Transparent background is not working

[shantanu-csedu]

There is no effect of transparent background. I tried to add "@android:color/transparent" in xml file but it didn't work. From code geckoView.setBackgroundColor(0x00000000) also doesn't work. Even if I load a html with transparent background in GeckoView, it shows darker color but not transparent.

Interesting is that when I add the following attribute in xml it's always bring the other view (below in framelayout) to top, doesn't matter what is the hierarchy.
android:background="@android:color/transparent"
android:layerType="software"