For your errors, you need to return the right type. Make sure your class extends the Loader class that matches the same interface (android.support.v4.content.Loader).
I'm already doing that: public class MainActivity extends Activity implements LoaderManager.LoaderCallbacks
is that what you mean?
That is one of the lines, yes. Which interface is it?
The android SDK people made a mistake when they reused the names. (It is a common enough mistake, but still very annoying and far too frequent.)
So which LoaderManager is it? Is that supposed to be android.support.v4.app.LoaderManager or android.app.LoaderManager ? Both of them are LoaderManager classes, but the two types are not compatible.
When in doubt give the full path.