1 00:00:04,440 --> 00:00:06,900 G'day everyone, welcome back. 2 00:00:06,900 --> 00:00:09,820 We're ready to test our AppDialog class, 3 00:00:09,820 --> 00:00:19,720 but first, I'll review the code that creates our dialog in the onDeleteClick function, on MainActivityFragment. 4 00:00:19,720 --> 00:00:25,680 The code adds the DIALOG_ID, the DIALOG_MESSAGE, 5 00:00:25,680 --> 00:00:32,860 and the caption for the DIALOG_POSITIVE_RID key of the bundle. 6 00:00:32,860 --> 00:00:38,360 After setting up the args bundle, it then creates a new AppDialog instance. 7 00:00:38,360 --> 00:00:42,020 The next two lines are very similar to what we did for our fragment, 8 00:00:42,020 --> 00:00:47,260 and we are using a DialogFragment after all, so it's not really surprising. 9 00:00:47,260 --> 00:00:54,540 AppDialog extends DialogFragment, so it's a fragment hosting the AlertDialog. 10 00:00:54,540 --> 00:00:58,820 The first argument to the dot show function is a bit different. 11 00:00:58,820 --> 00:01:06,240 Google's examples show how to show a dialog from an activity, but we're showing it from a fragment. 12 00:01:06,240 --> 00:01:12,820 That means we pass a childFragmentManager, rather than a supportFragmentManager, 13 00:01:12,820 --> 00:01:15,580 which is what Google's examples show. 14 00:01:15,580 --> 00:01:23,920 That second argument to the dialog.show function is an optional tag that we can use if we need to find the fragment again. 15 00:01:23,920 --> 00:01:27,600 I can't think of a reason why you'd want to do that with a dialog, 16 00:01:27,600 --> 00:01:32,400 but it's just providing the same capabilities that any other fragment would have. 17 00:01:32,400 --> 00:01:35,720 As we're not going to use it, we pass in null. 18 00:01:35,720 --> 00:01:42,240 Okay, that should show the dialog to request confirmation, before deleting a task. 19 00:01:42,240 --> 00:01:46,980 It's worth running the app at this stage. We can check that the dialog does appear, 20 00:01:46,980 --> 00:01:50,520 and dismisses itself when we click one of the buttons. 21 00:01:50,520 --> 00:01:53,020 We'll start by testing our exceptions, 22 00:01:53,020 --> 00:01:59,580 if we try to use the AppDialog class from an activity that doesn't implement the required interface. 23 00:01:59,580 --> 00:02:06,240 When I run the app and delete a task, we get an error: 24 00:02:28,240 --> 00:02:36,380 ClassCastException: Fragment MainActivityFragment must implement AppDialog.DialogEvents interface. 25 00:02:36,380 --> 00:02:37,820 So that's pretty good. 26 00:02:37,820 --> 00:02:41,380 The app crashed, but told us exactly why. 27 00:02:41,380 --> 00:02:45,480 In fact, we can copy the full interface name from the error message, 28 00:02:45,480 --> 00:02:50,540 and add it to the declaration of MainActivityFragment. 29 00:03:04,540 --> 00:03:10,080 We've got the usual error, because we're not implementing the required function. 30 00:03:10,080 --> 00:03:18,940 I'll get Android Studio to generate the stub using Ctrl I, after the onTaskLongClick function. 31 00:03:30,940 --> 00:03:42,300 Then add logging, so we can see the function is being called. 32 00:03:42,300 --> 00:03:50,260 Before I run the app again, remember that we put in a check that both an ID and a message were provided in the bundle. 33 00:03:50,260 --> 00:03:54,480 We should really test that. 34 00:03:54,480 --> 00:04:01,940 I'll comment out the line that adds the ID to the bundle. 35 00:04:01,940 --> 00:04:15,440 Then run the app again. 36 00:04:15,440 --> 00:04:27,300 Once again, I get an error when we delete a task. 37 00:04:27,300 --> 00:04:31,180 This time it's complaining that I've got an illegal argument exception: 38 00:04:31,180 --> 00:04:35,960 DIALOG_ID and/or DIALOG_MESSAGE are not present in the bundle. 39 00:04:35,960 --> 00:04:41,520 Now really, we should comment out the line that adds the message, and check that we get the same error. 40 00:04:41,520 --> 00:04:47,680 Then uncomment the ID line, and test we get the error if only the message isn't present. 41 00:04:47,680 --> 00:04:52,860 I'm not going to do that in this video because I'm going to run out of tasks to delete, 42 00:04:52,860 --> 00:05:00,160 but you should certainly test all three combinations, to make sure that our check works in all three situations. 43 00:05:00,160 --> 00:05:03,840 Hang on, I'm going to run out of tasks to delete? 44 00:05:03,840 --> 00:05:10,960 But surely, the tasks will only be deleted if I confirm it by tapping the dialog's delete button. 45 00:05:10,960 --> 00:05:15,000 Unfortunately not, and I'll be coming to that shortly. 46 00:05:15,000 --> 00:05:20,360 First, I'll uncomment the line that's causing the problem, 47 00:05:20,360 --> 00:05:26,580 and run the app again. 48 00:05:26,580 --> 00:05:29,760 I'm going to delete task 10, 49 00:05:29,780 --> 00:05:36,100 so make a mental note of the task name as I tap the delete button. 50 00:05:36,100 --> 00:05:37,980 And there's our dialog. 51 00:05:37,980 --> 00:05:42,240 It clearly states what the impact of deleting the record will be, 52 00:05:42,240 --> 00:05:46,940 and offers the user options to go ahead, or cancel the operation. 53 00:05:46,940 --> 00:05:48,400 Okay. 54 00:05:48,400 --> 00:05:51,860 Back to my running out of tasks comment. 55 00:05:51,860 --> 00:05:55,800 When you shift the focus from the dialog to the lists behind it, 56 00:05:55,800 --> 00:05:59,340 notice that task 10 has gone from the list. 57 00:05:59,340 --> 00:06:01,140 It's already deleted. 58 00:06:01,140 --> 00:06:06,640 Now, if you're new to programming, or new to programming in a GUI environment, 59 00:06:06,640 --> 00:06:09,660 you'll probably see nothing strange about that. 60 00:06:09,660 --> 00:06:15,620 After all, if I switch back to look at the onDeleteClick function, 61 00:06:15,620 --> 00:06:23,720 we can see it sets up the dialog, shows it, and then calls the ViewModel's delete function to delete the task. 62 00:06:23,720 --> 00:06:29,140 On the other hand, if you've got experience programming for Windows, for example, 63 00:06:29,140 --> 00:06:34,980 then you may have expected the code in onDeleteClick to pause after showing the dialog, 64 00:06:34,980 --> 00:06:38,449 and only resume once a dialog's dismissed. 65 00:06:38,449 --> 00:06:43,280 The term for the Windows behavior I've just described, is modal. 66 00:07:09,760 --> 00:07:13,160 Obviously, we have to make a change. 67 00:07:13,160 --> 00:07:20,560 We have to move that call to the ViewModel's delete function into onPositiveDialogResult. 68 00:11:27,900 --> 00:11:32,560 Okay, we still haven't managed to confirm the deletion of tasks, 69 00:11:32,560 --> 00:11:36,360 but it looks like our AppDialog class is working fine. 70 00:11:36,360 --> 00:11:40,440 The next step is to get MainActivity to use it properly, 71 00:11:40,440 --> 00:11:43,280 and we'll do that in the next video. 72 00:11:43,280 --> 00:11:45,820 See you then.