96 lines
4.4 KiB
Plaintext
96 lines
4.4 KiB
Plaintext
page.title=Best Practices for Web Apps
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@jd:body
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<style>
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.bold li {
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font-weight:bold;
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}
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.bold li * {
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font-weight:normal;
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}
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</style>
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<p>Developing web pages and web applications for mobile devices presents a different set of
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challenges compared to developing a web page for the typical
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desktop web browser. To help you get started, the following is a list of practices you should
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follow in order to provide the most effective web application for Android and other mobile
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devices.</p>
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<ol class="bold">
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<li>Redirect mobile devices to a dedicated mobile version of your web site
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<p>There are several ways you can redirect requests to the mobile version of your web site, using
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server-side redirects. Most often, this is done by "sniffing" the User Agent
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string provided by the web browser. To determine whether to serve a mobile version of your site, you
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should simply look for the "mobile" string in the User Agent, which matches a wide variety of mobile
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devices. If necessary, you can also identify the specific operating system in the User Agent string
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(such as "Android 2.1").</p>
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<p class="note"><strong>Note:</strong> Large screen Android-powered devices that should be served
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full-size web sites (such as tablets) do <em>not</em> include the "mobile" string in the user agent,
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while the rest of the user agent string is mostly the same. As such, it's important that you deliver
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the mobile version of your web site based on whether the "mobile" string exists in the user
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agent.</p>
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</li>
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<li>Use a valid markup DOCTYPE that's appropriate for mobile devices
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<p>The most common markup language used for mobile web sites is <a
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href="http://www.w3.org/TR/2008/REC-xhtml-basic-20080729/">XHTML Basic</a>. This standard
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ensures specific markup for your web site that works best on mobile devices. For instance, it does
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not allow HTML frames or nested tables, which perform poorly on mobile devices. Along with the
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DOCTYPE, be sure to declare the appropriate character encoding for the document (such as
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UTF-8).</p>
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<p>For example:</p>
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<pre>
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.1//EN"
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"http://www.w3.org/TR/xhtml-basic/xhtml-basic11.dtd">
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</pre>
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<p>Also be sure that your web page markup is valid against the declared DOCTYPE. Use a
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validator, such as the one available at
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<a href="http://validator.w3.org/">http://validator.w3.org</a>.</p>
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</li>
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<li>Use viewport meta data to properly resize your web page
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<p>In your document {@code <head>}, you should provide meta data that specifies how you
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want the browser's viewport to render your web page. For example, your viewport meta data can
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specify the height and width for the browser's viewport, the initial web page scale and even the
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target screen density.</p>
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<p>For example:</p>
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<pre>
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<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
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</pre>
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<p>For more information about how to use viewport meta data for Android-powered devices, read <a
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href="{@docRoot}guide/webapps/targeting.html">Targeting Screens from Web Apps</a>.</p>
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</li>
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<li>Avoid multiple file requests
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<p>Because mobile devices typically have a connection speed far slower than a desktop
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computer, you should make your web pages load as fast as possible. One way to speed it up is to
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avoid loading extra files such as stylesheets and script files in the {@code
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<head>}. Instead, provide your CSS and JavaScript directly in the <head> (or
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at the end of the <body>, for scripts that you don't need until the page is loaded).
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Alternatively, you should optimize the size and speed of your files by compressing them with tools
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like <a href="http://code.google.com/p/minify/">Minify</a>.</p>
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</li>
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<li>Use a vertical linear layout
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<p>Avoid the need for the user to scroll left and right while navigating your web
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page. Scrolling up and down is easier for the user and makes your web page simpler.</p>
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</li>
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</ol>
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<p>For a more thorough guide to creating great mobile web applications, see the W3C's <a
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href="http://www.w3.org/TR/mobile-bp/">Mobile Web Best Practices</a>. For other guidance on
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improving the speed of your web site (for mobile and desktop), see Yahoo!'s guide to <a
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href="http://developer.yahoo.com/performance/index.html#rules">Exceptional Performance</a> and
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Google's speed tutorials in <a href="http://code.google.com/speed/articles/">Let's make the web
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faster</a>.</p>
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