WEBVTT

1
00:00:01.986 --> 00:00:03.579
- [Tim] All right so moving on now.

2
00:00:03.579 --> 00:00:05.238
So we're at the stage
now where we're going

3
00:00:05.238 --> 00:00:07.308
to start populating the songs list

4
00:00:07.308 --> 00:00:08.918
when we actually click on an album.

5
00:00:08.918 --> 00:00:10.494
So it's really just more of the same.

6
00:00:10.494 --> 00:00:13.374
Now we don't really want
to do what I'm about to do.

7
00:00:13.374 --> 00:00:16.524
The long-winded way is to
create another function,

8
00:00:16.524 --> 00:00:18.010
get underscore songs, let's say

9
00:00:18.010 --> 00:00:20.449
and bind that to the album's ListBox.

10
00:00:20.449 --> 00:00:22.584
And the approach we'll
take in the next video

11
00:00:22.584 --> 00:00:24.955
is to subclass our ScrollBox class

12
00:00:24.955 --> 00:00:27.565
and get the ListBoxes
to populate themselves.

13
00:00:27.565 --> 00:00:30.128
Sometimes you have to
start duplicating code

14
00:00:30.128 --> 00:00:32.213
before you spot that there is duplication.

15
00:00:32.213 --> 00:00:34.277
So I'm going to get
this songs list working

16
00:00:34.277 --> 00:00:36.271
so we can see what the common code is

17
00:00:36.271 --> 00:00:38.679
and how we can ultimately avoid that.

18
00:00:38.679 --> 00:00:42.729
Now get_songs is going to be
very similar to get_albums,

19
00:00:42.729 --> 00:00:46.896
I'm going to add it just
below the get_albums function.

20
00:00:50.758 --> 00:00:52.207
And leaving two blank lines is normal

21
00:00:52.207 --> 00:00:54.989
between functions there or methods.

22
00:00:54.989 --> 00:00:58.156
Def get_songs(event):

23
00:01:00.480 --> 00:01:02.313
lb = event.widget

24
00:01:05.990 --> 00:01:08.715
now we want to do an index

25
00:01:08.715 --> 00:01:11.487
index = int(lb)

26
00:01:11.487 --> 00:01:15.070
Let's close down the update
or do that update a bit later.

27
00:01:15.070 --> 00:01:19.256
(lb.curselection()

28
00:01:19.256 --> 00:01:21.861
then we want square bracket zero

29
00:01:21.861 --> 00:01:23.360
and a right parentheses

30
00:01:23.360 --> 00:01:25.777
album_name = lb.getindex

31
00:01:29.017 --> 00:01:30.997
or get parentheses index I should say,

32
00:01:30.997 --> 00:01:34.319
then that all-important comma on the end.

33
00:01:34.319 --> 00:01:36.269
And then we're going to get the artist ID

34
00:01:36.269 --> 00:01:38.107
from the database row.

35
00:01:38.107 --> 00:01:41.774
So # get the artist ID
from the database row

36
00:01:44.007 --> 00:01:46.671
and when we do that by typing

37
00:01:46.671 --> 00:01:49.088
album_id = conn.execute

38
00:01:51.973 --> 00:01:54.162
parentheses and then double quotes,

39
00:01:54.162 --> 00:01:55.579
SELECT albums._id

40
00:02:02.783 --> 00:02:03.700
FROM albums

41
00:02:05.279 --> 00:02:06.696
where albums.name

42
00:02:09.741 --> 00:02:12.523
is equal to question
mark, end of double quote

43
00:02:12.523 --> 00:02:14.606
comma, space, album_name,

44
00:02:16.259 --> 00:02:19.551
finish the parentheses
and then dot fetchone()

45
00:02:19.551 --> 00:02:22.627
and make a call to that method.

46
00:02:22.627 --> 00:02:24.210
And alist = []

47
00:02:26.527 --> 00:02:30.520
and we want to select the
song, so we're going to do

48
00:02:30.520 --> 00:02:32.520
for x in conn.execute

49
00:02:34.367 --> 00:02:37.839
and the SQL line of code in double quotes

50
00:02:37.839 --> 00:02:39.339
SELECT songs.title

51
00:02:41.303 --> 00:02:42.636
FROM songs WHERE

52
00:02:44.187 --> 00:02:45.687
songs.album=?

53
00:02:49.014 --> 00:02:51.264
And ORDER BY songs.track"",

54
00:02:54.548 --> 00:02:56.297
double-quote, comma, space

55
00:02:56.297 --> 00:02:57.464
and album_id):

56
00:03:02.162 --> 00:03:03.495
and alist.append

57
00:03:05.245 --> 00:03:07.245
(x)[0])

58
00:03:08.478 --> 00:03:10.561
then end the parentheses,

59
00:03:10.561 --> 00:03:12.126
then the last line of code

60
00:03:12.126 --> 00:03:12.959
songLV.set

61
00:03:15.254 --> 00:03:17.602
I've seen this in the get_albums method

62
00:03:17.602 --> 00:03:21.602
(tuple(alist))

63
00:03:22.971 --> 00:03:24.725
So really apart from the
column and table names

64
00:03:24.725 --> 00:03:26.208
this code is pretty much identical

65
00:03:26.208 --> 00:03:29.290
to the get_albums function.

