Android getSystemService用法实例总结

VEBRATOR_SERVICE                    Vebrator                         手机震动的服务

CONNECTIVITY_SERVICE                Connectivity                     网络连接的服务

WIFI_SERVICE                        WifiManager                      Wi-Fi服务

TELEPHONY_SERVICE                   TeleponyManager                  电话服务

Wi-fi设计原理:

初始化

在 SystemServer 启动的时候,会生成一个 ConnectivityService 的实例,

try {
 Log.i(TAG, "Starting Connectivity Service.");
 ServiceManager.addService(Context.CONNECTIVITY_SERVICE, new
ConnectivityService(context));
  } catch (Throwable e) {
   Log.e(TAG, "Failure starting Connectivity Service", e);
  }

ConnectivityService 的构造函数会创建 WifiService,

if (DBG) Log.v(TAG, "Starting Wifi Service.");
mWifiStateTracker = new WifiStateTracker(context, handler);
WifiService wifiService = new WifiService(context, mWifiStateTracker);
ServiceManager.addService(Context.WIFI_SERVICE, wifiService);

WifiStateTracker 会创建 WifiMonitor 接收来自底层的事件,WifiService 和 WifiMonitor 是整个模块的核心。WifiService 负责启动关闭 wpa_supplicant、启动关闭 WifiMonitor 监视线程和把命令下发给 wpa_supplicant,而 WifiMonitor 则负责从 wpa_supplicant 接收事件通知。

1.连接 AP