ietf-bcp-47 相关问题

我有一些 CSV 文件，我想将其加载到数据库表中，如下所示数据库表创建表 [EVT_STREAM].[事件]( [系统名称] [varchar](25) NOT NULL, [路由器] [varchar](...

Vim 错误：处理函数时检测到错误<SNR>14_UseConfigFiles[26]..<SNR>14_Initialize[47]..<SNR>14_InitializePythonBuiltin:

当我简单地 $ vim CHANGELOG.md 时，出现以下错误 “变更日志.md”1788L，61291C 处理函数时检测到错误 14_UseConfigFiles[26]..14_Initialize[47]..<...

运行命令：“pip3 install pyaudio”时，出现以下错误： “收集pyaudio 使用缓存的 PyAudio-0.2.14.tar.gz (47 kB) 安装构建依赖项...完成得到

启动 Tomcat 上下文时出错。异常：org.springframework.beans.factory.UnsatisfiedDependencyException

我正在尝试设置克隆的 Spring boot 项目，但出现以下错误。 2024-04-27 13:47:46.737 INFO 56344 --- [ restartedMain] o.f.c.i.database.base.DatabaseType ：数据库：jdbc...

Cassandra cqlsh 节点

当我尝试 cqlsh 它返回的节点时，我有一个两节点 cassandra 集群 ubuntu@ip-172-31-47-96:~$ cqlsh 连接错误: ('无法连接到任何服务器', {'127.0.0.1:9042':

如何解决这个问题，我在 Linux 上使用 Python？

(modulos-proyectos) josue@josue-OptiPlex-3010:~/Decargas/portaudio$ pip install pyaudio 收集pyaudio 使用缓存的 PyAudio-0.2.14.tar.gz (47 kB) 安装构建依赖项...完成格...

Linux 上的 PyAudio 编译错误（Python.h：没有这样的文件或目录）

(modulos-proyectos) josue@josue-OptiPlex-3010:~/Decargas/portaudio$ pip install pyaudio 收集pyaudio 使用缓存的 PyAudio-0.2.14.tar.gz (47 kB) 安装构建依赖项...完成格...

如何将 DMS 转换为给定格式的弧度：Python 中的 DD-MM-SS [已关闭]

我想知道如何将 DMS 从给定格式 DD-MM-SS 转换为弧度这个“print (DMStoRAD(47-39-28))”的解应该是 0.831785 谢谢！

Google Sheet Formula 来查找最长的递增值链

我有如下数据以及我希望得到的数据：复制数据表：价值观 21 76 23 24 25 26 62 63 47 30 31 32 45 预期输出 1 1 4 2 1 3 1 其中 1 代表值

已使用内存，但我看不到使用它的进程（Debian）

这是我的问题：顶部 - 11:32:47 至 22:20，2 位用户，平均负载：0.03、0.72、1.27 任务：总共 112 个，1 个正在运行，110 个正在睡觉，1 个已停止，0 个僵尸 CPU：0.0%us、0.0%sy、0.0%ni、100.0%...

Biquery - 如何用窗口函数替换自连接以获得 +/- 7 天的 ids

我有一个如下所示的数据集客户ID 日期订单号时间戳 1 2024-01-01 XY 2024-01-01 18:47:33 1 2024-01-01 兹尔 2024-01-01 20:15:00 1 2024-01-06 df 2 2023-12-01 锰 2 2024-01-0...

SVG 可以有多小？

我刚刚缩小了这个SVG：我刚刚缩小了这个 SVG： <?xml version="1.0" standalone="no"?> <svg viewBox="0 0 480 150" style="background-color:#ffffff00" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xml:space="preserve" x="0px" y="0px" width="480" height="150"> <path d="M 0 35.5 L 6.5 22.5 L 16 37 L 23 24 L 34.8 43.7 L 42.5 30 L 50.3 47 L 59.7 27.7 L 69 47 L 85 17.7 L 98.3 39 L 113 9.7 L 127.7 42.3 L 136.3 23.7 L 147 44.3 L 158.3 20.3 L 170.3 40.3 L 177.7 25.7 L 189.7 43 L 199.7 21 L 207.7 35 L 219 11 L 233 37 L 240.3 23.7 L 251 43 L 263 18.3 L 272.7 33.3 L 283 10 L 295 32.3 L 301.3 23 L 311.7 37 L 323.7 7.7 L 339.3 39 L 346.3 25.7 L 356.3 42.3 L 369.7 15 L 376.3 25.7 L 384 9 L 393 28.3 L 400.3 19 L 411.7 38.3 L 421 21 L 434.3 43 L 445 25 L 453 36.3 L 464.3 18.3 L 476.2 40.3 L 480 33.5 L 480 215 L 0 215 L 0 35.5 Z" fill="#175720"/> </svg> 对此： <svg height="150" width="480"><path d="m0 35.5l6.5-13 9.5 14.5 7-13 11.8 19.7 7.7-13.7 7.8 17 9.4-19.3 9.3 19.3 16-29.3 13.3 21.3 14.7-29.3 14.7 32.6 8.6-18.6 10.7 20.6 11.3-24 12 20 7.4-14.6 12 17.3 10-22 8 14 11.3-24 14 26 7.3-13.3 10.7 19.3 12-24.7 9.7 15 10.3-23.3 12 22.3 6.3-9.3 10.4 14 12-29.3 15.6 31.3 7-13.3 10 16.6 13.4-27.3 6.6 10.7 7.7-16.7 9 19.3 7.3-9.3 11.4 19.3 9.3-17.3 13.3 22 10.7-18 8 11.3 11.3-18 11.9 22 3.8-6.8v181.5h-480v-179.5z" fill="#175720"/></svg> （我通过最小化程序运行它，然后删除了 <svg> 标签中的一堆属性。）我将它用作背景图像，它似乎在 Windows 上的 IE、Firefox 和 Chrome 中工作正常。我只是想知道如果其他信息对图像外观没有影响的话，它在那里做什么。因为我删除了该信息，会在某个地方出现兼容性问题吗？更新：我发现实际上，对于我的用例，我需要有 xmlns="http://www.w3.org/2000/svg"，否则它不会在 IE 或 Chrome 中呈现。删除 viewBox 会产生显着的语义差异，因为 SVG 将不再缩放（即响应 UA 调整大小）。这仅适用于您直接查看图像的情况，但如果您将其作为背景图像查看或通过 SVG <image> 标签或 html <img> 标签查看，则 SVG 将被绘制为好像它具有 viewBox 为“0 0 宽度高度”，除非 viewBox 已经存在。删除 background-color 将意味着 SVG 当放置在其他东西之上时将不再是不透明的。当然，如果你不这样做，你可能不会注意到。仅当 SVG 文件中有文本元素时，xml:space 属性才重要。如果 SVG 是内联的，其余的删除都是良性的。如果 SVG 是独立文件，则需要命名空间属性，但背景图像就是这种情况。简化版本不是有效的 SVG。它将被视为“任何”恰好具有名称为“svg”的根元素的 XML。要将片段转换为 the SVG，只有一个选项：将具有正确命名空间的 xmlns 属性添加到 svg 元素（正如您所发现的）不再建议在文档中添加 DOCTYPE，并且从 Chrome 53 起就不起作用。将文档作为 MIME 类型 image/svg+xml 提供服务也不够。示例： <svg xmlns="http://www.w3.org/2000/svg">（消费者选择的SVG版本） <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN" "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">（适用于 SVG 1.0）使用W3验证器检查您的文件。请务必检查检测到的文档类型是否为 SVG，因为该文档可能仍然有效，但作为一般/未知的 XML。 -- 他们还有测试页面。

