expected-exception 相关问题

Mockery\Exception\NoMatchingExpectationException：找不到 Mockery_1_::make 的匹配处理程序

我编写了此测试，返回以下错误： Mockery\Exception\NoMatchingExpectationException：没有匹配的处理程序找到了 Mockery_1_My_Class::make(array('valid_until'=>...

未捕获错误：未找到“Instamojo\Exception\InstamojoException”类

$authType = "应用程序/用户"; $api = Instamojo\Instamojo::init($authType,[ “client_id”=>“XXXXXQAZ”， “client_secret”=>“XXXXQWE”， ]，真的）; ...

获取 NullPointerException：“无法调用“ParkingSpace.getSpaceNum()”，因为“pl.parkingLot[5]”为空”？

我正在用Java开发一个停车场项目，当我运行我的程序时，我收到以下错误消息： Exception in thread "main" java.lang.NullPointerException: Cannot invoke...

Windows 7 无法创建 SSL/TLS 安全通道。”} System.Net.WebException

我正在运行 Windows 7 64 位专业版并尝试编写 RSS Feed 阅读器这是错误消息 - $Exception {“请求被中止：无法创建 SSL/TLS 安全通道。”} System.Net。

mongoose 中的 finOne() 失败并显示 MongoServerError: Expected field collationto be of type object

我正在尝试使用express和MongoDb实现简单的注册验证，但下面的代码行总是失败并出现以下错误 const emailExist = wait User.findOne({email: req.body.

如何在razor页面ASP.Net Core 8中的“a”标签后添加逗号

我试图在 foreach 中的“a”标签后面添加逗号（，），如下所示： @foreach（Model.Product.Categories 中的 var 项目） { 我试图在 foreach 中的“a”标签后面添加逗号（，），如下所示： @foreach (var item in Model.Product.Categories) { <a href="#" class="product-link product-cat-title">@item.Name</a> , } 但我收到错误消息“} Expected”。我该怎么办？我已经测试了@string.join(", ", Model.Categories.Select(p => p.Name).ToArray())，但这将返回字符串或文本。我要链接！值得一提的是，我不想添加其他标签，例如 <span> 或 <a>。我知道他们有效。如果有人能解释为什么它不起作用，我将不胜感激？谢谢 @foreach (var item in Model.Product.Categories) { <a href="#" class="product-link product-cat-title">@item.Name</a> <a >,</a> }

为什么每次我尝试将应用程序从 Anypoint Studio 部署到 CloudHub 时，我的 pom.xml 文件都会更新？

我的 pom.xml 文件中有以下部分用于我正在执行的虚拟项目： org.mule.tools.maven mule-maven-插件我正在做的一个虚拟项目的 pom.xml 文件中有以下部分： <plugin> <groupId>org.mule.tools.maven</groupId> <artifactId>mule-maven-plugin</artifactId> <version>${mule.maven.plugin.version}</version> <extensions>true</extensions> <configuration> <classifier>mule-application</classifier> </configuration> </plugin> 每当我尝试直接从 Studio 将应用程序部署到 CloudHub 时，上面的部分就会更改为以下部分： <plugin> <groupId>org.mule.tools.maven</groupId> <artifactId>mule-maven-plugin</artifactId> <version>${mule.maven.plugin.version}</version> <extensions>true</extensions> <configuration> <classifier>---- select project type ----</classifier> </configuration> </plugin> 然后部署失败并出现以下错误： Publication status: error [INFO] ------------------------------------------------------------ [INFO] Steps: [INFO] - Description: Publishing asset [INFO] - Status: error [INFO] - Errors: [The asset is invalid, Error while trying to set type: app. Expected type is: rest-api.] [INFO] ......................................... [INFO] ------------------------------------------------------------------------ [INFO] BUILD FAILURE [INFO] ------------------------------------------------------------------------ [INFO] Total time: 02:33 min [INFO] Finished at: 2024-01-08T14:11:31+05:30 [INFO] ------------------------------------------------------------------------ [ERROR] Failed to execute goal org.mule.tools.maven:exchange-mule-maven-plugin:0.0.17:exchange-deploy (default-exchange-deploy) on project super-biodata-sapi: Exchange publication failed: Publication ended with errors: [The asset is invalid, Error while trying to set type: app. Expected type is: rest-api.] -> [Help 1] 这可能是什么原因？以下是一些细节： Anypoint Studio版本：7.16.0 Maven版本：3.8.8 Mule 运行时版本：4.4.0 Mule Maven 插件版本：3.8.0/4.0.0（两者都尝试过） Java版本：OpenJDK 11.0.9 我以前使用过 Anypoint Studio 7.15，在那里完全相同的项目没有任何问题。但更新后，我遇到了很多问题。我还尝试使用“rest-api”而不是“mule-application”。然后，首先在部署开始时，“rest-api”更改为“mule-application”，然后再次更改为“----选择项目类型----”，最后失败。我怀疑存在混乱。您提到您正在尝试将 Mule 4 应用程序部署到 CloudHub，但对资产的引用和错误消息与将资产发布到 Any point Exchange 相关。 CloudHub是一个部署和执行Mule应用程序的云平台。 Anypoint Exchange 是资产存储库，包括 REST API 的定义，但不包括 Mule 4 应用程序，也不用于执行任何操作。有关有效资产的详细信息，请参阅文档。由于 mule-application 不是发布到 Exchange 的有效资产类型（对于 Mule 4），那么 Studio 似乎试图让您更改为有效的资产类型。如果您尝试部署到 CloudHub，请参阅文档了解不同的方法。

