1/*
2 * Copyright (C) 2016 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
17package android.media;
18
19import android.os.Handler;
20import android.os.Looper;
21
22/**
23 * AudioRouting defines an interface for controlling routing and routing notifications in
24 * AudioTrack and AudioRecord objects.
25 */
26public interface AudioRouting {
27    /**
28     * Specifies an audio device (via an {@link AudioDeviceInfo} object) to route
29     * the output/input to/from.
30     * @param deviceInfo The {@link AudioDeviceInfo} specifying the audio sink or source.
31     *  If deviceInfo is null, default routing is restored.
32     * @return true if succesful, false if the specified {@link AudioDeviceInfo} is non-null and
33     * does not correspond to a valid audio device.
34     */
35    public boolean setPreferredDevice(AudioDeviceInfo deviceInfo);
36
37    /**
38     * Returns the selected output/input specified by {@link #setPreferredDevice}. Note that this
39     * is not guaranteed to correspond to the actual device being used for playback/recording.
40     */
41    public AudioDeviceInfo getPreferredDevice();
42
43    /**
44     * Returns an {@link AudioDeviceInfo} identifying the current routing of this
45     * AudioTrack/AudioRecord.
46     * Note: The query is only valid if the AudioTrack/AudioRecord is currently playing.
47     * If it is not, <code>getRoutedDevice()</code> will return null.
48     */
49    public AudioDeviceInfo getRoutedDevice();
50
51    /**
52     * Adds an {@link AudioRouting.OnRoutingChangedListener} to receive notifications of routing
53     * changes on this AudioTrack/AudioRecord.
54     * @param listener The {@link AudioRouting.OnRoutingChangedListener} interface to receive
55     * notifications of rerouting events.
56     * @param handler  Specifies the {@link Handler} object for the thread on which to execute
57     * the callback. If <code>null</code>, the {@link Handler} associated with the main
58     * {@link Looper} will be used.
59     */
60    public void addOnRoutingChangedListener(OnRoutingChangedListener listener,
61            Handler handler);
62
63    /**
64     * Removes an {@link AudioRouting.OnRoutingChangedListener} which has been previously added
65     * to receive rerouting notifications.
66     * @param listener The previously added {@link AudioRouting.OnRoutingChangedListener} interface
67     * to remove.
68     */
69    public void removeOnRoutingChangedListener(OnRoutingChangedListener listener);
70
71    /**
72     * Defines the interface by which applications can receive notifications of routing
73     * changes for the associated {@link AudioRouting}.
74     */
75    public interface OnRoutingChangedListener {
76        public void onRoutingChanged(AudioRouting router);
77    }
78}
79