User interface 如何将小部件注入自定义子小部件并使用子小部件迭代索引?
我正在构建一个颤振应用程序。我构建了一个包含构造函数的类。我创建了构造函数,以便可以自定义我的ListTile,因为我将这个类用于多个页面,每次都需要更改文本颜色,有时甚至需要添加一个onTap函数User interface 如何将小部件注入自定义子小部件并使用子小部件迭代索引?,user-interface,dart,flutter,frontend,custom-widgets,User Interface,Dart,Flutter,Frontend,Custom Widgets,我正在构建一个颤振应用程序。我构建了一个包含构造函数的类。我创建了构造函数,以便可以自定义我的ListTile,因为我将这个类用于多个页面,每次都需要更改文本颜色,有时甚至需要添加一个onTap函数 class AppList extends StatefulWidget { @override AppListState createState() => AppListState(); AppList({Key key, this.child}) : super(k
class AppList extends StatefulWidget {
@override
AppListState createState() => AppListState();
AppList({Key key, this.child}) : super(key: key);
final Widget child;
}
class AppListState extends State<AppList> {
Widget child;
List<Map<String, String>> _installedApps;
@override
void initState() {
super.initState();
}
getApps() {
setState(() {
installedApps = _installedApps;
getApp();
});
}
@override
Widget build(BuildContext context) {
if (installedApps == null)
getApps();
return ListView.builder(
itemCount: installedApps == null ? 0 : installedApps.length,
itemBuilder: (context, index) {
return child; //This is where the ListTile will go.
},
);
}
}
//Just in case you were confused, I used a plugin for some of the features
类AppList扩展StatefulWidget{
@凌驾
AppListState createState()=>AppListState();
AppList({Key-Key,this.child}):super(Key:Key);
最后一个孩子;
}
类AppListState扩展状态{
小部件儿童;
列出已安装的应用程序;
@凌驾
void initState(){
super.initState();
}
getApps(){
设置状态(){
installedApps=_installedApps;
getApp();
});
}
@凌驾
小部件构建(构建上下文){
如果(installedApps==null)
getApps();
返回ListView.builder(
itemCount:installedApps==null?0:installedApps.length,
itemBuilder:(上下文,索引){
return child;//这是ListTile将要去的地方。
},
);
}
}
//为了防止你感到困惑,我为一些功能使用了一个插件
在我构建这个类之后,我把它放在我的示例类中
示例类:
class Example extends StatefulWidget {
@override
ExampleState createState() => ExampleState();
}
class ExampleState extends State<Example> {
@override
Widget build(BuildContext context) {
return MaterialApp (
debugShowCheckedModeBanner: false,
home: Scaffold (
body: Container (
color: Colors.black,
child: AppList (
child: ListTile (
title: Text(installedApps[index]["app_name"]) //this is the text
),
)
)
),
);
}
}
类示例扩展了StatefulWidget{
@凌驾
ExampleState createState()=>ExampleState();
}
类ExampleState扩展了状态{
@凌驾
小部件构建(构建上下文){
返回材料PP(
debugShowCheckedModeBanner:false,
家:脚手架(
主体:容器(
颜色:颜色,黑色,
孩子:阿普利斯特(
儿童:ListTile(
标题:Text(installedApps[index][“app_name”])//这是文本
),
)
)
),
);
}
}
之后,我添加了一个ListTile和一个文本。但是当我在写课文的时候,我意识到我不能把我想要的课文放进去。这是因为示例类中没有定义“index”
有没有一个好方法可以把这篇文章放到我的示例课上
完整代码:
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'dart:async';
import 'dart:io';
import 'package:flutter_appavailability/flutter_appavailability.dart';
void main() {
SystemChrome.setEnabledSystemUIOverlays([]);
runApp(Example());
}
Future<void> getApp() async {
if (Platform.isAndroid) {
installedApps = await AppAvailability.getInstalledApps();
print(await AppAvailability.checkAvailability("com.android.chrome"));
print(await AppAvailability.isAppEnabled("com.android.chrome"));
}
else if (Platform.isIOS) {
installedApps = iOSApps;
print(await AppAvailability.checkAvailability("calshow://"));
}
}
List<Map<String, String>> installedApp;
List<Map<String, String>> installedApps;
List<Map<String, String>> iOSApps = [
{
"app_name": "Calendar",
"package_name": "calshow://"
},
{
"app_name": "Facebook",
"package_name": "fb://"
},
{
"app_name": "Whatsapp",
"package_name": "whatsapp://"
}
];
class Example extends StatefulWidget {
@override
ExampleState createState() => ExampleState();
}
class ExampleState extends State<Example> {
@override
Widget build(BuildContext context) {
return MaterialApp (
debugShowCheckedModeBanner: false,
home: Scaffold (
body: Container (
color: Colors.black,
child: AppList ()
)
),
);
}
}
class AppList extends StatefulWidget {
