问题
I am building an Android app and want to have a button always visible on the actionBar. I followed this guide and others, but none of them seem to solve my problem (although they are very close I guess...).
I have the package "app" and use app:showAsAction="always". No error is shown, but no button on the bar as well. When I change it to android:showAsAction="always" the button appears on the bar, but AndroidStudio tells me I should go for "app:showAsAction with appCompat...".
I have a custom theme with parent="@android:style/Theme.Holo.Light.DarkActionBar"> and for the bar itself: parent="@android:style/Widget.Holo.Light.ActionBar.Solid.Inverse">.
Should I change something and get app:showAsAction working, or ignore AndroidStudio error message and go for android:showAsAction?
回答1:
This is the documentation of the lint rule:
AppCompatResource
Summary: Menu namespace
Priority: 5 / 10
Severity: Error
Category: Usability
When using the appcompat library, menu resources should refer to the showAsAction in the app: namespace, not the android: namespace.
Similarly, when not using the appcompat library, you should be using the android:showAsAction attribute.
I think the problem is that you are mixing Framework Activity and AppCompat menu.
You should use AppCompatActivity with AppCompat Action bar and app:showAsAction; or Activity with android:showAsAction.
来源：https://stackoverflow.com/questions/26412474/appshowasaction-vs-androidshowasaction