Apss 脚本“if”条件评估不正确

oldnames[i+3]='汤姆' newnames[i]='汤姆' 当两个参数具有相同的值时（见上文），为什么我的代码会执行？对于 (var i=0 ; i oldnames[i+3]='汤姆' newnames[i]='汤姆' 当两个参数具有相同的值（见上文）时，为什么我的代码会执行？ for (var i=0 ; i<pocet2 ; i++) { var oldnaz=(oldnames[i+3]).toString(); var newnaz=(newnames[i]); oldnaz=oldnaz.toString(); newnaz=newnaz.toString(); //Logger.log("oldname = "+oldnaz); //Logger.log("newname = "+newnaz); if(newnames[i]=='' ) { //Logger.log(ss.getSheetByName(oldnames[i+3]).getSheetName()); //Logger.log(i); //Logger.log(i+3); ss.getSheetByName(oldnames[i+3]).setName((i+1).toString()); } ** else if(newnames[i] != oldnames[i+3]) { //Logger.log(newnames[i]); //Logger.log(oldnames[i+3]); ss.getSheetByName(oldnames[i+3]).setName(newnames[i]); }** else { //Nothing } } 我尝试对代码进行一些更改，但结果在各方面都是如此：条件为 TRUE。但是当第一个值是 Tom 并且第二个值是 Tom 时，则 else if(Tom != Tom) 应该为 FALSE。非常感谢您的提示。如果 oldnames 和 newnames 来自使用 range.getValues() 的范围，则这两个变量都是二维数组而不是一维数组。因此，oldnames[i+3]='Tom' newnames[i]='Tom'是假的，那就是 oldnames[i+3]=['Tom']; //array newnames[i]=['Tom']; /*<ignore>*/console.config({maximize:true,timeStamps:false,autoScroll:false});/*</ignore>*/ const newname=['Tom']; const oldname=['Tom']; console.log(newname != oldname);//expected true  <script src="https://gh-canon.github.io/stack-snippet-console/console.min.js"></script> 两个数组无法进行比较。获取里面的字符串并比较： else if(newnames[i][0] != oldnames[i+3][0])

嵌套 useFetch 导致 Nuxt 3 中的 Hydration 节点不匹配

在 Nuxt 3 页面内，我通过从 pinia 存储调用操作来获取帖子数据： {{ 发布数据 }} {{ 帖子内容... 在 Nuxt 3 页面内，我通过从 pinia 商店调用操作来获取帖子数据： <template> <div v-if="postData && postContent"> {{ postData }} {{ postContent }} </div> </template> <script setup> const config = useRuntimeConfig() const route = useRoute() const slug = route.params.slug const url = config.public.wpApiUrl const contentStore = useContentStore() await contentStore.fetchPostData({ url, slug }) const postData = contentStore.postData const postContent = contentStore.postContent </script> 那是我的商店： import { defineStore } from 'pinia' export const useContentStore = defineStore('content',{ state: () => ({ postData: null, postContent: null }), actions: { async fetchPostData({ url, slug }) { try { const { data: postData, error } = await useFetch(`${url}/wp/v2/posts`, { query: { slug: slug }, transform(data) { return data.map((post) => ({ id: post.id, title: post.title.rendered, content: post.content.rendered, excerpt: post.excerpt.rendered, date: post.date, slug: post.slug, })); } }) this.postData = postData.value; if (postData && postData.value && postData.value.length && postData.value[0].id) { const {data: postContent} = await useFetch(`${url}/rl/v1/get?id=${postData.value[0].id}`, { method: 'POST', }); this.postContent = postContent.value; } } catch (error) { console.error('Error fetching post data:', error) } } } }); 浏览器中的输出正常，但我在浏览器控制台中收到以下错误： entry.js:54 [Vue warn]: Hydration node mismatch: - rendered on server:  - expected on client: div at <[slug] onVnodeUnmounted=fn<onVnodeUnmounted> ref=Ref< undefined > > at <Anonymous key="/news/hello-world()" vnode= {__v_isVNode: true, __v_skip: true, type: {…}, props: {…}, key: null, …} route= {fullPath: '/news/hello-world', hash: '', query: {…}, name: 'news-slug', path: '/news/hello-world', …} ... > at <RouterView name=undefined route=undefined > at <NuxtPage> at <Default ref=Ref< undefined > > at <LayoutLoader key="default" layoutProps= {ref: RefImpl} name="default" > at <NuxtLayoutProvider layoutProps= {ref: RefImpl} key="default" name="default" ... > at <NuxtLayout> at <App key=3 > at <NuxtRoot> 如何解决这个问题？我尝试在 onMounted 中获取帖子数据，但在这种情况下 postData 和 postContent 保持为空 onMounted(async () => { await contentStore.fetchPostData({ url, slug }) }) 您可以使用 ClientOnly 组件来消除该警告。请参阅文档了解更多信息。该组件仅在客户端渲染其插槽。

