Flutter GridView.builder 滚动抖动和断断续续 (>10 fps)
[英]Flutter GridView.builder scrolling jittery and choppy (>10 fps)
问题描述
我对 flutter 比较陌生，现在遇到了一个问题，我在网上找不到任何解决方案。
我正在构建一个 GridView 产品，每个产品都有 3 个按钮/手势检测器，一些文本和一个网络图像。
下面的代码显示了 FutureBuilder - 传递给它的未来是一个 List<List> ，其中包含产品的所有必要信息。
问题是一旦有超过 40 个 GridView 项目，滚动就会变得非常不稳定和抖动，在我的用例中，大约有 500 个产品，这使得滚动基本上是不可能的。 当我从 GridView 中移除 GestureDetectors/Buttons 时，项目滚动或多或少都可以正常工作，并且对于 20 个项目，即使使用按钮也可以正常工作。 同样在 Android 上，它并不像在 IOS 上那么糟糕。 我使用 IOS 15.2.1 在 iPhone XS Max 上测试了所有内容，我在发布模式下尝试过，我什至构建了应用程序并使用 Xcode 安装了它，但它并没有变得更好。 我尝试使用主通道以及 flutter 的稳定通道。
这是 iPhone XS Max 在发布模式下的视频： https://drive.google.com/file/d/1NX04z8O332t0tPvxc4wOCOXcIGtpzEVl/view?usp=sharing
我真的不知道该怎么做，因为 GridView.builder 应该只加载 ViewPort 中或附近的内容，但正如我所说的 ItemCount 越高，性能越差......
未来建造者：
import 'package:flutter/material.dart';
import 'package:progress_indicators/progress_indicators.dart';
import 'package:needs_on_demand/const.dart';
import 'package:needs_on_demand/Screens/product_screen.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:flutter/src/services/haptic_feedback.dart';
import 'dart:convert';
class ProductFutureBuilder extends StatefulWidget {
ProductFutureBuilder(
{Key? key,
required this.future,
required this.crossAxisCount,
required this.axis})
: super(key: key);
var future;
var crossAxisCount;
var axis;
@override
_ProductFutureBuilderState createState() => _ProductFutureBuilderState();
}
class _ProductFutureBuilderState extends State<ProductFutureBuilder> {
final Future<SharedPreferences> _prefs = SharedPreferences.getInstance();
List shoppingCartList = [];
/// Syncs the local List of products in the cart with the one stored in the shared preferences
/// Can be copied, is same across the app - but deals with state variables -> difficult to change scope
void updateProductList() async {
final SharedPreferences prefs = await _prefs;
if (prefs != null) {
if (prefs.getKeys().contains('currentShoppingCart')) {
String? stored = prefs.getString('currentShoppingCart');
if (stored != null) {
shoppingCartList = jsonDecode(stored);
}
}
}
}
@override
void initState() {
/// Syncing the local product list with the global one
updateProductList();
super.initState();
}
@override
Widget build(BuildContext context) {
return FutureBuilder(
future: widget.future,
builder: (context, AsyncSnapshot snapshot) {
if (snapshot.hasData) {
return GridView.builder(
shrinkWrap: true,
addAutomaticKeepAlives: true,
primary: false,
scrollDirection: widget.axis,
itemCount: snapshot.data?.length ?? 0,
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: widget.crossAxisCount),
itemBuilder: (context, index) {
return Container(
margin: EdgeInsets.symmetric(horizontal: 5, vertical: 5),
decoration: BoxDecoration(
color: Colors.pink,
borderRadius: BorderRadius.all(
Radius.circular(30),
),
),
child: Column(
children: [
Row(
children: [
IconButton(
onPressed: () async {
final SharedPreferences prefs = await _prefs;
HapticFeedback.heavyImpact();
setState(() {
shoppingCartList.add([
snapshot.data[index][ProductListAccess.id],
snapshot.data[index]
[ProductListAccess.imageUri],
snapshot.data[index]
[ProductListAccess.mehrWertSteuer],
snapshot.data[index][ProductListAccess.name],
snapshot.data[index][ProductListAccess.price],
snapshot.data[index][ProductListAccess.weight]
]);
});
await prefs.setString('currentShoppingCart',
jsonEncode(shoppingCartList));
updateProductList();
},
icon: Icon(Icons.add),
),
Text(
shoppingCartList
.where((element) =>
element[ProductListAccess.id] ==
snapshot.data[index][ProductListAccess.id])
.length
.toString(),
),
IconButton(
onPressed: () async {
final SharedPreferences prefs = await _prefs;
int temp = 1;
for (int i = 1;
i <=
shoppingCartList
.where((element) =>
element[ProductListAccess.id] ==
snapshot.data[index]
[ProductListAccess.id])
.length
.toInt();
i++) {
temp++;
}
setState(() {
shoppingCartList.removeWhere((item) =>
item[0] ==
snapshot.data[index][ProductListAccess.id]);
for (int i = 3; i <= temp; i++) {
shoppingCartList.add([
