Why is this preference not being saved?

Question

As far as I can tell, I am using the same key when getting as when setting, yet the preference does not save. I'm sure I'm missing something obvious.

My custom DialogPreference where I load the current preference and set the new one.

public class SemesterDialogPreference extends DialogPreference {

    View view;
    SharedPreferences settings;
    String semester_id_key = this.getContext().getApplicationContext().getString(R.string.pref_semester_id);

    DBAdapter db;

    @Override
    public void onBindDialogView(View view){
            this.view = view;
            settings = getSharedPreferences();

            int curSemesterId = settings.getInt(semester_id_key, 1);
            System.out.println("Incoming " + semester_id_key + " equals " + curSemesterId);

            // Here I do stuff...

            super.onBindDialogView(view);
    }


    public SemesterDialogPreference(Context context, AttributeSet attrs) {
        super(context, attrs);
        setDialogLayoutResource(R.layout.dialog_set_semester);

    }

    @Override
    protected void onDialogClosed(boolean positiveResult) {
        super.onDialogClosed(positiveResult);

        // Do things and set newId


        System.out.println("new int for " + semester_id_key + " is " + newId);
        Editor editor = getEditor();
        editor.putInt(semester_id_key, newId);
        editor.commit();
    }
}

The XML for my PreferenceScreen

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >

    <PreferenceCategory android:title="@string/pref_header_settings" >
            <com.NsouthProductions.gradetrackerpro.SemesterDialogPreference
                    android:title="@string/pref_title_semester"
                    android:summary="@string/pref_summary_semester"

                    android:key="@string/pref_semester_id"
                    android:dialogMessage="Are you sure?"
                    android:positiveButtonText="Clear Questss"
                    android:negativeButtonText="Cancel"/>

    </PreferenceCategory>

</PreferenceScreen>

Also, I don't understand why examples online don't include parameters in getSharedPreferences(). I thought that's how android knew which file to use.

The code you posted shows only *reading* of the `SharedPreferences` - where do you write into it ? — Nir Alfasi, Aug 01 '14 at 17:36
In onDialogClosed I have `editor.putInt(semester_id_key, newId)`. — NSouth, Aug 01 '14 at 17:39

Nir Alfasi · Accepted Answer · 2014-08-01T18:12:42.957

Here's how to write to SharedPreferences:

    public static final String PREFS_NAME   = "UNIQUE-NAME"; // settings will be saved here 

    // ...       
    SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
    Editor editor = settings.edit();
    editor.putString("abc", "123");
    editor.commit();

In case you get an error on:

SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);

you can do:

SharedPreferences settings = getActivity().getPreferences(PREFS_NAME, 0);

and if you're trying to approach it from a different activity, then do:

SharedPreferences settings = getSharedPreferences(YourBaseActivity.PREFS_NAME, 0);

(needless to say that you should replace YourBaseActivity with the name of the activity in which you declared the SharedPreferences to begin with).

This is the solution that worked for me! Thanks. Also, I apparently had my Main activity resetting this preference, so it's possible one of the other solutions would have worked, too. — NSouth, Aug 01 '14 at 19:25

score 0 · Answer 2 · answered Aug 01 '14 at 17:41

0

reffering to http://developer.android.com/guide/topics/data/data-storage.html

do it like:

SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
  SharedPreferences.Editor editor = settings.edit();
  editor.putBoolean("silentMode", mSilentMode);

  // Commit the edits!
  editor.commit();

answered Aug 01 '14 at 17:41

LibettenRadler

115
2
8

I don't think this works in a DialogPreference. Using that version of `getSharedPreferences` gives me an error. _The method getSharedPreferences() in the type Preference is not applicable for the arguments (String, int)_ – NSouth Aug 01 '14 at 17:57

score 0 · Answer 3 · answered Aug 01 '14 at 17:42

0

You need to call the editor like this:

...

View view;
SharedPreferences settings;
SharedPreferences.Editor editor;

...

Then in the next part:

settings = PreferenceManager.getDefaultSharedPreferences(this); // if this doesnt work, try getApplicationContext()

editor = settings.edit();
editor.putInt(semester_id_key, newId);
editor.commit();

Note:

It's recommended to use apply() rather than commit() whenever possible, because it is asynchronous, but both will work.

answered Aug 01 '14 at 17:42

SQLiteNoob

2,958
3
29
44

Thanks. I declared view, settings, and editor as fields as you suggested. I initialized settings using PreferenceManager in `onBindDialogView` as you suggested. In `onDialogClosed`, I used the editor field as you suggested. Now I get a NullPointerException on the `putInt` line :( – NSouth Aug 01 '14 at 18:02

Why is this preference not being saved?

3 Answers3