Custom layout for EditTextPreference with null validation in custom dialog

Question

I have PreferenceActivity in my app and I want to specify custom layout for EditTextPreference. I do it in an xml file with android:layout attribute. All is OK, the layout is getting changed but I can't change any value of its fields. The code is running without errors, in debug I can see that values are changed, but visually there are no changes. I've tried to call view.invalidate() and onContentChanged() but nothing changed. All of IDs are OK and no exceptions are being thrown. So I have no idea. I'll appreciate you help.

Here is code of my preferences_file_types.xml:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >
    <PreferenceCategory
        android:key="@string/preference_category_file_types"
        android:title="@string/settings_supported_file_types" >
        <EditTextPreference
            android:key="@string/preference_file_type_image"
            android:layout="@layout/file_types_list_item"
            android:title="@string/settings_supported_file_types_hint" />
    </PreferenceCategory>
</PreferenceScreen>

Here is code of my PreferenceActivity class:

public class FileTypesSettingsActivity extends PreferenceActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.preferences_file_types);
        LayoutInflater inflater = getLayoutInflater();
        EditTextPreference imageTypePreference = (EditTextPreference) findPreference(getString(R.string.preference_file_type_image));
        View specifiedView = inflater.inflate(imageTypePreference.getLayoutResource(), null);
        changeViewAttributes(specifiedView);    
    }

    private void changeViewAttributes(View view) {
        ImageView fileTypeIcon = (ImageView) view.findViewById(R.id.file_types_list_item_iv_icon);
        fileTypeIcon.setBackgroundResource(R.drawable.ic_file_image);

        TextView fileTypePredefined = (TextView) view.findViewById(R.id.file_types_list_item_tv_predefined_extensions);
        fileTypePredefined.setText("JPG BMP GIF PNG");

        TextView fileTypeAdded = (TextView) view.findViewById(R.id.file_types_list_item_tv_added_extensions);
        fileTypeAdded.setText("BLA BLA BLA");
    }
}