[#159][Part1] [Compose] Support datastore replacing shared preference

[lydiasama]

#159

What happened 👀

Part 1: Integrate for sample-compose
Part 2: Integrate for sample-xml
Part 3: Integrate for both template-xml & template-compose

Insight 📝

• Add the DataStore Preferences dependencies to the Sample-Compose project.
• Add use cases for GetFirstTimeLaunchPreferencesUseCase and UpdateFirstTimeLaunchPreferencesUseCase.
• At first, I attempt to call the use cases by the following approach:

init {
        execute {
            showLoading()
            getModelsUseCase()
                .catch {
                    _error.emit(it)
                }
                .collect { result ->
                    val uiModels = result.toUiModels()
                    _uiModels.emit(uiModels)
                }
            getFirstTimeLaunchUseCase()
                .catch {
                    _error.emit(it)
                }
                .collect { firstTimeLaunch ->
                    Timber.d("firstTimeLaunch: $firstTimeLaunch")
                    _firstTimeLaunch.emit(firstTimeLaunch)
                    if (firstTimeLaunch) {
                        updateFirstTimeLaunchUseCase(false)
                    }
                    Timber.d("firstTimeLaunch: after if")
                }
            hideLoading()
        }
    }

But it has never come to do the hideLoading() function. It seems it never ends the collect() function. So I changed the approach to be:

init {
        execute {
            showLoading()
            val getModelsFlow = getModelsUseCase()
            val getFirstTimeLaunchPreferencesFlow = getFirstTimeLaunchPreferencesUseCase()

            getModelsFlow.combine(getFirstTimeLaunchPreferencesFlow) { uiModels, firstTimeLaunch ->
                _uiModels.emit(uiModels.toUiModels())

                _firstTimeLaunch.emit(firstTimeLaunch)
                if (firstTimeLaunch) {
                    updateFirstTimeLaunchPreferencesUseCase(false)
                }
            }.catch {
                _error.emit(it)
                hideLoading()
            }.collect {
                hideLoading()
            }
        }
    }

And what's interesting is, when I tried the .onCompletion, it will do the onCompletion block when gets error, but not execute it when it succeeds. So in success case, it will not hide loading if we do the following code:

init {
        execute {
            val getModelsFlow = getModelsUseCase()
            val getFirstTimeLaunchPreferencesFlow = getFirstTimeLaunchPreferencesUseCase()
           ...
            }.onStart {
                showLoading()
            }.onCompletion {
                hideLoading()                
            }.catch {
                _error.emit(it)
            }.collect()
        }
    }

After discussing with @Wadeewee, we can wrap the appPreferencesDataStore.data with flow, so that we can use .first() to get only the first emit from the DataStore preferences and it can finish the collect() function.

💡 Here is the solution:

init {
        execute {
            val getModelsFlow = getModelsUseCase()
            val getFirstTimeLaunchPreferencesFlow = getFirstTimeLaunchPreferencesUseCase()
           ...
            }.onStart {
                showLoading()
            }.onCompletion {
                hideLoading()
            }.catch {
                _error.emit(it)
            }.collect()
        }
    }

• 💡 I have an idea to combine the _uiModels, _firstTimeLaunch, and showLoading flow in HomeViewState. So we can get rid of their public variables. Moreover, we can just observe only

val homeViewState: HomeViewState by viewModel.homeViewState.collectAsState()

in HomeScreen. BTW, I'm not sure if we could reduce the recomposition by doing this because when the HomeViewState's properties are changed, it might trigger to recompose anyway. So I'll keep the codebase as the same.

• I added these attributes to AndroidManifest because when I test uninstall and reinstall the app, sometimes the preferences does not remove entirely. But instead, it keep some caches. So it's better to not allow caching.
  Ref: https://stackoverflow.com/a/33176898

        android:allowBackup="false"
        android:fullBackupContent="false"

Proof Of Work 📹

Success case:

device-2023-01-11-181454.mp4

Error case:

device-2023-01-12-172134.mp4

How does it look like in the device's storage:

[github-actions]

	4 Warnings
⚠️	Uh oh! BaseViewModel.kt is under 95% coverage!
⚠️	Uh oh! HomeViewModel.kt is under 95% coverage!
⚠️	Uh oh! Your project is under 80% coverage!
⚠️	Uh oh! HomeScreen.kt is under 95% coverage!

Kover report for template-xml:

🧛 Template - XML Unit Tests Code Coverage: 29.95%

Coverage of Modified Files:

File	Coverage
BaseViewModel.kt	0.00%
HomeViewModel.kt	0.00%
UseCase.kt	100.00%

Modified Files Not Found In Coverage Report:

AndroidManifest.xml
AppPreferencesRepository.kt
AppPreferencesRepositoryImpl.kt
HomeScreen.kt
IsFirstTimeLaunchPreferencesUseCase.kt
IsFirstTimeLaunchPreferencesUseCaseTest.kt
PreferencesModule.kt
StorageModule.kt
UpdateFirstTimeLaunchPreferencesUseCase.kt
UpdateFirstTimeLaunchPreferencesUseCaseTest.kt
UseCaseTest.kt
Versions.kt
build.gradle.kts
build.gradle.kts

Codebase cunningly covered by count Shroud 🧛

Kover report for template-compose:

🧛 Template - Compose Unit Tests Code Coverage: 24.28%

Coverage of Modified Files:

File	Coverage
BaseViewModel.kt	97.62%
HomeScreen.kt	0.00%
HomeViewModel.kt	100.00%
UseCase.kt	100.00%

Modified Files Not Found In Coverage Report:

AndroidManifest.xml
AppPreferencesRepository.kt
AppPreferencesRepositoryImpl.kt
IsFirstTimeLaunchPreferencesUseCase.kt
IsFirstTimeLaunchPreferencesUseCaseTest.kt
PreferencesModule.kt
StorageModule.kt
UpdateFirstTimeLaunchPreferencesUseCase.kt
UpdateFirstTimeLaunchPreferencesUseCaseTest.kt
UseCaseTest.kt
Versions.kt
build.gradle.kts
build.gradle.kts

Codebase cunningly covered by count Shroud 🧛

Generated by 🚫 Danger

[toby-thanathip]

@lydiasama Will your issue be split up like this? 🙏

• Part 1: Integrate for sample-compose
• Part 2: Integrate for sample-xml
• Part 3: Integrate for both template-xml & template-compose

Also, please rebase 🚀

[lydiasama]

@Tuubz Updated. 🚀

[kaungkhantsoe]

LGTM 🚀

[lydiasama]

@luongvo @thiennguyen0196 Resolved all. Plus, unit tests are added.

[thiennguyen0196]

LGTM now

[luongvo]

rest lgtm, 1 last issue 👋

[luongvo]

LGTM 🎉

[chornerman]

Minor comment 🚀

[chornerman]

LGTM 👏🏼 👏🏼

[luongvo]

lgtm

[kaungkhantsoe]

@lydiasama Conflict 🦀

[lydiasama]

@kaungkhantsoe Thanks ❤️ Resolved!