0
1
00:00:00,840 --> 00:00:08,660
So, now that we've managed to make our to-do list app work using Realm to create new items, to save new
1

2
00:00:08,670 --> 00:00:17,040
items, to read the data from our Realm database, it's time to tackle updating data in the database. And you'll
2

3
00:00:17,040 --> 00:00:24,330
find that similar to Core Data, updating data is very, very similar to saving a new item,
3

4
00:00:24,330 --> 00:00:27,710
and we're going to be using realm.write to do the same thing.
4

5
00:00:27,810 --> 00:00:34,820
So the place that makes the most sense to update are realm is, again, inside our didSelectRowAt 
5

6
00:00:34,830 --> 00:00:36,090
indexPath Method.
6

7
00:00:36,090 --> 00:00:44,430
And this is the place where we select a cell inside our tableView in order to check or uncheck it by
7

8
00:00:44,460 --> 00:00:47,040
toggling this particular done property.
8

9
00:00:47,040 --> 00:00:52,500
So we're going to leave all of this commented out and I'm going to show you how you would do this using
9

10
00:00:52,500 --> 00:00:53,640
Realm.
10

11
00:00:53,700 --> 00:01:02,970
So what we can say is we can say if let item = todoItems, which, remember, is a container that
11

12
00:01:02,970 --> 00:01:10,290
contains a whole bunch of items and it's fetched from our realm, then we're going to grab the item at
12

13
00:01:10,350 --> 00:01:12,000
indexPath.row,
13

14
00:01:12,120 --> 00:01:13,800
so, the current selected row.
14

15
00:01:13,890 --> 00:01:22,650
And if this is not nil, then we're going to be able to access this Item object, and we can say
15

16
00:01:22,970 --> 00:01:23,950
try realm.write,
16

17
00:01:23,970 --> 00:01:31,200
and we're going to write item. equals the opposite of item.done.
17

18
00:01:31,530 --> 00:01:37,140
And because this can throw, then, again, we're going to wrap it inside a do catch block.
18

19
00:01:40,100 --> 00:01:50,650
And if there is an error, then we're going to say "Error saving done status."
19

20
00:01:50,770 --> 00:01:54,150
Let's just indent this for clarity sake.
20

21
00:01:54,160 --> 00:01:56,950
And now we have replaced this code.
21

22
00:01:56,980 --> 00:02:01,510
So just to run through it, we're checking to see if to-do list items is not nil,
22

23
00:02:01,840 --> 00:02:07,930
and if it's not, then we're going to pick out the item at indexPath.row and set it to equal item,
23

24
00:02:07,930 --> 00:02:15,070
and then we're going to try and write the updated property of item by toggling whatever it used to be before.
24

25
00:02:15,070 --> 00:02:17,980
So if it was false, it becomes true, true becomes false.
25

26
00:02:18,230 --> 00:02:25,450
And the last thing we need to do is, of course, call our trusty tableView.reloadData method to
26

27
00:02:25,450 --> 00:02:33,100
call this cellForRowAt indexPath method again and to update our cells based on this done property.
27

28
00:02:33,190 --> 00:02:34,320
And give it a check mark
28

29
00:02:34,330 --> 00:02:38,950
if it's done and remove the checkmark if it is not done.
29

30
00:02:38,950 --> 00:02:43,620
So all that's left for us to do is to run our app and see if it works.
30

31
00:02:43,630 --> 00:02:43,920
All right.
31

32
00:02:43,930 --> 00:02:50,320
So let's head into our Shopping category where we know we've got some items and let's select and say
32

33
00:02:50,320 --> 00:02:55,390
that we're done with buying peaches. And you can see that we've got a checkmark showing up and we can
33

34
00:02:55,390 --> 00:02:57,680
toggle these as we please.
34

35
00:02:57,810 --> 00:03:04,000
And if we have a look inside the Realm Browser, you'll see that as I check these, they get updated in
35

36
00:03:04,000 --> 00:03:06,920
real time and really, really fast as well.
36

37
00:03:07,000 --> 00:03:12,550
But when I check them over here, they will not get reflected in our table view because, as you remember,
37

38
00:03:13,030 --> 00:03:18,500
we cannot call reload table view from a different application into our app,
38

39
00:03:18,580 --> 00:03:20,660
so it has to happen over here.
39

40
00:03:20,800 --> 00:03:26,190
So that is how we can update our data using Realm. In the next lesson,
40

41
00:03:26,200 --> 00:03:29,260
we're going to talk about how to delete data using Realm.
41

42
00:03:29,290 --> 00:03:32,280
So all of that and more, see you on the next lesson.