What to do about ListActivity/MapActivity when con

问题:

I'm converting an existing app to the Fragments API using the compatibility library. I've read that you're supposed to update classes that extend Activity to now use FragmentActivity. This is fine for most cases, but what about classes that extend ListActivity or MapActivity? What is the preferred way to handle this? I was hoping there was a ListFragmentActivity or something along those lines, but I don't see one.

回答1:

There is a ListFragment: http://developer.android.com/reference/android/app/ListFragment.html

For MapActivity, unfortunately you will need to continue to use that; there is no Fragment API for it.

回答2:

This is what I do when converting a ListActivity to the fragments API:

1. Replace lv = getListView(); with lv = (ListView) findViewById(android.R.id.list);

2. Replace setListAdapter(adapter); with lv.setAdapter(adapter);

3. If you have overriden onListItemClick(), replace it with lv.setOnItemClickListener(new ListView.OnItemClickListener() {...

4. You'll have to set the empty view (that shows when there are no results) manually: lv.setEmptyView(findViewById(android.R.id.empty));

   If I'm using CursorLoader, I normally put this in onLoadFinished():

   // if there are no results
   if (data.getCount() == 0) {
       // let the user know
       lv.setEmptyView(findViewById(android.R.id.empty));
   } else {
       // otherwise clear it, so it won't flash in between cursor loads
       lv.setEmptyView(null);
   }
   

5. Speaking of cursor loaders, I'll also convert the activity to use CursorLoader if it isn't already by that point

回答3:

At least for the ListActivity You can change it to FragmentActivity (Still implementing OnItemCLickListener) and replace:

lv=getListView() to lv=(ListView) findViewById(R.id.your_list_view_id)

and

setListAdapter(favAdapter) to lv.setAdapter(adapter)

回答4:

It is possible to convert the ListActivity to a FragmentActivity.

1. Extend FragmentActivity instead of ListActivity
2. Create res/layout/your_activity.xml with an empty ListView with android:id="@+id/your_activity_list_view"
3. In the onCreate of your activity, setContentView(R.layout.your_activity);
4. Also change the onCreate of your activity to explicitly retrieve the ListView you just inflated

.

ListView lv = (ListView) findViewById(R.id.your_activity_list_view);
lv.setAdapter(adapter);
lv.setOnItemClickListener(this);