PreferenceActivity: save value as integer

Solution 1:

You could extend EditTextPreference:

public class IntEditTextPreference extends EditTextPreference {

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

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

    public IntEditTextPreference(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected String getPersistedString(String defaultReturnValue) {
        return String.valueOf(getPersistedInt(-1));
    }

    @Override
    protected boolean persistString(String value) {
        return persistInt(Integer.valueOf(value));
    }
}

It would be better to overwrite onSetInitialValue() and setText() methods, but then you would have to copy some code from a base class. Above solution is simplier, but it's quite tricky - "string" methods do something with ints. Try to not extend this class further ;-)

You could use it from XML by:

<package.name.IntEditTextPreference
    android:key="SomeKey"
    android:title="@string/some_title"
    android:summary="..."
    android:numeric="integer"
    android:maxLength="2"
/>

Solution 2:

Even if you set android:numeric="integer" it'll be text preference - as its name suggest. You could easily convert string value to int using Integer.valueOf(). Also you could overwrite PreferenceActivity to do conversion automatically on exit.

I think the best solution is to write simple method to get this value from preferences. Something like:

public static int getSomePref(Context context) {
    SharedPreferences prefs =
        PreferenceManager.getDefaultSharedPreferences(context);
    String value = prefs.getString("SomeKey", null);
    return value == null ? -1 : Integer.valueOf(value);
}

Then you could very easily use it from your code.

Solution 3:

Even though an Answer has been parked accepted I would like to share one more shorter way to achieve this :

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
int value = Integer.parseInt(preferences.getString("SomeKey", "-1"));

Since you have already set that only numbers can be entered this won't through any exception. yet to complete my answer :

<EditTextPref
    android:key="SomeKey"
    android:title="@string/some_title"
    android:summary="..."
    android:numeric="integer"
    android:maxLength="2" />