Question

我在flutter中有一个正在初始化某个类对象的类。我想调用该类，对象将被初始化，并且我想在调用者类中访问该对象。

下面是我的代码

import 'package:flutter/material.dart';

@immutable
class CardviewListItem {
  //final FlatButton icon;
  final IconData  icon;
  final String title;
  final String amount;

  const CardviewListItem({
    @required this.icon,
    @required this.title,
    @required this.amount,
  });
}

class SomeOtherClass {
  final summaryListItems = <CardviewListItem>[
    CardviewListItem(
        title: 'Total Income',
        amount:'4434.65',
        icon: makeIconWithCircle(Icons.attach_money) // call function to create an icon with a circle in the background.
    ),
  ];


  static Widget makeIconWithCircle(IconData iconData) { // function takes in the icon you want to create with a green background
    final circle =  Container(
      height: 25.0,
      width: 25.0,
      decoration: BoxDecoration(
          color: Colors.green,
          shape: BoxShape.circle
      ),
    );
    final icon = Icon(
      iconData, // iconData paramater is used here
      color: Colors.white,
      size: 18,
    );

    final iconWithCircle = Stack(
      alignment: Alignment.center,
      children: <Widget>[
        circle,
        icon
      ],
    );

    return iconWithCircle;
  }
}

我想调用SomeOtherClass并获得对summaryListItems对象的访问权限这是我的呼叫者班级

import 'package:flutter/material.dart';
import 'package:finsec/widget/cardview_widget.dart';
import 'package:finsec/utils/strings.dart';
import 'package:finsec/utils/dimens.dart';
import 'package:finsec/utils/colors.dart';
import 'package:finsec/data/cardview_list_item.dart';

void main() {
  runApp(new HomeScreen());
}

class HomeScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      child: new Stack(
        children: <Widget>[
          new Container(
            height: margin_200dp,
            color: colorPrimary,
          ),
          new Container(    //container to  overlay on top of blue container
            alignment: Alignment.topCenter,
            padding: new EdgeInsets.only(top: margin_0dp, right: margin_8dp, left: margin_8dp, bottom: margin_5dp),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.center,
              mainAxisSize: MainAxisSize.min,
              children: <Widget>[
                Text(
                  zeroAmount,
                  style: TextStyle(color: white, fontSize: 40.0, fontWeight: FontWeight.bold)
                ),
                Text(
                  currentBalance, style: TextStyle(color: white, fontSize: 20.0, fontWeight: FontWeight.bold)
                ),
                cardView(
                  header: summaryCard,
                  elevation: margin_4dp,
                  height: margin_220dp,
                  padding: margin_15dp,
                  listItems: <<I WANT TO ACCESS summaryListItems HERE>>
                ),

                //cardView(context)

              ],
            ),
          )
        ],
      ),
    );
  }
}

我希望能够调用SomeOtherClass并访问调用者类中的summaryListItems。参见上面的代码行listItems：<>

Answer 1

您只需要在HomeScreen中获取SomeOtherClass的实例，这取决于您要如何对其建模，某些类需要在屏幕上创建实例并将其注入到屏幕上，或者只是让屏幕创建它。最简单的方法是在屏幕上创建实例，基本上是：

class HomeScreen extends StatelessWidget {

SomeOtherClass someotherClass = SomeOtherClass();

然后在列表上只需使用

cardView(
    header: summaryCard,
    elevation: margin_4dp,
    height: margin_220dp,
    padding: margin_15dp,
    listItems: someotherClass.summaryListItems,
),

希望有帮助，

调用类并快速访问类对象

1 个答案: