BluetoothSettings.java::startScanning            ----packageLocalBluetoothAdapter.java::startScanning       ----packageBluetoothAdapter.java::startDiscovery            ----frameworkAdapterService.java::startDiscovery              ----packagecom_android_bluetooth_btservice_AdapterService.cpp::startDiscoveryNative -jni

  static jboolean startDiscoveryNative(JNIEnv* env, jobject obj) {                                                   ALOGV("%s:",__FUNCTION__); jboolean result = JNI_FALSE; if (!sBluetoothInterface) return result; int ret = sBluetoothInterface->start_discovery(); result = (ret == BT_STATUS_SUCCESS) ? JNI_TRUE : JNI_FALSE; return result; }

......
LOCAL_SHARED_LIBRARIES := \libandroid_runtime \libnativehelper \libcutils \libutils \liblog \libhardware
......

static const bt_interface_t bluetoothInterface = {sizeof(bluetoothInterface),    init,enable,disable,cleanup,get_adapter_properties,   get_adapter_property,set_adapter_property,get_remote_device_properties,  get_remote_device_property,    set_remote_device_property,    get_remote_service_record,get_remote_services,start_discovery,cancel_discovery,create_bond,remove_bond,cancel_bond,pin_reply,ssp_reply,get_profile_interface,dut_mode_configure,dut_mode_send,
#if BLE_INCLUDED == TRUE le_test_mode #else NULL #endif };

static int start_discovery(void)
{/* sanity check */ if (interface_ready() == FALSE) return BT_STATUS_NOT_READY; return btif_dm_start_discovery(); }

bt_status_t btif_dm_start_discovery(void)
{tBTA_DM_INQ inq_params;tBTA_SERVICE_MASK services = 0;BTIF_TRACE_EVENT1("%s", __FUNCTION__); /* TODO: Do we need to handle multiple inquiries at the same time? */ /* Set inquiry params and call API */ #if (defined(BLE_INCLUDED) && (BLE_INCLUDED == TRUE)) inq_params.mode = BTA_DM_GENERAL_INQUIRY|BTA_BLE_GENERAL_INQUIRY; #else inq_params.mode = BTA_DM_GENERAL_INQUIRY; #endif  inq_params.duration = BTIF_DM_DEFAULT_INQ_MAX_DURATION; inq_params.max_resps = BTIF_DM_DEFAULT_INQ_MAX_RESULTS; inq_params.report_dup = TRUE; inq_params.filter_type = BTA_DM_INQ_CLR; /* TODO: Filter device by BDA needs to be implemented here */ /* Will be enabled to TRUE once inquiry busy level has been received */ btif_dm_inquiry_in_progress = FALSE; /* find nearby devices */ //下面是关键语句 BTA_DmSearch(&inq_params, services, bte_search_devices_evt); return BT_STATUS_SUCCESS;

void BTA_DmSearch(tBTA_DM_INQ *p_dm_inq, tBTA_SERVICE_MASK services, tBTA_DM_SEARCH_CBACK *p_cback)
{tBTA_DM_API_SEARCH    *p_msg;  if ((p_msg = (tBTA_DM_API_SEARCH *) GKI_getbuf(sizeof(tBTA_DM_API_SEARCH))) != NULL) { memset(p_msg, 0, sizeof(tBTA_DM_API_SEARCH)); p_msg->hdr.event = BTA_DM_API_SEARCH_EVT; memcpy(&p_msg->inq_params, p_dm_inq, sizeof(tBTA_DM_INQ)); p_msg->services = services; p_msg->p_cback = p_cback; p_msg->rs_res = BTA_DM_RS_NONE; bta_sys_sendmsg(p_msg); } }

static void bte_search_devices_evt(tBTA_DM_SEARCH_EVT event, tBTA_DM_SEARCH *p_data)
{UINT16 param_len = 0; if (p_data) param_len += sizeof(tBTA_DM_SEARCH); /* Allocate buffer to hold the pointers (deep copy). The pointers will point to the end of the tBTA_DM_SEARCH */ switch (event) { case BTA_DM_INQ_RES_EVT: { if (p_data->inq_res.p_eir) param_len += HCI_EXT_INQ_RESPONSE_LEN; } break; case BTA_DM_DISC_RES_EVT: { if (p_data->disc_res.raw_data_size && p_data->disc_res.p_raw_data) param_len += p_data->disc_res.raw_data_size; } break; } BTIF_TRACE_DEBUG3("%s event=%s param_len=%d", __FUNCTION__, dump_dm_search_event(event), param_len); /* if remote name is available in EIR, set teh flag so that stack doesnt trigger RNR */ if (event == BTA_DM_INQ_RES_EVT) p_data->inq_res.remt_name_not_required = check_eir_remote_name(p_data, NULL, NULL); btif_transfer_context (btif_dm_search_devices_evt , (UINT16) event, (void *)p_data, param_len, (param_len > sizeof(tBTA_DM_SEARCH)) ? search_devices_copy_cb : NULL); }

