Android 8 蓝牙 连接过程
packages\apps\Settings\src\com\android\settings\bluetooth\BluetoothPairingDetail.java
@Override
void onDevicePreferenceClick(BluetoothDevicePreference btPreference) {
disableScanning();
super.onDevicePreferenceClick(btPreference);
}
packages\apps\Settings\src\com\android\settings\bluetooth\DeviceListPreferenceFragment.java
void onDevicePreferenceClick(BluetoothDevicePreference btPreference) {
btPreference.onClicked();
}
packages\apps\Settings\src\com\android\settings\bluetooth\BluetoothDevicePreference.java
void onClicked() {
Context context = getContext();
// 获取连接状态
int bondState = mCachedDevice.getBondState();
final MetricsFeatureProvider metricsFeatureProvider =
FeatureFactory.getFactory(context).getMetricsFeatureProvider();
// 已经连接
if (mCachedDevice.isConnected()) {
// 断开连接
metricsFeatureProvider.action(context,
MetricsEvent.ACTION_SETTINGS_BLUETOOTH_DISCONNECT);
askDisconnect();
// 以前连接过，不需要再配对，直接进行连接
} else if (bondState == BluetoothDevice.BOND_BONDED) {
metricsFeatureProvider.action(context,
MetricsEvent.ACTION_SETTINGS_BLUETOOTH_CONNECT);
mCachedDevice.connect(true);
// 没连接过，进行配对，需要连接的双方都同意之后才能连接
} else if (bondState == BluetoothDevice.BOND_NONE) {
metricsFeatureProvider.action(context,
MetricsEvent.ACTION_SETTINGS_BLUETOOTH_PAIR);
if (!mCachedDevice.hasHumanReadableName()) {
metricsFeatureProvider.action(context,
MetricsEvent.ACTION_SETTINGS_BLUETOOTH_PAIR_DEVICES_WITHOUT_NAMES);
}
pair();
}
}
1. 已经连接过的设备，直接断开
// Show disconnect confirmation dialog for a device.
private void askDisconnect() {
Context context = getContext();
String name = mCachedDevice.getName();
if (TextUtils.isEmpty(name)) {
name = context.getString(R.string.bluetooth_device);
}
String message = context.getString(R.string.bluetooth_disconnect_all_profiles, name);
String title = context.getString(R.string.bluetooth_disconnect_title);
// 对话框的listener
DialogInterface.OnClickListener disconnectListener = new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
mCachedDevice.disconnect();
}
};
// 显示断开对话框
mDisconnectDialog = Utils.showDisconnectDialog(context,
mDisconnectDialog, disconnectListener, title, Html.fromHtml(message));
}
2. 匹配过的设别，进行连接
frameworks\base\packages\SettingsLib\src\com\android\settingslib\bluetooth\CachedBluetoothDevice.java
public void connect(boolean connectAllProfiles) {
// 是否配对过
if (!ensurePaired()) {
return;
}
mConnectAttempted = SystemClock.elapsedRealtime();
connectWithoutResettingTimer(connectAllProfiles);
}
private void connectWithoutResettingTimer(boolean connectAllProfiles) {
// Try to initialize the profiles if they were not.
if (mProfiles.isEmpty()) {
// if mProfiles is empty, then do not invoke updateProfiles. This causes a race
// condition with carkits during pairing, wherein RemoteDevice.UUIDs have been updated
// from bluetooth stack but ACTION.uuid is not sent yet.
// Eventually ACTION.uuid will be received which shall trigger the connection of the
// various profiles
// If UUIDs are not available yet, connect will be happen
// upon arrival of the ACTION_UUID intent.
