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content"width=640,user-scalable=no" 然后再进行固定尺寸的px设计?

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WBOYOriginal
2016-06-07 08:43:323141Durchsuche

content"width=640,user-scalable=no" 然后再进行固定尺寸的px设计? 竟然也可以达到自适应的布局在手机上面
咱们不都是通常viewport content="width=device-width么 那么上面这种有没有什么坑呢 ,那么以后我是t content="width=device-width css3媒体查询 还是用content"width=640,user-scalable=no"这样的方法呢 我需要兼容手机浏览器和apk的webview

回复内容:

結論:content"width=640,user-scalable=no" 是一個很好的解決方案,荔枝FM,人人都是播客的移動站使用的就是此方案
固定宽度,viewport 缩放

视觉稿、页面宽度、viewport width 使用统一宽度,利用浏览器自身缩放完成适配。页面样式(包括图像元素)完全按照视觉稿的尺寸,使用定值单位 (px、em)即可完成。

优点:
  • 开发简单 缩放交给浏览器,完全按视觉稿切图。
  • 还原精准 绝对等比例缩放,可以精准还原视觉稿(不考虑清晰度的情况下)。
  • 测试方便 在PC端即可完成大部分测试,手机端只需酌情调整一些细节(比如图标、字体混合排列时,因为字体不同造成的对齐问题)。
存在的问题:
  • 像素丢失 对于一些分辨率较低的手机,可能设备像素还未达到指定的 viewport 宽度,此时屏幕的渲染可能就不准确了。比较常见的是边框“消失”了,不过随着手机硬件的更新,这个问题会越来越少的。
  • 缩放失效 某些安卓机不能正常的根据 meta 标签中 width 的值来缩放 viewport,需要配合initial-scale
  • 文本折行 存在于缩放失效的机型中,某些手机为了便于文本的阅读,在文本到达 viewport 边缘(非元素容器的边缘)时即进行折行,而当 viewport 宽度被修正后,浏览器并没有正确的重绘,所以就发现文本没有占满整行。一些常用的段落性文本标签会存在该问题。

缩放失效问题需通过 js 动态设定 initial-scale


利用 rem 布局

依照某特定宽度设定 rem 值(即 html 的 font-size),页面任何需要弹性适配的元素,尺寸均换算为 rem 进行布局;当页面渲染时,根据页面有效宽度进行计算,调整 rem 的大小,动态缩放以达到适配的效果。利用该方案,还可以根据 devicePixelRatio 设定 initial-scale 来放大 viewport,使页面按照物理像素渲染,提升清晰度。

优点:
  • 清晰度高,能达到物理像素的清晰度。
  • 能解决 DPR 引起的“1像素”问题。
  • 向后兼容较好,即便屏幕宽度增加、PPI 增加该方案依旧适用。
缺点:
  • 适配 js 需尽可能早进入,减少(避免)viewport 变化引起的重绘。
  • 某些Android机会丢掉 rem 小数部分。
  • 需要预编译库进行单位转换。
(轉自MobileWeb 适配总结) 别的不多说了,强烈建议看看前几天刚写的一篇文章:使用Flexible实现手淘H5页面的终端适配 应该能让你找到需要的答案 你在用的可能是:
<code class="language-html"> <span class="nt"><meta> <span class="na">name=</span><span class="s">"viewport"</span> <span class="na">content=</span><span class="s">"target-densitydpi=device-dpi,width=640,user-scalable=no"</span> <span class="nt">/></span>
</span></code>
这种做法就本质上是对界面进行线性缩放来适应不同大小的屏幕。对于一定尺寸范围内的设备是可以的。但如果想开发出跨越平板和手机的界面则不太合适。因为手机和平板屏幕尺寸差异太大,会导致缩放太大而是界面元素显得不太和谐。所以最好采用非线性缩放的办法。

<code class="language-js"><span class="c1">//首先检查浏览器类型</span>
<span class="kd">var</span> <span class="nx">browser</span> <span class="o">=</span> <span class="nx">getBrowser</span><span class="p">();</span>

