onPreferenceClick is not working with me

Question

I have tried to do some codes in my onPreferenceClick but it didn't work.

I made a SettingActivity Calss and I extends the PreferenceActivity.

Then I implements the OnPreferenceClickListener.

Here is my Setting Activity Class

    DecimalFormat df = new DecimalFormat("@##,###,###,###");
private Calculation mCalculation;
private TextView mCalculatorDisplay;

@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.xml.settings);

}

@SuppressWarnings("deprecation")
@Override
public boolean onPreferenceClick(Preference preference) {
    if (preference.getKey().equals("Point")) {
        mCalculatorDisplay.setText(df.format(mCalculation.getResult()).replaceAll(",", "."));

    } else if (preference.getKey().equals("Comma")) {
        mCalculatorDisplay.setText(df.format(mCalculation.getResult()).replaceAll(".", ","));

    } else if (preference.getKey().equals("Space")) {
        mCalculatorDisplay.setText(df.format(mCalculation.getResult()).replaceAll(",", " "));

    } else if (preference.getKey().equals("Off")) {
        mCalculatorDisplay.setText(df.format(mCalculation.getResult()).replaceAll(" ", ""));


        getPreferenceManager().getSharedPreferences().edit()
        .putInt("unreadcount", 0).commit();
    }
    return true;
}

Here is my arrays.xml

    <string-array name="decimalNumber">
    <item name="P">Point</item>
    <item name="C">Comma</item>
    <item name="S">Space</item>
    <item name="O">Off</item>
</string-array>
<string-array name="decimalNumberValues">
    <item name="P">P</item>
    <item name="C">C</item>
    <item name="S">S</item>
    <item name="O">O</item>
</string-array>

And settings.xml in xml folder:

    <PreferenceCategory android:title="@string/pref_user_settings" >
    <ListPreference
        android:entries="@array/decimalNumber"
        android:entryValues="@array/decimalNumberValues"
        android:key="prefdecimalNumber"
        android:summary="@string/number_format_summary"
        android:title="@string/number_format" />
</PreferenceCategory>

And here is a photo of my User Settings:

What I want to do is by clicking on each one of them change the way of decimal number formats.

Thanks in Advance :)

Update: I did this to register the PreferenceClickListener.

    @SuppressWarnings("deprecation")
@Override
protected void onPause() {
    super.onPause();

    getPreferenceScreen().getSharedPreferences()
            .registerOnSharedPreferenceChangeListener(
                    (OnSharedPreferenceChangeListener) this);
}

@SuppressWarnings("deprecation")
@Override
protected void onResume() {
    super.onResume();

    getPreferenceScreen().getSharedPreferences()
            .registerOnSharedPreferenceChangeListener(
                    (OnSharedPreferenceChangeListener) this);
}

public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
        String key) {
    if (key.equals("Point")) {
        mCalculatorDisplay.setText(df.format(mCalculation.getResult())
                .replaceAll(",", "."));
    } else if (key.equals("Comma")) {
        mCalculatorDisplay.setText(df.format(mCalculation.getResult())
                .replaceAll(".", ","));
    } else if (key.equals("Space")) {
        mCalculatorDisplay.setText(df.format(mCalculation.getResult())
                .replaceAll(",", " "));
    } else if (key.equals("Off")) {
        mCalculatorDisplay.setText(df.format(mCalculation.getResult())
                .replaceAll(" ", ""));
    }
}

Its giving me this error:

05-24 11:10:24.127: E/AndroidRuntime(1025): java.lang.RuntimeException: Unable to resume activity {com.com.ecalc/com.com.ecalc.Z_SettingsActivity}: java.lang.ClassCastException: com.com.ecalc.Z_SettingsActivity cannot be cast to android.content.SharedPreferences$OnSharedPreferenceChangeListener

Answer 1

i think you have to register your object on the sharedPreferenceChangeListener in your onPause() and onStart()-methode

look here: https://stackoverflow.com/a/16449611/2924941