在使用 TypeScript 进行 React 时，输入字段在“值”处给出错误

从“react”导入{SetStateAction，useState} const 登录表单 =() =>{ const [名称，setName] = useState(); const [全名，setFullname] = useState import { SetStateAction, useState } from "react" const Loginform =() =>{ const [name, setName] = useState<String | null>(); const [fullname, setFullname] = useState<String | null>(); const inputEvent =(event: { target: { value: SetStateAction< String |null | undefined >; }; })=>{ setName(event.target.value) } const Submit = ()=>{ setFullname(name) } return <> <h1>Enter Your Name </h1> <input type="text" placeholder="Enter your name" onChange={inputEvent} value={name}/> <button onClick={Submit}>Submit</button> <h1>Hi {fullname==null? "Guest" :fullname}</h1> </> } export default Loginform <input type="text" placeholder="Enter your name" onChange={inputEvent} value={name}/> 上一行中的“value”属性显示错误这是错误详细信息： (property) React.InputHTMLAttributes<HTMLInputElement>.value?: string | number | readonly string[] | undefined Type 'String | null | undefined' is not assignable to type 'string | number | readonly string[] | undefined'. Type 'null' is not assignable to type 'string | number | readonly string[] | undefined'.ts(2322) index.d.ts(2398, 9): The expected type comes from property 'value' which is declared here on type 'DetailedHTMLProps<InputHTMLAttributes<HTMLInputElement>, HTMLInputElement>' 也尝试写 return as any。或者尝试添加 string[]，但出现错误。进行以下调整：将 String 替换为 string，因为原始 Typescript 类型是小写的 (number, string, boolean, etc) TypeScript 报告此错误，因为属性值不接受 null 作为值，而是接受 undefined。将代码更新为： const [name, setName] = useState<string>() 这会使用 string 作为默认类型来初始化状态。初始状态隐式地被视为 undefined，因为如果未显式提供，TypeScript 会将类型的默认值设置为 undefined。为了简单起见，您不需要解构事件。使用内联函数，如下例所示： <input type="text" placeholder="Enter your name" onChange={(e) => setName(e.target.value)} value={name}/> 我使用你的代码创建了一个 CodeSanbox，它似乎只需要很少的修改就可以正常工作。您可以在这里找到沙盒这是我想出的代码 import { SetStateAction, useState } from "react"; const Loginform = () => { const [name, setName] = useState<string | null>(); const [fullname, setFullname] = useState<string | null>(); const inputEvent = (event: { target: { value: SetStateAction<string | null | undefined> }; }) => { setName(event.target.value); }; const Submit = () => { setFullname(name); }; return ( <div> <h1>Enter Your Name </h1> <input type="text" placeholder="Enter your name" onChange={inputEvent} value={name} /> <button onClick={Submit}>Submit</button> <h1>Hi {fullname == null ? "Guest" : fullname}</h1> </div> ); }; export default Loginform;

如何以 Svelte 方式设置导出和开槽零件的样式？

Svelte slot 的功能是否像 vanilla-js/dom 一样（我似乎无法让它工作）。在 html/js 中我可以这样做：身体{颜色：红色;} /* 从外部设置暴露部分的样式 */ ...</desc> <question vote="0"> <p>Svelte <pre><code>slot</code></pre>的功能是否像 vanilla-js/dom 一样（我似乎无法让它工作）。</p> <p>在 html/js 中我可以做：</p> <p></p><div data-babel="false" data-lang="js" data-hide="false" data-console="true"> <div> <pre><code><style> body {color: red;} /* style exposed part from outside */ my-element::part(header) {color: green;} </style> <h1>Hello World</h1> <my-element> <div slot="header"><strong>Header</strong></div> <div slot="body">Body</div> </my-element> <script> customElements.define('my-element', class extends HTMLElement { constructor() { super(); const shadowRoot = this.attachShadow({mode: 'open'}); shadowRoot.innerHTML = ` <style> .container { border: solid 1px blue; padding: 5px; position: relative; &:after { content: "my-element"; display: block; position: absolute; bottom: -.5em; right: 5px; border: inherit; background-color: white; padding: inherit; } } /* style inserted/slotted part from inside */ [part="body"] ::slotted(div) { background-color: lightyellow; } </style> <div class="container"> <header part="header"><slot name="header"></slot></header> <hr> <div part="body"><slot name="body"></slot></div> </div> `; } }); </script></code></pre> </div> </div> <p></p> <p>其中 <pre><code>h1</code></pre> 的全局样式为红色，标有 <pre><code>part="header"</code></pre> 的元素从外部设置为绿色，插入 <pre><code>slot="body"</code></pre> 的内容从内部（shadow dom）设置为绿色有浅黄色背景。</p> <p>我不知道如何在 svelte 中执行任何这种（受控）跨界样式？（例如，当使用 <pre><code>AppShell::part(content)</code></pre> 时，我收到错误：</p> <pre><code>[plugin:vite-plugin-svelte] C:/srv/svelte/yoda5/src/routes/+layout.svelte:23:18 Expected a valid CSS identifier C:/srv/svelte/yoda5/src/routes/+layout.svelte:23:18 21 | 22 | <style> 23 | AppShell::part(content) { | ^ </code></pre> </question> <answer tick="false" vote="0"> <p>这里有关于<a href="https://learn.svelte.dev/tutorial/slots" rel="nofollow noreferrer">老虎机的课程</a>。最好参考该工具的文档。 Svelte 的学习网站非常棒。</p> <pre><code>// Slotted component, say Test.svelte. <div class="private-parent"> <slot /> </div> <style> div.private-parent { color: blue; } </style> </code></pre> <p>然后，您使用该组件：</p> <pre><code><script> import Test from './Test.svelte'; </script> <Test>  <p class="outside-style">Hello!</p> </Test> <style> p.outside-style { color: darkred; } </style> </code></pre> </answer> </body></html>

