Toolbar is hidden in nested PreferenceScreen

Question

I use PreferenceFragment in ActionBarActivity from support-v7 library.
In the Activity I have Toolbar. Everything goes okay, until I o

Answer 1

In my solution you only need one AppCompatActivity and one PreferenceFragement, but several XML files, each having only one level of PreferenceScreens.

XML file list

• top level PreferenceScreen
• second level PreferenceScreen 0
• second level PreferenceScreen 1
• second level PreferenceScreen 2
• ...

This code is for one sub-level (for simplicity and to get the idea), but you can easily extend it to have arbitrary sub-levels of PreferenceScreens.

SettingsFragment.java

public class SettingsFragment extends PreferenceFragment
{
    private int xmlId;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        xmlId = R.xml.preferences;
        addPreferencesFromResource(xmlId);
    }

    public void changePrefScreen(int xmlId, int titleId)
    {
        this.xmlId = xmlId;
        ((AppCompatActivity)getActivity()).getSupportActionBar().setTitle(getActivity().getResources().getString(titleId));
        getPreferenceScreen().removeAll();
        addPreferencesFromResource(xmlId);
    }

    // will be called by SettingsActivity (Host Activity)
    public void onUpButton()
    {
        if(xmlId == R.xml.preferences) // in top-level
        {
            // Switch to MainActivity
            Intent intent = new Intent(getActivity(), MainActivity.class);
            startActivity(intent);
        }
        else // in sub-level
        {
            changePrefScreen(R.xml.preferences, R.string.settings);
        }
    }

    @Override
    public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen, Preference preference)
    {
        String key = preference.getKey();

        //
        // Top level PreferenceScreen
        //
        if(key.equals("top_key_0"))
        {
            changePrefScreen(R.xml.download_preference_screen, R.string.download_database); // descend into second level
        }

        // ...

        //
        // Second level PreferenceScreens
        //
        if (key.equals("second_level_key_0"))
        {
           // do something...
        }

        // ...
     }

SettingsActivity.java

public class SettingsActivity extends AppCompatActivity
{
    SettingsFragment settingsFragment;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        settingsFragment = new SettingsFragment();

        // Display the fragment as the main content.
        getFragmentManager().beginTransaction()
                .replace(android.R.id.content, settingsFragment)
                .commit();
    }

    //
    // Handle what happens on up button
    //
    @Override
    public boolean onOptionsItemSelected(MenuItem item) 
    {
        switch (item.getItemId()) 
        {
            case android.R.id.home:
                settingsFragment.onUpButton();
                return true;
        }
        return true;
    }

    // ...
}

Technically it should work for all Android versions for which the PreferenceFragment is available.