olshevski / viewmodel-easy-factories

Instantiate ViewModels inside a trailing lambda

Since Lifecycle 2.5.0 there are official viewModel methods for doing exactly the same. This library is discontinued.

Use a simple syntax to manually create new ViewModel instances and provide all parameters directly instead of using SavedStateHandle.

The usage looks like this:

val mainViewModel by viewModel {
    MainViewModel(args)
}

Here args is a reference of some arbitrary type you wanna pass into the MainViewModel.

If you need to use SavedStateHandle for saving state inside a ViewModel use savedStateViewModel instead:

val savedStateMainViewModel by savedStateViewModel { savedStateHandle ->
    SavedStateMainViewModel(args, savedStateHandle)
}

These methods are provided as extensions for ViewModelStoreOwner, which means they can be with Activity, Fragment or NavBackStackEntry as a receiver. Or simply inside you Activity or Fragment classes.

You may also find it convenient to use these methods together with Dagger and @AssistedInject. You may find the samples for Dagger/Hilt/Anvil in my navigation library project here: samples-di.

Note: As it is intended as an alternative to SavedStateHandle for passing parameters into a ViewModel, SavedStateHandle instances are not pre-filled with arguments from Activity, Fragment and NavBackStackEntry.

Jetpack Compose

There are similar methods for you to use inside your composables:

val composeViewModel = viewModel {
    ComposeViewModel(args)
}

val savedStateComposeViewModel = savedStateViewModel { savedStateHandle ->
    SavedStateComposeViewModel(args, savedStateHandle)
}

Setup

Just add:

implementation("dev.olshevski.viewmodel:easy-factories:1.0.0")

For Compose use this instead:

implementation("dev.olshevski.viewmodel:easy-factories-compose:1.0.0")