动态更改Custom PreferenceScreen的数据

Question

I am working on custom PreferenceScreen , I have created a custom screen for the settings page using PreferenceActivity .

Below is my preference screen.

Issue:- I need to change badge of Download data dynamically. I followed this question for achieve this layout. I already tried all answer of that question but not working single answer.

Is there any other way to find View which is inside preference?

settings.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">

<Preference android:title="@string/settings_user_profile" android:key="user_profile" android:summary="@string/settings_user_profile_desc" android:layout="@layout/setting_list"></Preference>
<Preference android:title="@string/settings_download" android:key="download_data" android:summary="@string/settings_download_desc" android:layout="@layout/setting_list"></Preference>
</PreferenceScreen>

Answer 1

You can subclass Preference , overriding onBindDialogView() - just remember to change the XML from <Preference...> to include your package and class <com.example.app.BadgedPreference...> :

@Override
protected void onBindDialogView(View v) {
    super.onBindDialogView(v);
    Log.v( "onBindDialogView()", v.getClass().getSimpleName() );
}

If your BadgedPreference has a method for handling your change, you can use it a bit more easily - from within your PreferenceActivity :

PreferenceScreen myPrefScreen = (PreferenceScreen)getPreferenceScreen();
BadgedPreference bp = (BadgedPreference)myPrefScreen.findPreference("download_data");
// Custom method
bp.setBadgeValue(12);

Even more simply, you can use a standard Preference , just style its summary field as a 'badge', then you can set the value using the included Summary field:

Preference pref = (Preference)myPrefScreen.findPreference("download_data");
pref.setSummary("12");

Let me know if you have any questions.

Answer 2

You can implement OnSharedPreferenceChangeListener Something like this:

  @Override
  public void onResume() {
      super.onResume();

      // Set up a listener whenever a key changes
      getPreferenceScreen().getSharedPreferences()
         .registerOnSharedPreferenceChangeListener(this);        
  }

  @Override
  protected void onPause() {
       super.onPause();

      // Unregister the listener whenever a key changes
      getPreferenceScreen().getSharedPreferences()
         .unregisterOnSharedPreferenceChangeListener(this);
  }

  @Override
  public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
        String key) {

       //update summary  
       updatePrefsSummary(sharedPreferences, findPreference(key));
  }

If you use standard Preference you can try something like this:

/**
 * Update summary
 * 
 * @param sharedPreferences
 * @param pref
 */
 protected void updatePrefsSummary(SharedPreferences sharedPreferences,
    Preference pref) {

if (pref == null)
    return;

if (pref instanceof ListPreference) {
    // List Preference
    ListPreference listPref = (ListPreference) pref;
    listPref.setSummary(listPref.getEntry());

} else if (pref instanceof EditTextPreference) {
    // EditPreference
    EditTextPreference editTextPref = (EditTextPreference) pref;
    editTextPref.setSummary(editTextPref.getText());

} else if (pref instanceof MultiSelectListPreference) {
    // MultiSelectList Preference
    MultiSelectListPreference mlistPref = (MultiSelectListPreference) pref;
    String summaryMListPref = "";
    String and = "";

    // Retrieve values
    Set<String> values = mlistPref.getValues();
    for (String value : values) {
        // For each value retrieve index
        int index = mlistPref.findIndexOfValue(value);
        // Retrieve entry from index
        CharSequence mEntry = index >= 0
                && mlistPref.getEntries() != null ? mlistPref
                .getEntries()[index] : null;
        if (mEntry != null) {
            // add summary
            summaryMListPref = summaryMListPref + and + mEntry;
            and = ";";
        }
    }
    // set summary
    mlistPref.setSummary(summaryMListPref);

} else if (pref instanceof RingtonePreference) {
    // RingtonePreference
    RingtonePreference rtPref = (RingtonePreference) pref;
    String uri;
    if (rtPref != null) {
        uri = sharedPreferences.getString(rtPref.getKey(), null);
        if (uri != null) {
            Ringtone ringtone = RingtoneManager.getRingtone(
                    getActivity(), Uri.parse(uri));
                pref.setSummary(ringtone.getTitle(getActivity()));
        }
    }

} 

}

If you use custom preference, you can do everything, and you can override setSummary(int value)

@Override
public void setSummary(int value) {
   setSummary(String.valueOf(value)+" ...." );
}