Storing data in local database like a boss: Introducing Room in Compose Multiplatform
Hi everyone,
So recently we achieved Room Database compatibility in Kotlin Multiplatform or Compose Multiplatform and I already had plans to write a CMP project making good use to newly introduced AndroidX libraries for KMP/CMP.
Let’s get started
Installation:
Step 1: Add these libraries in Version Catalog first, i.e. libs.version.toml file
Step 2: Add these dependencies/libs in build.gradle.kts which can be found in composeApp/build.gradle.kts
Once done, we can proceed with the rest of the setup, which is similar to Android.
Step 3: Creating Data class. Making it simple.
Step 4: Creating UserDao.
Edit: Notice, all functions are suspend functions and does not return Flow type here. Using Coroutines flow is a good practice but that does not lets you compile and target for all the targets.
It won’t work for any target as it could either be suspend or Deferred/Async return type.
Code example: https://bit.ly/suspend-fun-error-code-eg
Official Doc: https://bit.ly/suspend-dao-error-room-ofc-docError Log:
Step 5: Creating Database
We are done with the setup, now we just need to pass databaseBuilder as a parameter in App.kt from all the target sources. (i.e Android, iOS and Desktop)
Your common main code should look something like this:
As said, you should pass the userDao from all the target sources, and here we goooooooo.
For Android:
And pass it in MainActivity.kt like this:
For iOS:
And pass it in MainViewController.kt like this:
For Desktop:
And pass it in MainActivity.kt like this:
That’s it! We are done with the Room setup here.
Now, you can interact with your Room database
You can play around with the other possible interactions like creating, inserting, updating and deleting.
Improvements to Consider
1. Follow any architecture like MVI/MVVM
2. Create repositories and viewModels for clean UI and state management
3. Use Koin or other alternatives for Dependency Injection
That’s it, thank you for reading till the end. I hope I was able to contribute value to this community. 😁
Resources to know more:
Room KMP: https://developer.android.com/kotlin/multiplatform/room
KSP with KMP: https://kotlinlang.org/docs/ksp-multiplatform.html
Video tutorials:
Chris Athanas: https://www.youtube.com/watch?v=2E-3FDRPmYI
Blogs:
John O’Reilly: https://johnoreilly.dev/posts/jetpack_room_kmp/
Repositories:
- https://github.com/binayshaw7777/Knowtify
- https://github.com/joreilly/FantasyPremierLeague
- https://github.com/philipplackner/Room-CMP
- https://github.com/Maragues/kmp-persistence-room
- https://github.com/realityexpander/KMP_Room
Need help? https://www.jetbrains.com/kotlin-multiplatform/
Note: This blog was not written using any AI tools 😉
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