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，
- if (VDBG) log("connectBluetoothAudio()...");
- if (mBluetoothHeadset != null) {
-
- mBluetoothHeadset.connectAudio();
- }
-
-
-
-
-
- mBluetoothConnectionPending = true;
- mBluetoothConnectionRequestTime = SystemClock.elapsedRealtime();
接下来就跳到蓝牙应用的管辖范围，代码在packages/apps/Bluetooth/src/com/android/bluetooth/hfp/HeadsetService.java，
- public boolean connectAudio() {
- HeadsetService service = getService();
- if (service == null) return false;
- return service.connectAudio();
- }
很明显下一个目标是HeadsetService，直接看具体实现，这部分代码跳转都比较清晰，下面代码会先判断当前状态是否正确，关于HeadsetStateMachine几个状态可以参持这个/packages/apps/Bluetooth/src/com/android/bluetooth/hfp/HeadsetStateMachine.java的最前的代码注释。
- boolean connectAudio() {
-
- enforceCallingOrSelfPermission(BLUETOOTH_PERM, "Need BLUETOOTH permission");
- if (!mStateMachine.isConnected()) {
- return false;
- }
- if (mStateMachine.isAudioOn()) {
- return false;
- }
- mStateMachine.sendMessage(HeadsetStateMachine.CONNECT_AUDIO);
- return true;
- }
走进HeadsetStateMachine状态机，找到CONNECT_AUDIO分支，就看带Native的方法connectAudioNative(getByteAddress(mCurrentDevice))；
- 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;
- }
- 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;
- }
上面代码还可以进一步跟到下面/external/bluetooth/bluedroid/btif/src/btif_hf.c，到了这里其实流程已经结束了，对于这里消息流转估计要放到以后再写了
- 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);
-
- 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()) {
- return;
- }
- mConnectAttempted = SystemClock.elapsedRealtime();
- connectWithoutResettingTimer(connectAllProfiles);
- }
代码路径这里packages/apps/Settings/src/com/android/settings/bluetooth/CachedBluetoothDevice.java，具体代码看下面
- ...........
-
- mIsConnectingErrorPossible = true;
-
- int preferredProfiles = 0;
- for (LocalBluetoothProfile profile : mProfiles) {
- if (connectAllProfiles ? profile.isConnectable() : profile.isAutoConnectable()) {
- if (profile.isPreferred(mDevice)) {
- ++preferredProfiles;
- connectInt(profile);
- }
- }
- }
- .............
connectInt的实现很简单，直接跳过看里面的profile.connect(mDevice)，这里的profile是指A2dpProfile，所以connet()方法的具体实现在
- public boolean connect(BluetoothDevice device) {
- if (mService == null) return false;
- List<BluetoothDevice> sinks = getConnectedDevices();
- if (sinks != null) {
- for (BluetoothDevice sink : sinks) {
- mService.disconnect(sink);
- }}
- return mService.connect(device);
- }
下面是 BluetoothA2dp.java (frameworks\base\core\java\android\bluetooth) ，为什么是这样看下这个private BluetoothA2dp mService;就知道了
- 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);
- }
-
- }
之后的跳转和第一部分蓝牙接听电话跳转过程类似，就不重复了，最后会来到packages/apps/Bluetooth/jni/com_android_bluetooth_a2dp.cpp的connectA2dpNative，同样到下面的代码，我们能看到的开放的代码也就是这些，再下面要看vendor的具体实现了。
- 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 （五）接电话与听音乐,布布扣,bubuko.com
android -- 蓝牙 bluetooth （五）接电话与听音乐
原文：http://www.cnblogs.com/wangzehuaw/p/3806774.html
