RingtonePreference is always null :(

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <PreferenceCategory android:title="Notifications">
    <CheckBoxPreference 
            android:key="vibration"
            android:title="Vibrate" 
            android:summary="Vibrate phone for notifications" />
    <CheckBoxPreference 
     开发者_开发知识库       android:key="play_tone"
            android:title="Play Ringtone" 
            android:summary="Play Ringtone for notifications" />
    <RingtonePreference
            android:key="app_ringtone"
            android:dependency="play_tone"
            android:title="Select Ringtone"
            android:ringtoneType="notification"
            android:showDefault="true"
            android:shouldDisableView="true"
            android:summary="Pick a Ringtone" />
    </PreferenceCategory>
</PreferenceScreen>

This is my preference xml. But,

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
prefs.getString("app_ringtone", null);

always returns null. I am debugging on a device (HTC Wildfire).

In my case problem was that I overrided onActivityResult in PreferenceActivity and didn't invoke super.onActivityResult(...). Now it works fine:

public synchronized void onActivityResult(final int requestCode,
    int resultCode, final Intent data) {

    super.onActivityResult(requestCode, resultCode, data);
}

Here is a sample project demonstrating collecting preferences, including ringtones. If this does not work on your device, then there may be a compatibility problem with the device.

Problematic XML:

<activity android:name="Activity1" 
    android:label="Activity 1"/>
<activity android:name="Activity2" 
    android:label="Activity 2" />
<activity android:name="Settings"  
    android:label="Settings" />

I changed the android:name="Activity1" to android:name=".Activity1" FOR ALL ACTIVITIES and the code started working. The code also malfunctions if the android:showSilent="false" attribute is included in the RingtonePreference may be this is a bug. I figured this out after a lot of trial and errors. Any ideas, pls enlighten @Commonsware.

Working XML:

<activity android:name=".Activity1" 
    android:label="Activity 1"/>
<activity android:name=".Activity2" 
    android:label="Activity 2" />
<activity android:name=".Settings"  
    android:label="Settings" />