What's different between OnPreferenceChangeListener and OnSharedPreferenceChangeListener

问题

I want to get value of a checkboxpreference. which method is suitable for listen to preference?

And what's real difference between OnPreferenceChangeListener and OnSharedPreferenceChangeListener ?!

UPDATE Why onSharedPreferenceChanged not called?

public class Setting extends PreferenceActivity implements
        OnSharedPreferenceChangeListener // ,OnPreferenceChangeListener
{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.preferences);// deprecated warning
    }

    @Override
    public void onSharedPreferenceChanged(
            SharedPreferences sharedPreferences, String key) {// DO Stuff
    }

    @Override
    protected void onResume() {
        super.onResume();
        // getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(this);
        // PreferenceManager.getDefaultSharedPreferences(this).registerOnSharedPreferenceChangeListener(this);
        this.getSharedPreferences("myPrefDB", MODE_PRIVATE)
                .registerOnSharedPreferenceChangeListener(this);
    }

    @Override
    protected void onPause() {
        super.onPause();
        // getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(this);
        // PreferenceManager.getDefaultSharedPreferences(this).unregisterOnSharedPreferenceChangeListener(this);
        this.getSharedPreferences("myPrefDB", MODE_PRIVATE)
                .unregisterOnSharedPreferenceChangeListener(this);
    }
}

回答1:

The difference between these 2 is that OnPreferenceChangeListener is a callback called only when its preference changes (applies to a single key), while OnSharedPreferenceChange is a callback called whenever any of the preferences in that SharedPreferences object changes (applies to all keys).

So, in your case, you need to use the OnPreferenceChangeListener with your CheckBoxPreference.

Here is an example:

Preference ckboxPref = this.findPreference(CKBOX_PREF_KEY);
ckboxPref.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {

    @Override
    public boolean onPreferenceChange(Preference preference,
            Object newValue) {
        //Do stuff
    }
});

The method findPreference does not work if you use fragments, but you aren't using any so it is fine.

来源：https://stackoverflow.com/questions/13321637/whats-different-between-onpreferencechangelistener-and-onsharedpreferencechange

标签

android

sharedpreferences

android-preferences