项目中涉及低功耗蓝牙手柄的开发，GattCallback onConnectionStateChange接口返回状态status值有多个
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
LogUtil.e("status :" +status +" ,newState :"+ newState);
switch (status){
case BluetoothGatt.GATT_SUCCESS://0
break;
case BluetoothGatt.GATT_FAILURE://257
break;
case 133:
case 8:
case 22:
break;
}
}
}其中GATT_SUCCESS和GATT_FAILURE(不常见)在BluetoothGatt源码中可以找到外，其他8、22、133等status状态值不知道其意义，对于断开连接的原因就不好判断了。
下面我们从framework源码追查这几个状态
_bluetoothGatt = device.connectGatt(_context, false, mGattCallback);BluetoothDevice connectGatt方法将mGattCallback传入
public BluetoothGatt connectGatt(Context context, boolean autoConnect,
BluetoothGattCallback callback, int transport) {
// TODO(Bluetooth) check whether platform support BLE
// Do the check here or in GattServer?
BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
IBluetoothManager managerService = adapter.getBluetoothManager();
try {
IBluetoothGatt iGatt = managerService.getBluetoothGatt();
if (iGatt == null) {
// BLE is not supported
return null;
}
BluetoothGatt gatt = new BluetoothGatt(iGatt, this, transport);
gatt.connect(autoConnect, callback);
return gatt;
} catch (RemoteException e) {Log.e(TAG, "", e);}
return null;
}connect方法中创建了BluetoothGatt对象，gatt connect方法将callback导入，我们继续看BluetoothGatt源码
/*package*/ boolean connect(Boolean autoConnect, BluetoothGattCallback callback) {
if (DBG) Log.d(TAG, "connect() - device: " + mDevice.getAddress() + ", auto: " + autoConnect);
synchronized(mStateLock) {
if (mConnState != CONN_STATE_IDLE) {
throw new IllegalStateException("Not idle");
}
mConnState = CONN_STATE_CONNECTING;
}
mAutoConnect = autoConnect;
if (!registerApp(callback)) {
synchronized(mStateLock) {
mConnState = CONN_STATE_IDLE;
}
Log.e(TAG, "Failed to register callback");
return false;
}
// The connection will continue in the onClientRegistered callback
return true;
}继续看reigsterApp方法
private boolean registerApp(BluetoothGattCallback callback) {
if (DBG) Log.d(TAG, "registerApp()");
if (mService == null) return false;
mCallback = callback;
UUID uuid = UUID.randomUUID();
if (DBG) Log.d(TAG, "registerApp() - UUID=" + uuid);
try {
mService.registerClient(new ParcelUuid(uuid), mBluetoothGattCallback);
} catch (RemoteException e) {
Log.e(TAG,"",e);
return false;
}
return true;
}mService是IBluetoothGatt接口的Proxy端
查找源码发现IBluetoothGatt的Stub端在GattService中实现，我们看GattService的registerClient方法
void registerClient(UUID uuid, IBluetoothGattCallback callback) {
enforceCallingOrSelfPermission(BLUETOOTH_PERM, "Need BLUETOOTH permission");
if (DBG) Log.d(TAG, "registerClient() - UUID=" + uuid);
mClientMap.add(uuid, callback, this);
gattClientRegisterAppNative(uuid.getLeastSignificantBits(),
uuid.getMostSignificantBits());
}mClientMap管理各个APP的callback对象
void onConnected(int clientIf, int connId, int status, String address)
throws RemoteException {
if (DBG) Log.d(TAG, "onConnected() - clientIf=" + clientIf
+ ", connId=" + connId + ", address=" + address);
if (status == 0) mClientMap.addConnection(clientIf, connId, address);
ClientMap.App app = mClientMap.getById(clientIf);
if (app != null) {
app.callback.onClientConnectionState(status, clientIf,
(status==BluetoothGatt.GATT_SUCCESS), address);
}
}
void onDisconnected(int clientIf, int connId, int status, String address)
throws RemoteException {
if (DBG) Log.d(TAG, "onDisconnected() - clientIf=" + clientIf
+ ", connId=" + connId + ", address=" + address);
mClientMap.removeConnection(clientIf, connId);
ClientMap.App app = mClientMap.getById(clientIf);
if (app != null) {
app.callback.onClientConnectionState(status, clientIf, false, address);
}
}在GattService的onConnected和onDisconnected方法中我们找到了callback.onClientConnectionState的调用，那么这两个方法是谁调用的，很显然这个调用者来自jni底层
method_onConnected = env->GetMethodID(clazz, "onConnected", "(IIILjava/lang/String;)V");
method_onDisconnected = env->GetMethodID(clazz, "onDisconnected", "(IIILjava/lang/String;)V");com_android_bluetooth_gatt.cpp中有关于这两个方法的反射调用
