1
00:00:04,939 --> 00:00:07,480
G'day everyone, welcome back.

2
00:00:07,480 --> 00:00:11,300
Now that we've created our TaskTimerViewModel class,

3
00:00:11,300 --> 00:00:14,040
we need to subscribe to the ViewModel.

4
00:00:14,040 --> 00:00:17,920
We do that in MainActivityFragment.

5
00:00:17,920 --> 00:00:27,960
We create a ViewModel instance first,
as we saw in the previous section

6
00:00:27,960 --> 00:00:29,760
and we've got an error.

7
00:00:29,760 --> 00:00:33,240
ViewModelProviders isn't recognized.

8
00:00:33,240 --> 00:00:38,920
Your first mini-challenge is to work out why and to fix the problem.

9
00:00:38,920 --> 00:00:46,280
We did discuss this back in the previous section, so refer
to that, if you can't work out why there's an error.

10
00:00:46,280 --> 00:00:51,400
Pause the video now and we'll continue in a few minutes.

11
00:00:51,400 --> 00:00:53,780
Did you work out what was wrong?

12
00:00:53,780 --> 00:01:00,360
We haven't added the dependency for the ViewModel
and LiveData libraries to our build.gradle file.

13
00:01:00,360 --> 00:01:07,060
Let's have a look.

14
00:01:07,060 --> 00:01:15,140
Let's add in our missing code

15
00:01:15,140 --> 00:01:19,620
and then click sync now.

16
00:01:19,620 --> 00:01:27,120
This is also a good time to review the versions,
to see if any of the components have been updated.

17
00:01:27,120 --> 00:01:30,280
Ok, we've got a ViewModel instance.

18
00:01:30,280 --> 00:01:43,500
Next, we need to subscribe to it.
I'll do that in the onCreate function.

19
00:01:43,500 --> 00:01:54,680
Choose the Android.arch.lifecycle.observer import, if you're prompted.

20
00:01:54,680 --> 00:02:02,960
This is where we'll call our adapter's swapCursor function, to provide the new cursor, when we observe that it has changed.

21
00:02:02,960 --> 00:02:07,480
When the cursor changes, we pass the new one to swapCursor,

22
00:02:07,480 --> 00:02:10,139
causing the adapter to get the new data.

23
00:02:10,139 --> 00:02:17,080
We wrote swapCursor to return the old cursor,
allowing us to call its close function here.

24
00:02:17,080 --> 00:02:21,060
That takes care of freeing up the cursor resources.

25
00:02:21,060 --> 00:02:25,200
We use a safe core, in case the return cursor is null.

26
00:02:25,200 --> 00:02:37,320
We can now run the app and we should see our
tasks appearing in the list.

27
00:02:37,320 --> 00:02:41,260
That's looking good but it's still not quite finished.

28
00:02:41,260 --> 00:02:48,700
To see why, watch what happens when I add a new task.

29
00:02:48,700 --> 00:02:58,140
We're up to task 5, so I'm going to add tasks 6,

30
00:02:58,140 --> 00:03:02,040
and we'll give it the sort order of 6.

31
00:03:02,040 --> 00:03:10,340
When I tap on the Save button, we return to the task list
but the new task doesn't appear.

32
00:03:10,340 --> 00:03:21,760
It has been successfully saved, as we can
see if I close the app and then run it again.

33
00:03:21,760 --> 00:03:27,800
We'll look at how to fix that in the next video. See you then.