CarAppViewModelFactory.java
/*
* Copyright 2021 The Android Open Source Project
*
* 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.
*/
package androidx.car.app.activity;
import static androidx.annotation.RestrictTo.Scope.LIBRARY;
import android.app.Application;
import android.content.ComponentName;
import androidx.annotation.NonNull;
import androidx.annotation.RestrictTo;
import androidx.lifecycle.ViewModel;
import androidx.lifecycle.ViewModelProvider;
import java.util.HashMap;
import java.util.Map;
/**
* A factory to provide a unique {@link CarAppViewModel} for each given {@link ComponentName}.
*
* @hide
*/
@RestrictTo(LIBRARY)
class CarAppViewModelFactory implements ViewModelProvider.Factory {
private static final Map<ComponentName, CarAppViewModelFactory> sInstances = new HashMap<>();
Application mApplication;
ComponentName mComponentName;
private CarAppViewModelFactory(@NonNull ComponentName componentName,
@NonNull Application application) {
mComponentName = componentName;
mApplication = application;
}
/**
* Retrieve a singleton instance of CarAppViewModelFactory for the given key.
*
* @return A valid {@link CarAppViewModelFactory}
*/
@NonNull
static CarAppViewModelFactory getInstance(Application application,
ComponentName componentName) {
CarAppViewModelFactory instance = sInstances.get(componentName);
if (instance == null) {
instance = new CarAppViewModelFactory(componentName, application);
sInstances.put(componentName, instance);
}
return instance;
}
@SuppressWarnings("unchecked")
@NonNull
@Override
public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {
return (T) new CarAppViewModel(mApplication, mComponentName);
}
}