通过更少的 Java API 调用来映射 Google 云端硬盘内容的有效方法

大家好，我有一个代码，用于列出共享驱动器中存在的文件（以便稍后下载并创建相同的文件夹路径）目前我做这样的事情：哈希映射大家好，我有一个代码，用于列出共享驱动器中存在的文件（以便稍后下载并创建相同的文件夹路径）目前我正在做这样的事情： HashMap<String, Strin> foldersPathToID = new HashMap<>(); //searching all folders first saving their IDs searchAllFoldersRecursive(folderName.trim(), driveId, foldersPathToID); //then listing files in all folders HashMap<String, List<File>> pathFile = new HashMap<>(); for (Entry<String, String> pathFolder : foldersPathToID.entrySet()) { List<File> result = search(Type.FILE, pathFolder.getValue()); if (result.size() > 0) { String targetPathFolder = pathFolder.getKey().trim(); pathFile.putIfAbsent(targetPathFolder, new ArrayList<>()); for (File file : result) { pathFile.get(targetPathFolder).add(file); } } } 递归方法在哪里： private static void searchAllFoldersRecursive(String nameFold, String id, HashMap<String, String> map) throws IOException, RefreshTokenException { map.putIfAbsent(nameFold, id); List<File> result; result = search(Type.FOLDER, id); // dig deeper if (result.size() > 0) { for (File folder : result) { searchAllFoldersRecursive(nameFold + java.io.File.separator + normalizeName(folder.getName()), folder.getId(), map); } } } 搜索功能是： private static List<com.google.api.services.drive.model.File> search(Type type, String folderId) throws IOException, RefreshTokenException { String nextPageToken = "go"; List<File> driveFolders = new ArrayList<>(); com.google.api.services.drive.Drive.Files.List request = service.files() .list() .setQ("'" + folderId + "' in parents and mimeType" + (type == Type.FOLDER ? "=" : "!=") + "'application/vnd.google-apps.folder' and trashed = false") .setPageSize(100).setFields("nextPageToken, files(id, name)"); while (nextPageToken != null && nextPageToken.length() > 0) { try { FileList result = request.execute(); driveFolders.addAll(result.getFiles()); nextPageToken = result.getNextPageToken(); request.setPageToken(nextPageToken); return driveFolders; } catch (TokenResponseException tokenError) { if (tokenError.getDetails().getError().equalsIgnoreCase("invalid_grant")) { log.err("Token no more valid removing it Please retry"); java.io.File cred = new java.io.File("./tokens/StoredCredential"); if (cred.exists()) { cred.delete(); } throw new RefreshTokenException("Creds invalid will retry re allow for the token"); } log.err("Error while geting response with token for folder id : " + folderId, tokenError); nextPageToken = null; } catch (Exception e) { log.err("Error while reading folder id : " + folderId, e); nextPageToken = null; } } return new ArrayList<>(); } 我确信有一种方法可以通过很少的 api 调用（甚至可能是一个调用？）对每个文件（使用文件夹树路径）进行正确的映射，因为在我的版本中，我花了很多时间进行调用 service.files().list().setQ("'" + folderId+ "' in parents and mimeType" + (type == Type.FOLDER ? "=" : "!=") + "'application/vnd.google-apps.folder' and trashed = false").setPageSize(100).setFields("nextPageToken, files(id, name)"); 每个子文件夹至少一次......并且递归搜索所有内容需要很长时间。最后，映射比下载本身花费的时间更多...... 我搜索了文档，也在此处搜索，但没有找到任何内容来列出具有一个库的所有驱动器调用任何想法？我想使用专用的 java API 来获取共享 GoogleDrive 中的所有文件及其相对路径，但调用次数尽可能少。提前感谢您的时间和答复我建议您使用高效的数据结构和逻辑来构建文件夹树并将文件映射到其路径，如下所示 private static void mapDriveContent(String driveId) throws IOException { // HashMap to store folder ID to path mapping HashMap<String, String> idToPath = new HashMap<>(); // HashMap to store files based on their paths HashMap<String, List<File>> pathToFile = new HashMap<>(); // Fetch all files and folders in the drive List<File> allFiles = fetchAllFiles(driveId); // Build folder path mapping and organize files for (File file : allFiles) { String parentId = (file.getParents() != null && !file.getParents().isEmpty()) ? file.getParents().get(0) : null; String path = buildPath(file, parentId, idToPath); if (file.getMimeType().equals("application/vnd.google-apps.folder")) { idToPath.put(file.getId(), path); } else { pathToFile.computeIfAbsent(path, k -> new ArrayList<>()).add(file); } } // Now, pathToFile contains the mapping of paths to files // Your logic to handle these files goes here } private static List<File> fetchAllFiles(String driveId) throws IOException { // Implement fetching all files and folders here // Make sure to handle pagination if necessary // ... } private static String buildPath(File file, String parentId, HashMap<String, String> idToPath) { // Build the file path based on its parent ID and the idToPath mapping // ... }

SecurityException：不允许启动服务Intent { act=com.google.android.c2dm.intent.REGISTER pkg=com.google.android.gms （有额外功能）}

