我有file.a，其中包含一个数组：
final _likes = <String>[];
根据用户选择的答案，将项目添加到此数组中。
然后，我希望能够通过按一下按钮向用户显示数组中的项目。
问题在于，我希望用户按下的按钮是在file.b中定义的（因为图标在AppBar上）。
当变量file.b驻留在_likes中时，如何赋予file.a查看变量file.a并访问其中的数据的能力？
import 'package:flutter/material.dart';
import './main.dart';
class Images extends StatefulWidget {
@override
_ImagesState createState() => _ImagesState();
}
class _ImagesState extends State<Images> with SingleTickerProviderStateMixin {
AnimationController _controller;
Animation _animation;
@override
// ignore: must_call_super
void initState() {
_controller = AnimationController(
vsync: this,
duration: Duration(seconds: 1),
);
_animation = Tween(
begin: 0.0,
end: 1.0,
).animate(_controller);
}
@override
dispose() {
_controller.dispose();
super.dispose();
}
int index = 0;
final likes = <String>[];
@override
Widget build(BuildContext context) {
_controller.forward();
return GestureDetector(
onHorizontalDragEnd: (DragEndDetails dragEndDetails) {
if (dragEndDetails.primaryVelocity == 0) return;
if (dragEndDetails.primaryVelocity.compareTo(0) == -1)
setState(() {
_controller.reset();
dateIdeas.removeAt(index);
});
else
setState(() {
_controller.reset();
likes.add(dateIdeas[index]['Description']);
dateIdeas.removeAt(index);
});
},
child: new Column(
children: <Widget>[
Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
Column(
children: <Widget>[
Padding(
padding: const EdgeInsets.only(left: 8.0, right: 8.0),
child: FadeTransition(
opacity: _animation,
child: Container(
decoration: BoxDecoration(
border: Border.all(
color: Colors.pink[200],
width: 7,
),
borderRadius: BorderRadius.circular(9),
),
child: new Container(
child: new Image.asset(dateIdeas[index]['Image']),
),
),
),
),
Container(
alignment: Alignment.topCenter,
child: Text(dateIdeas[index]['Description'],
style: TextStyle(
fontSize: 30,
color: Colors.black,
fontFamily: 'IndieFlower',
)),
),
],
),
],
)
],
),
);
}
}
：
file.b import 'package:flutter/material.dart';
import './surprises.dart';
import './images.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'SO Surprises',
theme: ThemeData(
primaryColor: Colors.pink[200],
),
home: MyHomePage(title: ''),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage>
{
int ideaCount = 1;
int _swipeCount = 0;
void _swipe() {
setState(() {
_swipeCount++;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
actions: <Widget>[
Container(
height: 150,
width: 150,
child: IconButton(
icon: Image.asset('assets/images/SO.png'),
padding:
const EdgeInsets.only(right: 40.0, top: 10, bottom: 10.0),
),
),
GestureDetector(
onTap: () => print(Images.likes),
child: Padding(
padding: const EdgeInsets.only(right: 10.0),
child: Icon(
Icons.star,
color: Colors.white,// add custom icons also
),
),
),
],
),
body: _swipeCount == 0
? Stack(
children: <Widget>[
GestureDetector(
onHorizontalDragEnd: (DragEndDetails dragEndDetails) {
if(dragEndDetails.primaryVelocity == 0) return;
_swipe();
},
child: Container(
color: Colors.transparent,
alignment: Alignment.center,
child: Text("Swipe to get started! $_swipeCount"),
),
),
],
)
: Template(),
);
}
}
：
//so lets say i have an Animal:
public Animal()
{
name = null;
age = 0;
mass = 0;
}
答案 0 :(得分：1)
通过在您的likes列表前面加上下划线（_），这意味着您也使该方法也只能在其所属的类内部访问。
要在程序的其他部分中使用该方法，请删除下划线（_）。
删除_后，您将使likes列表可从代码的其他部分访问。