I have an imageView that uses an alpha channel, is round and basically made up only from black outlines. In a simple instance, I need to, however, display the imageview not as black, but as white. Everything else needs to stay the same. After a bit of googling, this is what I came up with:
ImageButton btnHeader = new ImageButton(this);
btnHeader.SetBackgroundResource(Resource.Drawable.mainmenu_btn_news_bol);
btnHeader.SetColorFilter(new Color(Color.White), PorterDuff.Mode.SrcIn);
This should at least have some effect on the ImageView , but it just doesn't. It is, as if the 3rd line of code just gets jumped. Can anyone maybe explain to me if this is a bug or me?
Setting a color filter directly on the ImageButton will affect only its source image, not the background. That is, it will affect those images set with the SetImage*() methods. If that's what you mean to do, then simply change the SetBackgroundResource() call to SetImageResource().
If, instead, you are trying to filter the background specifically, you'll need to set the filter directly on the background Drawable. For example:
btnHeader.Background.SetColorFilter(new Color(Color.White), PorterDuff.Mode.SrcIn);
Furthermore, separate Drawables created from the same resource will share a common state by default, so if you have multiple Views using the same resource image, then setting a filter on one will affect all of the others, as well. You can force a new, separate state to be created for a particular Drawable by calling Mutate() on it first, before applying the filter. For example, with the background image:
btnHeader.Background.Mutate().SetColorFilter(new Color(Color.White), PorterDuff.Mode.SrcIn);