Flutter：下拉框选择

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b70dec92594838a8b2c130717938aa.png)

文档地址dropdown_button2

  // 限价、市价 状态
  final List<String> orderTypes = ['普通委托', '市价委托'];
  String? selectedOrderType = '普通委托';
  changeOrderType(String type) {
    selectedOrderType = type;
    update(["continuous"]);
  }

  // 杠杆
  final List<String> leverages = ['1X', '5X', '10X', '20X', '50X'];
  String? selectedLeverage = '1X';
  changeLeverage(String leverage) {
    selectedLeverage = leverage;
    update(["continuous"]);
  }



  // 委托
  Widget _buildLeftOrderType() {
    return DropdownButtonHideUnderline(
      child: DropdownButton2<String>(
        isExpanded: true,
        value: controller.selectedOrderType,
        items: controller.orderTypes.map((item) => DropdownMenuItem<String>(
          value: item,
          child: TextWidget.body(item,size: 26.sp,color: AppTheme.color000,),
        )).toList(),
        onChanged: (value) {
          controller.changeOrderType(value!);
        },
        buttonStyleData: ButtonStyleData(
          height: 72.w, // 高度和你的红框一致
          width: 180.w, // 宽度自适应父容器
          padding: EdgeInsets.only(left: 20.w, right: 0,),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(10.w),
            color: AppTheme.colorGreen,
          ),
        ),
        dropdownStyleData: DropdownStyleData(
          width: null, // 跟随按钮宽度
          decoration: BoxDecoration(
            color: AppTheme.dividerColor,
            borderRadius: BorderRadius.circular(4),
          ),
          offset: const Offset(0, 0), // 默认正下方弹出
        ),
      ),
    );
  }

  // 杠杆
  Widget _buildLeftLeverage() {
    return DropdownButtonHideUnderline(
      child: DropdownButton2<String>(
        isExpanded: true,
        value: controller.selectedLeverage,
        items: controller.leverages.map((item) => DropdownMenuItem<String>(
          value: item,
          child: TextWidget.body(item,size: 26.sp,color: AppTheme.color000,),
        )).toList(),
        onChanged: (value) {
          controller.changeLeverage(value!);
        },
        buttonStyleData: ButtonStyleData(
          height: 72.w, // 高度和你的红框一致
          width: 140.w, // 宽度自适应父容器
          padding: EdgeInsets.only(left: 20.w, right: 0,),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(10.w),
            border: Border.all(width: 1,color: AppTheme.dividerColor2),
          ),
        ),
        dropdownStyleData: DropdownStyleData(
          width: null, // 跟随按钮宽度
          decoration: BoxDecoration(
            color: AppTheme.dividerColor,
            borderRadius: BorderRadius.circular(4),
          ),
          offset: const Offset(0, 0), // 默认正下方弹出
        ),
      ),
    );
  }