1 /* 2 * Copyright (C) 2015 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.android.tv; 18 19 import android.support.annotation.MainThread; 20 import android.support.annotation.NonNull; 21 import android.support.annotation.Nullable; 22 import android.util.ArraySet; 23 import com.android.tv.data.api.Channel; 24 import java.util.Set; 25 26 /** 27 * A wrapper for safely getting the current {@link MainActivity}. Note that this class is not 28 * thread-safe. All the public methods should be called on main thread. 29 */ 30 @MainThread 31 public final class MainActivityWrapper { 32 private MainActivity mActivity; 33 34 private final Set<OnCurrentChannelChangeListener> mListeners = new ArraySet<>(); 35 36 /** 37 * Returns the current main activity. <b>WARNING</b> do not keep a reference to MainActivity, 38 * leaking activities is expensive. 39 */ getMainActivity()40 MainActivity getMainActivity() { 41 return mActivity; 42 } 43 44 /** Checks if the given {@code activity} is the current main activity. */ isCurrent(MainActivity activity)45 boolean isCurrent(MainActivity activity) { 46 return activity != null && mActivity == activity; 47 } 48 49 /** Sets the currently created main activity instance. */ onMainActivityCreated(@onNull MainActivity activity)50 public void onMainActivityCreated(@NonNull MainActivity activity) { 51 mActivity = activity; 52 } 53 54 /** Unsets the main activity instance. */ onMainActivityDestroyed(@onNull MainActivity activity)55 public void onMainActivityDestroyed(@NonNull MainActivity activity) { 56 if (mActivity == activity) { 57 mActivity = null; 58 } 59 } 60 61 /** Notifies the current channel change. */ notifyCurrentChannelChange(@onNull MainActivity caller, @Nullable Channel channel)62 void notifyCurrentChannelChange(@NonNull MainActivity caller, @Nullable Channel channel) { 63 if (mActivity == caller) { 64 for (OnCurrentChannelChangeListener listener : mListeners) { 65 listener.onCurrentChannelChange(channel); 66 } 67 } 68 } 69 70 /** Checks if the main activity is created. */ isCreated()71 public boolean isCreated() { 72 return mActivity != null; 73 } 74 75 /** Checks if the main activity is started. */ isStarted()76 public boolean isStarted() { 77 return mActivity != null && mActivity.isActivityStarted(); 78 } 79 80 /** Checks if the main activity is resumed. */ isResumed()81 public boolean isResumed() { 82 return mActivity != null && mActivity.isActivityResumed(); 83 } 84 85 /** Adds OnCurrentChannelChangeListener. */ addOnCurrentChannelChangeListener(OnCurrentChannelChangeListener listener)86 public void addOnCurrentChannelChangeListener(OnCurrentChannelChangeListener listener) { 87 mListeners.add(listener); 88 } 89 90 /** Removes OnCurrentChannelChangeListener. */ removeOnCurrentChannelChangeListener(OnCurrentChannelChangeListener listener)91 public void removeOnCurrentChannelChangeListener(OnCurrentChannelChangeListener listener) { 92 mListeners.remove(listener); 93 } 94 95 /** Listener for the current channel change in main activity. */ 96 public interface OnCurrentChannelChangeListener { 97 /** Called when the current channel changes. */ onCurrentChannelChange(@ullable Channel channel)98 void onCurrentChannelChange(@Nullable Channel channel); 99 } 100 } 101