Adding PreferenceFragment to FragmentPagerAdapter

Question

I am trying to add a PreferenceFragment to a FragmentPagerAdapter.

My class extends FragmentActivity, I have tried FragmentTransaction, as shown below as well as trying to add to the container and can't seem to get anything to work. No errors are thrown, in fact nothing happens.

Main Activity:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
    mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setAdapter(mSectionsPagerAdapter);
}

activity_main.xml:

<android.support.v4.view.ViewPager 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >
</android.support.v4.view.ViewPager>

My Options menu selection:

android.app.FragmentManager fm;
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case R.id.menu_settings:
        JJSettings settings = new JJSettings();
        fm = getFragmentManager();
        FragmentTransaction fragTrans = fm.beginTransaction();
        // I also tried `replace()` here as well. Same 'nothing happens' result.
        fragTrans.add(settings, "settings");
        fragTrans.commit();
        return true;
    case R.id.menu_help:
        menuHelp();
        return true;
    default:
        return super.onOptionsItemSelected(item);
    }
}

My settings Fragment:

public class JJSettings extends PreferenceFragment {

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

My preference would be to stick with Fragments if possible, meaning I'd rather not extend PreferenceActivity or take the user to another Activity that calls the PreferenceFragment, if at all possible. I'm just hoping I missed something in my research.

---

Edit

public class SectionsPagerAdapter extends FragmentPagerAdapter {
    private int _count = 2;

    public SectionsPagerAdapter(FragmentManager fm) { super(fm); }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        return super.instantiateItem(container, position);
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
        case 0:
            return new JJMainFragment();
        case 1:
            return new JJPendingFragment();
        default:
            return null;
        }
    }

    public void setCount(int count) { this._count = count; }

    @Override
    public int getCount() { return this._count; }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
        case 0:
            return getString(R.string.c_list).toUpperCase(Locale.ENGLISH);
        case 1:
            return getString(R.string.c_pending).toUpperCase(Locale.ENGLISH);
        }
        return null;
    }
}

Answer 1

This answer led me to the solution of using the v13 support library, which includes a FragmentPagerAdapter that uses bona-fide android.app.Fragments so it can support the PreferenceFragment.

Assuming you use Eclipse and run the new app wizard with the "Scrollable Tabs + Swipe" Navigation (which gives you the v4 pager boilerplate), here are the modifications you need to make to upgrade to v13:

• Delete "android-support-v4.jar" file from your libs folder
• Copy "android-support-v13.jar" from SDK_PATH\extras\android\support\v13; if it's not there, use the SDK manager to install or update "Extras/Android Support Library"

Then, in the Java file:

• Change FragmentPagerAdapter import from v4 to v13
• Change FragmentActivity to a plain Activity
• Change calls to getSupportFragmentManager to getFragmentManager
• Import all necessary classes from android.app instead of android.support.v4
• (Except: you still need to use the v4 ViewPager, but it's compatible)

I've copied the modified source below, verified on latest Jellybean.

MainActivity.java:

package com.example.pagerwithpreferencesfragment;

import java.util.Locale;

import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.os.Bundle;
import android.preference.PreferenceFragment;
import android.support.v13.app.FragmentPagerAdapter; // instead of v4.app...
import android.support.v4.view.ViewPager;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class MainActivity extends Activity { // no longer FragmentActivity

    // these comments are now out-of-date; v13, not v4
    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
     * will keep every loaded fragment in memory. If this becomes too memory
     * intensive, it may be best to switch to a
     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    SectionsPagerAdapter mSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    ViewPager mViewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Create the adapter that will return a fragment for each of the three
        // primary sections of the app.
        mSectionsPagerAdapter = new SectionsPagerAdapter(
                getFragmentManager()); // instead of getSupportFragmentMangager

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.pager);
        mViewPager.setAdapter(mSectionsPagerAdapter);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            // this is just to show it compiles
            if (position == 0) {
                // you should really make this a public class elsewhere..
                return new PreferenceFragment() {
                    @Override
                    public void onCreate(Bundle savedInstanceState) {
                        super.onCreate(savedInstanceState);
                        addPreferencesFromResource(R.xml.settings_preferences);
                    }
                };
            }
            // getItem is called to instantiate the fragment for the given page.
            // Return a DummySectionFragment (defined as a static inner class
            // below) with the page number as its lone argument.
            Fragment fragment = new DummySectionFragment();
            Bundle args = new Bundle();
            args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
            fragment.setArguments(args);
            return fragment;
        }

        @Override
        public int getCount() {
            // Show 3 total pages.
            return 3;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            Locale l = Locale.getDefault();
            switch (position) {
            case 0:
                return getString(R.string.title_section1).toUpperCase(l);
            case 1:
                return getString(R.string.title_section2).toUpperCase(l);
            case 2:
                return getString(R.string.title_section3).toUpperCase(l);
            }
            return null;
        }
    }

    /**
     * A dummy fragment representing a section of the app, but that simply
     * displays dummy text.
     */
    public static class DummySectionFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        public static final String ARG_SECTION_NUMBER = "section_number";

        public DummySectionFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main_dummy,
                    container, false);
            TextView dummyTextView = (TextView) rootView
                    .findViewById(R.id.section_label);
            dummyTextView.setText(Integer.toString(getArguments().getInt(
                    ARG_SECTION_NUMBER)));
            return rootView;
        }
    }

}

settings_preferences.xml:

<?xml version="1.0" encoding="utf-8"?>

<PreferenceScreen
   xmlns:android="http://schemas.android.com/apk/res/android">

   <PreferenceCategory
      android:key="my_category_key"
      android:title="My Title">

       <CheckBoxPreference
         android:key="pref_key"
         android:title="Title"
         android:summary="Summary"
         android:defaultValue="false"
         />

   </PreferenceCategory>

</PreferenceScreen>