[Android] 建立Class定義共同參數 SharedPreferences

======================================================================================
public class Param
{
public void setSharedPreferences(String columns, String data, Context ctxs)
    {
       SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(ctxs);
       SharedPreferences.Editor editor = settings.edit();  
       editor.putString(columns, data);
       editor.commit();
    }

public String getSharedPreferences(String columns, Context ctxs)
    {
     String param="no";
     try{
           SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(ctxs);
           param=sp.getString(columns, param);
     }catch(Exception ex){}
       return param;
    }
}
==============================extends Fragment==============================
Activity mActivity;
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
mActivity = (Activity) activity;
}
@Override
public void onCreate(Bundle savedInstanceState) {
        Param pm = new Param();
        pm.setSharedPreferences("startDay", "20150402", mActivity);
        String startDay = pm.getSharedPreferences("startDay", mActivity);
}

==============================extends Activity==============================
@Override
public void onCreate(Bundle savedInstanceState) {
        Param pm = new Param();
        pm.setSharedPreferences("startDay", "20150402", this);
        String startDay = pm.getSharedPreferences("startDay", this);
}