Action Tab background during orientation change doesn't change properly

Question

Action bar navigation tabs are merged in the action bar when going into landscape mode, so I defined a values-land folder with a colors.xml file where I set the appropriate background color and text color for the merged tabs. Long story short:

these are the correct colors for portrait mode

this is what happens when I rotate the screen to landscape mode

When i launch the app starting from landscape mode instead, and then changing to portrait, this is what I get:

the activity starts with the correct colors for landscape, as defined by me in values-land/colors.xml

these is what happens when rotating the screen to portrait mode

Only the tab's text color changes accordingly to my instructions. The activity has launchMode="singleTask" (which is mandatory for my case), but even with launchMode="standard" the problem persists. I'm starting to think this is an API bug... Is there any workaround for this, like some way to force the redrawing of the action bar?

edit: my <activity> tag:

<activity
        android:name="com.rocca.controlloSpese.MainActivity"
        android:label="@string/app_name"
        android:launchMode="singleTask">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

Answer 1

after deeper research and a few attempts, I found out what it was. When switching to landscape mode, the system looks for "-land" qualifiers and updates the views accordingly, like everybody knows. Therefore it updates my tab's text color because it finds a values-land/ directory in which there is a colors.xml file with the specific colors. The tabs' background is defined by drawables and I put them in the drawable directory, because they are the same shape both for landscape and portrait, only colors change. So there is no drawable-land directory, but this means that the system will not redraw the backgrounds and will recycle them, missing the fact that inside those drawables there are references to values that must change. The solution was to add a drawable-land directory with a copy of the background drawables, so that the system will know that it must redraw the views. It will redraw the same views, but at least it will use the different colors.

Answer 2

It seems like you've set up the Android manifest such that the activity isn't destroyed during rotations. Unless you have a strong case to do that, you should let the activity be destroyed and recreated when rotating.