我知道有很多类似的问题，但大多数都已经过时了。我最近在运行时在我的 Web 项目中遇到了常见的 TypeError: Cannot read properties of undefined (reading ...)...
我知道有很多类似的问题，但大多数问题都已经过时了。我最近 TypeError: Cannot read properties of undefined (reading ... 在 Chrome 上运行时，在我的 Web 项目中遇到了这个常见问题。
第一次启动后就会出现错误。当我在 Chrome 中刷新页面时，它就消失了。每次启动应用程序时，“阅读”之后的部分也不同，目前是 ...undefined (reading 'MaterialApp') .
完整错误：
EXCEPTION CAUGHT BY WIDGETS LIBRARY
The following JSNoSuchMethodError was thrown building LayoutBuilder:
TypeError: Cannot read properties of undefined (reading 'MaterialApp')
The relevant error-causing widget was:
LayoutBuilder
LayoutBuilder:file:///Users/janhecker/Development/vamos_events_dashboard/lib/vamos_events_dashboard.dart:142:16
vamos_events_dashboard.dart:142
When the exception was thrown, this was the stack:
packages/vamos_events_dashboard/vamos_events_dashboard.dart 146:34 <fn>
packages/flutter/src/widgets/layout_builder.dart 119:70 layoutCallback
packages/flutter/src/widgets/framework.dart 2682:19 buildScope
packages/flutter/src/widgets/layout_builder.dart 153:5 [_layout]
packages/flutter/src/rendering/object.dart 2300:59 <fn>
packages/flutter/src/rendering/object.dart 1056:15 [_enableMutationsToDirtySubtrees]
packages/flutter/src/rendering/object.dart 2300:7 invokeLayoutCallback
packages/flutter/src/widgets/layout_builder.dart 228:7 rebuildIfNecessary
packages/flutter/src/widgets/layout_builder.dart 313:5 performLayout
packages/flutter/src/rendering/object.dart 2189:7 layout
packages/flutter/src/rendering/box.dart 2430:11 layout
packages/flutter/src/rendering/view.dart 175:7 performLayout
packages/flutter/src/rendering/object.dart 2027:7 [_layoutWithoutResize]
packages/flutter/src/rendering/object.dart 1020:17 flushLayout
packages/flutter/src/rendering/binding.dart 516:19 drawFrame
packages/flutter/src/widgets/binding.dart 865:13 drawFrame
packages/flutter/src/rendering/binding.dart 381:5 [_handlePersistentFrameCallback]
packages/flutter/src/scheduler/binding.dart 1289:15 [_invokeFrameCallback]
packages/flutter/src/scheduler/binding.dart 1218:9 handleDrawFrame
packages/flutter/src/scheduler/binding.dart 942:7 <fn>
dart-sdk/lib/_internal/js_dev_runtime/private/isolate_helper.dart 48:19 internalCallback
我的 pubspec.yaml 文件：
name: vamos_events_dashboard
description: Create, manage, publish and share your events in the vamos! Events Dashboard.
