判断手机连接方式（3G or wifi）

private boolean networkState() {

ConnectivityManager
mConnectivity = (ConnectivityManager)
getSystemService(Context.CONNECTIVITY_SERVICE);

TelephonyManager mTelephony =
(TelephonyManager) this

.getSystemService(TELEPHONY_SERVICE);

//
检查网络连接，如果无网络可用，就不需要进行连网操作等

NetworkInfo info =
mConnectivity.getActiveNetworkInfo();

if (info == null ||
!mConnectivity.getBackgroundDataSetting()) {

return
false;

}

//
判断网络连接类型，只有在3G或wifi里进行一些数据更新。

int netType =
info.getType();

int netSubtype =
info.getSubtype();

if (netType ==
ConnectivityManager.TYPE_WIFI) {

return
info.isConnected();

} else if (netType ==
ConnectivityManager.TYPE_MOBILE

&&
netSubtype == TelephonyManager.NETWORK_TYPE_UMTS

&&
!mTelephony.isNetworkRoaming()) {

return
info.isConnected();

} else {

return
false;

}

}