我可以在Flutter中创建类似Toasts的东西吗?
只是一个很小的通知窗口,不直接面对用户,也不锁定或淡出它后面的视图。
我可以在Flutter中创建类似Toasts的东西吗?
只是一个很小的通知窗口,不直接面对用户,也不锁定或淡出它后面的视图。
当前回答
使用这个依赖:
toast: ^0.1.3
然后在页面中导入toast的依赖关系:
import 'package:toast/toast.dart';
然后在小部件的onTap()上:
Toast.show("Toast plugin app", context, duration:Toast.LENGTH_SHORT, gravity: Toast.BOTTOM);
其他回答
正如Darky指出的那样,SnackBar绝对是正确的类。
关于showSnackBar的一个棘手的事情是到达Scaffold state,如果你试图在构建方法中调用showSnackBar。
您可能会看到这样的错误,其中包括一些解释如何解决问题的文本。
══╡ EXCEPTION CAUGHT BY GESTURE ╞═══════════════════════════════════════════════════════════════════
The following assertion was thrown while handling a gesture:
Scaffold.of() called with a context that does not contain a Scaffold.
No Scaffold ancestor could be found starting from the context that was passed to Scaffold.of(). This
usually happens when the context provided is from the same StatefulWidget as that whose build
function actually creates the Scaffold widget being sought.
There are several ways to avoid this problem. The simplest is to use a Builder to get a context that
is "under" the Scaffold. For an example of this, please see the documentation for Scaffold.of():
https://docs.flutter.io/flutter/material/Scaffold/of.html
A more efficient solution is to split your build function into several widgets. This introduces a
new context from which you can obtain the Scaffold. In this solution, you would have an outer widget
that creates the Scaffold populated by instances of your new inner widgets, and then in these inner
widgets you would use Scaffold.of().
A less elegant but more expedient solution is assign a GlobalKey to the Scaffold, then use the
key.currentState property to obtain the ScaffoldState rather than using the Scaffold.of() function.
The context used was:
MyHomePage
When the exception was thrown, this was the stack:
#0 Scaffold.of (package:flutter/src/material/scaffold.dart:444:5)
#1 MyHomePage.build.<anonymous closure> (/Users/jackson/Library/Developer/CoreSimulator/Devices/7072C907-DBAD-44FE-8F40-0257442C51D9/data/Containers/Data/Application/77FEC1A4-1453-442C-8208-96E0323DEFB2/tmp/so_scratch2Tkq9Jb/so_scratch2/lib/main.dart:23:24)
#2 _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:323:14)
#3 _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:375:30)
#4 GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:102:24)
#5 TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:149:9)
#6 TapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:119:7)
#7 GestureArenaManager.sweep (package:flutter/src/gestures/arena.dart:156:27)
#8 BindingBase&SchedulerBinding&GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:147:20)
#9 BindingBase&SchedulerBinding&GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:121:22)
#10 BindingBase&SchedulerBinding&GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:101:7)
#11 BindingBase&SchedulerBinding&GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:64:7)
#12 BindingBase&SchedulerBinding&GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:48:7)
#13 _invoke1 (file:///b/build/slave/Mac_Engine/build/src/flutter/lib/ui/hooks.dart:100)
#14 _dispatchPointerDataPacket (file:///b/build/slave/Mac_Engine/build/src/flutter/lib/ui/hooks.dart:58)
Handler: onTap
Recognizer:
TapGestureRecognizer#69dbc(debugOwner: GestureDetector, state: ready)
════════════════════════════════════════════════════════════════════════════════════════════════════
你可以将GlobalKey传递给你的Scaffold构造函数:
class MyHomePage extends StatelessWidget {
@override
Widget build(BuildContext context) {
final key = new GlobalKey<ScaffoldState>();
return new Scaffold(
key: key,
floatingActionButton: new Builder(
builder: (BuildContext context) {
return new FloatingActionButton(
onPressed: () {
key.currentState.showSnackBar(new SnackBar(
content: new Text("Sending Message"),
));
},
tooltip: 'Increment',
child: new Icon(Icons.add),
);
}
),
);
}
}
或者你可以使用一个Builder来创建一个BuildContext,它是Scaffold的子对象。
class MyHomePage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new Scaffold(
floatingActionButton: new Builder(
builder: (BuildContext context) {
return new FloatingActionButton(
onPressed: () {
Scaffold.of(context).showSnackBar(new SnackBar(
content: new Text("Sending Message"),
));
},
tooltip: 'Increment',
child: new Icon(Icons.add),
);
}
),
);
}
}
最后,您可以将小部件分成多个类,这是最佳的长期方法。
你可以用这个包装:吐司
将这一行添加到依赖项中
toast: ^0.1.5
然后这样使用它:
import 'package:toast/toast.dart';
Toast.show("Toast plugin app", context, duration: Toast.LENGTH_SHORT, gravity: Toast.BOTTOM);
你可以直接使用小吃店的元素
ScaffoldMessenger.of(context).showSnackBar(
SnackBar(
content: Text("Successfully!"),
behavior: SnackBarBehavior.floating,
margin: EdgeInsets.all(20),
shape: StadiumBorder(),
action: SnackBarAction(
label: 'Dismiss',
disabledTextColor: Colors.white,
textColor: Colors.blue,
onPressed: () {
//Do whatever you want
},
),
),
);
对此,有不同的版本。
首先,您可以使用SnackBar,这是Flutter中的一个小部件。 您可以使用pub.dev中的toast - flutter_toast等库。 第三个版本是创建自定义小部件。它可以在Flutter中使用Overlay小部件和动画创建。
您可以通过本教程了解更多相关知识。这里有一个链接。
更新:Scaffold.of(上下文)。showSnackBar在Flutter 2.0.0中已弃用(稳定)
你可以使用ScaffoldMessenger.of(context)访问父类ScaffoldMessengerState。
然后做一些类似的事情
ScaffoldMessenger.of(context).showSnackBar(SnackBar(
content: Text("Sending Message"),
));
零食条是材料设计的官方“吐司”。看到间小吃店。
下面是一个完整的例子:
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return const MaterialApp(
home: Home(),
);
}
}
class Home extends StatelessWidget {
const Home({
Key key,
}) : super(key: key);
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Snack bar'),
),
body: Center(
child: RaisedButton(
onPressed: () => _showToast(context),
child: const Text('Show toast'),
),
),
);
}
void _showToast(BuildContext context) {
final scaffold = ScaffoldMessenger.of(context);
scaffold.showSnackBar(
SnackBar(
content: const Text('Added to favorite'),
action: SnackBarAction(label: 'UNDO', onPressed: scaffold.hideCurrentSnackBar),
),
);
}
}