haskell - 如何更改 in an IHP app?</h1> <div id="body"><p>I see <code><title>App</title></code> is hardcoded in <code>defaultLayout</code> in Web/View/Layout.hs, and Web/View/Context.hs has</p> <pre&g</a></h1> <div class="ml12 aside-cta flex--item print:d-none sm:ml0 sm:mb12 sm:order-first sm:as-end"> <a href="https://stackoverflow.com/questions/ask" target="_blank" class="ws-nowrap s-btn s-btn__primary">问问题</a></div> </div> <div class="d-flex fw-wrap pb8 mb16 bb bc-black-075"> <div class="flex--item ws-nowrap mr16 mb8"> <span class="fc-light mr2"></span> </div> <div class="flex--item ws-nowrap mr16 mb8" title="2022-04-17 15:46:40Z"> <span class="fc-light mr2">问问题</span> <time itemprop="dateCreated" datetime="2020-10-10T15:30:29.223">2020-10-10T15:30:29.223</time> </div> <div class="flex--item ws-nowrap mb8" title="Viewed 6 times"> <span class="fc-light mr2"></span> 112 次 </div> </div> <div id="mainbar" role="main" aria-label="question and answers"> <div class="question" data-questionid="4" data-position-on-page="0" data-score="763" id="question"> <div class="post-layout"> <div class="votecell post-layout--left"> <div class="js-voting-container d-flex jc-center fd-column ai-stretch gs4 fc-black-200" data-post-id="4"> <button class="js-vote-up-btn flex--item s-btn s-btn__unset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Up vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-peeufs8c"> <svg aria-hidden="true" class="svg-icon iconArrowUpLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 25h32L18 9 2 25Z"></path></svg> </button> <div id="--stacks-s-tooltip-peeufs8c" class="s-popover s-popover__tooltip pe-none" aria-hidden="true" role="tooltip">This question shows research effort; 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height: auto; display: none;"></div> <div class="js-report-ad-button-container mx-auto" style="width: 300px"></div> </div> <div id="answers"> <a name="tab-top"></a> <div id="answers-header"> <div class="answers-subheader d-flex ai-center mb8"> <div class="flex--item fl1"> <h2 class="mb0" data-answercount=""> 2 回答 <span style="display:none;" itemprop="answerCount">2</span> </h2> </div> </div> </div> <a name="7"></a> <div id="answer-7" class="answer js-answer accepted-answer" data-answerid="7" data-parentid="4" data-score="506" data-position-on-page="1" data-highest-scored="1" data-question-has-accepted-highest-score="1" itemprop="suggestedAnswer" itemscope="" itemtype="https://schema.org/Answer"> <div class="post-layout"> <div class="votecell post-layout--left"> <div class="js-voting-container d-flex jc-center fd-column ai-stretch gs4 fc-black-200" data-post-id="7"> <button class="js-vote-up-btn flex--item s-btn s-btn__unset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Up vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-dgvag2l3"> <svg aria-hidden="true" class="svg-icon iconArrowUpLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 25h32L18 9 2 25Z"></path></svg> </button><div id="--stacks-s-tooltip-dgvag2l3" class="s-popover s-popover__tooltip pe-none" aria-hidden="true" role="tooltip">This answer is useful<div class="s-popover--arrow"></div></div> <div class="js-vote-count flex--item d-flex fd-column ai-center fc-black-500 fs-title" itemprop="upvoteCount" data-value="3"> 3 </div> <button class="js-vote-down-btn flex--item s-btn s-btn__unset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Down vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-gn8ppsfv"> <svg aria-hidden="true" class="svg-icon iconArrowDownLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 11h32L18 27 2 11Z"></path></svg> </button> </div> </div> <div class="answercell post-layout--right"> <div class="s-prose js-post-body" itemprop="text"> <p>想通了：有一个<code>beforeRender</code>你可以在类中重写的函数<code>View</code>，你可以设置它，例如</p> <pre><code>data ShowView = ShowView { targets :: [Include "comments" Post], postTitle :: Text } instance View ShowView ViewContext where beforeRender (context, view) = (context { layout = myLayout (postTitle view) }, view) html ShowView { .. } = [hsx| … |] </code></pre> <p>（并<code>postTitle</code>在 Web/Controller/Posts.hs 中设置），然后将 Web/View/Layout.hs 更改为</p> <pre><code>defaultLayout :: Html -> Html