1 /* 2 * Copyright (C) 2020 The Dagger Authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package dagger.hilt.android.components; 18 19 import dagger.hilt.DefineComponent; 20 import dagger.hilt.android.scopes.ViewModelScoped; 21 22 /** 23 * A Hilt component that has the lifetime of a single {@link androidx.lifecycle.ViewModel}. 24 * 25 * <p>This Hilt component is the source of {@link 26 * dagger.hilt.android.lifecycle.HiltViewModel}-annotated {@link androidx.lifecycle.ViewModel}s 27 * used by the {@link dagger.hilt.android.lifecycle.HiltViewModelFactory}. It contains a default 28 * binding for the {@link androidx.lifecycle.SavedStateHandle} associated with the {@code 29 * ViewModel} that can be used by other dependencies provided by the component. 30 * 31 * <p>Dependencies available in the {@link dagger.hilt.components.SingletonComponent} and {@link 32 * ActivityRetainedComponent} are also available in this component since it is a child of {@code 33 * ActivityRetainedComponent}. 34 * 35 * <p>Example usage: 36 * 37 * <pre> 38 * @Module 39 * @InstallIn(ViewModelComponent.class) 40 * public final class ViewModelMovieModule { 41 * @Provides 42 * public static MovieRepository provideRepo(SavedStateHandle handle) { 43 * return new MovieRepository(handle.getString("movie-id")); 44 * } 45 * } 46 * </pre> 47 * 48 * <p>Dependencies in the {@code ViewModelComponent} can be scoped using the {@link ViewModelScoped} 49 * annotation. This allows for a single instance of a dependency to be provided across the 50 * dependencies of a single {@link dagger.hilt.android.lifecycle.HiltViewModel}-annotated {@code 51 * ViewModel}. 52 * 53 * @see dagger.hilt.android.lifecycle.HiltViewModel 54 * @see dagger.hilt.android.scopes.ViewModelScoped 55 */ 56 @ViewModelScoped 57 @DefineComponent(parent = ActivityRetainedComponent.class) 58 public interface ViewModelComponent {} 59