@override
AppListState createState() => AppListState();
AppList({Key key, this.child}) : super(key: key);
final Widget child;
}
class AppListState extends State<AppList> {
Widget child;
List<Map<String, String>> _installedApps;
@override
void initState() {
super.initState();
}
getApps() {
setState(() {
installedApps = _installedApps;
getApp();
});
}
@override
Widget build(BuildContext context) {
if (installedApps == null)
getApps();
return ListView.builder(
itemCount: installedApps == null ? 0 : installedApps.length,
itemBuilder: (context, index) {
return ListTile (
title: Text(installedApps[index]["app_name"])
);
},
);
}
}
导入“包装:颤振/材料.省道”;
导入“包:flifter/services.dart”;
导入“dart:async”;
导入“dart:io”;
进口“包装:flutter_appavailability/flutter_appavailability.dart”;
void main(){
SystemChrome.SetEnabledSystemEmioVerlays([]);
runApp(示例());
}
Future getApp()异步{
if(Platform.isAndroid){
installedApps=等待AppAvailability.getInstalledApps();
打印(等待AppAvailability.checkAvailability(“com.android.chrome”);
打印(wait AppAvailability.isappeabled(“com.android.chrome”);
}
else if(Platform.isIOS){
installedApps=iOSApps;
打印(等待AppAvailability.checkAvailability(“calshow://”);
}
}
列出已安装的App;
列出已安装的应用程序;
列出iOSApps=[
{
“应用程序名称”:“日历”,
“程序包名称”:“calshow://”
},
{
“应用程序名称”:“Facebook”,
“包名称”:“fb://”
},
{
“应用程序名称”:“Whatsapp”,
“包装名称”:“whatsapp://”
}
];
类示例扩展StatefulWidget{
@凌驾
ExampleState createState()=>ExampleState();
}
类ExampleState扩展了状态{
@凌驾
小部件构建(构建上下文){
返回材料PP(
debugShowCheckedModeBanner:false,
家:脚手架(
主体:容器(
颜色:颜色,黑色,
子项:AppList()
)
),
);
}
}
类AppList扩展StatefulWidget{
@凌驾
AppListState createState()=>AppListState();
AppList({Key-Key,this.child}):super(Key:Key);
最后一个孩子;
}
类AppListState扩展状态{
小部件儿童;
列出已安装的应用程序;
@凌驾
void initState(){
super.initState();
}
getApps(){
设置状态(){
installedApps=_installedApps;
getApp();
});
}
@凌驾
小部件构建(构建上下文){
如果(installedApps==null)
getApps();
返回ListView.builder(
itemCount:installedApps==null?0:installedApps.length,
itemBuilder:(上下文,索引){
返回列表块(
标题:文本(installedApps[索引][“应用程序名称”])
);
},
);
}
}
以下是您的修复代码:
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'dart:async';
import 'dart:io';
import 'package:flutter_appavailability/flutter_appavailability.dart';
void main() {
SystemChrome.setEnabledSystemUIOverlays([]);
runApp(Example());
}
Future<void> getApp() async {
if (Platform.isAndroid) {
installedApps = await AppAvailability.getInstalledApps();
print(await AppAvailability.checkAvailability("com.android.chrome"));
print(await AppAvailability.isAppEnabled("com.android.chrome"));
}
else if (Platform.isIOS) {
installedApps = iOSApps;
print(await AppAvailability.checkAvailability("calshow://"));
}
}
List<Map<String, String>> installedApp;
List<Map<String, String>> installedApps;
List<Map<String, String>> iOSApps = [
{
"app_name": "Calendar",
"package_name": "calshow://"
},
{
"app_name": "Facebook",
"package_name": "fb://"
},
{
"app_name": "Whatsapp",
"package_name": "whatsapp://"
}
];
class Example extends StatefulWidget {
@override
ExampleState createState() => ExampleState();
}
class ExampleState extends State<Example> {
@override
Widget build(BuildContext context) {
return MaterialApp (
debugShowCheckedModeBanner: false,
home: Scaffold (
body: Container (
child: AppList ()
)
),
);
}
}
class AppList extends StatefulWidget {
@override
AppListState createState() => AppListState();
AppList({Key key, this.child}) : super(key: key);
final Widget child;
}
class AppListState extends State<AppList> {
Widget child;
List<Map<String, String>> _installedApps;
@override
void initState() {
super.initState();
}
getApps() {
setState(() {
installedApps = _installedApps;
getApp();
});
}
@override
Widget build(BuildContext context) {
if (installedApps == null)
getApps();
return ListView.builder(
itemCount: installedApps == null ? 0 : installedApps.length,
itemBuilder: (context, index) {
