71 lines
2.7 KiB
Java
71 lines
2.7 KiB
Java
/*
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* Copyright (C) 2011 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.example.android.musicplayer;
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import android.content.Context;
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import android.media.AudioManager;
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/**
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* Convenience class to deal with audio focus. This class deals with everything related to audio
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* focus: it can request and abandon focus, and will intercept focus change events and deliver
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* them to a MusicFocusable interface (which, in our case, is implemented by {@link MusicService}).
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*
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* This class can only be used on SDK level 8 and above, since it uses API features that are not
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* available on previous SDK's.
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*/
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public class AudioFocusHelper implements AudioManager.OnAudioFocusChangeListener {
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AudioManager mAM;
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MusicFocusable mFocusable;
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public AudioFocusHelper(Context ctx, MusicFocusable focusable) {
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mAM = (AudioManager) ctx.getSystemService(Context.AUDIO_SERVICE);
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mFocusable = focusable;
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}
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/** Requests audio focus. Returns whether request was successful or not. */
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public boolean requestFocus() {
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return AudioManager.AUDIOFOCUS_REQUEST_GRANTED ==
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mAM.requestAudioFocus(this, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN);
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}
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/** Abandons audio focus. Returns whether request was successful or not. */
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public boolean abandonFocus() {
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return AudioManager.AUDIOFOCUS_REQUEST_GRANTED == mAM.abandonAudioFocus(this);
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}
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/**
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* Called by AudioManager on audio focus changes. We implement this by calling our
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* MusicFocusable appropriately to relay the message.
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*/
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public void onAudioFocusChange(int focusChange) {
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if (mFocusable == null) return;
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switch (focusChange) {
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case AudioManager.AUDIOFOCUS_GAIN:
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mFocusable.onGainedAudioFocus();
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break;
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case AudioManager.AUDIOFOCUS_LOSS:
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case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
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mFocusable.onLostAudioFocus(false);
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break;
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case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
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mFocusable.onLostAudioFocus(true);
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break;
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default:
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}
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}
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}
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