Log.d(TAG, "No profiles. Maybe we will connect later");
return;
}
// Reset the only-show-one-error-dialog tracking variable
mIsConnectingErrorPossible = true;
int preferredProfiles = 0;
for (LocalBluetoothProfile profile : mProfiles) {
// connectAllProfile传进来的是true
if (connectAllProfiles ? profile.isConnectable() : profile.isAutoConnectable()) {
if (profile.isPreferred(mDevice)) {
++preferredProfiles;
connectInt(profile); // 连接对应的profile
}
}
}
if (DEBUG) Log.d(TAG, "Preferred profiles = " + preferredProfiles);
if (preferredProfiles == 0) {
connectAutoConnectableProfiles();
}
}
private void connectAutoConnectableProfiles() {
if (!ensurePaired()) {
return;
}
// Reset the only-show-one-error-dialog tracking variable
mIsConnectingErrorPossible = true;
for (LocalBluetoothProfile profile : mProfiles) {
if (profile.isAutoConnectable()) {
profile.setPreferred(mDevice, true);
connectInt(profile);
}
}
}
3. 没有配对的设备，先进行配对
private void pair() {
if (!mCachedDevice.startPairing()) {
Utils.showError(getContext(), mCachedDevice.getName(),
R.string.bluetooth_pairing_error_message);
}
}
frameworks\base\packages\SettingsLib\src\com\android\settingslib\bluetooth\CachedBluetoothDevice.java
public boolean startPairing() {
// Pairing is unreliable while scanning, so cancel discovery
// 配对的时候，关闭扫描
if (mLocalAdapter.isDiscovering()) {
mLocalAdapter.cancelDiscovery();
}
if (!mDevice.createBond()) {
return false;
}
return true;
}
frameworks\base\core\java\android\bluetooth\BluetoothDevice.java
@RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
public boolean createBond() {
final IBluetooth service = sService;
if (service == null) {
Log.e(TAG, "BT not enabled. Cannot create bond to Remote Device");
return false;
}
try {
Log.i(TAG, "createBond() for device " + getAddress()
+ " called by pid: " + Process.myPid()
+ " tid: " + Process.myTid());
return service.createBond(this, TRANSPORT_AUTO);
} catch (RemoteException e) {
Log.e(TAG, "", e);
}
return false;
}
packages\apps\Bluetooth\src\com\android\bluetooth\btservice\AdapterService.java
private static class AdapterServiceBinder extends IBluetooth.Stub {
public boolean createBond(BluetoothDevice device, int transport) {
if (!Utils.checkCallerAllowManagedProfiles(mService)) {
Log.w(TAG, "createBond() - Not allowed for non-active user");
return false;
}
AdapterService service = getService();
if (service == null) return false;
return service.createBond(device, transport, null); // bond
}
// 建立bond
boolean createBond(BluetoothDevice device, int transport, OobData oobData) {
enforceCallingOrSelfPermission(BLUETOOTH_ADMIN_PERM,
"Need BLUETOOTH ADMIN permission");
DeviceProperties deviceProp = mRemoteDevices.getDeviceProperties(device);
if (deviceProp != null && deviceProp.getBondState() != BluetoothDevice.BOND_NONE) {
return false;
}
// 在多播的时候不要进行bond，不明白这个multicast是什么意思
// Multicast: Do not allow bonding while multcast
A2dpService a2dpService = A2dpService.getA2dpService();
if (a2dpService != null &&
a2dpService.isMulticastFeatureEnabled() &&
a2dpService.isMulticastOngoing(null)) {
Log.i(TAG,"A2dp Multicast is ongoing, ignore bonding");
return false;
}
mRemoteDevices.setBondingInitiatedLocally(Utils.getByteAddress(device));
// Pairing is unreliable while scanning, so cancel discovery
// Note, remove this when native stack improves
if (!mAdapterProperties.isDiscovering()) {
Log.i(TAG,"discovery not active, no need to send cancelDiscovery");
} else {
cancelDiscoveryNative();
}
// 或去状态机的消息
Message msg = mBondStateMachine.obtainMessage(BondStateMachine.CREATE_BOND);
msg.obj = device;
msg.arg1 = transport;
if (oobData != null) {
Bundle oobDataBundle = new Bundle();
oobDataBundle.putParcelable(BondStateMachine.OOBDATA, oobData);
msg.setData(oobDataBundle);
}
// 发送消息给状态机
mBondStateMachine.sendMessage(msg);
return true;
}
packages\apps\Bluetooth\src\com\android\bluetooth\btservice\BondStateMachine.java
private class StableState extends State {
@Override
public void enter() {
infoLog("StableState(): Entering Off State");
}
@Override
public synchronized boolean processMessage(Message msg) {
BluetoothDevice dev = (BluetoothDevice)msg.obj;
switch(msg.what) {
case CREATE_BOND:
OobData oobData = null;
if (msg.getData() != null)
oobData = msg.getData().getParcelable(OOBDATA);
createBond(dev, msg.arg1, oobData, true);
break;
case REMOVE_BOND:
removeBond(dev, true);
break;
case BONDING_STATE_CHANGE:
int newState = msg.arg1;
/* if incoming pairing, transition to pending state */
if (newState == BluetoothDevice.BOND_BONDING)
{
if(!mDevices.contains(dev)) {
mDevices.add(dev);
}
sendIntent(dev, newState, 0);
transitionTo(mPendingCommandState);
}
else if (newState == BluetoothDevice.BOND_NONE)
{
/* if the link key was deleted by the stack */
sendIntent(dev, newState, 0);
}
else
{
Log.e(TAG, "In stable state, received invalid newState: " + newState);
}
break;
case CANCEL_BOND:
default:
Log.e(TAG, "Received unhandled state: " + msg.what);
return false;
}
return true;
}
}
private boolean createBond(BluetoothDevice dev, int transport, OobData oobData,
boolean transition) {
if(mAdapterService == null) return false;
if (dev.getBondState() == BluetoothDevice.BOND_NONE) {
infoLog("Bond address is:" + dev);
byte[] addr = Utils.getBytesFromAddress(dev.getAddress());
boolean result;
// 调用JNI
if (oobData != null) {
result = mAdapterService.createBondOutOfBandNative(addr, transport, oobData);
} else {
result = mAdapterService.createBondNative(addr, transport);
}
if (!result) {
sendIntent(dev, BluetoothDevice.BOND_NONE,
BluetoothDevice.UNBOND_REASON_REMOVED);
return false;
} else if (transition) {
transitionTo(mPendingCommandState);
}
return true;
}
return false;
}
Liu Tao
2019-3-27