我尝试从 Google 获取我的 GCM 注册 ID。我的代码：字符串SENDER_ID =“722*****53”; /** * 向 GCM 服务器异步注册应用程序。 * * 存储注册信息... 我尝试从 Google 获取我的 GCM 注册 ID。我的代码： String SENDER_ID = "722******53"; /** * Registers the application with GCM servers asynchronously. * <p> * Stores the registration ID and the app versionCode in the application's * shared preferences. */ private void registerInBackground() { new AsyncTask<Void, Void, String>() { @Override protected String doInBackground(Void... params) { String msg = ""; try { if (gcm == null) { gcm = GoogleCloudMessaging.getInstance(context); } regid = gcm.register(SENDER_ID); msg = "Device registered, registration ID=" + regid; // You should send the registration ID to your server over // HTTP, so it // can use GCM/HTTP or CCS to send messages to your app. sendRegistrationIdToBackend(); // For this demo: we don't need to send it because the // device will send // upstream messages to a server that echo back the message // using the // 'from' address in the message. // Persist the regID - no need to register again. storeRegistrationId(context, regid); } catch (IOException ex) { msg = "Error :" + ex.getMessage(); // If there is an error, don't just keep trying to register. // Require the user to click a button again, or perform // exponential back-off. } return msg; } @Override protected void onPostExecute(String msg) { mDisplay.append(msg + "\n"); } }.execute(null, null, null); } 我收到错误： 03-01 19:15:36.261: E/AndroidRuntime(3467): FATAL EXCEPTION: AsyncTask #1 03-01 19:15:36.261: E/AndroidRuntime(3467): java.lang.RuntimeException: An error occured while executing doInBackground() 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.os.AsyncTask$3.done(AsyncTask.java:299) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.FutureTask.setException(FutureTask.java:219) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.FutureTask.run(FutureTask.java:239) 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.lang.Thread.run(Thread.java:841) 03-01 19:15:36.261: E/AndroidRuntime(3467): Caused by: java.lang.SecurityException: Not allowed to start service Intent { act=com.google.android.c2dm.intent.REGISTER pkg=com.google.android.gms (has extras) } without permission com.google.android.c2dm.permission.RECEIVE 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.app.ContextImpl.startServiceAsUser(ContextImpl.java:1800) 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.app.ContextImpl.startService(ContextImpl.java:1772) 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.content.ContextWrapper.startService(ContextWrapper.java:480) 03-01 19:15:36.261: E/AndroidRuntime(3467): at com.google.android.gms.gcm.GoogleCloudMessaging.b(Unknown Source) 03-01 19:15:36.261: E/AndroidRuntime(3467): at com.google.android.gms.gcm.GoogleCloudMessaging.register(Unknown Source) 03-01 19:15:36.261: E/AndroidRuntime(3467): at com.example.gcm.DemoActivity$1.doInBackground(DemoActivity.java:177) 03-01 19:15:36.261: E/AndroidRuntime(3467): at com.example.gcm.DemoActivity$1.doInBackground(DemoActivity.java:1) 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.os.AsyncTask$2.call(AsyncTask.java:287) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.FutureTask.run(FutureTask.java:234) 03-01 19:15:36.261: E/AndroidRuntime(3467): ... 4 more 这是我的清单： <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.manyexampleapp" android:installLocation="preferExternal" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="11" android:targetSdkVersion="18" /> <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" /> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> <uses-permission android:name="android.permission.GET_ACCOUNTS" /> <uses-permission android:name="android.permission.WAKE_LOCK" /> <uses-permission android:name="com.example.manyexampleapp.c2dm.permission.RECEIVE" /> <uses-permission android:name="com.example.manyexampleapp.gcm.permission.C2D_MESSAGE" /> <permission android:name="com.example.manyexampleapp.gcm.permission.C2D_MESSAGE" android:protectionLevel="signature" /> <application android:name="com.zoomer.ifs.BaseApplication" android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <meta-data android:name="com.google.android.gms.version" android:value="@integer/google_play_services_version" /> <activity android:name="com.zoomer.ifs.MainActivity" android:label="@string/app_name" android:configChanges="orientation|keyboardHidden|screenSize" android:launchMode="singleTop">  </activity>   <receiver android:name="com.example.gcm.GcmBroadcastReceiver" android:permission="com.google.android.c2dm.permission.SEND" > <intent-filter>  <action android:name="com.google.android.c2dm.intent.RECEIVE" /> <category android:name="com.example.manyexampleapp" /> </intent-filter> </receiver> <service android:name="com.example.gcm.GcmIntentService" /> <activity android:name="com.example.gcm.DemoActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity>  <activity android:name="com.example.db.DbActivity" android:label="@string/app_name" > <intent-filter> </intent-filter> </activity> <activity android:name="com.example.http.RestGetActivity" android:label="@string/app_name" android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen" > </activity> <activity android:name="com.example.fb.FacebookLoginActivity" android:label="@string/app_name" >  </activity> <activity android:name="com.example.http.SendFeedbackActivity" android:label="@string/app_name" >  </activity> <activity android:name="com.zoomer.general.SearchNearbyOffersActivity" android:label="@string/app_name" > <intent-filter> </intent-filter> </activity> <activity android:name="com.facebook.LoginActivity" android:label="@string/app_name" > <intent-filter> </intent-filter> </activity> <activity android:name="com.example.manyexampleapp.StoresListActivity" > <intent-filter> </intent-filter> </activity> <activity android:name="com.example.fb.ShareActivity" > <intent-filter> </intent-filter> </activity> <activity android:name="com.example.notifications.NotificationsActivity" > <intent-filter> </intent-filter> </activity> <activity android:name="com.example.fb2.no_use.MainActivity" > <intent-filter> </intent-filter> </activity> <activity android:name="com.zoomer.offers.OffersListActivity" >  </activity> <activity android:name="com.example.http.SearchNearbyOffersActivity" >  </activity> <service android:name="com.example.geo.LocationService" android:enabled="true" /> <receiver android:name="com.example.manyexampleapp.BootReceiver" > <intent-filter> <action android:name="android.intent.action.BOOT_COMPLETED" /> <action android:name="com.example.manyexampleapp.LocationService.LOCATION_BROAD_MSG" /> </intent-filter> </receiver> <meta-data android:name="com.facebook.sdk.ApplicationId" android:value="@string/app_id" /> </application> </manifest> 改变 <uses-permission android:name="com.example.manyexampleapp.c2dm.permission.RECEIVE" /> 到  <uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" /> 您收到异常是因为您尚未定义所需的权限如果应用程序开发后安装了播放服务，可能会发生 com.google.android.c2dm.permission.RECEIVE 权限已被授予但 android 仍在抱怨同样的错误。在这种情况下，您必须完全重新安装开发的应用程序才能使此权限发挥作用。我认为你必须检查 Kotlin 版本兼容性。

