Fragment Transaction Handler

gistfile1.java

public class LinesFragment extends ContextMenuSherlockListFragment implements LoaderCallbacks<List<LineInfo>>, Callback { 

    ... 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        handler = new Handler(this); 
        adapter = new LinesAdapter(getActivity()); 
    }

    @Override 
    public void onActivityCreated(Bundle savedInstanceState) { 
        super.onActivityCreated(savedInstanceState); 
        setListAdapter(adapter); 
        setListShown(false); 
        getLoaderManager().initLoader(LINES_LOADER_ID, null, this); 
    }

    @Override 
    public Loader<List<LineInfo>> onCreateLoader(int id, Bundle args) { 
        return new LinesLoader(getActivity()); 
    }

    @Override 
    public void onLoadFinished(Loader<List<LineInfo>> loader, List<LineInfo> data) { 
        if (data != null) { 
            adapter.setLinesList(data); 
        } else if (isResumed()) { 
            handler.sendEmptyMessage(LINES_LOADING_ERROR_WHAT); 
        }
        // The list should now be shown. 
        if (isResumed()) { 
            setListShown(true); 
        } else { 
            setListShownNoAnimation(true); 
        } 
    }

    @Override 
    public void onLoaderReset(Loader<List<LineInfo>> loader) { 
        adapter.setLinesList(null); 
    }

    @Override 
    public boolean handleMessage(Message message) { 
        switch (message.what) { 
            case LINES_LOADING_ERROR_WHAT: 
                MessageDialogFragment 
                .newInstance(R.string.error_title, R.string.lines_loading_error) 
                .show(getFragmentManager()); 
                return true; 
        }
        return false; 
    }
    ...
}