首先在AndroidManifest.xml 里增加检查网络状态的权限
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

 

/*
*@return boolean return true if the application can access the internet
*/
private boolean haveInternet(){
NetworkInfo info=(ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE).getActiveNetworkInfo();
if(info==null || !info.isConnected()){
return false;
}
if(info.isRoaming()){
//here is the roaming option you can change it if you want to disable internet while roaming, just return false
return true;
}
return true;
}