defaultLayout = myLayout "App" myLayout :: Text -> Html -> Html myLayout title inner = H.docTypeHtml ! A.lang "en" $ [hsx| <head> {metaTags} {stylesheets} {scripts} <title>{title}</title> </head> <body> <div class="container mt-4"> {renderFlashMessages} {inner} </div> </body> |] </code></pre> </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2020-10-10T15:30:29.223 回答</div> </div> </div> </div> </div><a name="7"></a> <div id="answer-7" class="answer js-answer accepted-answer" data-answerid="7" data-parentid="4" data-score="506" data-position-on-page="1" data-highest-scored="1" data-question-has-accepted-highest-score="1" itemprop="suggestedAnswer" itemscope="" itemtype="https://schema.org/Answer"> <div class="post-layout"> <div class="votecell post-layout--left"> <div class="js-voting-container d-flex jc-center fd-column ai-stretch gs4 fc-black-200" data-post-id="7"> <button class="js-vote-up-btn flex--item s-btn s-btn__unset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Up vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-dgvag2l3"> <svg aria-hidden="true" class="svg-icon iconArrowUpLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 25h32L18 9 2 25Z"></path></svg> </button><div id="--stacks-s-tooltip-dgvag2l3" class="s-popover s-popover__tooltip pe-none" aria-hidden="true" role="tooltip">This answer is useful<div class="s-popover--arrow"></div></div> <div class="js-vote-count flex--item d-flex fd-column ai-center fc-black-500 fs-title" itemprop="upvoteCount" data-value="1"> 1 </div> <button class="js-vote-down-btn flex--item s-btn s-btn__unset c-pointer " data-controller="s-tooltip" data-s-tooltip-placement="right" aria-pressed="false" aria-label="Down vote" data-selected-classes="fc-theme-primary" data-unselected-classes="" aria-describedby="--stacks-s-tooltip-gn8ppsfv"> <svg aria-hidden="true" class="svg-icon iconArrowDownLg" width="36" height="36" viewBox="0 0 36 36"><path d="M2 11h32L18 27 2 11Z"></path></svg> </button> </div> </div> <div class="answercell post-layout--right"> <div class="s-prose js-post-body" itemprop="text"> <p>现在有一个<code>pageTitle</code>你可以在视图中使用的函数（例如你的布局），如下所示：</p> <pre class="lang-hs prettyprint-override"><code>[hsx| <head> <title>{pageTitle}</title> </head> |] </code></pre> <p><a href="https://github.com/digitallyinduced/ihp/blob/18f104da69c526ff9e8ad3a6cdaedc6d39afb38c/IHP/PageTitle/ViewFunctions.hs#L54" rel="nofollow noreferrer">https://github.com/digitallyducing/ihp/blob/18f104da69c526ff9e8ad3a6cdaedc6d39afb38c/IHP/PageTitle/ViewFunctions.hs#L54</a></p> <p>反过来可以使用<code>setTitle</code></p> <pre class="lang-hs prettyprint-override"><code>action ShowProjectAction { projectId } = do project <- fetch projectId setTitle (get #title project) </code></pre> <p><a href="https://github.com/digitallyinduced/ihp/blob/d98c3d6eb8145d859c9ce461e7d1367be5be7337/IHP/PageTitle/ControllerFunctions.hs#L32" rel="nofollow noreferrer">https://github.com/digitallyducing/ihp/blob/d98c3d6eb8145d859c9ce461e7d1367be5be7337/IHP/PageTitle/ControllerFunctions.hs#L32</a></p> <p>最新的 IHP 还生成以下布局，您可以通过后备自动获得它：</p> <pre class="lang-hs prettyprint-override"><code>defaultLayout :: Html -> Html defaultLayout inner = H.docTypeHtml ! A.lang "en" $ [hsx| <head> {metaTags} {stylesheets} {scripts} <title>{pageTitleOrDefault "App"}</title> </head> <body> <div class="container mt-4"> {renderFlashMessages} {inner} </div> </body> |] </code></pre> </div> <div class="mt24"> <div class="user-action-time" style="color:#999;text-align:right;">于 2021-09-12T18:37:16.523 回答</div> </div> </div> </div> </div></div> </div> <div id="sidebar" class="show-votes" role="complementary" aria-label="sidebar"> <div class="module sidebar-related"> <h4 id="h-related">Related</h4> <div class="related js-gps-related-questions" data-tracker="rq=1"> <div class="spacer"> <a href="/questions/13565174" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">4</div> </a> <a href="/questions/13565174" class="question-hyperlink">java - 为什么Java中有2个布尔类型运算符？</a> </div><div class="spacer"> <a href="/questions/13565177" title="Question score (upvotes - downvotes)"> <div class="answer-votes large">2</div> </a> <a 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