Gears Android WIFI/基站定位源代码分析

核心提示：// Avoid holding the mutex locked while notifying observers.data_mutex_.Unlock();if (is_update_available) {is_first_scan_complete_ = true;NotifyListeners();}#if

// Avoid holding the mutex locked while notifying observers.

data_mutex_.Unlock();

if (is_update_available) {

is_first_scan_complete_ = true;

NotifyListeners();

}

#if USING_CCTESTS

// This is needed for running the WiFi test on the emulator.

// See wifi_data_provider_android.h for details.

if (!first_callback_made_ && wifi_data_.access_point_data.empty()) {

first_callback_made_ = true;

NotifyListeners();

}

#endif

}

从以上代码可以看出，WIFI定位和基站定位的逻辑差不多，只是前者获取的WIFI的扫描结果，而后者获取的基站信息。后面代码的基本上就统一起来了，接下来我们继续看。

5.把变化(WIFI/基站)通知给相应的监听者。

AndroidWifiDataProvider和AndroidRadioDataProvider都是继承了 DeviceDataProviderImplBase，DeviceDataProviderImplBase的主要功能就是管理所有Listeners。

static DeviceDataProvider *Register(ListenerInterface *listener) {

MutexLock mutex(&instance_mutex_);

if (!instance_) {

instance_ = new DeviceDataProvider();

}

assert(instance_);

instance_->Ref();

instance_->AddListener(listener);

return instance_;

}

static bool Unregister(ListenerInterface *listener) {

MutexLock mutex(&instance_mutex_);

if (!instance_->RemoveListener(listener)) {

return false;

}

if (instance_->Unref()) {

delete instance_;

instance_ = NULL;

}

return true;

}

6.谁在监听变化(WIFI/基站)

NetworkLocationProvider在监听变化(WIFI/基站):

radio_data_provider_ = RadioDataProvider::Register(this);

wifi_data_provider_ = WifiDataProvider::Register(this);

当有变化时，会调用函数DeviceDataUpdateAvailable：