83 lines
15 KiB
HTML
83 lines
15 KiB
HTML
<!DOCTYPE html><html lang="en"><head><meta charSet="utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=edge"/><title>React Navigation · React Native Camera</title><meta name="viewport" content="width=device-width"/><meta name="generator" content="Docusaurus"/><meta name="description" content="<p>React-navigation does not unmount components when switching between tabs. So when you leave and return back to the screen with the camera component it will just be black view. So a good solution is to use <code>componentDidMount</code> and added two listeners <code>willFocus</code> and <code>willBlur</code> to help you mount and unmount the views.</p>
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"/><meta name="docsearch:language" content="en"/><meta property="og:title" content="React Navigation · React Native Camera"/><meta property="og:type" content="website"/><meta property="og:url" content="https://react-native-community/github.io/react-native-camera/"/><meta property="og:description" content="<p>React-navigation does not unmount components when switching between tabs. So when you leave and return back to the screen with the camera component it will just be black view. So a good solution is to use <code>componentDidMount</code> and added two listeners <code>willFocus</code> and <code>willBlur</code> to help you mount and unmount the views.</p>
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"/><meta property="og:image" content="https://react-native-community/github.io/react-native-camera/img/undraw_online.svg"/><meta name="twitter:card" content="summary"/><meta name="twitter:image" content="https://react-native-community/github.io/react-native-camera/img/undraw_tweetstorm.svg"/><link rel="shortcut icon" href="/react-native-camera/img/community.png"/><link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/atom-one-dark.min.css"/><link rel="stylesheet" href="/css/code-block-buttons.css"/><script type="text/javascript" src="https://buttons.github.io/buttons.js"></script><script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/clipboard.js/2.0.0/clipboard.min.js"></script><script type="text/javascript" src="/js/code-blocks-buttons.js"></script><script src="/react-native-camera/js/scrollSpy.js"></script><link rel="stylesheet" href="/react-native-camera/css/prism.css"/><link rel="stylesheet" href="/react-native-camera/css/main.css"/><script src="/react-native-camera/js/codetabs.js"></script></head><body class="sideNavVisible separateOnPageNav"><div class="fixedHeaderContainer"><div class="headerWrapper wrapper"><header><a href="/react-native-camera/"><img class="logo" src="/react-native-camera/img/community.png" alt="React Native Camera"/><h2 class="headerTitleWithLogo">React Native Camera</h2></a><div class="navigationWrapper navigationSlider"><nav class="slidingNav"><ul class="nav-site nav-site-internal"><li class="siteNavGroupActive"><a href="/react-native-camera/docs/installation" target="_self">Docs</a></li><li class="siteNavGroupActive"><a href="/react-native-camera/docs/expo_usage" target="_self">Guides</a></li><li class="siteNavGroupActive"><a href="/react-native-camera/docs/api" target="_self">API</a></li><li class=""><a href="/react-native-camera/docs/qa" target="_self">Help</a></li><li class=""><a href="https://github.com/react-native-community/react-native-camera" target="_self">GitHub</a></li></ul></nav></div></header></div></div><div class="navPusher"><div class="docMainWrapper wrapper"><div class="container docsNavContainer" id="docsNav"><nav class="toc"><div class="toggleNav"><section class="navWrapper wrapper"><div class="navBreadcrumb wrapper"><div class="navToggle" id="navToggler"><div class="hamburger-menu"><div class="line1"></div><div class="line2"></div><div class="line3"></div></div></div><h2><i>›</i><span>Guides</span></h2><div class="tocToggler" id="tocToggler"><i class="icon-toc"></i></div></div><div class="navGroups"><div class="navGroup"><h3 class="navGroupCategoryTitle">Getting Started</h3><ul class=""><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/installation">Installation</a></li><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/contributing">Contributing</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Guides</h3><ul class=""><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/expo_usage">Expo Usage</a></li><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/GradleUpgradeGuide">Gradle Upgrade Guide</a></li><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/migration">Migrating from RCTCamera to RNCamera</a></li><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/migrationv2">Migrating from version 1.x to 2.x</a></li><li class="navListItem navListItemActive"><a class="navItem" href="/react-native-camera/docs/react-navigation">React Navigation</a></li><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/recipes">Recipes</a></li><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/rncamera">RNCamera</a></li><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/tests">Testing</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">API</h3><ul class=""><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/api">Work in progress</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Help</h3><ul class=""><li class="navListItem"><a class="navItem" href="/react-native-camera/docs/qa">Q & A</a></li></ul></div></div></section></div><script>
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</script></nav></div><div class="container mainContainer"><div class="wrapper"><div class="post"><header class="postHeader"><a class="edit-page-link button" href="https://github.com/react-native-community/react-native-camera/master/docs/react-navigation.md" target="_blank" rel="noreferrer noopener">Edit</a><h1 class="postHeaderTitle">React Navigation</h1></header><article><div><span><p>React-navigation does not unmount components when switching between tabs. So when you leave and return back to the screen with the camera component it will just be black view. So a good solution is to use <code>componentDidMount</code> and added two listeners <code>willFocus</code> and <code>willBlur</code> to help you mount and unmount the views.</p>