更新 MyBatis 中的值列表 - SQLSyntaxErrorException

更新 MyBatis 中的值列表时出现 SQLSyntaxErrorException。我正在使用分隔符=“;”在 forecach 标签中，但我仍然收到错误。下面是我的sql查询更新 MyBatis 中的值列表时出现 SQLSyntaxErrorException。我在 forecach 标签中使用 separator=";" ，但仍然收到错误。下面是我的sql查询 <update id="updateComplianceCheckListResponse" parameterType="java.util.List"> <foreach collection="list" item="response" separator=";"> UPDATE AM_ComplianceChecklistResponse SET complianceDetailsId = #{response.complianceDetailsId}, complianceChecklistId = #{response.complianceChecklistId}, questionResponse = #{response.questionResponse}, expiryDate = #{response.expiryDate}, documentName = #{response.documentName}, comments = #{response.comments} WHERE id = #{response.id} </foreach> </update> org.apache.ibatis.exceptions.PersistenceException：更新数据库时出错。原因：java.sql.SQLSyntaxErrorException：您的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，了解在“UPDATE AM_ComplianceChecklistResponse”附近使用的正确语法 SET complianceDetailsId = 1, com' at line 10 错误可能存在于 com/am/dao/managecompliance/ComplianceChecklistResponse.xml 中错误可能涉及ComplianceChecklistResponse.updateComplianceCheckListResponse-Inline 设置参数时出现错误 SQL： UPDATE AM_ComplianceChecklistResponse SETcomplianceDetailsId = ？，complianceChecklistId = ？，questionResponse = ？，expiryDate = ？，documentName = ？，comments = ？哪里 id = ？ ; UPDATE AM_ComplianceChecklistResponse SET complianceDetailsId = ?、complianceChecklistId = ?、questionResponse = ?、expiryDate = ?、documentName = ?、comments = ?哪里 id = ? 原因：java.sql.SQLSyntaxErrorException：您的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，了解在“UPDATE AM_ComplianceChecklistResponse”附近使用的正确语法 SET complianceDetailsId = 1, com' at line 10 at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30) at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:196) at com.am.dao.managecompliance.ComplianceChecklistResponseDAO.updateComplianceCheckListResponse(ComplianceChecklistResponseDAO.java:50) at com.am.service.managecompliance.ComplianceChecklistResponseService.updateComplianceCheckListResponse(ComplianceChecklistResponseService.java:122) at com.am.webservice.controller.managecompliance.ManageComplianceController.updateComplianceCheckListResponse(ManageComplianceController.java:230) at com.am.webservice.controller.managecompliance.ManageComplianceController$$FastClassBySpringCGLIB$$e3100610.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) at org.springframework.aop.framework.CglibAopProxy.invokeMethod(CglibAopProxy.java:386) at org.springframework.aop.framework.CglibAopProxy.access$000(CglibAopProxy.java:85) at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:704) at com.am.webservice.controller.managecompliance.ManageComplianceController$$EnhancerBySpringCGLIB$$4a5751a4.updateComplianceCheckListResponse(<generated>) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:568) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1071) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:964) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) at javax.servlet.http.HttpServlet.service(HttpServlet.java:555) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) at javax.servlet.http.HttpServlet.service(HttpServlet.java:623) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:209) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:337) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:115) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:81) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:122) at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:116) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:149) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at com.dbp.security.auth.spring.StatelessAuthenticationFilter.doFilter(StatelessAuthenticationFilter.java:55) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:90) at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:75) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:221) at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:186) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:354) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:267) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:168) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:481) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:670) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:390) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:928) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1794) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:833) 引起：java.sql.SQLSyntaxErrorException：您的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，了解在“UPDATE AM_ComplianceChecklistResponse”附近使用的正确语法设置合规性详细信息 ID = 1, com' 在第 10 行在 com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120) 在com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException（SQLExceptionsMapping.java:122）在com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal（ClientPreparedStatement.java:916）在 com.mysql.cj.jdbc.ClientPreparedStatement.execute(ClientPreparedStatement.java:354) 在 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0（本机方法）在 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) 在java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在 java.base/java.lang.reflect.Method.invoke(Method.java:568) 在org.apache.ibatis.logging.jdbc.PreparedStatementLogger.invoke（PreparedStatementLogger.java:59）在 jdk.proxy5/jdk.proxy5.$Proxy81.execute（来源未知）在 org.apache.ibatis.executor.statement.PreparedStatementHandler.update(PreparedStatementHandler.java:47) 在 org.apache.ibatis.executor.statement.RoutingStatementHandler.update(RoutingStatementHandler.java:74) 在 org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:50) 在 org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:117) 在 org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:76) 在 org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:194) ...省略69个常用框架修复为 <insert id="updateComplianceCheckListResponse" parameterType="java.util.List"> insert into AM_ComplianceChecklistResponse (id,complianceDetailsId,complianceChecklistId,questionResponse,expiryDate,documentName,comments) VALUES <foreach collection="list" item="response" separator="," open="(" close=")"> #{response.id}, #{response.complianceDetailsId},#{response.complianceChecklistId},#{response.questionResponse},#{response.expiryDate},#{response.documentName},#{response.comments} </foreach> on duplicate key update complianceDetailsId= VALUES(complianceDetailsId), complianceChecklistId=VALUES(complianceChecklistId), questionResponse=VALUES(questionResponse), expiryDate=VALUES(expiryDate), documentName=VALUES(documentName), comments=VALUES(comments) </insert>