snapshot.data[index][ProductListAccess.id],
snapshot.data[index]
[ProductListAccess.imageUri],
snapshot.data[index]
[ProductListAccess.mehrWertSteuer],
snapshot.data[index]
[ProductListAccess.name],
snapshot.data[index]
[ProductListAccess.price],
snapshot.data[index]
[ProductListAccess.weight]
]);
}
});
await prefs.setString('currentShoppingCart',
jsonEncode(shoppingCartList));
HapticFeedback.heavyImpact();
await Future.delayed(
Duration(milliseconds: 100),
);
HapticFeedback.heavyImpact();
updateProductList();
},
icon: Icon(Icons.remove),
),
],
mainAxisAlignment: MainAxisAlignment.center,
),
GestureDetector(
child: Column(
children: [
ClipRRect(
borderRadius: BorderRadius.circular(15.0),
child: Image.network(
snapshot.data[index]
[ProductListAccess.imageUri],
fit: BoxFit.fill,
height: 100,
loadingBuilder: (BuildContext context,
Widget child,
ImageChunkEvent? loadingProgress) {
if (loadingProgress == null) return child;
return Center(
child: CircularProgressIndicator(
value:
loadingProgress.expectedTotalBytes !=
null
? loadingProgress
.cumulativeBytesLoaded /
loadingProgress
.expectedTotalBytes!
: null,
),
);
},
),
),
Container(
child: Text(
snapshot.data[index][ProductListAccess.name],
overflow: TextOverflow.ellipsis,
textAlign: TextAlign.center,
),
margin: EdgeInsets.symmetric(horizontal: 10),
),
],
),
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) =>
ProductScreen(productAsList: [
snapshot.data[index][ProductListAccess.id],
snapshot.data[index][ProductListAccess.bioBool],
snapshot.data[index]
[ProductListAccess.category],
snapshot.data[index]
[ProductListAccess.description],
snapshot.data[index]
[ProductListAccess.imageUri],
snapshot.data[index]
[ProductListAccess.mehrWertSteuer],
snapshot.data[index][ProductListAccess.name],
snapshot.data[index][ProductListAccess.price],
snapshot.data[index]
[ProductListAccess.pricePer100G],
snapshot.data[index]
[ProductListAccess.subCategory],
snapshot.data[index]
[ProductListAccess.subSubCategory],
snapshot.data[index]
[ProductListAccess.timestamp],
snapshot.data[index][ProductListAccess.weight]
]),
),
);
},
),
],
),
);
});
} else if (snapshot.hasError) {
return Text(snapshot.error.toString());
} else {
return Center(
child: JumpingDotsProgressIndicator(
fontSize: 40,
));
}
},
);
}
}
flutter 医生 -v output：
[✓] Flutter (Channel master, 2.10.0-1.0.pre.341, on macOS 12.1 21C52 darwin-x64, locale de-DE)
• Flutter version 2.10.0-1.0.pre.341 at /Users/maxdeboer/Dev/flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision 3a20b2c323 (vor 16 Stunden), 2022-01-31 11:15:21 -0500
• Engine revision c2bcffb07e
• Dart version 2.17.0 (build 2.17.0-67.0.dev)
• DevTools version 2.10.0-dev.1
[✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
• Android SDK at /Users/maxdeboer/Library/Android/sdk
• Platform android-31, build-tools 31.0.0
• Java binary at: /Applications/Android Studio.app/Contents/jre/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 11.0.11+0-b60-7590822)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 13.2.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• CocoaPods version 1.11.2
[✓] Chrome - develop for the web
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
[✓] Android Studio (version 2021.1)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 11.0.11+0-b60-7590822)
[✓] IntelliJ IDEA Community Edition (version 2020.1.2)
• IntelliJ at /Applications/IntelliJ IDEA CE.app
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart
[✓] Connected device (3 available)
• iPhone von Max (mobile) • 00008020-000249E82E50003A • ios • iOS 15.2.1 19C63
• macOS (desktop) • macos • darwin-x64 • macOS 12.1 21C52 darwin-x64
• Chrome (web) • chrome • web-javascript • Google Chrome 97.0.4692.99
[✓] HTTP Host Availability
• All required HTTP hosts are available
• No issues found!
0 个解决方案
如何在 flutter 中计算 GridView.builder 的 childAspectRatio
[英]How to calculate childAspectRatio for GridView.builder in flutter
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