How can I maintain state when switching between action bar tabs / fragments?

android, java

Solution

When you are switching between fragments, don't detach fragments just hide. Example:

@Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
      FragmentManager fm = getFragmentManager(); 
      if(fm.findFragmentByTag(tab.getTag().toString()) == null){
           ft = fm.beginTransaction();
           FragmentContent contentfrag = new FragmentContent();
           ft.add(R.id.framelayout, contentfrag, tab.getTag().toString());
           ft.addToBackStack("BackStack" + tab.getTag().toString());
       }
       else{
           Fragment frag = fm.findFragmentByTag(tab.getTag().toString());
           ft.show(frag);
      }
}

    @Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        Fragment frag = this.getFragmentManager().findFragmentByTag(tab.getTag().toString());
    ft.hide(frag);

}

Problem

I have a number of fragments attached to the Android action bar as tabs. I can switch between them without problems. However, if one of the fragments has a `TextView` (for example), and I alter the text of that `TextView`, the new text is not kept if I switch to another tab and back. I've tried overriding `onSaveInstanceState()`, but it appears it is not called when I switch tabs, as `savedInstanceState` is `null` every time `onActivityCreated()` is called (i.e. every time that tab is reopened). I looked into altering `onPause()` such that it calls `onSaveInstanceState()`, but `onPause()` doesn't have access to the state bundle, so I don't see how I can do that. What is the best way to keep state in a tab when going back and forth between tabs?

Original source