如何在Android 5.0中删除旋转位图图像后的黑色背景

Question

i have try to remove the black background after the rotate image in my code

Bitmap rotate(float x, Bitmap bitmapOrg) {

    int width = bitmapOrg.getWidth();
    int height = bitmapOrg.getHeight();
    int newWidth = 200;
    int newHeight = 200;

    float scaleWidth = ((float) newWidth) / width;
    float scaleHeight = ((float) newHeight) / height;

    Matrix matrix = new Matrix();

    matrix.postScale(scaleWidth, scaleHeight);
    matrix.postRotate(x);

    Bitmap resizedBitmap = Bitmap.createBitmap(bitmapOrg, 0, 0, width,height, matrix, true);
    //Canvas canvas = new Canvas(resizedBitmap);
    //canvas.drawColor(Color.TRANSPARENT);


    return resizedBitmap;
}

how can i remove black background i have seen that only in my android lolipop , i also try in my emulator Google galaxy nexus - 4.2.2 in that black background is not display .

Answer 1

You must use resizedBitmap.setHasAlpha(true); put that line of code right after you declare your bitmap.