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Welcome back. All right.

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Did you spot what we did in TaskTimerViewModel

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that we didn't do in DurationsViewModel.

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We're not observing the changes to the database

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and don't update the adapter when the data changes.

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The code is almost identical to the code we used in TaskTimerViewModel.

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So I'll copy and paste it from there.

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Accept the imports then change the function name.

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We called it LoadTasks in TaskTimerViewModel,

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but it's called LoadData in this class,

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that's declared our ContentObserver. Now we have to register it.

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We do that in the init block.

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Once again, that's very similar to the code in the TaskTimerViewModel class.

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We're observing changes to the timings table

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rather than the tasks table

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so we use the timings contract content URI.

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I've also obtained the application reference a bit differently.

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Inside the init block,

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we still have access to any arguments passed to the constructor

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that means we don't have to call get application,

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we can use application directly.

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I wanted to point that out

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but I'd probably use get application throughout the class

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as I did in the TaskTimerViewModel.

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It's less confusing if all the references to the application object

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are obtained in the same way.

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But if you see other android view model classes that access

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application directly in their init block,

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you now know that it's exactly the same object

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the get application returns.

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The last thing we need to do is stop observing

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when our ViewModel is being destroyed.

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That's important, failing to do it can result in your app leaking resources.

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I'll copy the entire uncleared function

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from TaskTimerViewModel and paste it at the end of this class.

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That's all the changes we need to make, let's see if it works.

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I'll run the app again

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and delete all the records before the 15th of May

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2019.

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This time the display updates as soon as I confirm the change.

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Creating observers is a flexible way for your classes to react to changes

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in other parts of the system.

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Our activities are observing the live data objects

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in the ViewModel classes,

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and our ViewModels are observing the URIs

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that they pass to the on ContentResolver.

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We haven't had to create interfaces

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to implement CallBack functions

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to let the ViewModels know the data has changed.

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As long as you remember to unregister your observers to avoid memory leaks,

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you'll find observers are very useful.

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We'll be using another observer later when we get the reports to update

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if the user changes the settings.

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But before that,

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we've got a small bug in our code,

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I'll demonstrate it in the next video. See you there.