1.蓝牙耳机接听电话
/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(); }
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() { // 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; }
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; } //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; }
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); /* 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
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 }
代码路径这里packages/apps/Settings/src/com/android/settings/bluetooth/CachedBluetoothDevice.java,具体代码看下面
// 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, } } } .............
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; }
那到此为止,本文关于蓝牙耳机与蓝牙接听电话的流程分析也就结束了,同时蓝牙这一系列的文章也暂时结束,当然后续依然会关注蓝牙。本系列的第一篇文章标题是入门,现在想想,这五篇文章下来也不过是刚刚入门而已,协议部分更是没怎么涉及呢,对于蓝牙BT需要深入研究的地方还有很多,仅希望这五篇文章可以帮你快速了解android蓝牙代码流程,回顾以前四篇文章请点击链接: