(L1) AudioService AudioHandler setDeviceVolume, setAllVolumes, persistVolume

前言

setDeviceVolume, setAllVolumes, persistVolume是volume中较通用的函数

@Override
public void handleMessage(Message msg) {
switch (msg.what) {

case MSG_SET_DEVICE_VOLUME:
setDeviceVolume((VolumeStreamState) msg.obj, msg.arg1);
break;

case MSG_SET_ALL_VOLUMES:
setAllVolumes((VolumeStreamState) msg.obj);
break;

case MSG_PERSIST_VOLUME:
persistVolume((VolumeStreamState) msg.obj, msg.arg1);
break;

http://blog.csdn.net/wlia/article/details/46877123

setDeviceVolume

private void setDeviceVolume(VolumeStreamState streamState, int device) {

synchronized (VolumeStreamState.class) {
// Apply volume
streamState.applyDeviceVolume_syncVSS(device);

// Apply change to all streams using this one as alias
int numStreamTypes = AudioSystem.getNumStreamTypes();
for (int streamType = numStreamTypes - 1; streamType >= 0; streamType--) {

</pre><pre name="code" class="java">

src stream不同（其他的VolumeStreamState），<span style="font-family: Arial, Helvetica, sans-serif;">dst stream相同 （</span>dst stream 是该VolumeStreamState的src stream），那么必须有<span style="font-family: Arial, Helvetica, sans-serif;">VolumeStreamState的</span>src stream就是dst stream, 这种stream 没有alias

</pre><pre name="code" class="java">                    if (streamType != streamState.mStreamType &&
mStreamVolumeAlias[streamType] == streamState.mStreamType) {

// Make sure volume is also maxed out on A2DP device for aliased stream
// that may have a different device selected

</pre><pre name="code" class="java">get device
int streamDevice = getDeviceForStream(streamType);

</pre><pre name="code" class="java">对A2DP有判断
if ((device != streamDevice) && mAvrcpAbsVolSupported &&
((device & AudioSystem.DEVICE_OUT_ALL_A2DP) != 0)) {
mStreamStates[streamType].applyDeviceVolume_syncVSS(device);
}

apply
mStreamStates[streamType].applyDeviceVolume_syncVSS(streamDevice);
}
}
}

持久保存
// Post a persist volume msg
sendMsg(mAudioHandler,
MSG_PERSIST_VOLUME,
SENDMSG_QUEUE,
device,
0,
streamState,
PERSIST_DELAY);

}

http://blog.csdn.net/wlia/article/details/46877123

相关函数

applyDeviceVolume_syncVSS

通过getIndex取得数据，那么之前setIndex,所以这里传入device即可。

A2DP index max

<pre name="code" class="java">AudioSystem.setStreamVolumeIndex下派参数

public void applyDeviceVolume_syncVSS(int device) {
int index;
if (isMuted_syncVSS()) {
index = 0;
} else if (((device & AudioSystem.DEVICE_OUT_ALL_A2DP) != 0 && mAvrcpAbsVolSupported)
|| ((device & mFullVolumeDevices) != 0)) {
index = (mIndexMax + 5)/10;
} else {
index = (getIndex(device) + 5)/10;
}
AudioSystem.setStreamVolumeIndex(mStreamType, index, device);
}

http://blog.csdn.net/wlia/article/details/46877123

persistVolume

private void persistVolume(VolumeStreamState streamState, int device) {
if (mUseFixedVolume) {
return;
}

</pre><pre name="code" class="java">电视只有music才允许persist

if (isPlatformTelevision() && (streamState.mStreamType != AudioSystem.STREAM_MUSIC)) {
return;
}
System.putIntForUser(mContentResolver,
streamState.getSettingNameForDevice(device),
(streamState.getIndex(device) + 5)/ 10,
UserHandle.USER_CURRENT);
}

http://blog.csdn.net/wlia/article/details/46877123

setAllVolumes

private void setAllVolumes(VolumeStreamState streamState) {

// Apply volume
streamState.applyAllVolumes();

// Apply change to all streams using this one as alias
int numStreamTypes = AudioSystem.getNumStreamTypes();
for (int streamType = numStreamTypes - 1; streamType >= 0; streamType--) {
if (streamType != streamState.mStreamType &&
mStreamVolumeAlias[streamType] == streamState.mStreamType) {
mStreamStates[streamType].applyAllVolumes();
}
}
}

http://blog.csdn.net/wlia/article/details/46877123

相关函数

applyAllVolumes

        public void applyAllVolumes() {

synchronized (VolumeStreamState.class) {

<ul style="margin: 0px; padding: 0px; border: 0px; outline: 0px; list-style: none; color: rgb(67, 67, 67); font-family: Tahoma, Arial; line-height: 24px; widows: auto; background-color: rgb(242, 242, 242);"><li style="margin: 0px; padding: 0px; border: 0px; outline: 0px; list-style: none;">按照惯例,<span style="widows: auto; background-color: rgb(240, 240, 240);">apply default volume first.看来是AudioPolicyManager需要</span></li></ul>                // apply default volume first: by convention this will reset all
// devices volumes in audio policy manager to the supplied value

int index;

有Mute则为0
if (isMuted_syncVSS()) {
index = 0;
} else {
index = (getIndex(AudioSystem.DEVICE_OUT_DEFAULT) + 5)/10;
}

下派参数
AudioSystem.setStreamVolumeIndex(mStreamType, index, AudioSystem.DEVICE_OUT_DEFAULT);
// then apply device specific volumes

对mIndex中每个选项进行处理Set set = mIndex.entrySet();Iterator i = set.iterator();while (i.hasNext()) {Map.Entry entry = (Map.Entry)i.next();int device <span style="font-family: Arial, Helvetica, sans-serif;">= ((Integer)entry.getKey()).intValue();</span>

<span style="font-family: Arial, Helvetica, sans-serif;"></span>

如果是default device,则不再处理。。。这些代码真臭！if(  == out default) return;更好！Google也不过如此。

if (device != AudioSystem.DEVICE_OUT_DEFAULT) {

还是先处理muteif (isMuted_syncVSS()) {index = 0;

out A2DP, mAvrcpAbsVolSupported则max} else if (((device & AudioSystem.DEVICE_OUT_ALL_A2DP) != 0 &&mAvrcpAbsVolSupported)|| ((device & mFullVolumeDevices) != 0)){index = (mIndexMax + 5)/10;} else {

最普通的情况往往在最后index = ((Integer)entry.getValue() + 5)/10;}AudioSystem.setStreamVolumeIndex(mStreamType, index, device);}}}}

http://blog.csdn.net/wlia/article/details/46877123