Android how to set opacity in bitmap xml

Question

I need to create a bitmap resource via xml, like:

<?xml version="1.0" encoding="utf-8"?>
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
    android:src="@drawable/btn_home"
    >
</bitmap>

But I need to set opacity to this bitmap. Is there a way I can do this using this xml? I know that it would work if Shape tag was allowed inside of the bitmap tag, but I tried with no success.

I added android:alpha=".5" to the bitmap definition with no luck. Anyone else been able to figure this out? — lostintranslation, Dec 06 '15 at 14:29

score 3 · Answer 1 · edited May 23 '17 at 12:31

If you’re displaying the Bitmap in an ImageView, you can probably use the ImageView.setAlpha(int) method. However, if the ImageView is accesed via RemoteViews, as is the case when updating a widget, you won’t be able to invoke this method (if you try to call it via RemoteViews.setInt(int, String, int) you’ll get an exception telling you as much).

 private Bitmap adjustOpacity(Bitmap bitmap, int opacity)
    {
        Bitmap mutableBitmap = bitmap.isMutable()
                               ? bitmap
                               : bitmap.copy(Bitmap.Config.ARGB_8888, true);
        Canvas canvas = new Canvas(mutableBitmap);
        int colour = (opacity & 0xFF) << 24;
        canvas.drawColor(colour, PorterDuff.Mode.DST_IN);
        return mutableBitmap;
    }

More info. and most common just like you problem. How to Set Opacity (Alpha) for View in Android

Documentation of Bitmap from developer.android.com.

Thanks for your input. But I would like to set the opacity in the xml, so I can use in a selector later. — Comic Sans MS Lover, May 29 '12 at 14:06
@ComicSansMSLover: I have used `android:alpha="0.6"` in selector but its not working in APL level 20 and below. Did you get any way to do this? — Ashish Tiwari, May 25 '16 at 06:36

Android how to set opacity in bitmap xml

1 Answers1