Question

I’m compiling using API 16, but with the minimum supported API set to 8. I’m trying to set the alpha of an ImageView in XML, but every time I use

<ImageView 
    android:id="@+id/image"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:alpha="0"
    .
    .
    . />

AAPT complains that alpha isn’t a valid attribute, even if the documentation in the android site states that ImageView's supposed to inherit it from View.

Is this a bug, or is this really how it’s supposed to work. I’d set the Visibility, but that won’t work well with my animations to show and hide the image.

Answer 1

Yes. You said that your min is 8. However, the View’s alpha xml attribute doesn’t appear until API Level 11.

http://developer.android.com/reference/android/view/View.html#setAlpha(float)