publish_to: 'none'
version: 1.0.0+1
environment:
sdk: '>=2.18.6 <3.0.0'
dependencies:
cloud_firestore: ^4.3.1
collection: ^1.17.0
deep_pick: ^0.10.0
file_picker: ^5.2.5
firebase_auth: ^4.2.5
firebase_core: ^2.4.1
firebase_storage: ^11.0.10
flutter:
sdk: flutter
flutter_gen: ^5.2.0
flutter_svg: ^2.0.0+1
freezed_annotation: ^2.2.0
geoflutterfire2: ^2.3.14
gleap_sdk: ^9.0.1
go_router: ^6.0.1
json_annotation: ^4.8.0
provider: ^6.0.5
shared_preferences: ^2.0.17
universal_html: ^2.0.0
url_strategy: ^0.2.0
dev_dependencies:
build_runner: ^2.3.3
flutter_gen_runner: ^5.2.0
flutter_test:
sdk: flutter
freezed: ^2.3.2
json_serializable: ^6.6.1
lint: ^2.0.0
flutter:
uses-material-design: true
assets:
- assets/images/
- assets/icons/
fonts:
- family: Agrandir
fonts:
- asset: assets/fonts/Agrandir-GrandHeavy.ttf
- family: DMSans
fonts:
- asset: assets/fonts/DMSans-Regular.ttf
flutter_gen:
output: lib/theme/gen/
line_length: 120
integrations:
flutter_svg: true
universal_html: true
我的index.html文件：
<!DOCTYPE html>
<html>
<head>
<!-- Loading animation -->
<style>
body {
background-color: #F1F1F1;
}
.loading {
display: flex;
justify-content: center;
align-items: center;
margin: 0;
position: absolute;
top: 50%;
left: 50%;
-ms-transform: translate(-50%, -50%);
transform: translate(-50%, -50%);
}
.loader {
border: 6px solid #F1F1F1;
border-radius: 50%;
border: 5px solid;
border-top: 6px solid #916EFF;
border-right: 6px solid #F1F1F1;
border-bottom: 6px solid #916EFF;
border-left: 6px solid #F1F1F1;
width: 42px;
height: 42px;
-webkit-animation: spin 2s linear infinite;
animation: spin 2s linear infinite;
}
@-webkit-keyframes spin {
0% {
-webkit-transform: rotate(0deg);
}
100% {
-webkit-transform: rotate(360deg);
}
}
@keyframes spin {
0% {
transform: rotate(0deg);
}
100% {
transform: rotate(360deg);
}
}
</style>
<!-- Gleap -->
<script>
!function (Gleap, t, i) { if (!(Gleap = window.Gleap = window.Gleap || []).invoked) { for (window.GleapActions = [], Gleap.invoked = !0, Gleap.methods = ["identify", "setEnvironment", "clearIdentity", "attachCustomData", "setCustomData", "removeCustomData", "clearCustomData", "registerCustomAction", "trackEvent", "log", "preFillForm", "showSurvey", "sendSilentCrashReport", "startFeedbackFlow", "setAppBuildNumber", "setAppVersionCode", "setApiUrl", "setFrameUrl", "isOpened", "open", "close", "on", "setLanguage", "setOfflineMode", "initialize"], Gleap.f = function (e) { return function () { var t = Array.prototype.slice.call(arguments); window.GleapActions.push({ e: e, a: t }) } }, t = 0; t < Gleap.methods.length; t++)Gleap[i = Gleap.methods[t]] = Gleap.f(i); Gleap.load = function () { var t = document.getElementsByTagName("head")[0], i = document.createElement("script"); i.type = "text/javascript", i.async = !0, i.src = "https://sdk.gleap.io/latest/index.js", t.appendChild(i) }, Gleap.load() } }();
</script>
<base href="$FLUTTER_BASE_HREF">
<meta charset="UTF-8">
<meta content="IE=Edge" http-equiv="X-UA-Compatible">
<meta name="description" content="A new Flutter project.">
<!-- iOS meta tags & icons -->
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<meta name="apple-mobile-web-app-title" content="vamos_events_dashboard">
<!-- <link rel="apple-touch-icon" href="icons/Icon-192.png"> -->
<!-- Favicon -->
<link rel="icon" type="image/png" href="favicon-64.png" />
<title>vamos! Events Dashboard</title>
<link rel="manifest" href="manifest.json">
<script>
// The value below is injected by flutter build, do not touch.
var serviceWorkerVersion = null;
</script>
<!-- This script adds the flutter initialization JS code -->
<script src="flutter.js" defer></script>
</head>
<body>
<!-- Loading animation -->
<div class="loading">
<div class="loader"></div>
</div>
<script src="main.dart.js" type="application/javascript"></script>
<!-- Flutter -->
<script>
window.addEventListener('load', function (ev) {
// Download main.dart.js
_flutter.loader.loadEntrypoint({
serviceWorker: {
serviceWorkerVersion: serviceWorkerVersion,
}
}).then(function (engineInitializer) {
return engineInitializer.initializeEngine();
}).then(function (appRunner) {
return appRunner.runApp();
});
});
</script>
</body>
</html>
