Display ListPreference selected item on summary
Refer to the article "Implement ListPreference in PreferenceFragment", the default display on summary field is hard-coded in /res/xml/preferences.xml. Such that, the user cannot know the current selected item of ListPreference, without open the ListPreference dialog.To update summary of ListPreference programmatically, call ListPreference.setSummary().
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| Display ListPreference selected item on summary |
Implement updateListPrefSummary_PREF_LIST() to update summary of ListPreference with key="PREF_LIST", call it in onCreate() in fragment start-up. And also implement OnSharedPreferenceChangeListener to call it when ListPreference with key="PREF_LIST" changed. Register and Unregister in onResume() and onPause().
package com.example.androidpreferencefragment;
import android.content.SharedPreferences;
import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
import android.os.Bundle;
import android.preference.ListPreference;
import android.preference.PreferenceFragment;
public class PrefFragment extends PreferenceFragment
implements OnSharedPreferenceChangeListener{
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
updateListPrefSummary_PREF_LIST();
}
@Override
public void onResume() {
super.onResume();
getPreferenceScreen().getSharedPreferences()
.registerOnSharedPreferenceChangeListener(this);
}
@Override
public void onPause() {
super.onPause();
getPreferenceScreen().getSharedPreferences()
.unregisterOnSharedPreferenceChangeListener(this);
}
//Apply for ListPreference with key="PREF_LIST"
private void updateListPrefSummary_PREF_LIST(){
ListPreference preference = (ListPreference)findPreference("PREF_LIST");
CharSequence entry = ((ListPreference) preference).getEntry();
preference.setSummary("current selection: " + entry);
}
@Override
public void onSharedPreferenceChanged(
SharedPreferences sharedPreferences, String key) {
//if changed SharedPreference is ListPreference with key="PREF_LIST",
// update summary
if(key.equals("PREF_LIST")){
updateListPrefSummary_PREF_LIST();
};
}
}
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