0
1
00:00:00,740 --> 00:00:01,250
All right.
1

2
00:00:01,310 --> 00:00:07,700
So I'm putting my trust in you that you've given it a really, really good try and that you're here because
2

3
00:00:07,700 --> 00:00:11,310
you have some bugs or you just want to see how I might choose to do it.
3

4
00:00:11,330 --> 00:00:14,140
Now, in our challenges, I like to say that there's no correct way,
4

5
00:00:14,180 --> 00:00:16,100
there's only different paths.
5

6
00:00:16,100 --> 00:00:21,410
And as long as it leads you to the result that we wanted, then you have succeeded in the challenge.
6

7
00:00:21,410 --> 00:00:24,070
So let's have a look at how we might do this.
7

8
00:00:24,200 --> 00:00:25,990
Let's think about it logically.
8

9
00:00:26,120 --> 00:00:35,000
What we need to happen is that when we create a new category, it needs to be associated with a new piece
9

10
00:00:35,000 --> 00:00:43,030
of data, not just a name or a list of items, but it now needs a color.
10

11
00:00:43,040 --> 00:00:53,750
So in our category class, we're going to have to need to add a new property that is called to say colour
11

12
00:00:54,210 --> 00:01:02,430
and this is going to be set as a string data type because we're going to save a hex string into this
12

13
00:01:02,430 --> 00:01:03,780
property.
13

14
00:01:03,780 --> 00:01:10,170
Now, let's head back over to our CategoryViewController and think about where is the first time point
14

15
00:01:10,290 --> 00:01:12,620
where we create our categories.
15

16
00:01:12,810 --> 00:01:19,920
Well, that's, of course, inside our addButtonPressed method, and we need to be in here because when we
16

17
00:01:19,920 --> 00:01:27,630
create a new category, we give it values for all of its properties including the category's name.
17

18
00:01:27,930 --> 00:01:34,520
And now, we'll also need to give it a colour when we create it.
18

19
00:01:34,740 --> 00:01:44,190
So we're going to set this to equal UIColor.randomFlat. hexValue.
19

20
00:01:44,610 --> 00:01:50,490
And this is now a string, as you can see over here.
20

21
00:01:50,850 --> 00:02:01,140
So that string gets saved into that property colour and gets persisted when we call save to our newCategory.
21

22
00:02:01,140 --> 00:02:04,660
Now, once it's been saved, then we'll need to retrieve it,
22

23
00:02:04,680 --> 00:02:05,170
right?
23

24
00:02:05,400 --> 00:02:14,820
So when we retrieve--so we retrieve our data when we call loadCategories inside viewDidLoad. 
24

25
00:02:14,820 --> 00:02:23,160
And loadCategories pulls out all of the objects that are of the type Category, and it gets put into this array
25

26
00:02:23,220 --> 00:02:26,300
or result's container called categories.
26

27
00:02:26,610 --> 00:02:30,020
Now, when do we need to use that information?
27

28
00:02:30,210 --> 00:02:38,910
Well, we use it here to change the textLabel of the cell and we're also going to use it here to change
28

29
00:02:38,910 --> 00:02:41,640
the color of the cell.
29

30
00:02:41,640 --> 00:02:48,270
So we're going to set it to equal a UIColor using a hexString. And this placeholder is telling
30

31
00:02:48,270 --> 00:02:50,760
us that we need to put a String inside here.
31

32
00:02:50,850 --> 00:02:52,890
So let's go ahead and do that.
32

33
00:02:52,890 --> 00:02:54,560
So what is our string going to be?
33

34
00:02:54,600 --> 00:03:06,110
Well, it's going to be the categories at indexPath.row.colour. Now, the first issue we get is that
34

35
00:03:06,110 --> 00:03:09,030
categories is an optional,
35

36
00:03:09,200 --> 00:03:15,920
so we would have to use optional chaining in order to make sure that we don't try to use a nil value.
36

37
00:03:15,920 --> 00:03:23,990
So if categories is not nil, then we're going to grab the category at indexPath.row, and then we're
37

38
00:03:23,990 --> 00:03:26,340
going to tap into the colour property.
38

39
00:03:26,570 --> 00:03:29,840
Now, colour may or may not have a value.
39

40
00:03:30,110 --> 00:03:34,890
So if it doesn't have a value, then we're going to do the same thing as we did up here.
40

