Question

Edit: For a detailed how-to, check out my answer.

I’m struggling with it for two days now, hope someone can help.

I’m trying to use the newest ActionBarSherlock (4.0) with a MapView. I knew it’s problematic with fragments, but I don’t need them in this activity. But I need Loaders and it appears, that to use Loaders I have to extend the FragmentActivity too. No problem, I thought, we have the android-support-v4-googlemaps from Pete Doyle. As suggested on many SO threads and Google Groups I build the ABS with android-support-v4-googlemaps JAR (android-support-v13-r7-googlemaps.jar actually) instead of android-support-v4.jar. Then I used it as a library for my project.

Now, I would like to have my activity this way:

public class BananoutMapActivity extends SherlockFragmentActivity implements LoaderCallbacks<ArrayList<EventItem>>{

The problem:

It compiles, but throws a runtime error: E/AndroidRuntime(29159): java.lang.NoClassDefFoundError: ndl.klimczak.bananout.BananoutMapActivity

Things I’ve triple checked:

• both ActionBarSherlock library project and my project are targeted at Google APIs 4.0.3
• I have <uses-library android:name="com.google.android.maps" /> and I have it in the application tag.
• I also have the same android-support-v13-r7-googlemaps.jar in the build path of my project
• I have .BananoutMapActivity declared in my manifest

What is interesting:

• When I run it on an ICS emulator it works (the error appears on 2.* emulators and my 2.3.7 device), on Honeycomb it would work too probably, it’s the question of using the ACL I guess

• When I remove the implements LoaderCallbacks<ArrayList<EventItem>> part it works too, but this way I’m not able to use LoaderManager

Why on earth the NoClassDefFoundError error and how to get the Loaders working in my MapCapableSherlockEnabledFragmentActivity?

Answer 1

You need to use the loaders from the support library rather than the ones from the platform. Since those are only available on Android 3.0+ and the fact that you’ve included them in your class definition will cause the pre-3.0 classloader to reject your class outright. Switching your imports to the support library variants should be all that’s needed for that.

If you look above the exception in Logcat you should see one or more VerifyErrors which will outline specifically what it took issue with.

You also can only use the android-support-v13 library on Android 3.2 and up (hence the v13 in its name).