Stacked ActionBar tab bar not filling parent

Question

I\'m creating Action Bar navigation tabs, but when the Action Bar is stacked the tabs are not getting the whole width space. I have a foto to illustrate it.

Answer 1

I don't think that's feasible at the moment. I've been trying to do the same thing for the past few days, and here's what I have found so far.

The Android framework uses a class called ActionBarPolicy to set some rules regarding the ActionBar's behavior. In this file (which can be found here : https://github.com/android/platform_frameworks_base/blob/master/core/java/com/android/internal/view/ActionBarPolicy.java), you'll find a method called getStackedTabMaxWidth() which returns a dimen value (currently set in the ressources at 160dip).

This value is used is the inner class TabView placed in ScrollingTabContainerView (https://github.com/android/platform_frameworks_base/blob/master/core/java/com/android/internal/widget/ScrollingTabContainerView.java). TabView is the private implementation of the ActionBar's TabBar.

Now I don't think this value nor this behavior can be modified, except maybe using Reflection. I don't know enough about it to do so, so if someone could manage such a thing, don't hesitate to say so, because this really is a bad behavior which doesn't look great on some tablets.

Answer 2

Android stacked action bar tabs do not have adjustable widths.

"Stacked action bar tabs now have a width limit. This prevents super-wide tabs that can span the whole screen. The cluster of tabs is centered if it does not span the full width. " https://android.googlesource.com/platform/frameworks/base/+/b8139af3dcae80c0030afd0354dc424a7c72c3d9

The solution is to use the TabLayout API from the Android Design Support Library released with Android 5.0. The Android Support library requires the appcompat library, but that dependency is resolved for you if you build using gradle.

For most developers, this will not be an issue, but the TabLayout setup requries at least SDK API level 22, because the appcompat dependency is compiled against 22. However, TabLayout does not have a runtime dependency on 22, meaning you can run it on devices up to API level 7.

tl;r - Use Tablayout from Android Design Library. Requires API level 22 on developer, but can run on older phones up to v7.