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<pre><code class="hljs css language-jsx"><span class="token function">componentDidMount</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">const</span> <span class="token punctuation">{</span> navigation <span class="token punctuation">}</span> <span class="token operator">=</span> <span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">;</span>
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navigation<span class="token punctuation">.</span><span class="token function">addListener</span><span class="token punctuation">(</span><span class="token string">'willFocus'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=></span>
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<span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span> focusedScreen<span class="token punctuation">:</span> <span class="token boolean">true</span> <span class="token punctuation">}</span><span class="token punctuation">)</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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navigation<span class="token punctuation">.</span><span class="token function">addListener</span><span class="token punctuation">(</span><span class="token string">'willBlur'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=></span>
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<span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span> focusedScreen<span class="token punctuation">:</span> <span class="token boolean">false</span> <span class="token punctuation">}</span><span class="token punctuation">)</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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<span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">const</span> <span class="token punctuation">{</span> hasCameraPermission<span class="token punctuation">,</span> focusedScreen <span class="token punctuation">}</span> <span class="token operator">=</span> <span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">;</span>
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<span class="token keyword">if</span> <span class="token punctuation">(</span>hasCameraPermission <span class="token operator">===</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">return</span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span><span class="token class-name">View</span></span> <span class="token punctuation">/></span></span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>hasCameraPermission <span class="token operator">===</span> <span class="token boolean">false</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">return</span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span><span class="token class-name">Text</span></span><span class="token punctuation">></span></span>No access to camera<span class="token tag"><span class="token tag"><span class="token punctuation"></</span><span class="token class-name">Text</span></span><span class="token punctuation">></span></span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>focusedScreen<span class="token punctuation">)</span><span class="token punctuation">{</span>
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<span class="token keyword">return</span> <span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">cameraView</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
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<span class="token keyword">return</span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span><span class="token class-name">View</span></span> <span class="token punctuation">/></span></span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">}</span>
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</code></pre>
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</span></div></article></div><div class="docLastUpdate"><em>Last updated on 6/2/2019 by Ronaldo Lima</em></div><div class="docs-prevnext"><a class="docs-prev button" href="/react-native-camera/docs/migrationv2"><span class="arrow-prev">← </span><span>Migrating from version 1.x to 2.x</span></a><a class="docs-next button" href="/react-native-camera/docs/recipes"><span>Recipes</span><span class="arrow-next"> →</span></a></div></div></div><nav class="onPageNav"></nav></div><footer class="nav-footer" id="footer"><section class="sitemap"><a href="/react-native-camera/" class="nav-home"><img src="/react-native-camera/img/community.png" alt="React Native Camera" width="66" height="58"/></a><div><h5>Docs</h5><a href="/react-native-camera/docs/en/installation.html">Getting Started</a><a href="/react-native-camera/docs/en/expo_usage.html">Guides</a><a href="/react-native-camera/docs/en/api.html">API Reference</a></div><div><h5>Community</h5><a href="/react-native-camera/en/users.html">User Showcase</a><a href="https://stackoverflow.com/questions/tagged/react-native-camera" target="_blank" rel="noreferrer noopener">Stack Overflow</a><a href="https://spectrum.chat/">Project Chat</a></div><div><h5>More</h5><a href="https://github.com/react-native-community/react-native-camera">GitHub</a><a class="github-button" href="https://github.com/react-native-community/react-native-camera" data-icon="octicon-star" data-count-href="/facebook/docusaurus/stargazers" data-show-count="true" data-count-aria-label="# stargazers on GitHub" aria-label="Star this project on GitHub">Star</a></div></section><a href="https://opensource.facebook.com/" target="_blank" rel="noreferrer noopener" class="fbOpenSource"><img src="/react-native-camera/img/oss_logo.png" alt="Facebook Open Source" width="170" height="45"/></a><section class="copyright">Copyright © 2019</section></footer></div></body></html> |