Deprecated: Use Hilt and Androidx Hilt

Assisted Injection for Android ViewModels

This library is based on and depends heavily on Assisted Inject

ViewModelInject supports Dagger2 and SavedStateHandle

NOTE

This is using alpha versions of the Androidx/JetPack libraries. Use at your own risk.

This Library will go 1.0 when Assisted Inject goes 1.0.

Usage

ViewModel

Java

class MyViewModel extends ViewModel {
    @ViewModelInject
    MyViewModel(Long foo, @Assisted SavedStateHandle savedStateHandle) {}
}

Kotlin

class MyViewModel
@ViewModelInject constructor(
    foo: Long, @Assisted savedStateHandle: SavedStateHandle
): ViewModel() {}

Module

In order to allow Dagger to use the generated factory, define an assisted dagger module anywhere in the same gradle module:

Java

@ViewModelModule
@Module(includes = ViewModelInject_VMModule.class)
abstract class VMModule {}

Kotlin

@ViewModelModule
@Module(includes = [ViewModelInject_VMModule::class])
abstract class VMModule

The library will generate the ViewModelInject_VMModule for us.

Factory

Inside your Activity or Fragment inject one of the following factories:

If you are not using a SavedStateHandle inject the ViewModelFactory

Java

@Inject ViewModelFactory viewModelFactory;

public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    MyViewModel viewModel = ViewModelProviders.of(this, viewModelFactory)
                                .get(MainViewModel.class);
    // ...
}

Kotlin

@Inject 
lateinit var viewModelFactory: ViewModelFactory

public void onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    val viewModel = ViewModelProviders.of(this, viewModelFactory)
                                .get(MainViewModel::class.java)
    // ...
}

If you are using a SavedStateHandle inject the SavedStateViewModelFactory.Factory

Java

@Inject SavedStateViewModelFactory.Factory viewModelFactoryFactory;

fun onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    MyViewModel viewModel = ViewModelProviders.of(this, viewModelFactoryFactory.create(this, intent.getExtras()))
                                .get(MainViewModel.class);
    // ...
}

Kotlin

@Inject
lateinit var viewModelFactoryFactory: SavedStateViewModelFactory.Factory

fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    val viewModel = ViewModelProviders.of(this, viewModelFactoryFactory.create(this, intent.getExtras()))
                                .get(MainViewModel::class.java)
    // ...
}

The SavedStateViewModelFactory handles both ViewModels with and without a SavedStateHandle. If you are using SavedStateHandles anywhere in your project it is recommended to always use the SavedStateViewModelFactory

For optimal build speed, all the referred @Injected types should be compiled with the Dagger processor. This is also a requirement for incremental annotation processing with kapt. Given that SavedStateViewModelFactory.Factory is an external dependency, you should provide an instance using a @Provides method. For example, if you use SavedStateViewModelFactory:

Java

@Module
public class AppViewModelFactoryFactoryModule {
    @Provides
    @Singleton
    public static SavedStateViewModelFactory.Factory provideViewModelFactoryFactory(
            Map<Class<?>, AbstractViewModelFactory> factories
    ) {
        return new SavedStateViewModelFactory.Factory(factories);
    }
}

Kotlin

@Module
object AppViewModelFactoryFactoryModule {
    @Provides
    @Singleton
    fun provideViewModelFactoryFactory(
            factories: Map<Class<*>, @JvmSuppressWildcards AbstractViewModelFactory>
    ): SavedStateViewModelFactory.Factory {
        return SavedStateViewModelFactory.Factory(factories)
    }
}

Download

implementation 'com.vikingsen.inject:viewmodel-inject:0.3.3'
annotationProcessor 'com.vikingsen.inject:viewmodel-inject-processor:0.3.3' // or `kapt` for Kotlin

For Snapshots include the following repository:

repositories {
    // ...
    maven { url 'https://oss.sonatype.org/content/repositories/snapshots' }
}

License

Copyright 2019 Jordan Hansen

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.