Android UI How to - Using a PreferenceFragment

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In Android, you can use the PreferenceActivity base class to display an activity for the user to edit the preferences.

You can use the PreferenceFragment class to do the same thing.

Example

Populate the res/xml/preferences.xml file as follows:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen
    xmlns:android="http://schemas.android.com/apk/res/android">

    <PreferenceCategory android:title="Category 1">
        <CheckBoxPreference
            android:title="Checkbox"
            android:defaultValue="false"
            android:summary="True of False"
            android:key="checkboxPref" />
        </PreferenceCategory>

    <PreferenceCategory android:title="Category 2">
        <EditTextPreference
            android:name="EditText"
            android:summary="Enter a string"
            android:defaultValue="[Enter a string here]"
            android:title="Edit Text"
            android:key="editTextPref" />
        <RingtonePreference
            android:name="Ringtone Preference"
            android:summary="Select a ringtone"
            android:title="Ringtones"
            android:key="ringtonePref" />
        <PreferenceScreen
            android:title="Second Preference Screen"
            android:summary=
                "Click here to go to the second Preference Screen"
            android:key="secondPrefScreenPref">
            <EditTextPreference
                android:name="EditText"
                  android:summary="Enter a string"
                  android:title="Edit Text (second Screen)"
                  android:key="secondEditTextPref" />
          </PreferenceScreen>
      </PreferenceCategory>

</PreferenceScreen>

Populate the Fragment1.java file as follows:

import android.os.Bundle;
import android.preference.PreferenceFragment;

public class Fragment1 extends PreferenceFragment {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //---load the preferences from an XML file---
        addPreferencesFromResource(R.xml.preferences);
    }
}

Modify the MainActivity.java file as shown:

import android.app.Activity;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
//from ww w . j  a  v a2 s.co  m
public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction =
            fragmentManager.beginTransaction();
        Fragment1 fragment1 = new Fragment1();
        fragmentTransaction.replace(android.R.id.content, fragment1);
        fragmentTransaction.addToBackStack(null);
        fragmentTransaction.commit();
    }
}

If you look at the File Explorer (available in the DDMS perspective), you will be able to locate the preferences file located in the /data/data/com.java2s.PreferenceFragmentExample/shared_prefs/ folder.

All changes made by the user are persisted in this file.

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