Change the summary of a ListPreference with the new value (Android)

Question

How can I modify the summary of a ListPreference to the new \"Entry\" string selected by the user (not the entry value)

I suppouse its with setOnPreferenceChangeList

Answer 1

Just set the summary value to %s in the xml description.

EDIT: I've tested it on several devices and it doesn't work really. That's strange because according to docs it must work: ListPreference.getSummary().

But it's possible to implement this functionality by oneself. The implementation requires to inherit from the ListPreference class:

public class MyListPreference extends ListPreference {
    public MyListPreference(final Context context) {
        this(context, null);
    }

    public MyListPreference(final Context context, final AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public CharSequence getSummary() {
        final CharSequence entry = getEntry();
        final CharSequence summary = super.getSummary();
        if (summary == null || entry == null) {
             return null;
        } else {
            return String.format(summary.toString(), entry);
        }
    }

    @Override
    public void setValue(final String value) {
        super.setValue(value);
        notifyChanged();
    }
}

As you can see MyListPreference has its own summary field which can contain formatting markers. And when a preference's value changes, Preference.notifyChanged() method is called and it causes MyListPreference.getSummary() method to be called from Preference.onBindView().

P.S.: This approach hasn't been tested sufficiently so it may contain errors.

Answer 2

i solved this problem with another and simple solution (https://gist.github.com/brunomateus/5617025):

public class ListPreferenceWithSummary extends ListPreference{

public ListPreferenceWithSummary(Context context, AttributeSet attrs) {
    super(context, attrs);
}

public ListPreferenceWithSummary(Context context) {
    super(context);
}

@Override
public void setValue(String value) {
    super.setValue(value);
    setSummary(value);
}

@Override
public void setSummary(CharSequence summary) {
    super.setSummary(getEntry());
}
}

This worked very fine on my GirgerBeard device. Even when is the first time running your app. Don't forget to provide default value on your xml prefence:

android:defaultValue="default value"

and set default values on your PreferenceActivity or PrefenceFragment:

 PreferenceManager.setDefaultValues(this, R.xml.you pref file, false);

Answer 3

Referring to the accepted answer ( @Michael ), if you modify the MyListPreference to add an onPreferenceChangeListener:

public MyListPreference(final Context context, final AttributeSet attrs) {
    super(context, attrs);
    setOnPreferenceChangeListener(this);
}

and have the listener implementation return true:

public boolean onPreferenceChange(Preference preference, Object newValue) {
    // Do other stuff as needed, e.g. setTitle()
    return true;
}

the summary '%s' always resolves to the latest setting. Otherwise, it always has the default setting.

Don't forget to add implements:

public class MyListPreference extends ListPreference implements Preference.OnPreferenceChangeListener

Answer 4

I also faced this problem and I finally found a solution by using the value coming from the listener. In my example below (for a ListPreference), I first get the index of the value in the ListPreference array, then I retrieve the label of the value using this index:

passwordFrequencyLP.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {
        @Override
        public boolean onPreferenceChange(Preference preference, Object newValue) {
            int newFrequency = Integer.valueOf(newValue.toString());

            prefs.edit().putInt("settings_key_password_frequency", newFrequency).commit();

            //get the index of the new value selected in the ListPreference array
            int index = passwordFrequencyLP.findIndexOfValue(String.valueOf(newValue));
            //get the label of the new value selected
            String label = (String) passwordFrequencyLP.getEntries()[index];

            passwordFrequencyLP.setSummary(label);

            makeToast(getResources().getString(R.string.password_frequency_saved));
            return true;
        }
    });

This little trick works well, I found many different possible solutions to this problem but only this one worked for me.

Answer 5

Simplest way in Kotlin

findPreference<ListPreference>(getString(R.string.pref_some_key)).apply {
    summary = entry
    setOnPreferenceChangeListener { _, newValue ->
        summary = entries[entryValues.indexOf(newValue)]
        return@setOnPreferenceChangeListener true
    }
}

Answer 6

This is the most simplified way I have implemented. Just take the values given by the onPreferenceChange listener

    ListPreference preference;        
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    preference = (ListPreference)findPreference("myKey");
    preference.setSummary(preferenceColorButtons.getEntry());
    preference.setOnPreferenceChangeListener(new        OnPreferenceChangeListener() {

        @Override
        public boolean onPreferenceChange(Preference preference, Object newValue) {
            ListPreference listPreference = (ListPreference)preference;
            int id = 0;
            for (int i = 0; i < listPreference.getEntryValues().length; i++)
            {
                if(listPreference.getEntryValues()[i].equals(newValue.toString())){
                    id = i;
                    break;
                }
            }
            preference.setSummary(listPreference.getEntries()[id]);
            return true;
        }
    });

}