static void btif_dm_search_devices_evt (UINT16 event, char *p_param)
{switch (event) { case BTA_DM_INQ_RES_EVT: { /* inquiry result */ UINT32 cod; UINT8 *p_eir_remote_name = NULL; bt_bdname_t bdname; bt_bdaddr_t bdaddr; UINT8 remote_name_len; UINT8 *p_cached_name = NULL; tBTA_SERVICE_MASK services = 0; bdstr_t bdstr; p_search_data = (tBTA_DM_SEARCH *)p_param; //解析mac地址 bdcpy(bdaddr.address, p_search_data->inq_res.bd_addr); /* Callback to notify upper layer of device */ //下面是关键语句，回调方法  HAL_CBACK(bt_hal_cbacks, device_found_cb, num_properties, properties); } } break; ......

static bool initNative(JNIEnv* env, jobject obj) {ALOGV("%s:",__FUNCTION__); ...... if (sBluetoothInterface) { int ret = sBluetoothInterface->init(&sBluetoothCallbacks); 　　...... }

bt_callbacks_t sBluetoothCallbacks = {sizeof(sBluetoothCallbacks),   adapter_state_change_callback, adapter_properties_callback,   remote_device_properties_callback,device_found_callback,discovery_state_changed_callback,pin_request_callback,ssp_request_callback,bond_state_changed_callback,   acl_state_changed_callback,    callback_thread_event,dut_mode_recv_callback,le_test_mode_recv_callback
};

/** Bluetooth DM callback structure. */
typedef struct { /** set to sizeof(bt_callbacks_t) */ size_t size; adapter_state_changed_callback adapter_state_changed_cb; adapter_properties_callback adapter_properties_cb; remote_device_properties_callback remote_device_properties_cb; device_found_callback device_found_cb; discovery_state_changed_callback discovery_state_changed_cb; pin_request_callback pin_request_cb; ssp_request_callback ssp_request_cb; bond_state_changed_callback bond_state_changed_cb; acl_state_changed_callback acl_state_changed_cb; callback_thread_event thread_evt_cb; dut_mode_recv_callback dut_mode_recv_cb; le_test_mode_callback le_test_mode_cb; } bt_callbacks_t;

static const bt_interface_t bluetoothInterface = {sizeof(bluetoothInterface),    init,enable,disable,cleanup,get_adapter_properties,get_adapter_property,set_adapter_property,get_remote_device_properties,  get_remote_device_property,    set_remote_device_property,    get_remote_service_record,get_remote_services,start_discovery,cancel_discovery,create_bond,remove_bond,cancel_bond,pin_reply,ssp_reply,get_profile_interface,dut_mode_configure,dut_mode_send,
#if BLE_INCLUDED == TRUE le_test_mode #else NULL #endif };

static int init(bt_callbacks_t* callbacks )
{ALOGI("init"); /* sanity check */ if (interface_ready() == TRUE) return BT_STATUS_DONE; /* store reference to user callbacks */ bt_hal_cbacks = callbacks; //这里为bt_hal_cbacks对象赋值 /* add checks for individual callbacks ? */ bt_utils_init(); /* init btif */ btif_init_bluetooth(); return BT_STATUS_SUCCESS; }

#define HAL_CBACK(P_CB, P_CBACK, ...)\if (P_CB && P_CB->P_CBACK) {            \BTIF_TRACE_API2("HAL %s->%s", #P_CB, #P_CBACK); \ P_CB->P_CBACK(__VA_ARGS__); \ } \ else { \ ASSERTC(0, "Callback is NULL", 0); \ }

static void device_found_callback(int num_properties, bt_property_t *properties) {......callbackEnv->CallVoidMethod(sJniCallbacksObj, method_deviceFoundCallback, addr); 　　......