Will LoaderManager.restartLoader() always result in a call to onCreateLoader()?

Question

LoaderManager has this method restartLoader():

public abstract Loader restartLoader (int id, Bundle args, LoaderCallbacks

Answer 1

The simple answer to your question is yes, a call to restartLoader() will call onCreateLoader() again.

You can start more than one loader in parallel (say you have two SimpleCursorAdapters to fill), e.g.:

getLoaderManager().initLoader(0, null, this);  //id = 0
getLoaderManager().initLoader(1, null, this);  //id = 1

onCreateLoader is then called by the Loader Manager for each id (the loader that is returned is then built asynchronously by the Loader Manager):

public Loader onCreateLoader(int id, Bundle args)
{
    if (id == 0)
        //return a Loader for id 0
    else if (id == 1)
        //return a Loader for id 1
}

The Loader Manager passes the resulting loader to onLoadFinished:

public void onLoadFinished(Loader loader, Cursor cursor)
{
    if (loader.getId() == 0)
        //cursor was returned from onCreateLoader for id 0
        //perhaps do swapCursor(cursor) on an adapter using this loader
    else if (loader.getId() == 1)
        //cursor was returned from onCreateLoader for id 1
        //perhaps do swapCursor(cursor) on an adapter using this loader
}

When you subsequently call restart loader:

getLoaderManager().restartLoader(0, null, this);  //id = 0

...onLoaderReset is first called:

public void onLoaderReset(Loader loader)
{
    if (loader.getId() == 0)
        //perhaps do swapCursor(null) on an adapter using this loader
    else if (loader.getId() == 1)
        //perhaps do swapCursor(null) on an adapter using this loader
}

...followed by a new call to onCreateLoader. So in that respect, onCreateLoader is used both to start a brand new loader and when an existing loader is reset.