Flutter时间选择器(城市选择器，时间选择器，数量选择器)

倒入第三方库：

flutter_picker: 1.1.0

github:https://github.com/yangyxd/flutter_picker

flutter_picker的作者提供了多种adapter来处理不同的情况(NumberPickerAdapter，PickerDataAdapter，DateTimePickerAdapter),主要处理数据对应就行了。

简单的封装了下，方便调用；

import 'package:flutter/material.dart';
import 'package:flutter_picker/flutter_picker.dart';
import 'package:percentage_flutter/config/city.dart';
import 'package:percentage_flutter/kit/util/date_util.dart';

const double _kPickerSheetHeight = 216.0;
const double _kPickerItemHeight = 32.0;

typedef PickerConfirmCityCallback = void Function(
    List stringData, List selecteds);

class PickHelper {
  ///普通简易选择器
  static void openSimpleDataPicker(
    BuildContext context, {
    @required List list,
    String title,
    @required T value,
    PickerDataAdapter adapter,
    @required PickerConfirmCallback onConfirm,
  }) {
    var incomeIndex = 0;
    if (list != null) {
      for (int i = 0; i < list.length; i++) {
        if (list[i] == value) {
          incomeIndex = i;
          break;
        }
      }
    }
    openModalPicker(context,
        adapter: adapter ??
            PickerDataAdapter(
              pickerdata: list,
              isArray: false,
            ),
        onConfirm: onConfirm,
        selecteds: [incomeIndex],
        title: title);
  }

  ///数字选择器
  static void openNumberPicker(
    BuildContext context, {
    String title,
    List datas,
    NumberPickerAdapter adapter,
    @required PickerConfirmCallback onConfirm,
  }) {
    openModalPicker(context,
        adapter: adapter ?? NumberPickerAdapter(data: datas ?? []),
        title: title,
        onConfirm: onConfirm);
  }

  ///日期选择器
  static void openDateTimePicker(
    BuildContext context, {
    String title,
    DateTime maxValue,
    DateTime minValue,
    DateTime value,
    DateTimePickerAdapter adapter,
    @required PickerConfirmCallback onConfirm,
  }) {
    openModalPicker(context,
        adapter: adapter ??
            DateTimePickerAdapter(
                type: PickerDateTimeType.kYMD,
                isNumberMonth: true,
                yearSuffix: "年",
                maxValue: maxValue ?? DateUtil.after(year: 20),
                minValue: minValue ?? DateUtil.before(year: 100),
                value: value ?? DateTime.now(),
                monthSuffix: "月",
                daySuffix: "日"),
        title: title,
        onConfirm: onConfirm);
  }

  ///地址选择器
  static void openCityPicker(BuildContext context,
      {String title,
      @required PickerConfirmCityCallback onConfirm,
      String selectCity=""}) {
    var proIndex = 0;
    var cityIndex = 0;
    openModalPicker(context,
        adapter: PickerDataAdapter(
            data: CityData.asMap().keys.map((provincePos) {
          var province = CityData[provincePos];
          List citys = province['city'];
          return PickerItem(
              text: Text(
                province['name'],
              ),
              value: province['name'],
              children: citys.asMap().keys.map((cityPos) {
                var city=citys[cityPos];
                if(city['name']==selectCity){
                  proIndex=provincePos;
                  cityIndex=cityPos;
                }
                return PickerItem(text: Text(city['name']));
              }).toList());
        }).toList()),
        title: title, onConfirm: (pick, value) {
      var p = CityData[value[0]];
      List citys = p['city'];
      onConfirm([p['name'], citys[value[1]]['name']], value);
    },selecteds: [proIndex,cityIndex]);
  }

  static void openModalPicker(
    BuildContext context, {
    @required PickerAdapter adapter,
    String title,
    List selecteds,
    @required PickerConfirmCallback onConfirm,
  }) {
    new Picker(
      adapter: adapter,
      title: new Text(title ?? ""),
      selecteds: selecteds,
      cancelText: '取消',
      confirmText: '确定',
      cancelTextStyle: TextStyle(color: Colors.black,fontSize: 16.0),
      confirmTextStyle: TextStyle(color: Colors.black,fontSize: 16.0),
      textAlign: TextAlign.right,
      itemExtent: _kPickerItemHeight,
      height: _kPickerSheetHeight,
      selectedTextStyle: TextStyle(color: Colors.black),
      onConfirm: onConfirm,
    ).showModal(context);
  }
}

其中城市的数据还是要看数据源的格式，CityData是一个城市集合（类似于这样的数据结构）

const CityData=[
{
    "name": "北京",
    "city": [
      {"name": "北京", "area": []}
    ]
  },
  {
    "name": "上海",
    "city": [
      {"name": "上海", "area": []}
    ]
  },
  {
    "name": "天津",
    "city": [
      {"name": "天津", "area": []}
    ]
  },
  {
    "name": "重庆",
    "city": [
      {"name": "重庆", "area": []}
    ]
  },
  {
    "name": "浙江",
    "city": [
      {"name": "杭州", "area": []},
      {"name": "嘉兴", "area": []},
      {"name": "宁波", "area": []},
      {"name": "绍兴", "area": []},
      {"name": "金华", "area": []},
      {"name": "湖州", "area": []},
      {"name": "舟山", "area": []},
      {"name": "衢州", "area": []},
      {"name": "温州", "area": []},
      {"name": "丽水", "area": []},
      {"name": "台州", "area": []}
    ]
  }
];

flutter_picker还有dialog等多种弹出方式。