Android Preferences: How to load the default values when the user hasn't used the preferences-screen?

Question

I am using a PreferenceActivity to let the user set some values. I am feeding it the xml file with the defined preferences.

I have set all the android:defaultValue="" for them.

When I start my application, I need the preferences, or if they are not set yet manually, I want the default values:

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
boolean value = prefs.getBoolean("key"), false); 

However, when android:defaultValue="true" I still get false. So, it looks like the defaultValues set in the XML are not used anywhere but when initializing the preferences-screen.

I don't want to hardcode the default values in the getBoolean() method. So, is there a way get the default-values with only defining these in 1 place?

Answer 1

For example extending DialogPreference I do this:

@Override
protected void onSetInitialValue(boolean restore, Object defaultValue) {
    super.onSetInitialValue(restore, defaultValue);

    if (restore) {
        mValue = shouldPersist() ? getPersistedString(mDefault) : mDefault;
    } else {
        mValue = mDefault;
    }
}

mDefault can be:

• mContext.getResources().getString(attrs.getAttributeResourceValue(androidns,"defaultValue", 100));
• something you have indexed in R.

Answer 2

Hi, this question is similar to mine:

initialize-preferences-from-xml-in-main-activity

Just use this code in onCreate method:

PreferenceManager.setDefaultValues(this, R.xml.preference, false);

It will load your preferences from XML, and last parameter (readAgain) will guarantee that user preferences won't be overwritten.

Take a look into PreferenceManager.setDefaultValues in Android API for further investigation.