android - 绘制具有不同边框颜色的圆形Android

Question

public static Bitmap drawCircle(int width,int height, int borderWidth) {
    Bitmap canvasBitmap = Bitmap.createBitmap( width, height, Bitmap.Config.ARGB_8888);
    BitmapShader shader = new BitmapShader(canvasBitmap, TileMode.CLAMP,      
            TileMode.CLAMP);
    Paint paint = new Paint();
    paint.setAntiAlias(true);
    paint.setShader(shader);
    paint.setShader(null);
    paint.setStyle(Paint.Style.STROKE);
    paint.setColor(Color.WHITE);
    paint.setStrokeWidth(borderWidth);  
    Canvas canvas = new Canvas(canvasBitmap);
    float radius = width > height ? ((float) height) / 2f : ((float) width) / 2f;
    canvas.drawCircle(width / 2, height / 2, radius - borderWidth / 2, paint);
    return canvasBitmap;
}

简单的这段代码绘制了一个带有白色边框的圆，但是我希望边框的一部分是黑色的，而另一部分是白色的。 40% 黑色，60% 白色

如何做到这一点？

Answer 1

试试这段代码

class MyView extends View
{
    private Paint paint;

    public MyView(Context context, int x, int y)
    {
        super(context);
        paint = new Paint();
        // PorterDuffXfermode xfermode = new PorterDuffXfermode(PorterDuff.Mode.CLEAR);

        paint.setStyle(Paint.Style.STROKE);
        paint.setColor(Color.RED);


        paint.setAlpha(255);
        // paint.setXfermode(xfermode);
        paint.setAntiAlias(true);
        // setBackgroundColor(Color.BLACK);
    }

    @Override
    protected void onDraw(Canvas canvas)
    {
        canvas.drawCircle(100, 100, 50, paint);
    }
}