GridView.builder 不滚动

问题描述

我有这个代码，我正在尝试使这个 gridview 可滚动，无论我做什么，它都不会滚动。我不断收到此渲染溢出错误。我试图将它包裹在 SingleChildScroll 视图和 Physics: ScrollPhysics() 的属性中，但没有任何效果。我只需要使这个 gridView 可滚动，而不是它下面的文本。我已经尝试了几种方法，但到目前为止没有任何方法适用于它。可能是我在这里做的一个愚蠢的错误，但无法弄清楚。 编辑：当我在脚手架的 body 标记之后设置 singleChildScrollView 时它工作正常，但当我将它应用到 GridView 时不起作用。

    class _CartGridViewState extends State<CartGridView> {
  @override
  Widget build(BuildContext context) {
    final User user = FirebaseAuth.instance.currentUser;
    double sum = 0;
    print(user);
    return StreamBuilder(
      stream: FirebaseFirestore.instance
          .collection('Users')
          .doc(user.uid)
          .collection('Cart')
          .snapshots(),builder: (BuildContext context,snapshot) {
        if (!snapshot.hasData) {
          return Center(
            child: CircularProgressIndicator(),);
        }
        var document = snapshot.data.docs;

        return Padding(
          padding: const EdgeInsets.all(10.0),child: SingleChildScrollView(
            physics: ScrollPhysics(),child: GridView.builder(
                physics: ScrollPhysics(),scrollDirection: Axis.vertical,primary: false,shrinkWrap: true,itemCount: document.length,gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
                  crossAxisCount: 2,childAspectRatio: MediaQuery.of(context).size.height / 800,),itemBuilder: (context,index) {
                  if (document[index].data()["name"] == null) {
                    return Text('There are $index items in cart');
                  } else {
                    return Card(
                      child: GestureDetector(
                        onTap: () {
                          Navigator.push(
                            context,MaterialPageRoute(
                                builder: (context) => CartView(
                                      document[index].data()["name"],document[index]
                                          .data()["price"]
                                          .todouble(),document[index].data()["image"],index,)),);
                        },child: Stack(children: [
                          ListView(physics: ScrollPhysics(),children: [
                            Hero(
                              tag: 'tagImage$index',child: Image.network(
                                "${document[index].data()["image"]}",height: 150,Center(
                                child: Text(
                                    "Price ${document[index].data()["price"]}")),]),DeleteCartItems(index),);
                  }
                }),);
      },);
    
  }
}

解决方法

我们可以利用 Expanded widget 来获得可滚动的 GridView 请参考以下代码

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',theme: ThemeData(
        primarySwatch: Colors.blue,visualDensity: VisualDensity.adaptivePlatformDensity,),home: MyHomePage(title: 'Flutter Demo Home Page'),);
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key,this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  List<String> images = [
    "https://images.unsplash.com/photo-1614961234425-dedd96e5e699?ixlib=rb-1.2.1&ixid=MXwxMjA3fDB8MHxleHBsb3JlLWZlZWR8M3x8fGVufDB8fHw%3D&auto=format&fit=crop&w=500&q=60","https://images.unsplash.com/photo-1614961234425-dedd96e5e699?ixlib=rb-1.2.1&ixid=MXwxMjA3fDB8MHxleHBsb3JlLWZlZWR8M3x8fGVufDB8fHw%3D&auto=format&fit=crop&w=500&q=60",];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),body: Padding(
        padding: EdgeInsets.symmetric(
          horizontal: 12.0,child: Expanded(
          child: GridView.builder(
            itemCount: images.length,shrinkWrap: true,gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
                crossAxisCount: 2,crossAxisSpacing: 8.0,mainAxisSpacing: 10.0),itemBuilder: (BuildContext context,int index) {
              return Image.network(images[index]);
            },);
  }
}