无法处理SocketException

Question

我已经关闭了手机以触发SocketException错误。我进行了api调用，在堆栈的顶部，就在await调用之前，我的调试器上可以看到错误。我想在UI层处理这个错误。在调用堆栈的底部，我看到了getData方法。我的理解是:我可以将它包装在try/catch中并处理异常。但是我似乎不能理解这个错误..下面是方法：

Future<String> getData(String query) async {
    try {
      List<Suburb> suburbs = await model.getSuburbs('au', query);

      if (suburbs.length == 1) {
        suburbCode = suburbs[0].code;
        isButtonDisabled = false;
        return suburbs[0].name;
      }
      return showDialog<String>(
          barrierDismissible: false,
          context: context,
          builder: (context) => SimpleDialog(
                backgroundColor: Colors.black,
                title: Text('Please choose your Suburb:'),
                children: suburbs
                    .map((suburb) => SimpleDialogOption(
                        child: Text(suburb.name),
                        onPressed: () {
                          suburbCode = suburb.code;
                          isButtonDisabled = false;

                          Navigator.of(context).pop(suburb.name);
                        }))
                    .toList(),
              ));
    } on SocketException catch (e) {
      print(e);
    }
  }

行List<Suburb> suburbs = await model.getSuburbs('au', query);是我进行api调用的地方，也是调试器指向的地方。但我似乎不能“进入catch积木”

Answer 1

在Http post/get调用中也需要try-catch块。因此，只要在getSuburbs()中捕获套接字异常，执行必要的操作，并在需要时从那里抛出一个通用异常。类似于下面的代码将会起作用：

Future<string> getSuburbs(string country, string query){
    try {
        http.Response response =
            await http.post(.........
      } on SocketException catch (e) {
        print(e);
        throw Error.noNetworkConnection;
      } catch (e) {
        print(e);
        throw Error.unknown;
      }
}