一、後臺Service在系統啓動時被SystemServer開啓
1. MountService:監聽是否有SD卡安裝與移除
2. ClipboardService:提供剪切板功能
3. PackageManagerService: 提供軟件包的安裝移除及查看
4. 電量、網絡連接狀態等等
二、getSystemService()——繼承自Activity的方法
傳入字符串NAME——>得到Object——>轉成服務對象
//檢測網絡是否連接
ConnectivityManager connectivityManager = (ConnectivityManager)context.getSystemService(CONNECTIVITY_SERVICE);
NetworkInfo netWorkInfo = connectivityManager.getActiveNetworkInfo();
if(netWorkInfo!=null)
{
//已連接了網絡
return netWorkInfo.isAvailable();
}
//開關wifi——需要ACCESS、CHANGE_WIFI_STATE權限
WifiManager wifiManager = (WifiManager)context.getSystemService(WIFI_SERVICE);
if(wifiManager.isWifiEnabled()){
wifiManager.setWifiEnabled(false);//false:關閉wifi
}
//獲取當前進程包名
ActivityManager am =(ActivityManager)MainActivity.this.getSystemService(ACTIVITY_SERVICE);
String packageName = am.getRunningTasks(1).get(0).topActivity.getPackageName();