你会如何在Flutter应用程序中添加启动画面?它应该在任何其他内容之前加载和显示。目前,在Scaffold(home:X)小部件加载之前,会有一个短暂的颜色闪烁。
当前回答
对于那些像我一样严格按照步骤来做的人来说,它仍然没有发挥作用……
如果你有一个drawable-v21文件夹,请注意,因为你需要将你的代码从drawable文件夹> launch_background.xml code复制到drawable-v21文件夹> launch_background.xml
我的项目不喜欢android:src="@mipmap/launch" />
因此,我有android:src="@drawable/launch" />
其他回答
添加如下所示的页面和路由可能会有所帮助
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutkart/utils/flutkart.dart';
import 'package:flutkart/utils/my_navigator.dart';
class SplashScreen extends StatefulWidget {
@override
_SplashScreenState createState() => _SplashScreenState();
}
class _SplashScreenState extends State<SplashScreen> {
@override
void initState() {
// TODO: implement initState
super.initState();
Timer(Duration(seconds: 5), () => MyNavigator.goToIntro(context));
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Stack(
fit: StackFit.expand,
children: <Widget>[
Container(
decoration: BoxDecoration(color: Colors.redAccent),
),
Column(
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
Expanded(
flex: 2,
child: Container(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
CircleAvatar(
backgroundColor: Colors.white,
radius: 50.0,
child: Icon(
Icons.shopping_cart,
color: Colors.greenAccent,
size: 50.0,
),
),
Padding(
padding: EdgeInsets.only(top: 10.0),
),
Text(
Flutkart.name,
style: TextStyle(
color: Colors.white,
fontWeight: FontWeight.bold,
fontSize: 24.0),
)
],
),
),
),
Expanded(
flex: 1,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
CircularProgressIndicator(),
Padding(
padding: EdgeInsets.only(top: 20.0),
),
Text(
Flutkart.store,
softWrap: true,
textAlign: TextAlign.center,
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 18.0,
color: Colors.white),
)
],
),
)
],
)
],
),
);
}
}
如果你想坚持到底,请参见: https://www.youtube.com/watch?v=FNBuo-7zg2Q
杰尔迪·巴特的密码对我没用。
Flutter抛出“请求的导航器操作具有不包括导航器的上下文”。
正如本文中提到的,我修复了将Navigator使用者组件包装在另一个使用路由初始化Navigator上下文的组件中的代码。
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:my-app/view/main-view.dart';
class SplashView extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
home: Builder(
builder: (context) => new _SplashContent(),
),
routes: <String, WidgetBuilder>{
'/main': (BuildContext context) => new MainView()}
);
}
}
class _SplashContent extends StatefulWidget{
@override
_SplashContentState createState() => new _SplashContentState();
}
class _SplashContentState extends State<_SplashContent>
with SingleTickerProviderStateMixin {
var _iconAnimationController;
var _iconAnimation;
startTimeout() async {
var duration = const Duration(seconds: 3);
return new Timer(duration, handleTimeout);
}
void handleTimeout() {
Navigator.pushReplacementNamed(context, "/main");
}
@override
void initState() {
super.initState();
_iconAnimationController = new AnimationController(
vsync: this, duration: new Duration(milliseconds: 2000));
_iconAnimation = new CurvedAnimation(
parent: _iconAnimationController, curve: Curves.easeIn);
_iconAnimation.addListener(() => this.setState(() {}));
_iconAnimationController.forward();
startTimeout();
}
@override
Widget build(BuildContext context) {
return new Center(
child: new Image(
image: new AssetImage("images/logo.png"),
width: _iconAnimation.value * 100,
height: _iconAnimation.value * 100,
)
);
}
}
如果有人在应用验证答案后发现图像不存在,请确保您添加的是@mipmap/ic_launcher而不是@mipmap/ic_launcher .png
对于Android,进入Android > app > src > main > res > drawable > launcher_background.xml
现在取消注释,用你的图像位置替换@mipmap/launch_image。
<item>
<bitmap
android:gravity="center"
android:src="@mipmap/launch_image" />
</item>
你可以在这里改变屏幕的颜色
<item android:drawable="@android:color/white" />
你应该试试下面的代码,为我工作
import 'dart:async';
import 'package:attendance/components/appbar.dart';
import 'package:attendance/homepage.dart';
import 'package:flutter/material.dart';
class _SplashScreenState extends State<SplashScreen>
with SingleTickerProviderStateMixin {
void handleTimeout() {
Navigator.of(context).pushReplacement(new MaterialPageRoute(
builder: (BuildContext context) => new MyHomePage()));
}
startTimeout() async {
var duration = const Duration(seconds: 3);
return new Timer(duration, handleTimeout);
}
@override
void initState() {
// TODO: implement initState
super.initState();
_iconAnimationController = new AnimationController(
vsync: this, duration: new Duration(milliseconds: 2000));
_iconAnimation = new CurvedAnimation(
parent: _iconAnimationController, curve: Curves.easeIn);
_iconAnimation.addListener(() => this.setState(() {}));
_iconAnimationController.forward();
startTimeout();
}
@override
Widget build(BuildContext context) {
return new Scaffold(
body: new Scaffold(
body: new Center(
child: new Image(
image: new AssetImage("images/logo.png"),
width: _iconAnimation.value * 100,
height: _iconAnimation.value * 100,
)),
),
);
}
}