Android Semitransparent Bitmap Background Is Black

I'm trying to create semitransparent bitmaps, I used this code: private Bitmap SemiTransparent(Bitmap bitmap, int opacity) { // Create an array to hold the data of bitmap for

Solution 1:

Use this method to make a bitmap transparent:

/**
 * @param bitmap The source bitmap.
 * @param opacity a value between 0 (completely transparent) and 255 (completely
 * opaque).
 * @return The opacity-adjusted bitmap.  If the source bitmap is mutable it will be
 * adjusted and returned, otherwise a new bitmap is created.
 */private Bitmap adjustOpacity(Bitmap bitmap, int opacity)
{
    BitmapmutableBitmap= bitmap.copy(Bitmap.Config.ARGB_8888, true);
    Canvascanvas=newCanvas(mutableBitmap);
    intcolour= (opacity & 0xFF) << 24;
    canvas.drawColor(colour, PorterDuff.Mode.DST_IN);
    return mutableBitmap;
}

See an explanation here: http://blog.uncommons.org/2011/01/12/adjusting-the-opacity-of-an-android-bitmap/

In the blog-post it checks if the bitmap is mutable or not - which can cause problems if the bitmap is mutable but doesn't have the config ARGB_8888 - so use my method instead.