/**   * 判断网络功能是否可用   * 需要权限< uses-permission android:name="android.permission.ACCESS_NETWORK_STATE">   * @param ctx   * @return   */  public static boolean isNetworkAvailable(Context ctx){      ConnectivityManager cm = (ConnectivityManager)ctx.getSystemService(Context.CONNECTIVITY_SERVICE);      NetworkInfo info = cm.getActiveNetworkInfo();      return (info != null && info.isConnected());  }

注意需要权限<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE">