Android API Level 21 新增 API android.net.NetworkCapabilities
判断是否能访问 Internet
val networkCapabilities = connectivityManager.getNetworkCapabilities(connectivityManager.activeNetwork)
return networkCapabilities != null
&& networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
&& networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)