在 C# 中将 Task<T> 转换为 Task<object>，无需 T

我有一个充满扩展方法的静态类，其中每个方法都是异步的并返回一些值 - 像这样：公共静态类 MyContextExtensions{ 公共静态异步任务我有一个充满扩展方法的静态类，其中每个方法都是异步的并返回一些值 - 像这样： public static class MyContextExtensions{ public static async Task<bool> SomeFunction(this DbContext myContext){ bool output = false; //...doing stuff with myContext return output; } public static async Task<List<string>> SomeOtherFunction(this DbContext myContext){ List<string> output = new List<string>(); //...doing stuff with myContext return output; } } 我的目标是能够从另一个类中的单个方法调用这些方法中的任何一个，并将其结果作为对象返回。它看起来像这样： public class MyHub: Hub{ public async Task<object> InvokeContextExtension(string methodName){ using(var context = new DbContext()){ //This fails because of invalid cast return await (Task<object>)typeof(MyContextExtensions).GetMethod(methodName).Invoke(null, context); } } } 问题是转换失败。我的困境是我无法将任何类型参数传递给“InvokeContextExtension”方法，因为它是 SignalR 中心的一部分并且由 javascript 调用。在某种程度上，我不关心扩展方法的返回类型，因为它只会序列化为 JSON 并发送回 javascript 客户端。但是，我确实必须将 Invoke 返回的值转换为任务才能使用等待运算符。我必须为该“任务”提供一个通用参数，否则它将把返回类型视为 void。因此，这一切都归结为如何成功地将具有通用参数 T 的任务转换为具有对象通用参数的任务，其中 T 表示扩展方法的输出。您可以分两步完成 - await使用基类执行任务，然后使用反射或dynamic收获结果： using(var context = new DbContext()) { // Get the task Task task = (Task)typeof(MyContextExtensions).GetMethod(methodName).Invoke(null, context); // Make sure it runs to completion await task.ConfigureAwait(false); // Harvest the result return (object)((dynamic)task).Result; } 这是一个完整的运行示例，它将上述通过反射调用 Task 的技术置于上下文中： class MainClass { public static void Main(string[] args) { var t1 = Task.Run(async () => Console.WriteLine(await Bar("Foo1"))); var t2 = Task.Run(async () => Console.WriteLine(await Bar("Foo2"))); Task.WaitAll(t1, t2); } public static async Task<object> Bar(string name) { Task t = (Task)typeof(MainClass).GetMethod(name).Invoke(null, new object[] { "bar" }); await t.ConfigureAwait(false); return (object)((dynamic)t).Result; } public static Task<string> Foo1(string s) { return Task.FromResult("hello"); } public static Task<bool> Foo2(string s) { return Task.FromResult(true); } } 一般来说，要将 Task<T> 转换为 Task<object>，我会简单地采用简单的连续映射： Task<T> yourTaskT; // .... Task<object> yourTaskObject = yourTaskT.ContinueWith(t => (object) t.Result); （文档链接在这里）但是，您实际的具体需求是通过反射调用 Task 并获取其（未知类型）结果。为此，您可以参考完整的dasblinkenlight的答案，它应该适合您的具体问题。我想提供一个实现，恕我直言，这是早期答案的最佳组合：精确的参数处理无动态调度通用扩展方法给你： /// <summary> /// Casts a <see cref="Task"/> to a <see cref="Task{TResult}"/>. /// This method will throw an <see cref="InvalidCastException"/> if the specified task /// returns a value which is not identity-convertible to <typeparamref name="T"/>. /// </summary> public static async Task<T> Cast<T>(this Task task) { if (task == null) throw new ArgumentNullException(nameof(task)); if (!task.GetType().IsGenericType || task.GetType().GetGenericTypeDefinition() != typeof(Task<>)) throw new ArgumentException("An argument of type 'System.Threading.Tasks.Task`1' was expected"); await task.ConfigureAwait(false); object result = task.GetType().GetProperty(nameof(Task<object>.Result)).GetValue(task); return (T)result; } 您不能将 Task<T> 转换为 Task<object>，因为 Task<T> 不是协变的（也不是逆变的）。