1 /* 2 * Copyright (C) 2018 The Android Open Source Project 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 com.example.android.intentplayground; 18 19 import androidx.lifecycle.LiveData; 20 import androidx.lifecycle.MutableLiveData; 21 import androidx.lifecycle.ViewModel; 22 23 import java.util.List; 24 import java.util.function.Consumer; 25 26 public class BaseActivityViewModel extends ViewModel { 27 enum FabAction {Show, Hide} 28 29 private final MutableLiveData<FabAction> mFabActions; 30 31 /** 32 * Republish {@link BaseActivity#addTrackerListener(Consumer)} in a lifecycle safe manner. 33 * The {@link BaseActivity#addTrackerListener(Consumer)} that is registered in this class, 34 * forwards the value to this, to enjoy all the guarantees {@link import 35 * androidx.lifecycle.LiveData;} gives. 36 */ 37 private final MutableLiveData<List<Tracking.Task>> mRefreshTree; 38 private final Consumer<List<Tracking.Task>> mTrackingListener; 39 40 public BaseActivityViewModel() { 41 mFabActions = new MutableLiveData<>(); 42 mRefreshTree = new MutableLiveData<>(); 43 mTrackingListener = tasks -> mRefreshTree.setValue(tasks); 44 BaseActivity.addTrackerListener(mTrackingListener); 45 } 46 47 48 public void actOnFab(FabAction action) { 49 mFabActions.setValue(action); 50 } 51 52 public LiveData<FabAction> getFabActions() { 53 return mFabActions; 54 } 55 56 /** 57 * @return LiveData that publishes the new state of {@link com.android.server.wm.Task} and 58 * {@link android.app.Activity}-s whenever that state has been changed. 59 */ 60 public LiveData<List<Tracking.Task>> getRefresh() { 61 return mRefreshTree; 62 } 63 64 @Override 65 public void onCleared() { 66 BaseActivity.removeTrackerListener(mTrackingListener); 67 } 68 } 69 70
