android -- 蓝牙 bluetooth （五）接电话与听音乐
前段时间似乎所有的事情都赶在一起，回家、集体出游、出差，折腾了近一个月，终于算暂时清静了，但清静只是暂时，估计马上又要出差了，所以赶紧把蓝牙这一部分的文章了结下，按之前提到的目录，本文是关于蓝牙接打电话和听音乐的流程分析，对应蓝牙HFP/A2DP的profile，由于这部分也算是蓝牙的经典功能，所以代码流程并不是很复杂，当然不复杂仅是对于代码调用流程而言，对于HFP/A2DP协议相关的东东还没有精力去看，其难易程序也无法评价。下面从两个点HFP与A2DP来展开本文的代码跟踪：
正文开始之前，先说点题外话，在android系统中蓝牙耳机和听筒两者的音频通道是不一样的，使用蓝牙耳机接听电话和听音乐不仅涉及到本文下面提到的流程，更要牵扯的音频通道的切换，这是一个相对比较复杂的过程，android的音频系统相关内容可不算少，个人感觉多少了下解相关知识可能有助于我们更好的蓝牙这部分功能，不过本文的主题当然还是下面两个。
1.蓝牙耳机接听电话
这个就对应HFP（
Hands-freeProfile），Free your Hand，蓝牙的初衷之一。先来看这个功能的场景，手机来电，手机与蓝牙耳机已连接，这时会优先触发蓝牙接听电话的代码流程，起步代码在phone\src\com\android\phone\nCallScreen.java的connectBluetoothAudio() /disconnectBluetoothAudio()，只看连接部分好了，注意下面代码里的注释，
/* package */ void connectBluetoothAudio() {
if (VDBG) log("connectBluetoothAudio()...");
if (mBluetoothHeadset != null) {
// TODO(BT) check return
mBluetoothHeadset.connectAudio();
}
// Watch out: The bluetooth connection doesn't happen instantly;
// the connectAudio() call returns instantly but does its real
// work in another thread. The mBluetoothConnectionPending flag
// is just a little trickery to ensure that the onscreen UI updates
// instantly. (See isBluetoothAudioConnectedOrPending() above.)
mBluetoothConnectionPending = true;
mBluetoothConnectionRequestTime = SystemClock.elapsedRealtime();
} public boolean connectAudio() {
HeadsetService service = getService();
if (service == null) return false;
return service.connectAudio();
} boolean connectAudio() {
// TODO(BT) BLUETOOTH or BLUETOOTH_ADMIN permission
enforceCallingOrSelfPermission(BLUETOOTH_PERM, "Need BLUETOOTH permission");
if (!mStateMachine.isConnected()) {
return false;
}
if (mStateMachine.isAudioOn()) {
return false;
}
mStateMachine.sendMessage(HeadsetStateMachine.CONNECT_AUDIO);
return true;
}static jboolean connectAudioNative(JNIEnv *env, jobject object, jbyteArray address) {
jbyte *addr;
bt_status_t status;
if (!sBluetoothHfpInterface) return JNI_FALSE;
addr = env->GetByteArrayElements(address, NULL);
if (!addr) {
jniThrowIOException(env, EINVAL);
return JNI_FALSE;
}
//连接在这里
if ( (status = sBluetoothHfpInterface->connect_audio((bt_bdaddr_t *)addr)) !=
BT_STATUS_SUCCESS) {
ALOGE("Failed HF audio connection, status: %d", status);
}
env->ReleaseByteArrayElements(address, addr, 0);
return (status == BT_STATUS_SUCCESS) ? JNI_TRUE : JNI_FALSE;
}static bt_status_t connect_audio( bt_bdaddr_t *bd_addr )
{
CHECK_BTHF_INIT();
if (is_connected(bd_addr))
{
BTA_AgAudioOpen(btif_hf_cb.handle);
/* Inform the application that the audio connection has been initiated successfully */
btif_transfer_context(btif_in_hf_generic_evt, BTIF_HFP_CB_AUDIO_CONNECTING,
(char *)bd_addr, sizeof(bt_bdaddr_t), NULL);
return BT_STATUS_SUCCESS;
}
return BT_STATUS_FAIL;
}2.在蓝牙列表中连接蓝牙耳机
A2dp的连接过程，在蓝牙搜索结果列表连接一个蓝牙耳机，既然是从设备列表开始，所以起步代码自然是这个了
DevicePickerFragment.java (settings\src\com\android\settings\bluetooth) 3884 2013-6-26
void onClicked() {
int bondState = mCachedDevice.getBondState();
if (mCachedDevice.isConnected()) {
askDisconnect();
} else if (bondState == BluetoothDevice.BOND_BONDED) {
mCachedDevice.connect(true);
} .......
}
void connect(boolean connectAllProfiles) {
if (!ensurePaired()) { //要先确保配对
return;
}
mConnectAttempted = SystemClock.elapsedRealtime();
connectWithoutResettingTimer(connectAllProfiles);//没别的了，只能看到这里
} // Try to initialize the profiles if they were not.
...........
// Reset the only-show-one-error-dialog tracking variable
mIsConnectingErrorPossible = true;
int preferredProfiles = 0;
for (LocalBluetoothProfile profile : mProfiles) {
if (connectAllProfiles ? profile.isConnectable() : profile.isAutoConnectable()) {
if (profile.isPreferred(mDevice)) {
++preferredProfiles;
connectInt(profile);//连接在这里，
}
}
}
............. public boolean connect(BluetoothDevice device) {
if (mService == null) return false;
List sinks = getConnectedDevices();
if (sinks != null) {
for (BluetoothDevice sink : sinks) {
mService.disconnect(sink);
}}
return mService.connect(device);
} public boolean connect(BluetoothDevice device) {
if (mService != null && isEnabled() &&
isValidDevice(device)) {
try {
return mService.connect(device);
} catch (RemoteException e) {
Log.e(TAG, "Stack:" + Log.getStackTraceString(new Throwable()));
return false;
}
}...........
return false;
Binder跳转
public boolean connect(BluetoothDevice device) {
A2dpService service = getService();
if (service == null) return false;
return service.connect(device);
}
} static jboolean connectA2dpNative(JNIEnv *env, jobject object, jbyteArray address) {
jbyte *addr;
bt_bdaddr_t * btAddr;
bt_status_t status;
ALOGI("%s: sBluetoothA2dpInterface: %p", __FUNCTION__, sBluetoothA2dpInterface);
if (!sBluetoothA2dpInterface) return JNI_FALSE;
addr = env->GetByteArrayElements(address, NULL);
btAddr = (bt_bdaddr_t *) addr;
if (!addr) {
jniThrowIOException(env, EINVAL);
return JNI_FALSE;
}
if ((status = sBluetoothA2dpInterface->connect((bt_bdaddr_t *)addr)) != BT_STATUS_SUCCESS) {
ALOGE("Failed HF connection, status: %d", status);
}
env->ReleaseByteArrayElements(address, addr, 0);
return (status == BT_STATUS_SUCCESS) ? JNI_TRUE : JNI_FALSE;
}
android -- 蓝牙 bluetooth （一） 入门
android -- 蓝牙 bluetooth （二） 打开蓝牙
android -- 蓝牙 bluetooth （三）搜索蓝牙
android -- 蓝牙 bluetooth （四）OPP文件传输
最后感谢在前面文章中网友的热心回复与纠正，学习路上一起分享是快乐的。谢谢！