isValidFragment Android API 19

Question

When I try my app with Android KitKat I have an error in PreferenceActivity.

Subclasses of PreferenceActivity must override isValidFragment(String) to ve

Answer 1

this is my solution:

• if u need dynamic rebuild headers

• if u use extras to start preference activity - onBuildHeaders() approach will fail! (with below start intent extras - why ??? - simple because onBuildHeaders() is never called):

  Intent.putExtra(PreferenceActivity.EXTRA_SHOW_FRAGMEN,Fragment.class.getName()); Intent.putExtra(PreferenceActivity.EXTRA_NO_HEADERS, true);

This is example class:

/**
 * Preference Header for showing settings and add view as two panels for tablets
 * for ActionBar we need override onCreate and setContentView
 */
public class SettingsPreferenceActivity extends PreferenceActivity {

    /** valid fragment list declaration */
    private List<String> validFragmentList;

    /** some example irrelevant class for holding user session  */
    SessionManager _sessionManager;

    @Override
    public void onBuildHeaders(List<Header> target) {
        /** load header from res */
        loadHeadersFromResource(getValidResId(), target);
    }

    /**
     * this API method was added due to a newly discovered vulnerability.
     */
    @Override
    protected boolean isValidFragment(String fragmentName) {
        List<Header> headers = new ArrayList<>();
        /** fill fragments list */
        tryObtainValidFragmentList(getValidResId(), headers);
        /** check  id valid */
        return validFragmentList.contains(fragmentName);
    }

    /** try fill list of valid fragments */
    private void tryObtainValidFragmentList(int resourceId, List<Header> target) {  
        /** check for null */
        if(validFragmentList==null) {
            /** init */
            validFragmentList = new ArrayList();
        } else {
            /** clear */
            validFragmentList.clear();
        }
        /** load headers to list */
        loadHeadersFromResource(resourceId, target);
        /** set headers class names to list */
        for (Header header : target) {
            /** fill */
            validFragmentList.add(header.fragment);
        }
    }

    /** obtain valid res id to build headers */
    private int getValidResId() {
        /** get session manager */
        _sessionManager = SessionManager.getInstance();
        /** check if user is authorized */
        if (_sessionManager.getCurrentUser().getWebPart().isAuthorized()) {
            /** if is return full preferences header */
            return R.xml.settings_preferences_header_logged_in;
        } else {
            /** else return short header */
            return R.xml.settings_preferences_header_logged_out;
        }
    }
}

Answer 2

Try this... this is how we check validity of fragment.

protected boolean isValidFragment(String fragmentName) {
  return StockPreferenceFragment.class.getName().equals(fragmentName);
}

Answer 3

Verified with an actual 4.4 device:

(1) if your proguard.cfg file has this line (which many define anyway):

-keep public class com.fullpackage.MyPreferenceFragment

(2) than the most efficient implementation would be:

@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public class EditPreferencesHC extends PreferenceActivity {
...
   protected boolean isValidFragment (String fragmentName) {

     return "com.fullpackage.MyPreferenceFragment".equals(fragmentName);

   }
}

Answer 4

I am not sure if lane's implementation is free of the vulnerabilities discussed here but if it is, then i think a better solution would be to avoid using that static list and simply do the following :

 @Override
    protected boolean isValidFragment(String fragmentName)
    {
        ArrayList<Header> target = new ArrayList<>();
        loadHeadersFromResource(R.xml.pref_headers, target);
        for (Header h : target) {
            if (fragmentName.equals(h.fragment)) return true;
        }
        return false;
    }

Answer 5

Out of pure curiosity, you can also do this as well:

@Override
protected boolean isValidFragment(String fragmentName) {
    return MyPreferenceFragmentA.class.getName().equals(fragmentName)
            || MyPreferenceFragmentB.class.getName().equals(fragmentName)
            || // ... Finish with your last fragment.

;}

Answer 6

my solution (instead of creating ArrayList of class) since the fragments that are loaded suppose to be subclass of PreferenceFragment.class run this check in the @OverRide method

@Override
protected boolean isValidFragment(String fragmentName) {
    try {
        Class cls = Class.forName(fragmentName);
        return (cls.getSuperclass().equals(PreferenceFragment.class));
                                  // true if superclass is PreferenceFragmnet
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }
    return false;
}