Flutter-无法建立,因为frawework已经建立

我正在构建一个页面,并动态生成一些视图。在我的情况下,显示的列表将根据用户输入(用作过滤器)进行更新。

使用Text Widget进行动态渲染时,所有工具都运行良好,但是当我尝试切换到Column或Gridview时,一切都出错了,并且出现了以下错误

The following assertion was thrown building ServerGrid(dirty; state: _ServerGridState#59211289()):

I/flutter (14351): setState() or markNeedsBuild() called during build.

I/flutter (14351): This Overlay widget cannot be marked as needing to build because the framework is already in the

I/flutter (14351): process of building widgets. A widget can be marked as needing to be built during the build phase

I/flutter (14351): only if one of its ancestors is currently building. This exception is allowed because the framework

I/flutter (14351): builds parent widgets before children, which means a dirty descendant will always be built.

I/flutter (14351): Otherwise, the framework might not visit this widget during this build phase.

I/flutter (14351): The widget on which setState() or markNeedsBuild() was called was:

I/flutter (14351): Overlay([LabeledGlobalKey<OverlayState>#774312152]; state: OverlayState#252339409(entries:

I/flutter (14351): [OverlayEntry#727022347(opaque: false; maintainState: false), OverlayEntry#1051156104(opaque:

I/flutter (14351): false; maintainState: true), OverlayEntry#280497357(opaque: false; maintainState: false),

I/flutter (14351): OverlayEntry#41791024(opaque: false; maintainState: true), OverlayEntry#444321361(opaque: false;

I/flutter (14351): maintainState: false), OverlayEntry#717668788(opaque: false; maintainState: true)]))

这是我到目前为止得到的代码,

错误的 导入’package:flutter / material.dart’;

import'package:firebase_sandbox/models/server.dart';

class ServerGrid extends StatefulWidget {

ServerGrid({Key key, this.servers}) : super(key: key);

final servers;

@override

State createState() => new _ServerGridState();

}

class _ServerGridState extends State<ServerGrid> {

showInfos(serv){

showDialog(context: context, child: new AlertDialog(content: new Text(serv.toString())));

}

Widget buildServerTile(Server serv) {

return new InkWell(

onTap: showInfos(serv),

child :

new Column(

children: [

new CircleAvatar(child : new Image.network(serv.image)),

new Text(

serv.name,

style : new TextStyle(fontWeight: FontWeight.bold),

),

new Text(

serv.description,

style : new TextStyle(color : Colors.grey[500]),

),

],

),

);

}

List<Widget> buildGrid() {

var theGrid = <Widget>[];

for(Server s in widget.servers) {

theGrid.add(buildServerTile(s));

}

return theGrid;

}

@override

Widget build(BuildContext context) {

// return new Text("${widget.servers.toString()}"); //Working perfectly

return new GridView(

gridDelegate: new SliverGridDelegateWithFixedCrossAxisCount(

crossAxisCount: 3,

),

children: buildGrid(),

);

}

}

控制器调用视图进行更新:

  filter(value) {

filteredList = _servers.where(

(serv) =>

serv.name.contains(value) || serv.tags

.where((tag) => tag.contains(value))

.length > 0

).toList();

print(filteredList);

setState(() {

serverList = new ServerGrid(servers : filteredList);

});

}

一直在搜索,但是在构建Gridview时我不知道出了什么问题

回答:

您的onTap处理程序有问题。它试图在构建功能期间立即显示对话框,这是不允许的。

onTap: showInfos(serv),

将您的处理程序更改为函数:

onTap: () => showInfos(serv),

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