HTML如何使用javascript清除输入？

我有这个输入，每次我们点击它里面的时候它都会被清除。问题：我只想在 value = [email protected] 时清除函数clearThis(tar...</desc> <question vote="47"> <p>我有这个INPUT，每次我们点击它里面它就会清除。</p> <p>问题：我只想在值 = <a href="/cdn-cgi/l/email-protection" data-cfemail="2d485548405d41426d485548405d4142034e4240">[电子邮件受保护]</a></p> 时清除 <pre><code><script type="text/javascript"> function clearThis(target) { target.value= ""; } </script> <input type="text" name="email" value="<a href="/cdn-cgi/l/email-protection" data-cfemail="9cf9e4f9f1ecf0f3dcf9e4f9f1ecf0f3b2fff3f1">[email protected]</a>" size="30" onfocus="clearThis(this)"> </code></pre> <p>有人可以帮我做到这一点吗？我不知道如何比较，我已经尝试过但没有成功。</p> </question> <answer tick="true" vote="57"> <pre><code><script type="text/javascript"> function clearThis(target) { if (target.value == '<a href="/cdn-cgi/l/email-protection" data-cfemail="4a2f322f273a26250a2f322f273a262564292527">[email protected]</a>') { target.value = ""; } } </script> </code></pre> <p>这真的是您想要的吗？</p> </answer> <answer tick="false" vote="18"> <p>对我来说这是最好的方法：</p> <p></p><div data-babel="false" data-lang="js" data-hide="false" data-console="false"> <div> <pre><code><form id="myForm"> First name: <input type="text" name="fname" value="Demo"><br> Last name: <input type="text" name="lname"><br><br> <input type="button" onclick="myFunction()" value="Reset form"> </form> <script> function myFunction() { document.getElementById("myForm").reset(); } </script></code></pre> </div> </div> <p></p> </answer> <answer tick="false" vote="4"> <p>您可以使用属性<pre><code>placeholder</code></pre></p> <pre><code><input type="text" name="email" placeholder="<a href="/cdn-cgi/l/email-protection" data-cfemail="42273a272f322e2d02273a272f322e2d6c212d2f">[email protected]</a>" size="30" /> </code></pre> <p>或者在旧版浏览器上尝试这个</p> <pre><code><input type="text" name="email" value="<a href="/cdn-cgi/l/email-protection" data-cfemail="bdd8c5d8d0cdd1d2fdd8c5d8d0cdd1d293ded2d0">[email protected]</a>" size="30" onblur="if(this.value==''){this.value='<a href="/cdn-cgi/l/email-protection" data-cfemail="aacfd2cfc7dac6c5eacfd2cfc7dac6c584c9c5c7">[email protected]</a>';}" onfocus="if(this.value=='<a href="/cdn-cgi/l/email-protection" data-cfemail="03667b666e736f6c43667b666e736f6c2d606c6e">[email protected]</a>'){this.value='';}"> </code></pre> </answer> <answer tick="false" vote="4"> <p>您可以使用占位符，因为它可以为您做到这一点，但对于不支持占位符的旧浏览器，请尝试以下操作：</p> <pre><code><script> function clearThis(target) { if (target.value == "<a