java连接蓝牙原理流程_Bluetooth源码分析（三）蓝牙配对流程
先附上总结的时序图:
蓝牙配对时序图.png
1 UI
蓝牙配对开始于settings设备列表 /packages/apps/Settings/src/com/android/settings/bluetooth/DeviceListPreferenceFragment.java中。
DeviceListPreferenceFragment是蓝牙扫描到的设备列表，点击其中一个蓝牙设备，调用onPreferenceTreeClick方法开始蓝牙的配对过程。
@Override
public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen,
Preference preference) {
if (KEY_BT_SCAN.equals(preference.getKey())) {
mLocalAdapter.startScanning(true);
return true;
}
if (preference instanceof BluetoothDevicePreference) {
BluetoothDevicePreference btPreference = (BluetoothDevicePreference) preference;
CachedBluetoothDevice device = btPreference.getCachedDevice();
mSelectedDevice = device.getDevice();
//配对连接
onDevicePreferenceClick(btPreference);
return true;
}
return super.onPreferenceTreeClick(preferenceScreen, preference);
}
在本地onDevicePreferenceClick方法中调用/packages/apps/Settings/src/com/android/settings/bluetooth/BluetoothDevicePreference.java的onClicked方法：
void onClicked() {
Context context = getContext();
int bondState = mCachedDevice.getBondState();// 获取设备的绑定状态
final MetricsFeatureProvider metricsFeatureProvider =
FeatureFactory.getFactory(context).getMetricsFeatureProvider();
if (mCachedDevice.isConnected()) {
metricsFeatureProvider.action(context,
MetricsEvent.ACTION_SETTINGS_BLUETOOTH_DISCONNECT);
askDisconnect(); // 已连接，询问是否断开连接
} else if (bondState == BluetoothDevice.BOND_BONDED) {
metricsFeatureProvider.action(context,
MetricsEvent.ACTION_SETTINGS_BLUETOOTH_CONNECT);
mCachedDevice.connect(true);// 已绑定，则进行连接
} 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();// 如果未绑定，则进行配对
}
}
这里先获取mCachedDevice的绑定状态，如果已经连接，则询问是否断开；如果已经绑定未连接，则开始连接；如果未连接也未绑定，则开始配对。这里我们先看配对。配对调用的是本地的pair方法：
private void pair() {
if (!mCachedDevice.startPairing()) {
Utils.showError(getContext(), mCachedDevice.getName(),
R.string.bluetooth_pairing_error_message);
}
}
pair方法会调用/frameworks/base/packages/SettingsLib/src/com/android/settingslib/bluetooth/CachedBluetoothDevice.java中的startPairing，启动配对
2 framework
public boolean startPairing() {
// Pairing is unreliable while scanning, so cancel discovery
// 配对时，如果正在扫描，则取消扫描
if (mLocalAdapter.isDiscovering()) {
mLocalAdapter.cancelDiscovery();
}
// 开始配对
if (!mDevice.createBond()) {
return false;
}
// 标识位，配对完成后，自动连接
mConnectAfterPairing = true; // auto-connect after pairing
return true;
}
createBond调用/frameworks/base/core/java/android/bluetooth/BluetoothDevice.java
中的createBond方法：
public boolean createBond(int transport) {
final IBluetooth service = sService;
if (service == null) {
Log.e(TAG, "BT not enabled. Cannot create bond to Remote Device");
return false;
}
if (TRANSPORT_AUTO > transport || transport > TRANSPORT_LE) {
throw new IllegalArgumentException(transport + " is not a valid Bluetooth transpo