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/*
* Copyright (C) 2016 The CyanogenMod 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 cyanogenmod.media;
import android.content.Context;
import android.os.IBinder;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.util.Log;
import java.util.Collections;
import java.util.List;
import cyanogenmod.app.CMContextConstants;
/**
* Manager for extended audio system capabilities provided by
* CyanogenMod.
*
* Currently, this API provides an application the ability to
* query active global audio sessions, and receive broadcasts
* when new audio sessions are created and destroyed.
*
* Applications wishing to receive audio session information
* should register for the {@link ACTION_AUDIO_SESSIONS_CHANGED}
* broadcast. This broadcast requires an application to hold the
* {@link cyanogenmod.permission.OBSERVE_AUDIO_SESSIONS}
* permission. When receiving the broadcast, {@link EXTRA_SESSION_INFO}
* will hold the {@link AudioSessionInfo} object associated
* with the session. {@link EXTRA_SESSION_ADDED} will hold
* a boolean value, true if the session is added, false if it
* is being removed.
*
* It is important for applications to be cautious about which
* audio streams effects are attached to when using this API as
* it may interfere with their normal operation. An equalizer
* application for example would only want to react to streams
* with the type of {@link android.media.AudioManager.STREAM_MUSIC}.
*
* @see android.media.AudioManager
*
* @hide
*/
public final class CMAudioManager {
private static final String TAG = "CMAudioManager";
/**
* Broadcast sent when audio session are added and removed.
*/
public static final String ACTION_AUDIO_SESSIONS_CHANGED =
"cyanogenmod.intent.action.ACTION_AUDIO_SESSIONS_CHANGED";
/**
* Extra containing {@link AudioSessionInfo}
*/
public static final String EXTRA_SESSION_INFO = "session_info";
/**
* Boolean extra, true if session is being added.
*/
public static final String EXTRA_SESSION_ADDED = "added";
private Context mContext;
private static CMAudioManager sInstance;
private static ICMAudioService sService;
/**
* @hide to prevent subclassing from outside of the framework
*/
private CMAudioManager(Context context) {
Context appContext = context.getApplicationContext();
if (appContext != null) {
mContext = appContext;
} else {
mContext = context;
}
sService = getService();
if (!context.getPackageManager().hasSystemFeature(
CMContextConstants.Features.AUDIO) || !checkService()) {
throw new RuntimeException("Unable to get CMAudioService. The service either" +
" crashed, was not started, or the interface has been called to early in" +
" SystemServer init");
}
}
/**
* Get or create an instance of the {@link cyanogenmod.media.CMAudioManager}
* @param context
* @return {@link CMAudioManager}
*/
public synchronized static CMAudioManager getInstance(Context context) {
if (sInstance == null) {
sInstance = new CMAudioManager(context);
}
return sInstance;
}
/** @hide */
public static ICMAudioService getService() {
if (sService != null) {
return sService;
}
IBinder b = ServiceManager.getService(CMContextConstants.CM_AUDIO_SERVICE);
if (b != null) {
sService = ICMAudioService.Stub.asInterface(b);
return sService;
}
return null;
}
/**
* @return true if service is valid
*/
private boolean checkService() {
if (sService == null) {
Log.w(TAG, "not connected to CMAudioService");
return false;
}
return true;
}
/**
* List audio sessions for the given stream type defined in
* {@link android.media.AudioManager}, for example,
* {@link android.media.AudioManager#STREAM_MUSIC}.
*
* @param streamType from {@link android.media.AudioManager}
* @return list of {@link AudioSessionInfo}, or empty list if none found
* @see android.media.AudioManager
*/
public List<AudioSessionInfo> listAudioSessions(int streamType) {
if (checkService()) {
try {
final List<AudioSessionInfo> sessions = sService.listAudioSessions(streamType);
if (sessions != null) {
return Collections.unmodifiableList(sessions);
}
} catch (RemoteException e) {
Log.e(TAG, "Failed to list audio sessions!", e);
}
}
return Collections.emptyList();
}
/**
* List all audio sessions.
*
* @return list of {@link AudioSessionInfo}, or empty list if none found
* @see android.media.AudioManager
*/
public List<AudioSessionInfo> listAudioSessions() {
return listAudioSessions(-1);
}
}
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