1 00:00:04,400 --> 00:00:05,600 Welcome back everyone. 2 00:00:06,800 --> 00:00:09,160 We've created a very basic activity 3 00:00:09,160 --> 00:00:11,660 to test our adapter and our layouts. 4 00:00:12,260 --> 00:00:14,260 There's still work to do in the activity. 5 00:00:14,760 --> 00:00:18,060 We're going to add a menu to allow the reports to be filtered by date. 6 00:00:18,720 --> 00:00:22,080 And we'll also let our users sort the report on different columns. 7 00:00:22,980 --> 00:00:27,440 First though, we're going to do things properly and use a ViewModel 8 00:00:27,440 --> 00:00:30,440 to handle fetching the data from the database. 9 00:00:32,240 --> 00:00:33,840 Create a new Kotlin class, 10 00:00:34,240 --> 00:00:37,240 which I'll call DurationsViewModel. 11 00:00:53,540 --> 00:00:56,640 The basics will be very similar to our existing view model. 12 00:00:57,190 --> 00:01:01,390 I'll start with the basics and we'll add the code to work with dates later. 13 00:01:02,050 --> 00:01:05,050 It's going to be useful to put a lot of logging in this class. 14 00:01:12,050 --> 00:01:14,850 Just like the TaskTimerViewModel class, 15 00:01:14,850 --> 00:01:17,550 we're going to subclass AndroidViewModel. 16 00:01:18,100 --> 00:01:22,500 That's because we need an application instance for accessing the content resolver. 17 00:01:37,700 --> 00:01:41,060 At the moment, our activity is fetching the data from the database. 18 00:01:41,920 --> 00:01:45,470 We don't want the activity to deal with anything that isn't concerned 19 00:01:45,470 --> 00:01:46,770 with the user interface. 20 00:01:47,370 --> 00:01:51,770 Anything else will be the responsibility of our DurationsViewModel class. 21 00:01:52,370 --> 00:01:54,370 I'll cut the database cursor, 22 00:01:54,370 --> 00:01:59,360 sort order and selection variables from the DurationsReport activity. 23 00:02:18,960 --> 00:02:23,260 The cursor shouldn't be a field because the activity is going to observe it. 24 00:02:23,660 --> 00:02:26,660 Just like we did in the TaskTimerViewModel class, 25 00:02:27,360 --> 00:02:30,660 it needs to be a live data object. In fact, 26 00:02:30,960 --> 00:02:34,260 I can copy the declaration from TaskTimerViewModel 27 00:02:34,510 --> 00:02:35,810 and paste it in here. 28 00:02:55,810 --> 00:02:57,810 We've now got a live data object 29 00:02:57,810 --> 00:03:00,810 that the DurationsReport activity can observe 30 00:03:00,810 --> 00:03:03,010 to get the cursor it needs for its adapter. 31 00:03:03,810 --> 00:03:07,410 We also want the activity to be able to change the sort order. 32 00:03:08,010 --> 00:03:12,410 When it does, the data will need to be re-queried to get the data in the correct order. 33 00:03:13,290 --> 00:03:17,390 I'll add a setter to the set order field to take care of that. 34 00:03:32,190 --> 00:03:34,690 Because we're re-querying the database, 35 00:03:35,090 --> 00:03:37,690 we check to make sure that the value has changed. 36 00:03:38,240 --> 00:03:40,040 There's no point accessing the database 37 00:03:40,040 --> 00:03:42,940 if sort order is set to the value it already had. 38 00:03:43,440 --> 00:03:47,430 We've got an error because we haven't written the load data function yet. 39 00:03:48,310 --> 00:03:51,810 Well, that's not true we have written it it's just in the wrong class. 40 00:03:52,360 --> 00:03:55,130 I'll cut it out of the DurationsReport activity, 41 00:03:55,530 --> 00:03:56,630 and paste it in here. 42 00:04:20,130 --> 00:04:22,330 That's almost fine as it is. 43 00:04:22,930 --> 00:04:25,700 The report adapter is owned by the activity. 44 00:04:25,700 --> 00:04:29,800 Instead of swapping the cursor, we just update the live data object 45 00:04:29,800 --> 00:04:31,500 that the activity is observing. 46 00:04:47,160 --> 00:04:48,520 We've still got an error. 47 00:04:49,220 --> 00:04:52,580 Remember that we can't use property access syntax 48 00:04:52,580 --> 00:04:55,880 to refer to the application in a ViewModel class. 49 00:04:56,430 --> 00:05:00,830 We have to call the getApplication getter function instead. 50 00:05:11,090 --> 00:05:11,990 All right. 51 00:05:11,990 --> 00:05:14,790 That's looking good we've got no errors at least. 52 00:05:15,450 --> 00:05:19,250 One thing we're not doing though is calling the LoadData function. 53 00:05:20,050 --> 00:05:22,410 It gets called when the sort order changes 54 00:05:22,960 --> 00:05:27,460 but we don't want to present the user with a blank screen until they sort the report. 55 00:05:28,660 --> 00:05:31,860 I'll add an init block to call LoadData. 56 00:05:32,630 --> 00:05:36,830 I'll put it after the field declarations, just before the LoadData function. 57 00:05:48,430 --> 00:05:51,430 I'll finish the video with one more change. 58 00:05:51,980 --> 00:05:55,280 Our sort columns enum really belongs in here 59 00:05:55,280 --> 00:05:57,080 rather than in the activity. 60 00:06:16,880 --> 00:06:18,780 This ViewModel should work, 61 00:06:19,330 --> 00:06:21,930 but we've made a real mess of durations report. 62 00:06:22,830 --> 00:06:27,030 We'll fix that and test everything still works in the next video.