href="/cdn-cgi/l/email-protection" data-cfemail="402538252d302c2f002538252d302c2f6e232f2d">[email protected]</a>") { target.value = ""; } } function replace(target) { if (target.value == "" || target.value == null) { target.value == "<a href="/cdn-cgi/l/email-protection" data-cfemail="73160b161e031f1c33160b161e031f1c5d101c1e">[email protected]</a>"; } } </script> <input type="text" name="email" value="<a href="/cdn-cgi/l/email-protection" data-cfemail="ddb8a5b8b0adb1b29db8a5b8b0adb1b2f3beb2b0">[email protected]</a>" size="x" onfocus="clearThis(this)" onblur="replace(this)" /> </code></pre> <p>代码说明：当文本框获得焦点时，清除该值。当文本框未聚焦且文本框为空时，替换值。</p> <p>我希望这有效，我一直遇到同样的问题，但后来我尝试了这个，它对我有用。</p> </answer> <answer tick="false" vote="0"> <p>试试这个：</p> <pre><code><script type="text/javascript"> function clearThis(target){ if(target.value == "<a href="/cdn-cgi/l/email-protection" data-cfemail="67021f020a170b0827021f020a170b084904080a">[email protected]</a>") { target.value= ""; } } </script> </code></pre> <p></p> </answer> <answer tick="false" vote="0"> <pre><code><script type="text/javascript"> function clearThis(target){ if (target.value === "<a href="/cdn-cgi/l/email-protection" data-cfemail="a2c7dac7cfd2cecde2c7dac7cfd2cecd8cc1cdcf">[email protected]</a>") { target.value= ""; } } </script> <input type="text" name="email" value="<a href="/cdn-cgi/l/email-protection" data-cfemail="c7a2bfa2aab7aba887a2bfa2aab7aba8e9a4a8aa">[email protected]</a>" size="30" onfocus="clearThis(this)"> </code></pre> <p>在这里尝试一下：<a href="http://jsfiddle.net/2K3Vp/" rel="nofollow">http://jsfiddle.net/2K3Vp/</a></p> </answer> <answer tick="false" vote="0"> <p>你不需要为此烦恼。就写吧</p> <pre><code><input type="text" name="email" placeholder="<a href="/cdn-cgi/l/email-protection" data-cfemail="06637e636b766a6946637e636b766a692865696b">[email protected]</a>" size="30"> </code></pre> <p>用占位符替换该值</p> </answer> <answer tick="false" vote="0"> <p>不要使用 <strong>placeholder</strong> 属性清除名称文本，这是一个很好的做法</p> <pre><code><input type="text" placeholder="name" name="name"> </code></pre> </answer> <answer tick="false" vote="0"> <p>我对所有这些答案感到惊讶，没有人提到最简单、现代的方法来做到这一点：</p> <pre><code><input type="text" placeholder="Your Name" onfocus="this.placeholder=''" onblur="this.placeholder='Your Name'" > </code></pre> <p>仅当您想在用户单击远离输入后恢复原始占位符时，才需要 <pre><code>onblur</code></pre>。</p> </answer> </body></html>

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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