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Welcome back, everyone.

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In the last video we moved the code to access the database

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into our ViewModel.

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To test the change we need to make some changes

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to the durations report activity.

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First, I'll declare an instance of our ViewModel

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and use lazy initialization.

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In the oncreate function,

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we'll observe the durations ViewModel instead of calling LoadData.

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If you're prompted for the observer import,

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make sure you choose androidx.lifecycle.observer.

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All right. Our activity is still very basic.

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We've got to add the ability to select different dates

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and sort by columns,

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but it should still work. I like to test apps often

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whenever they're in a state that should run,

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so does it work, run the app and tap the reports icon.

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And that looks good. We've got our data for May displayed.

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Make sure the logcat's visible,

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and add a comment rotating at the end.

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Next, rotate the device.

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This time the database isn't re-queried.

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That's good. We've kept our durations report activity

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focused just on the UI

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and also prevented unnecessary work.

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I know we're using a local database here,

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but it's still going to save the user's batteries,

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and you can use exactly this approach when collecting data over the internet.

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That would have a far greater impact on battery life

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and also on your users pockets if they're on a meted connection.

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In the next, video we'll start adding the remaining functionality to the reports.

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We've still got to allow the report to be filtered by date

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display either a single day or a full week

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and implement sorting by the various columns.

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We've got lots to do, I'll see you there.