直设置不对，后来画了个图，算了一下到底应该是多少，才弄对，看来数学还是很有用的。

效果图：

原图是没有变形的，一个正圆的圆环，不知道上传之后会变成什么样子。