41
00:03:35,030 --> 00:03:40,600
We're going to say if there is no value, then here is a default value.
41

42
00:03:40,850 --> 00:03:46,050
So the default value that we're going to give as the hex code is we're going to go into
42

43
00:03:46,050 --> 00:03:52,700
our Main.storyboard and we're going to find that nice blue color that we've got as the title, and we're going to look
43

44
00:03:52,700 --> 00:03:57,040
at that colors hex color inside the RGB Sliders
44

45
00:03:57,170 --> 00:04:04,430
under this particular tab. So we're going to copy that code over and we're going to paste it inside here,
45

46
00:04:04,850 --> 00:04:08,790
so that we can use it as the default hex color.
46

47
00:04:08,810 --> 00:04:14,600
So if your category doesn't have a color yet, then we're going to use a default value for the color.
47

48
00:04:14,750 --> 00:04:24,550
So you can shorten these two lines of code if you wish by saying if let category = categories?
48

49
00:04:25,340 --> 00:04:29,760
optional chain to indexPath.row.
49

50
00:04:29,990 --> 00:04:38,240
And if that is not nil, then we're going to call these two lines of code. And instead of using categories
50

51
00:04:38,780 --> 00:04:46,520
at indexPath.row, we're simply going to use our new constant called category, and we can replace
51

52
00:04:46,520 --> 00:04:48,290
it in those two places.
52

53
00:04:48,290 --> 00:04:53,360
All right, so let's give it a go and see if we manage to solve that challenge.
53

54
00:04:53,360 --> 00:04:58,650
So the first thing that will happen when you run your app is your app is going to crash.
54

55
00:04:58,850 --> 00:05:04,870
And that's because if we open up our Realm Browser, you'll remember that category already has three items.
55

56
00:05:04,880 --> 00:05:11,660
Now, these three items don't have the third property color yet, but color is going to be used inside our
56

57
00:05:11,750 --> 00:05:12,280
app.
57

58
00:05:12,320 --> 00:05:16,170
So when this mismatch happens, you get this particular error:
58

59
00:05:16,310 --> 00:05:24,690
"Error Domain=io.realm Code=10. Migration is required
because Category.colour has been added."
59

60
00:05:24,950 --> 00:05:37,380
So, what we have to do, if you remember, is you will have to hold your app, delete it, and rerun your app.
60

61
00:05:37,540 --> 00:05:41,670
And that wipes all of your data, so that everything is consistent.
61

62
00:05:41,860 --> 00:05:42,250
Okay.
62

63
00:05:42,250 --> 00:05:49,970
So let's go ahead and add a new category, and let's say, let's call our category Home as we did before.
63

64
00:05:50,250 --> 00:05:50,590
Okay.
64

65
00:05:50,600 --> 00:05:56,830
So home is green. And let's add another one called Work. work is brown.
65

66
00:05:56,890 --> 00:06:01,510
Now, you'll see that the contrast between the text and the background is not great at the moment,
66

67
00:06:01,510 --> 00:06:05,940
but we're going to fix that a little bit later on using another of Chameleon's methods.
67

68
00:06:05,980 --> 00:06:09,180
But for now, this is pretty good.
68

69
00:06:09,220 --> 00:06:10,720
We're getting random colors.
69

70
00:06:10,870 --> 00:06:12,640
And here's the litmus test.
70

71
00:06:12,640 --> 00:06:20,990
If we terminate our app and go back into Todoey, look, Home is still green, Work is still brown.
71

72
00:06:21,220 --> 00:06:26,580
I completely agree with the color choices that have been randomly generated by my app.
72

73
00:06:26,590 --> 00:06:30,100
So did you manage to get the challenge? If you didn't,
73

74
00:06:30,190 --> 00:06:35,540
then this is a good time to go back and fix any bugs you might have and try to get it working.
74

75
00:06:35,560 --> 00:06:41,500
So in the next lesson-- Now, in the next lesson, we're going to be-- In the next lesson,
75

76
00:06:41,560 --> 00:06:46,490
we're going to be adding some gradient colors to our TodoListViewController.
76

77
00:06:46,510 --> 00:06:49,410
So if you want to see that, then I'll see you on the next lesson.