如何在Android中使用圆角位图边框?

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我用下面的方法制作了一个圆角的位图。现在我想围绕位图画一条线:

private BitmapDrawable roundCornered(BitmapDrawable scaledBitmap, int i) {

        Bitmap bitmap = scaledBitmap.getBitmap();

        result = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(),
                Bitmap.Config.ARGB_8888);
        canvas = new Canvas(result);

        color = 0xff424242;
        paint = new Paint();
        rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
        rectF = new RectF(rect);
        roundPx = i;
        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(Color.BLUE);
        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);

        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);
        BitmapDrawable finalresult = new BitmapDrawable(result);
        return finalresult;
    }

我得到了下面的图像,但我的实际需要是我必须在图像周围绘制边框:

提问于
用户回答回答于

我将以下内容放在一起:

public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, int color, int cornerDips, int borderDips, Context context) {
    Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(),
            Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(output);

    final int borderSizePx = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, (float) borderDips,
            context.getResources().getDisplayMetrics());
    final int cornerSizePx = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, (float) cornerDips,
            context.getResources().getDisplayMetrics());
    final Paint paint = new Paint();
    final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
    final RectF rectF = new RectF(rect);

    // prepare canvas for transfer
    paint.setAntiAlias(true);
    paint.setColor(0xFFFFFFFF);
    paint.setStyle(Paint.Style.FILL);
    canvas.drawARGB(0, 0, 0, 0);
    canvas.drawRoundRect(rectF, cornerSizePx, cornerSizePx, paint);

    // draw bitmap
    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
    canvas.drawBitmap(bitmap, rect, rect, paint);

    // draw border
    paint.setColor(color);
    paint.setStyle(Paint.Style.STROKE);
    paint.setStrokeWidth((float) borderSizePx);
    canvas.drawRoundRect(rectF, cornerSizePx, cornerSizePx, paint);

    return output;
}
用户回答回答于

你可以准备下面的9-patch图像,并使用它将其设置为背景 android:background{}:

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