用于Fragment（非活动）类中的edittext的setOnFocusChangeListener不起作用

Question

我是android新手。我试图在焦点上更改edittext的边框。 Edittext存在于非活动类中。我使用了drawable资源和setOnFocusChange方法来设置边框。但它不起作用。

这是我的代码。 ViewMap.java

public class ViewMap extends Fragment {

Context mContext;
public ViewMap(Context mContext)
{
    this.mContext = mContext;
}

MapView mapView;
GoogleMap map;

@Override
public View onCreateView(LayoutInflater inflater,
         ViewGroup container,  Bundle savedInstanceState) {

    View v = inflater.inflate(R.layout.view_map, container, false);
     EditText txt = (EditText) v.findViewById(R.id.search);
        txt.setOnFocusChangeListener(new View.OnFocusChangeListener() {

            @Override
            public void onFocusChange(View view, boolean hasFocus) {
                if(hasFocus){
                    view.setBackgroundResource(R.drawable.focus_border_style);
                }
                else
                {
                    view.setBackgroundResource(R.drawable.lost_focus_border_style);
                }
            }
        });
 }
    @Override
    public void onResume() {
    super.onResume();
    }
    @Override
    public void onDestroy() {
    super.onDestroy();
    }
    @Override
    public void onLowMemory() {
    super.onLowMemory();
    }
 }

view_map.xml

<EditText android:id="@+id/search"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content" 
 android:hint="Search location"/>

 <Button android:id="@+id/searchButton"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:text="Search"/>