为什么这个循环只发生一次Flutter dart

这是因为您在循环内部调用了Return，所以在第一个循环中，当它得到Return时，它停止循环.试试这个:

Future<List<Evsebillall>> fetcheach() async {
    int i = 1;
    List<Evsebillall> result = []; // <--add this
    while (i < 12) {
      print(i);
      i++;
      String? token = await this.storage.read(key: "token");
      Map<String, String> headers = {
        "Content-Type": "application/json",
        "Accept": "application/json",
        "Authorization": "Bearer " + (token ?? ""),
      };
      final response = await http.get(
          Uri.parse(this.serverIP +
              ':' +
              this.serverPort +
              '/user/contractedChargeTransactions?month=$i&year=2022'),
          headers: headers);
      if (response.statusCode == 200) {
        setState(() {
          cardBillsTotaleach =
              jsonDecode(response.body)["cardBillsTotal"] as List;
          var resultTotal =
              cardBillsTotaleach.map((e) => Evsebill.fromJson(e)).toList();
          if (resultTotal.isNotEmpty) {
            TotalTotaleach = (resultTotal[0].total);
            print("totaleach =$TotalTotaleach");
            Totaleachlist.add(TotalTotaleach);
          }
          print("listtotal =$Totaleachlist");
        });
        result.addAll(cardBillsall.map((e) => Evsebillall.fromJson(e)).toList());// <--add this
      } else {
        throw Exception('Failed to load Bills');
      }
    }

    return result;// <--add this
    
  }