Flutter-无法建立，因为frawework已经建立 [英] Flutter - Cannot build because the frawework is already building

问题描述

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。

I am building a page, dynamicly generating some views into it. In my case the list showned will updated given the user input (used as a filter).

在使用Text Widget动态呈现时，所有功能均正常运行，但是当我尝试切换到Column或Gridview，所有操作都出错，并且出现了以下错误

All was working perfectly when using a Text Widget to be dynamicly rendered, but when I tried to switch to a Column or Gridview, all went wrong And a got the folowwing error

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)]))

这是我到目前为止获得的代码，

Here is the code I got so far,

ServerGrid ，这是引发错误的地方
import'package：flutter / material.dart';

ServerGrid which is where the error is thrown import '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：

Controller calling the view to update :

  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);
    });
  }

曾经搜索过，但是我无法弄清楚构建我的错误是什么Gridview

Been searching, but I can't figure out what is wrong when building my Gridview

推荐答案

您的 onTap 处理程序遇到问题。

You have an issue with your onTap handler. It is trying to show the dialog immediately during your build function, which is not allowed.

onTap: showInfos(serv),

将处理程序更改为函数：

Change your handler to be a function:

onTap: () => showInfos(serv),

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