return ListTile (
title: Text('${installedApps[index]["app_name"]}')
);
},
);
}
}
导入“包装:颤振/材料.省道”;
导入“包:flifter/services.dart”;
导入“dart:async”;
导入“dart:io”;
进口“包装:flutter_appavailability/flutter_appavailability.dart”;
void main(){
SystemChrome.SetEnabledSystemEmioVerlays([]);
runApp(示例());
}
Future getApp()异步{
if(Platform.isAndroid){
installedApps=等待AppAvailability.getInstalledApps();
打印(等待AppAvailability.checkAvailability(“com.android.chrome”);
打印(wait AppAvailability.isappeabled(“com.android.chrome”);
}
else if(Platform.isIOS){
installedApps=iOSApps;
打印(等待AppAvailability.checkAvailability(“calshow://”);
}
}
列出已安装的App;
列出已安装的应用程序;
列出iOSApps=[
{
“应用程序名称”:“日历”,
“程序包名称”:“calshow://”
},
{
“应用程序名称”:“Facebook”,
“包名称”:“fb://”
},
{
“应用程序名称”:“Whatsapp”,
“包装名称”:“whatsapp://”
}
];
类示例扩展StatefulWidget{
@凌驾
ExampleState createState()=>ExampleState();
}
类ExampleState扩展了状态{
@凌驾
小部件构建(构建上下文){
返回材料PP(
debugShowCheckedModeBanner:false,
家:脚手架(
主体:容器(
子项:AppList()
)
),
);
}
}
类AppList扩展StatefulWidget{
@凌驾
AppListState createState()=>AppListState();
AppList({Key-Key,this.child}):super(Key:Key);
最后一个孩子;
}
类AppListState扩展状态{
小部件儿童;
列出已安装的应用程序;
@凌驾
void initState(){
super.initState();
}
格塔普
typedef Widget MyListTileBuilder(int index);
final Widget child;
final MyListTileBuilder childBuilder;
Widget MyListTileBuilderImplementation (int index) {
return ListTile (
title: Text(installedApps[index]["app_name"]) //this is the text
),
}
AppList (
childBuilder: MyListTileBuilderImplementation
)
itemBuilder: (context, index) {
return childBuilder(index); //This is where the ListTile will go.
},
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'dart:async';
import 'dart:io';
//import 'package:flutter_appavailability/flutter_appavailability.dart';
typedef Widget MyListTileBuilder(int index);
void main() {
SystemChrome.setEnabledSystemUIOverlays([]);
runApp(Example());
}
Future<void> getApp() async {
if (Platform.isAndroid) {
//installedApps = await AppAvailability.getInstalledApps();
//print(await AppAvailability.checkAvailability("com.android.chrome"));
//print(await AppAvailability.isAppEnabled("com.android.chrome"));
}
else if (Platform.isIOS) {
installedApps = iOSApps;
//print(await AppAvailability.checkAvailability("calshow://"));
}
}
List<Map<String, String>> installedApp;
List<Map<String, String>> installedApps=[
{"app_name":"app1"},
{"app_name":"app2"},
{"app_name":"app3"},
];
List<Map<String, String>> iOSApps = [
{
"app_name": "Calendar",
"package_name": "calshow://"
},
{
"app_name": "Facebook",
"package_name": "fb://"
},
{
"app_name": "Whatsapp",
"package_name": "whatsapp://"
}
];
class Example extends StatefulWidget {
@override
ExampleState createState() => ExampleState();
}
class ExampleState extends State<Example> {
Widget MyListTileBuilderImplementation (int index) {
return ListTile (
title: Text(installedApps[index]["app_name"] + " index:" + index.toString()) //this is the text
);
}
@override
Widget build(BuildContext context) {
return MaterialApp (
debugShowCheckedModeBanner: false,
home: Scaffold (
body: Container (
color: Colors.white,
child: AppList (childBuilder: this.MyListTileBuilderImplementation)
)
),
);
}
}
class AppList extends StatefulWidget {
@override
AppListState createState() => AppListState();
AppList({Key key, this.childBuilder}) : super(key: key);
final MyListTileBuilder childBuilder;
}
class AppListState extends State<AppList> {
List<Map<String, String>> _installedApps;
@override
void initState() {
super.initState();
}
getApps() {
setState(() {
installedApps = _installedApps;
getApp();
});
}
@override
Widget build(BuildContext context) {
if (installedApps == null)
getApps();
return ListView.builder(
itemCount: installedApps == null ? 0 : installedApps.length,
itemBuilder: (context, index) {
return widget.childBuilder(index);
},
);
}
}