1 00:00:05,200 --> 00:00:08,200 Welcome back. All right let's review our code 2 00:00:08,500 --> 00:00:12,300 and see if there's anything we can improve or anything we shouldn't be doing. 3 00:00:13,000 --> 00:00:16,560 This is also a good chance to check any suggestions or warnings 4 00:00:16,560 --> 00:00:19,460 that android studio's lint checker is giving us. 5 00:00:20,360 --> 00:00:24,760 The first one's in AddEditFragment. So open that file up. 6 00:00:34,560 --> 00:00:38,160 I'll close the project pane to make more room on the screen. 7 00:00:40,150 --> 00:00:44,450 A new version of the androidx lifecycle extensions library was released 8 00:00:44,700 --> 00:00:46,700 towards the end of January 2020. 9 00:00:47,600 --> 00:00:51,400 You'll have seen me change my version of that library in the last video. 10 00:00:52,300 --> 00:00:54,100 That causes a small problem 11 00:00:54,400 --> 00:00:58,600 because Google have deprecated the ViewModelProviders class. 12 00:00:59,500 --> 00:01:02,500 You'll have a warning about that on line 12 13 00:01:02,500 --> 00:01:05,800 and then again when we use it on line 33. 14 00:01:06,300 --> 00:01:08,500 It's no longer necessary to use it. 15 00:01:08,800 --> 00:01:12,400 We can call the ViewModelProvider constructor directly. 16 00:01:28,650 --> 00:01:31,850 If your Kotlin classes aren't importing automatically, 17 00:01:32,100 --> 00:01:37,000 go to settings then editor general auto import. 18 00:01:45,360 --> 00:01:49,350 The recent versions of android studio now have a separate section 19 00:01:49,350 --> 00:01:52,950 where you can specify the auto import behavior for Kotlin. 20 00:01:53,550 --> 00:01:55,150 Tick both these boxes 21 00:01:55,950 --> 00:01:59,750 if you want android studio to auto import into your Kotlin code. 22 00:02:02,740 --> 00:02:07,370 We need to make the same change in our other three activity and fragment classes, 23 00:02:07,870 --> 00:02:09,669 but we'll do that when we come to them. 24 00:02:10,870 --> 00:02:13,470 There's a suggestion on line 58, 25 00:02:13,470 --> 00:02:15,670 in the OnViewCreated function. 26 00:02:16,470 --> 00:02:19,470 We should use Kotlin's ToString function 27 00:02:19,470 --> 00:02:22,470 rather than calling the function in the integer class. 28 00:02:26,470 --> 00:02:28,970 Click the ToString function in the code 29 00:02:28,970 --> 00:02:31,470 and use the lightbulb to accept the suggestion. 30 00:02:33,670 --> 00:02:35,970 The next change is a bit more serious. 31 00:02:36,470 --> 00:02:38,970 Have a look in on activity created 32 00:02:39,170 --> 00:02:41,070 and see if you can spot what it is. 33 00:02:43,570 --> 00:02:48,470 The function works but the code is doing something that it really shouldn't be doing. 34 00:02:48,830 --> 00:02:51,630 What we've done is assumed that the listener 35 00:02:51,630 --> 00:02:55,430 on line 106 will always be our activity. 36 00:02:55,430 --> 00:02:59,630 Most of the time, it probably will be but it doesn't have to be. 37 00:02:59,990 --> 00:03:03,390 Looking at the declaration of listener up on line 32 38 00:03:05,190 --> 00:03:07,990 is declared as an OnSaveClicked object. 39 00:03:08,870 --> 00:03:12,860 The only thing that we can be sure of is that it implements our 40 00:03:12,860 --> 00:03:14,750 OnSavedClick interface. 41 00:03:15,350 --> 00:03:18,350 We shouldn't be making any other assumptions about it, 42 00:03:18,550 --> 00:03:21,750 and we certainly shouldn't be assuming that it can be safely cast 43 00:03:21,750 --> 00:03:23,450 to an appcompat activity. 44 00:03:23,750 --> 00:03:26,350 If we use another object as our listener, 45 00:03:26,350 --> 00:03:28,950 we'll fail to set the activities action bar. 46 00:03:31,250 --> 00:03:33,750 It's the activity that will have the action bar, 47 00:03:33,750 --> 00:03:37,650 so we should be using the activity there. I'll change the code. 48 00:03:47,550 --> 00:03:50,250 We're indebted to Sebastian Arbogast, 49 00:03:50,250 --> 00:03:52,250 another instructor here on Udemy 50 00:03:52,450 --> 00:03:55,050 for spotting that potential issue with the code. 51 00:03:55,650 --> 00:03:58,250 We set listener in the OnAttach function, 52 00:03:58,250 --> 00:03:59,500 just below this one. 53 00:04:00,050 --> 00:04:02,050 As our code is at the moment 54 00:04:02,050 --> 00:04:05,410 using listener instead of activity to get the action bar 55 00:04:05,410 --> 00:04:07,010 wouldn't have caused a problem. 