| /* |
| * Copyright (C) 2011 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 com.example.android.musicplayer; |
| |
| import android.content.Context; |
| import android.media.AudioManager; |
| |
| /** |
| * Convenience class to deal with audio focus. This class deals with everything related to audio |
| * focus: it can request and abandon focus, and will intercept focus change events and deliver |
| * them to a MusicFocusable interface (which, in our case, is implemented by {@link MusicService}). |
| * |
| * This class can only be used on SDK level 8 and above, since it uses API features that are not |
| * available on previous SDK's. |
| */ |
| public class AudioFocusHelper implements AudioManager.OnAudioFocusChangeListener { |
| AudioManager mAM; |
| MusicFocusable mFocusable; |
| |
| public AudioFocusHelper(Context ctx, MusicFocusable focusable) { |
| mAM = (AudioManager) ctx.getSystemService(Context.AUDIO_SERVICE); |
| mFocusable = focusable; |
| } |
| |
| /** Requests audio focus. Returns whether request was successful or not. */ |
| public boolean requestFocus() { |
| return AudioManager.AUDIOFOCUS_REQUEST_GRANTED == |
| mAM.requestAudioFocus(this, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN); |
| } |
| |
| /** Abandons audio focus. Returns whether request was successful or not. */ |
| public boolean abandonFocus() { |
| return AudioManager.AUDIOFOCUS_REQUEST_GRANTED == mAM.abandonAudioFocus(this); |
| } |
| |
| /** |
| * Called by AudioManager on audio focus changes. We implement this by calling our |
| * MusicFocusable appropriately to relay the message. |
| */ |
| public void onAudioFocusChange(int focusChange) { |
| if (mFocusable == null) return; |
| switch (focusChange) { |
| case AudioManager.AUDIOFOCUS_GAIN: |
| mFocusable.onGainedAudioFocus(); |
| break; |
| case AudioManager.AUDIOFOCUS_LOSS: |
| case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT: |
| mFocusable.onLostAudioFocus(false); |
| break; |
| case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK: |
| mFocusable.onLostAudioFocus(true); |
| break; |
| default: |
| } |
| } |
| } |