66
00:03:29.290 --> 00:03:31.022
So we just have to bind the function now

67
00:03:31.022 --> 00:03:33.744
to the album ListBox selected event

68
00:03:33.744 --> 00:03:36.438
and the songs list will
hopefully be updated

69
00:03:36.438 --> 00:03:38.493
when we click on a new album.

70
00:03:38.493 --> 00:03:41.243
So we'll go to our albums ListBox

71
00:03:42.098 --> 00:03:45.624
and after the config border=2 line

72
00:03:45.624 --> 00:03:46.614
we're going to type

73
00:03:46.614 --> 00:03:47.781
albumList.bind

74
00:03:50.545 --> 00:03:51.970
('<<

75
00:03:51.970 --> 00:03:54.714
single quotes, less than, less than

76
00:03:54.714 --> 00:03:55.547
and it's going to be

77
00:03:55.547 --> 00:03:57.238
ListboxSelect>>',

78
00:03:57.238 --> 00:04:00.580
again greater than sign,
greater than sign, single quote,

79
00:04:00.580 --> 00:04:01.413
get_songs)

80
00:04:04.478 --> 00:04:05.626
to call that method.

81
00:04:05.626 --> 00:04:07.238
Again there's no parentheses there

82
00:04:07.238 --> 00:04:09.676
after the get_songs.

83
00:04:09.676 --> 00:04:11.509
So now if we run this,

84
00:04:17.986 --> 00:04:20.474
we should see that the songs will update

85
00:04:20.474 --> 00:04:21.539
when we select an album.

86
00:04:21.539 --> 00:04:23.872
So let's just click on AC DC

87
00:04:24.775 --> 00:04:26.197
For Those About to Rock

88
00:04:26.197 --> 00:04:28.078
And you can now see the
songs are now showing up here

89
00:04:28.078 --> 00:04:28.911
on the right-hand side.

90
00:04:28.911 --> 00:04:29.744
So excellent.

91
00:04:29.744 --> 00:04:30.951
We got that to work.

92
00:04:30.951 --> 00:04:33.261
But there is a bit of
a problem here still,

93
00:04:33.261 --> 00:04:34.417
so we select another album,

94
00:04:34.417 --> 00:04:37.000
like for example Axel Rudi Pell

95
00:04:38.009 --> 00:04:40.461
select one of the albums to show.

96
00:04:40.461 --> 00:04:42.995
That's fine but if we now
select a different artist,

97
00:04:42.995 --> 00:04:45.141
the songs from the Axel Rudi Pell album

98
00:04:45.141 --> 00:04:47.001
are still being displayed.

99
00:04:47.001 --> 00:04:48.547
So come over here

100
00:04:48.547 --> 00:04:50.137
they haven't been reset in other words,

101
00:04:50.137 --> 00:04:52.933
until we actually select a different album

102
00:04:52.933 --> 00:04:54.485
for that particular artist.

103
00:04:54.485 --> 00:04:56.653
So really we need to reset the songs list

104
00:04:56.653 --> 00:04:58.717
whenever the artist changes.

105
00:04:58.717 --> 00:05:01.543
So let's go ahead and do that.

106
00:05:01.543 --> 00:05:03.989
And that's pretty easy to do.

107
00:05:03.989 --> 00:05:06.741
And it's done down here,
or up here I should say,

108
00:05:06.741 --> 00:05:08.824
In the get_albums method.

109
00:05:13.237 --> 00:05:14.625
So we initialise it in there, so we put

110
00:05:14.625 --> 00:05:18.792
songLV.set(("Choose an album",))

111
00:05:29.513 --> 00:05:32.180
so let's try running that again.

112
00:05:33.908 --> 00:05:35.349
So we'll do the same thing now.

113
00:05:35.349 --> 00:05:38.003
We'll just choose Axel Rudi Pell

114
00:05:38.003 --> 00:05:39.429
choose an album

115
00:05:39.429 --> 00:05:40.433
that works okay.

116
00:05:40.433 --> 00:05:42.421
And if we go back to say to AC DC,

117
00:05:42.421 --> 00:05:45.525
we can see the songs is correctly updated,

118
00:05:45.525 --> 00:05:48.683
or the message, default
message, is now showing

119
00:05:48.683 --> 00:05:49.792
in the songs list

120
00:05:49.792 --> 00:05:52.051
and the previous selection,
or list of songs,

121
00:05:52.051 --> 00:05:53.384
has been cleared.

122
00:05:53.384 --> 00:05:55.103
So basically the song list now is cleared

123
00:05:55.103 --> 00:05:56.761
whenever a new artist is selected

124
00:05:56.761 --> 00:06:00.219
and that's actually quite important

125
00:06:00.219 --> 00:06:03.113
because it does have a slight
impact on our subclass.

126
00:06:03.113 --> 00:06:06.696
But we'll see about
that in the next video.