MyApplication.java

public class MyApplication extends Application {
	private SharedPreferences mPrefs;

	@Override
	public void onCreate() {
		super.onCreate();
		mPrefs = PreferenceManager.getDefaultSharedPreferences(this);
	}

	public String getUsername(){
		return mPrefs.getString("username", null);
	}
	
	public String getPassword(){
		return mPrefs.getString("password", null);
	}

}