最简单的解决方案是使用更多反射： var task = (Task) mi.Invoke (obj, null) ; var result = task.GetType ().GetProperty ("Result").GetValue (task) ; 这很慢且效率低下，但如果不经常执行此代码则可用。顺便说一句，如果您要阻塞等待其结果，那么异步 MakeMyClass1 方法有什么用呢？另一种可能性是为此目的编写一个扩展方法： public static Task<object> Convert<T>(this Task<T> task) { TaskCompletionSource<object> res = new TaskCompletionSource<object>(); return task.ContinueWith(t => { if (t.IsCanceled) { res.TrySetCanceled(); } else if (t.IsFaulted) { res.TrySetException(t.Exception); } else { res.TrySetResult(t.Result); } return res.Task; } , TaskContinuationOptions.ExecuteSynchronously).Unwrap(); } 它是非阻塞解决方案，将保留任务的原始状态/异常。最有效的方法是自定义等待者： struct TaskCast<TSource, TDestination> where TSource : TDestination { readonly Task<TSource> task; public TaskCast(Task<TSource> task) { this.task = task; } public Awaiter GetAwaiter() => new Awaiter(task); public struct Awaiter : System.Runtime.CompilerServices.INotifyCompletion { System.Runtime.CompilerServices.TaskAwaiter<TSource> awaiter; public Awaiter(Task<TSource> task) { awaiter = task.GetAwaiter(); } public bool IsCompleted => awaiter.IsCompleted; public TDestination GetResult() => awaiter.GetResult(); public void OnCompleted(Action continuation) => awaiter.OnCompleted(continuation); } } 具有以下用法： Task<...> someTask = ...; await TaskCast<..., object>(someTask); 这种方法的局限性在于结果不是 Task<object> 而是一个可等待的对象。我根据dasblinkenlight的回答做了一个小小的扩展方法： public static class TaskExtension { public async static Task<T> Cast<T>(this Task task) { if (!task.GetType().IsGenericType) throw new InvalidOperationException(); await task.ConfigureAwait(false); // Harvest the result. Ugly but works return (T)((dynamic)task).Result; } } 用途： Task<Foo> task = ... Task<object> = task.Cast<object>(); 这样您就可以将 T 中的 Task<T> 更改为您想要的任何内容。对于最佳方法，不使用反射和动态丑陋语法，也不传递泛型类型。我将使用两种扩展方法来实现这个目标。 public static async Task<object> CastToObject<T>([NotNull] this Task<T> task) { return await task.ConfigureAwait(false); } public static async Task<TResult> Cast<TResult>([NotNull] this Task<object> task) { return (TResult) await task.ConfigureAwait(false); } 用途： Task<T1> task ... Task<T2> task2 = task.CastToObject().Cast<T2>(); 这是我的第二种方法，但不推荐： public static async Task<TResult> Cast<TSource, TResult>([NotNull] this Task<TSource> task, TResult dummy = default) { return (TResult)(object) await task.ConfigureAwait(false); } 用途： Task<T1> task ... Task<T2> task2 = task.Cast((T2) default); // Or Task<T2> task2 = task.Cast<T1, T2>(); 这是我的第三种方法，但是不推荐：（类似于第二种） public static async Task<TResult> Cast<TSource, TResult>([NotNull] this Task<TSource> task, Type<TResult> type = null) { return (TResult)(object) await task.ConfigureAwait(false); } // Dummy type class public class Type<T> { } public static class TypeExtension { public static Type<T> ToGeneric<T>(this T source) { return new Type<T>(); } } 用途： Task<T1> task ... Task<T2> task2 = task.Cast(typeof(T2).ToGeneric()); // Or Task<T2> task2 = task.Cast<T1, T2>(); 将 await 与动态/反射调用混合使用并不是一个好主意，因为 await 是一条编译器指令，它会围绕调用的方法生成大量代码，并且使用更多反射来“模拟”编译器工作并没有真正的意义，延续、包装等因为您需要的是在运行时管理代码，然后忘记在编译时工作的 asyc await 语法糖。重写 SomeFunction 和 SomeOtherFunction 而不使用它们，并在运行时创建的您自己的任务中开始操作。您将得到相同的行为，但代码非常清晰。

