在android中主要活动中接收首选项更改

Question

I'm having an issue with my android app. It is a simple application that is going to draw a rectangle of the specified size overtop of an image view in the main Activity. The issue is receiving the value of the changed preference that is the size of either the width or height of the rectangle. I have tried multiple approaches. Right now I have my main activity, a preference fragment, and a ShowPreferences activity that is simply used by the main activity to create an intent and start that intent to show the preferences fragment. This is done so that when I press the back button it returns the main screen without issue. I have tried to listen for the preference changes in the SettingsFragment but the issue is I can not access the variables in the main activity because calling getActivity() within the SettingsFragment returns ShowPreferences because that is technically the activity that called it through the intent. Thus I have moved on to detecting the preference changes through the main activity. Now the issue is that the findPreference() method cannot be resolved because it is within the main activity not the SettingsFragment class. How can I turn the key into an EditTextPrefernce instance in order to make the necessary change to the variable in the main Activity. Any other suggestions would be greatly appreciated I am very new to android development. :)
Here is my code right now.

SettingsFragment (where the onSharedPreferenceChangeListener used to be)

public class SettingsFragment extends PreferenceFragment {
    @Override
    public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.xml.preferences);
    }
}

ShowPreferences (simply to show the preference screen and allow for correct back button behavior)

public class ShowPreferences extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_preferences);
        getFragmentManager().beginTransaction().replace(android.R.id.content, new SettingsFragment()).commit();

    }
}

Within the main activity the onSharedPreferencesChangedListener

@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
    Preference pref = mContext.findPreference(key);
    if (pref instanceof EditTextPreference) {
        EditTextPreference etp = (EditTextPreference) pref;
        //now what?
        int newValue = Integer.parseInt(etp.getText());

        if(etp.toString().equals("Rectangle Width")){
            rectWidth = newValue;
        } else if (etp.toString().equals("Rectangle Height")){
            rectHeight = newValue;
        }
    }
}

Answer 1

Retrieve the value from SharedPreferences directly using the key.

public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
        if(key.equals("myKey"){
            int newValue = Integer.parseInt(sharedPreferences.getString(key, "0"));
        }
}