连接网络首先必须的就是设置权限，在配置清单文件中添加网络请求权限
<uses-permission android:name="android.permission.INTERNET" />
fun isNetworkConnected() : Boolean{
val mConnectManager : ConnectivityManager = this.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
val network = mConnectManager.getNetworkCapabilities(mConnectManager.activeNetwork)
return if (network != null){
true
}else{
false
}
}
