Android - 在 ImageView 周围绘制边框

Question

我定义了一个imageView，我想做两个操作：圆润其边缘并在位图周围绘制彩色边框。首先我做得很好，但第二个没有。

这是我对画布所做的：

    Bitmap resizedBitmap = Bitmap.createScaledBitmap(bm, 150, 150, false);
    int min = Math.min(resizedBitmap.getWidth(), resizedBitmap.getHeight());
     Bitmap bitmapRounded = Bitmap.createBitmap(min, min, resizedBitmap.getConfig());
                Canvas canvas = new Canvas(bitmapRounded);
                Paint paint = new Paint();
                paint.setAntiAlias(true);
                paint.setShader(new BitmapShader(resizedBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP));
                canvas.drawRoundRect((new RectF(0.0f, 0.0f, min, min)), min / 2, min / 2, paint);

    avatar.setImageBitmap(bitmapRounded);
    //I tried this, but don't work. 
    avatar.setPadding(1, 1, 1, 1);
    avatar.setBackgroundColor(getResources().getColor(R.color.negro));

谢谢！

Answer 1

你可以得到圆角位图的边框，如下所示

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;
    }