void btgattc_close_cb(int conn_id, int status, int clientIf, bt_bdaddr_t* bda)
{
CHECK_CALLBACK_ENV
char c_address[32];
snprintf(c_address, sizeof(c_address),"%02X:%02X:%02X:%02X:%02X:%02X",
bda->address[0], bda->address[1], bda->address[2],
bda->address[3], bda->address[4], bda->address[5]);
jstring address = sCallbackEnv->NewStringUTF(c_address);
sCallbackEnv->CallVoidMethod(mCallbacksObj, method_onDisconnected,
clientIf, conn_id, status, address);
sCallbackEnv->DeleteLocalRef(address);
checkAndClearExceptionFromCallback(sCallbackEnv, __FUNCTION__);
}com_android_bluetooth_gatt的btgattc_close_cb方法中调用了onDisconnected，但是status依然是外部导入的，我们继续追。
btgattc_close_cb是BTA client callback，所以答案应该在BTA
BTA就是Bluetooth Application，所有蓝牙请求都必须进过它，我们看bta目录下的h文件，目录是system/bt/bta
最终，我们在bta_gatt_api.h中找到了status 8, 22, 133等错误
#define BTA_GATT_OK GATT_SUCCESS
#define BTA_GATT_INVALID_HANDLE GATT_INVALID_HANDLE /* 0x0001 */
#define BTA_GATT_READ_NOT_PERMIT GATT_READ_NOT_PERMIT /* 0x0002 */
#define BTA_GATT_WRITE_NOT_PERMIT GATT_WRITE_NOT_PERMIT /* 0x0003 */
#define BTA_GATT_INVALID_PDU GATT_INVALID_PDU /* 0x0004 */
#define BTA_GATT_INSUF_AUTHENTICATION GATT_INSUF_AUTHENTICATION /* 0x0005 */
#define BTA_GATT_REQ_NOT_SUPPORTED GATT_REQ_NOT_SUPPORTED /* 0x0006 */
#define BTA_GATT_INVALID_OFFSET GATT_INVALID_OFFSET /* 0x0007 */
#define BTA_GATT_INSUF_AUTHORIZATION GATT_INSUF_AUTHORIZATION /* 0x0008 */
#define BTA_GATT_PREPARE_Q_FULL GATT_PREPARE_Q_FULL /* 0x0009 */
#define BTA_GATT_NOT_FOUND GATT_NOT_FOUND /* 0x000a */
#define BTA_GATT_NOT_LONG GATT_NOT_LONG /* 0x000b */
#define BTA_GATT_INSUF_KEY_SIZE GATT_INSUF_KEY_SIZE /* 0x000c */
#define BTA_GATT_INVALID_ATTR_LEN GATT_INVALID_ATTR_LEN /* 0x000d */
#define BTA_GATT_ERR_UNLIKELY GATT_ERR_UNLIKELY /* 0x000e */
#define BTA_GATT_INSUF_ENCRYPTION GATT_INSUF_ENCRYPTION /* 0x000f */
#define BTA_GATT_UNSUPPORT_GRP_TYPE GATT_UNSUPPORT_GRP_TYPE /* 0x0010 */
#define BTA_GATT_INSUF_RESOURCE GATT_INSUF_RESOURCE /* 0x0011 */
#define BTA_GATT_NO_RESOURCES GATT_NO_RESOURCES /* 0x80 */
#define BTA_GATT_INTERNAL_ERROR GATT_INTERNAL_ERROR /* 0x81 */
#define BTA_GATT_WRONG_STATE GATT_WRONG_STATE /* 0x82 */
#define BTA_GATT_DB_FULL GATT_DB_FULL /* 0x83 */
#define BTA_GATT_BUSY GATT_BUSY /* 0x84 */
#define BTA_GATT_ERROR GATT_ERROR /* 0x85 */
#define BTA_GATT_CMD_STARTED GATT_CMD_STARTED /* 0x86 */
#define BTA_GATT_ILLEGAL_PARAMETER GATT_ILLEGAL_PARAMETER /* 0x87 */
#define BTA_GATT_PENDING GATT_PENDING /* 0x88 */
#define BTA_GATT_AUTH_FAIL GATT_AUTH_FAIL /* 0x89 */
#define BTA_GATT_MORE GATT_MORE /* 0x8a */
#define BTA_GATT_INVALID_CFG GATT_INVALID_CFG /* 0x8b */
#define BTA_GATT_SERVICE_STARTED GATT_SERVICE_STARTED /* 0x8c */
#define BTA_GATT_ENCRYPED_MITM GATT_ENCRYPED_MITM /* GATT_SUCCESS */
#define BTA_GATT_ENCRYPED_NO_MITM GATT_ENCRYPED_NO_MITM /* 0x8d */
#define BTA_GATT_NOT_ENCRYPTED GATT_NOT_ENCRYPTED /* 0x8e */
#define BTA_GATT_CONGESTED GATT_CONGESTED /* 0x8f */
#define BTA_GATT_DUP_REG 0x90 /* 0x90 */
#define BTA_GATT_ALREADY_OPEN 0x91 /* 0x91 */
#define BTA_GATT_CANCEL 0x92 /* 0x92 */#define BTA_GATT_CONN_UNKNOWN 0
#define BTA_GATT_CONN_L2C_FAILURE GATT_CONN_L2C_FAILURE /* general l2cap resource failure */
#define BTA_GATT_CONN_TIMEOUT GATT_CONN_TIMEOUT /* 0x08 connection timeout */
#define BTA_GATT_CONN_TERMINATE_PEER_USER GATT_CONN_TERMINATE_PEER_USER /* 0x13 connection terminate by peer user */
#define BTA_GATT_CONN_TERMINATE_LOCAL_HOST GATT_CONN_TERMINATE_LOCAL_HOST/* 0x16 connectionterminated by local host */
#define BTA_GATT_CONN_FAIL_ESTABLISH GATT_CONN_FAIL_ESTABLISH /* 0x03E connection fail to establish */
#define BTA_GATT_CONN_LMP_TIMEOUT GATT_CONN_LMP_TIMEOUT /* 0x22 connection fail for LMP response tout */
#define BTA_GATT_CONN_CANCEL GATT_CONN_CANCEL /* 0x0100 L2CAP connection cancelled */
#define BTA_GATT_CONN_NONE 0x0101 /* 0x0101 no connection to cancel */status 133 GATT_ERROR,这个错误是Android源码的问题
status 22 GATT_CONN_TERMINATE_LOCAL_HOST
status 8 GATT_CONN_TIMEOUT
通过自上而下追踪status的轨迹，我们还间接了解了GATT蓝牙连接通信的架构
