判断网络是否可用

/** * 判断网络是否可用 */private boolean isNetworkAvailable(Context context) {    ConnectivityManager connectivity = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);    if (connectivity == null) {        return false;    } else {        NetworkInfo[] info = connectivity.getAllNetworkInfo();        if (info != null) {            for (int i = 0; i < info.length; i++) {                if (info[i].getState() == NetworkInfo.State.CONNECTED) {                    return true;                }            }        }    }    return false;}