imageview setbackgroundcolor在android中不起作用

Question

我在android中询问了关于ui更新的问题。（How to change imageview background color in a preference in android?）

它适用于Android 4.1.2版本。我在2.3.3,3.0和4.3安卓版本中测试它，我发现它在这些版本中不起作用。为了简化问题，我想问一下为什么下面的代码不适用于这些版本：

public class SettingsIncomingSearchFragment extends PreferenceListFragment 
implements SharedPreferences.OnSharedPreferenceChangeListener
{
    @Override
    public void onCreate(Bundle icicle) 
    {
     <!-- other codes -->
     setBackgroundColor() ;  
     <!-- other codes -->
    }  

private void setBackgroundColor() {
    // TODO Auto-generated method stub
    LinearLayout mainlayout ;
    LinearLayout sublayout ;
    View view ;
    ImageView img ;
    SharedPreferences sp ;
    sp = ctx.getSharedPreferences(SHARED_PREFS_NAME, ctx.MODE_PRIVATE);

       LayoutInflater inflater =  (LayoutInflater)
                getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        view = inflater.inflate(R.layout.rectangle_layout, null);

        mainlayout = (LinearLayout)view.findViewById(R.id.rectangle_main_layout_ll);

        sublayout = (LinearLayout)mainlayout.findViewById(R.id.rectangle_layout_ll);    

        String defValue = null ;      
        defValue = sp.getString("incomingsearchbackgroundcolor", String.valueOf(Color.BLACK));
        if(defValue != null)
        {
        img = (ImageView)sublayout.findViewById(R.id.iv_priority);
        img.setBackgroundColor(Integer.parseInt(defValue));

        }

}

谢谢！