安卓下出现了以下报错，不知道该如何解决

[wcyttt]

[wcyttt]

[wcyttt]

I/flutter ( 3263): The following NoSuchMethodError was thrown while notifying listeners for AnimationController:
I/flutter ( 3263): The method 'toDouble' was called on null.
I/flutter ( 3263): Receiver: null
I/flutter ( 3263): Tried calling: toDouble()
I/flutter ( 3263):
I/flutter ( 3263): When the exception was thrown, this was the stack:
I/flutter ( 3263): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
I/flutter ( 3263): #1 double./ (dart:core-patch/double.dart:52:23)
I/flutter ( 3263): #2 _GZXDropDownMenuState._animationListener (package:gzx_dropdown_menu/src/gzx_dropdown_menu.dart:140:40)
I/flutter ( 3263): #3 AnimationLocalListenersMixin.notifyListeners (package:flutter/src/animation/listener_helpers.dart:136:19)
I/flutter ( 3263): #4 AnimationController._tick (package:flutter/src/animation/animation_controller.dart:797:5)
I/flutter ( 3263): #5 Ticker._tick (package:flutter/src/scheduler/ticker.dart:238:12)
I/flutter ( 3263): #6 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1117:15)
I/flutter ( 3263): #7 SchedulerBinding.handleBeginFrame. (package:flutter/src/scheduler/binding.dart:1031:11)
I/flutter ( 3263): #8 _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:377:8)
I/flutter ( 3263): #9 SchedulerBinding.handleBeginFrame (package:flutter/src/scheduler/binding.dart:1029:17)
I/flutter ( 3263): #10 SchedulerBinding._handleBeginFrame (package:flutter/src/scheduler/binding.dart:963:5)
I/flutter ( 3263): #14 _invoke1 (dart:ui/hooks.dart:265:10)
I/flutter ( 3263): #15 _beginFrame (dart:ui/hooks.dart:192:3)
I/flutter ( 3263): (elided 3 frames from dart:async)
I/flutter ( 3263):
I/flutter ( 3263): The AnimationController notifying listeners was:
I/flutter ( 3263): AnimationController#81df6(▶ 0.000)

[GanZhiXiong]

你这是运行我的example报错吗？

[wcyttt]

1.这是我调用的地方，controller外部传入

SelectProject(
  dropdownMenuController: _dropdownMenuController,
  projects: _dynamicModel.projects,
)

2.这是我实现的地方

import 'package:flutter/material.dart';
import 'package:gtucloud/components/empty/index.dart';
import 'package:gzx_dropdown_menu/gzx_dropdown_menu.dart';
import 'provider_model.dart';
import 'package:provider/provider.dart';

class SelectProject extends StatefulWidget {
  final GZXDropdownMenuController dropdownMenuController;
  final List projects;
  SelectProject(
      {Key key, @required this.dropdownMenuController, @required this.projects})
      : super(key: key);

  @override
  _SelectProjectState createState() => _SelectProjectState();
}

class _SelectProjectState extends State<SelectProject> {
  // ignore: unused_field
  DynamicModel _dynamicModel;

  @override
  Widget build(BuildContext context) {
    _dynamicModel = context.watch<DynamicModel>();
    List projects = _dynamicModel.projects;
    String projectId = _dynamicModel.projectId;

    if (projects.length == 0) return EmptyWidget(description: "无项目");
    double _dropDownHeight;
    if (40.0 * projects.length > 300) _dropDownHeight = 300.0;

    return Container(
      child: GZXDropDownMenu(
        // controller用于控制menu的显示或隐藏
        controller: widget.dropdownMenuController,
        // 下拉菜单显示或隐藏动画时长
        animationMilliseconds: 300,
        // 下拉菜单，高度自定义，你想显示什么就显示什么，完全由你决定，你只需要在选择后调用widget.dropdownMenuController.hide();即可
        menus: [
          GZXDropdownMenuBuilder(
            dropDownHeight: _dropDownHeight,
            dropDownWidget: _buildConditionListWidget(
              projectId,
              projects,
              (value) {
                _dynamicModel.setSelectedProjectId(value["id"]);
                _dynamicModel
                    .getAuthDynamic(
                  projectId: value["id"],
                  dynamicTypingEnum: "ALL",
                  currentPage: 1,
                  pageSize: 999,
                )
                    .then((value) {
                  widget.dropdownMenuController.hide();
                });
              },
            ),
          ),
        ],
      ),
    );
  }

  _buildConditionListWidget(
    String selectedProjectId, // 选中项目的id
    List items,
    void itemOnTap(sortCondition),
  ) {
    // project name
    Widget title(Map item, String selectedID) {
      bool isChecked = false;
      if (item["id"] == selectedID) isChecked = true;
      return Expanded(
          child: Text(
        item["name"],
        style: TextStyle(
            color: isChecked ? Theme.of(context).primaryColor : Colors.black),
      ));
    }

    // project icon
    Widget icon(Map item, String selectedID) {
      bool isChecked = false;
      if (item["id"] == selectedID) isChecked = true;
      return isChecked
          ? Icon(
              Icons.check,
              color: Theme.of(context).primaryColor,
              size: 16,
            )
          : SizedBox();
    }

    return ListView.separated(
      shrinkWrap: true,
      scrollDirection: Axis.vertical,
      itemCount: items.length,
      // item 的个数
      separatorBuilder: (BuildContext context, int index) =>
          Divider(height: 1.0),
      // 添加分割线
      itemBuilder: (BuildContext context, int index) {
        Map item = items[index];
        return GestureDetector(
          onTap: () => itemOnTap(item),
          child: Container(
            height: 40,
            child: Row(
              children: <Widget>[
                SizedBox(width: 16),
                title(item, selectedProjectId),
                icon(item, selectedProjectId),
                SizedBox(width: 16),
              ],
            ),
          ),
        );
      },
    );
  }
}

[wcyttt]

我看了我传入的值都是有值的，我哪里用错了吗，我只需要一个下拉的菜单栏

[GanZhiXiong]

如果我写的example运行没有问题，你先对照我的example检查下。
最近比较忙，有时间我帮你看下。

[wcyttt]

好吧，现在找不到问题，看源码看不出啥，我只调用了GZXDropDownMenu一个Widget

[GanZhiXiong]

你搜索下toDouble ,我怀疑你传入的数值有问题

[wcyttt]

我搜不到toDouble，我直接搜索整个项目，我都没用过这个函数

[GanZhiXiong]

你用的flutter哪个版本？

[wcyttt]

这个

 AnimationController:
I/flutter ( 3263): The method 'toDouble' was called on null.

应该是你内部实现的吧，我外部没有传值，1.2.4好像

[wcyttt]

ios14.4版本没问题，14.3版本也有这个问题

[GanZhiXiong]

你还是先把我example的代码拷贝过去，多试试吧，应该是你的使用方式有问题

[wcyttt]

解决了，是我的问题

double _dropDownHeight;
    if (40.0 * projects.length > 300) _dropDownHeight = 300.0;

这句有问题，是null

[GanZhiXiong]

👍，good！

[wcyttt]

大意了啊，反复查值，但是这个数据在我电脑一定会走那个if，所以没看出来

[GanZhiXiong]

我一开始也怀疑过你那句代码有问题，只是没有看到报错定位到那行，所以不敢肯定。

给个star吧😂！
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