android.widget.ImageView cannot be cast to android.view.ViewGroup

Question

In an Android app, upon clicking on a menu button, MainActivity is supposed to replace an ImageView fragment with a WebView fragment. Instead, it throws:

java.lang.ClassCastException: android.widget.ImageView cannot be cast to android.view.ViewGroup

In Eclipse I cleaned the project, deleted the R file, checked the XML files as suggested in other threads, but no luck.

If you could help, much appreciated.

public class MainActivity extends FragmentActivity implements PhotoFragment.Callbacks {

[...]

public void onButtonInfoClicked(int index) {
    WebFragment web_f = WebFragment.newInstance(1, "Web Fragment");
    web_f.setIndex(index);

    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();       

    fragmentTransaction.addToBackStack(null);
    fragmentTransaction.replace(R.id.photoView, web_f);
    fragmentTransaction.commit();
}

fragment_photo.xml

<ImageView
    android:id="@+id/photoView"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:gravity="top"
    android:scaleType="fitXY" />

web_view.xml

<WebView
    android:id="@+id/webView"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:gravity="top"
    android:scaleType="fitXY" />

Answer 1

I found where the problem was.

I was trying to pass the resource id of the ImageView (R.id.photoView) used to build the fragment, not the actual fragment. Since this fragment was not created from a layout, I need to use its object reference and pass its containerViewId instead:

// fragment previously created in MainActivity:
PhotoFragment f = PhotoFragment.newInstance();

So to fix the problem I substituted:

fragmentTransaction.replace(R.id.photoView, web_f);

with:

fragmentTransaction.replace(((ViewGroup)f.getView().getParent()).getId() , web_f);