56 00:04:07,610 --> 00:04:10,290 But if we change the code to use some other object, 57 00:04:10,290 --> 00:04:11,890 we would have got a problem. 58 00:04:13,490 --> 00:04:15,790 The final change to AddEditFragment 59 00:04:15,790 --> 00:04:19,790 involves the lifecycle functions that are only used for logging. 60 00:04:20,290 --> 00:04:23,290 This is one of the classes I want to make some changes to, 61 00:04:23,590 --> 00:04:25,090 so I won't delete them yet. 62 00:04:25,890 --> 00:04:28,770 But I don't want to release the app with them still in. 63 00:04:29,670 --> 00:04:32,270 This is a good use for a to-do comment. 64 00:04:48,270 --> 00:04:49,970 Before releasing the app, 65 00:04:49,970 --> 00:04:54,330 we can use the to do tab down at the bottom of the android studio window 66 00:04:54,330 --> 00:04:57,130 to review all these notes that we've got for ourselves. 67 00:04:58,130 --> 00:05:00,830 As you can see, when you expand the entries, 68 00:05:00,830 --> 00:05:02,430 we've got a few things to do. 69 00:05:04,230 --> 00:05:06,230 You can double click one of the entries 70 00:05:06,530 --> 00:05:09,130 to go directly to that code in the editor. 71 00:05:16,490 --> 00:05:19,790 Okay. That's AddEditFragment sorted out. 72 00:05:20,290 --> 00:05:22,790 Next, we'll look at the AppDialog class. 73 00:05:28,990 --> 00:05:32,790 I've got three suggestions in here and I'll start at the bottom. 74 00:05:35,640 --> 00:05:39,440 The third one says variable dialog ID 75 00:05:39,440 --> 00:05:40,440 is never used. 76 00:05:40,990 --> 00:05:45,190 In fact, that line should have been commented out along with the line below. 77 00:05:45,390 --> 00:05:49,190 We did that back in section 13 but this line was left in. 78 00:05:49,590 --> 00:05:53,580 We only added it to see how we'd handle the dialogue being cancelled 79 00:05:53,780 --> 00:05:55,280 if we wanted to do that. 80 00:05:55,680 --> 00:05:57,480 We're not handling that in this app 81 00:05:57,480 --> 00:06:00,480 and the entire OnCancel function isn't needed. 82 00:06:00,980 --> 00:06:04,180 So we should delete it. I won't delete it though. 83 00:06:04,980 --> 00:06:07,750 As the app is at the moment, we should delete 84 00:06:08,000 --> 00:06:11,400 it but we're going to add it back in when we make some other changes. 85 00:06:12,000 --> 00:06:15,800 I'll comment the function out instead to save typing again later. 86 00:06:20,200 --> 00:06:24,400 Just to be clear, the only reason that I know that we need this function 87 00:06:24,400 --> 00:06:28,900 is because we've already developed all the code you'll be seeing in the next few videos. 88 00:06:29,500 --> 00:06:32,800 During the review, we did delete the OnCancel function 89 00:06:33,000 --> 00:06:34,600 but then we had to put it back again. 90 00:06:35,260 --> 00:06:37,260 The next two suggestions are similar. 91 00:06:37,660 --> 00:06:40,660 In the end of the OnCreateDialog function, 92 00:06:41,060 --> 00:06:43,660 that's on lines 96 to 98, 93 00:06:45,260 --> 00:06:48,760 though it's usually easier to click the ticks in the right margin to get to them. 94 00:06:49,560 --> 00:06:52,460 We don't use the dialog interface variable 95 00:06:52,460 --> 00:06:55,760 and android studio suggests we can replace it with an underscore. 96 00:06:56,260 --> 00:06:59,160 Doing that allows the compiler to optimize the code 97 00:06:59,560 --> 00:07:01,960 if we tell it that we're not going to use the argument. 98 00:07:02,460 --> 00:07:04,260 We talked about that in an earlier video. 99 00:07:04,760 --> 00:07:09,360 Use the light bulb to rename dialog interface to underscore for both those lines. 100 00:07:19,160 --> 00:07:22,520 After doing each line, you'll get a similar suggestion 101 00:07:22,520 --> 00:07:24,520 that which is also not used, 102 00:07:24,920 --> 00:07:27,220 so rename that one to an underscore as well. 103 00:07:36,580 --> 00:07:39,780 Okay. That's AddEditFragment 104 00:07:39,780 --> 00:07:42,980 and AppDialog finished. In the next video, 105 00:07:42,980 --> 00:07:46,180 we'll review the AppProvider class. I'll see you there.