错误：在此 BlocBuilder<InternetBloc> Widget<InternetBloc, InternetState> 上方找不到正确的提供程序

我在尝试将 flutter_bloc 集成到 flutter 项目中时遇到错误。错误：在此 BlocBuilder 上方找不到正确的 Provider 我在尝试将 flutter_bloc 集成到 flutter 项目中时遇到错误。错误：在此 BlocBuilder Widget 上方找不到正确的提供者这是我正在使用的代码示例。 internet_state.dart abstract class InternetState{} class InitialInternetState extends InternetState{} class LostConnectionInternetState extends InternetState{} class GainConnectionInternetState extends InternetState{} internet_event.dart abstract class InternetEvent{} class LostConnectionEvent extends InternetEvent{} class GainConnectionEvent extends InternetEvent{} internet_bloc.dart class InternetBloc extends Bloc<InternetEvent, InternetState>{ final Connectivity _connectivity = Connectivity(); StreamSubscription? streamSubscription; InternetBloc() : super(InitialInternetState()){ on<GainConnectionEvent>((event, emit) => emit(GainConnectionInternetState())); on<LostConnectionEvent>((event, emit) => emit(LostConnectionInternetState())); _connectivity.onConnectivityChanged.listen((event) { if(event == ConnectivityResult.mobile || event == ConnectivityResult.wifi){ add(GainConnectionEvent()); } else { add(LostConnectionEvent()); } }); } @override Future<void> close() { streamSubscription?.cancel(); return super.close(); } } main.dart class MyApp extends StatelessWidget { const MyApp({super.key}); @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple), useMaterial3: true, ), home: const MyHomePage(title: 'Flutter Demo Home Page'), ); } } class MyHomePage extends StatelessWidget { const MyHomePage({super.key, required this.title}); final String title; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar(title: Text(title),), body: SafeArea( child: Center(child: BlocBuilder<InternetBloc, InternetState>( builder: (context, state) { return const Text("hello"); }, )), ),); } } 我明白了。 ======== 小部件库捕获异常====================================== =================== 构建 MediaQuery(MediaQueryData(size: Size(392.7, 783.3), devicePixelRatio: 2.8, textScaler: noscaling, platformBrightness: Brightness.light, padding: EdgeInsets.zero, viewPadding: EdgeInsets.zero, viewInsets: EdgeInsets 时抛出以下 ProviderNotFoundException。零，systemGestureInsets：EdgeInsets（29.8，24.0，29.8，8.0），alwaysUse24HourFormat：假，accessibleNavigation：假，highContrast：假，onOffSwitchLabels：假，disableAnimations：假，invertColors：假，boldText：假，navigationMode：传统，gestureSettings：DeviceGestureSettings （touchSlop：8.0），显示功能：[]））：错误：无法在此 BlocBuilder Widget 之上找到正确的提供程序发生这种情况是因为您使用了不包含提供程序的 BuildContext 你的选择。有以下几种常见场景：您在main.dart中添加了一个新的提供程序并执行了热重载。要修复此问题，请执行热重启。您尝试阅读的提供商处于不同的路线。提供商具有“范围”。因此，如果您在路线中插入提供者，那么其他路线将无法访问该提供商。您使用了 BuildContext，它是您尝试读取的提供程序的祖先。确保 BlocBuilder 位于您的 MultiProvider/Provider 下。当您创建提供程序并尝试立即读取它时，通常会发生这种情况。例如，代替： Widget build(BuildContext context) { return Provider<Example>( create: (_) => Example(), // Will throw a ProviderNotFoundError, because `context` is associated // to the widget that is the parent of `Provider<Example>` child: Text(context.watch<Example>().toString()), ); } 考虑使用builder，如下所示： Widget build(BuildContext context) { return Provider<Example>( create: (_) => Example(), // we use `builder` to obtain a new `BuildContext` that has access to the provider builder: (context, child) { // No longer throws return Text(context.watch<Example>().toString()); } ); } 如果这些解决方案都不起作用，请考虑在 StackOverflow 上寻求帮助： https://stackoverflow.com/questions/tagged/flutter The relevant error-causing widget was: SafeArea SafeArea:file:///Users/../Projects/flutterTest/bloc_test/lib/main.dart:37:13 When the exception was thrown, this was the stack: #0 Provider._inheritedElementOf (package:provider/src/provider.dart:343:7) #1 Provider.of (package:provider/src/provider.dart:293:30) #2 ReadContext.read (package:provider/src/provider.dart:649:21) #3 _BlocBuilderBaseState.initState (package:flutter_bloc/src/bloc_builder.dart:130:36) #4 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:5602:55) #5 ComponentElement.mount (package:flutter/src/widgets/framework.dart:5447:5) ... Normal element mounting (4 frames) #9 Element.inflateWidget (package:flutter/src/widgets/framework.dart:4326:16) #10 Element.updateChild (package:flutter/src/widgets/framework.dart:3831:20) #11 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #12 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #13 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #14 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #15 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6743:14) #16 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #17 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #18 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #19 StatelessElement.update (package:flutter/src/widgets/framework.dart:5547:5) #20 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #21 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #22 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #23 StatelessElement.update (package:flutter/src/widgets/framework.dart:5547:5) #24 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #25 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #26 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #27 StatelessElement.update (package:flutter/src/widgets/framework.dart:5547:5) #28 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #29 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #30 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #31 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #32 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #33 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #34 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #35 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #36 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #37 Element.updateChildren (package:flutter/src/widgets/framework.dart:3964:32) #38 MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6896:17) #39 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #40 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #41 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #42 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #43 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #44 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #45 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #46 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #47 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #48 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #49 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #50 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #51 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #52 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #53 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #54 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #55 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #56 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #57 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #58 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #59 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #60 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #61 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #62 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #63 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6743:14) #64 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #65 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #66 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #67 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #68 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #69 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6743:14) #70 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #71 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #72 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #73 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #74 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #75 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #76 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #77 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #78 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #79 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #80 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #81 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #82 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #83 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #84 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #85 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #86 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #87 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #88 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #89 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #90 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #91 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #92 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #93 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #94 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #95 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #96 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #97 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #98 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #99 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #100 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #101 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #102 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #103 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #104 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #105 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #106 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #107 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #108 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #109 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2895:19) #110 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:984:21) #111 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:457:5) #112 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1325:15) #113 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1255:9) #114 SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:978:7) #118 _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12) (elided 3 frames from class _Timer and dart:async-patch) ==================================================================================================== 我不想使用像 MultiProvider 这样的全局提供程序。您应该在某处创建 InternetBloc 并提供它。 MultiProvider 本身并不是全局的，它只是多个。更多信息在这里：https://bloclibrary.dev/#/flutterbloccoreconcepts?id=blocprovider 所以，如果您不想使用全局提供程序，它将看起来像这样： class MyHomePage extends StatelessWidget { const MyHomePage({super.key, required this.title}); final String title; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(title), ), body: SafeArea( child: Center( child: BlocProvider<InternetBloc>( create: ( context) => InternetBloc(), child: BlocBuilder<InternetBloc, InternetState>( builder: (context, state) { return const Text("hello"); }, ), ), ), ), ); } } 要使用 BlocBuilder，您需要在 Widget 树中放置一个 BlocProvider。最佳实践是将其放置得尽可能深。在您的情况下，只需将 BlocProvider 放在 BlocBuilder 之上。此外 MultiProvider / MultiBlocProvider 不是全局 Provider。它只是一个提供多个 Provider/BlocProvider 的便捷小部件。 class MyHomePage extends StatelessWidget { const MyHomePage({super.key, required this.title}); final String title; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(title), ), body: SafeArea( child: Center( // Now everything below that can access the InternetBloc child: BlocProvider<InternetBloc>( create: (_) => InternetBloc(), child: BlocBuilder<InternetBloc, InternetState>( builder: (context, state) { return const Text("hello"); }, ), ), ), ), ); } }

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