<span class="k">if</span> <span class="p">(</span><span class="nb">window</span><span class="p">.</span><span class="nx">top</span> <span class="o">===</span> <span class="nb">window</span><span class="p">)</span> <span class="p">{</span>
	<span class="kd">var</span> <span class="nx">s</span><span class="p">,</span> <span class="nx">t</span><span class="p">,</span> <span class="nx">sw</span><span class="p">;</span>
	<span class="k">if</span> <span class="p">(</span><span class="nx">browser</span> <span class="o">===</span> <span class="s1">'Gecko'</span><span class="p">)</span> <span class="p">{</span>
		<span class="nx">s</span> <span class="o">=</span> <span class="nx">calcRato</span><span class="p">(</span><span class="nb">Math</span><span class="p">.</span><span class="nx">min</span><span class="p">(</span><span class="nx">screen</span><span class="p">.</span><span class="nx">width</span><span class="p">,</span> <span class="nx">screen</span><span class="p">.</span><span class="nx">height</span><span class="p">));</span>
		<span class="nb">document</span><span class="p">.</span><span class="nx">write</span><span class="p">(</span><span class="s1">'<meta name="viewport" content="width='</span> <span class=" o>+</span> <span class="mi">100</span> <span class="o">/</span> <span class="nx">s</span> <span class="o">+</span> <span class="s1">'%, user-scalable=no, initial-scale='</span> <span class="o">+</span> <span class="nx">s</span> <span class="o">+</span> <span class="s1">'"/>'</span><span class="p">);</span>
	<span class="p">}</span> <span class="k">else</span> <span class="k">if</span> <span class="p">(</span><span class="nx">browser</span> <span class="o">===</span> <span class="s1">'Trident'</span><span class="p">)</span> <span class="p">{</span>
		<span class="nb">document</span><span class="p">.</span><span class="nx">write</span><span class="p">(</span><span class="s1">'<meta name="viewport" content="width=device-width, user-scalable=no">'</span><span class="p">);</span>
		<span class="nb">document</span><span class="p">.</span><span class="nx">documentElement</span><span class="p">.</span><span class="nx">style</span><span class="p">.</span><span class="nx">zoom</span> <span class="o">=</span> <span class="nx">calcRato</span><span class="p">(</span><span class="nb">Math</span><span class="p">.</span><span class="nx">min</span><span class="p">(</span><span class="nx">screen</span><span class="p">.</span><span class="nx">width</span><span class="p">,</span> <span class="nx">screen</span><span class="p">.</span><span class="nx">height</span><span class="p">));</span>
	<span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
		<span class="nx">t</span> <span class="o">=</span> <span class="nb">document</span><span class="p">.</span><span class="nx">createElement</span><span class="p">(</span><span class="s1">'meta'</span><span class="p">);</span>
		<span class="nx">t</span><span class="p">.</span><span class="nx">name</span> <span class="o">=</span> <span class="s1">'viewport'</span><span class="p">;</span>
		<span class="nx">t</span><span class="p">.</span><span class="nx">content</span> <span class="o">=</span> <span class="s1">'width=device-width, user-scalable=no, initial-scale=1'</span><span class="p">;</span>
		<span class="nb">document</span><span class="p">.</span><span class="nx">head</span><span class="p">.</span><span class="nx">appendChild</span><span class="p">(</span><span class="nx">t</span><span class="p">);</span>
		<span class="nx">sw</span> <span class="o">=</span> <span class="nb">Math</span><span class="p">.</span><span class="nx">min</span><span class="p">(</span><span class="nx">screen</span><span class="p">.</span><span class="nx">width</span><span class="p">,</span> <span class="nx">screen</span><span class="p">.</span><span class="nx">height</span><span class="p">);</span>
		<span class="k">if</span> <span class="p">(</span><span class="nb">Math</span><span class="p">.</span><span class="nx">min</span><span class="p">(</span><span class="nx">screen</span><span class="p">.</span><span class="nx">width</span> <span class="o">/</span> <span class="nb">window</span><span class="p">.</span><span class="nx">innerWidth</span><span class="p">,</span> <span class="nx">screen</span><span class="p">.</span><span class="nx">height</span> <span class="o">/</span> <span class="nb">window</span><span class="p">.</span><span class="nx">innerHeight</span><span class="p">)</span> <span class="o">></span> <span class="mi">1</span><span class="p">)</span> <span class="p">{</span>
			<span class="nb">document</span><span class="p">.</span><span class="nx">documentElement</span><span class="p">.</span><span class="nx">style</span><span class="p">.</span><span class="nx">zoom</span> <span class="o">=</span> <span class="nx">calcRato</span><span class="p">(</span><span class="nx">sw</span> <span class="o">/</span> <span class="nx">devicePixelRatio</span><span class="p">);</span>
		<span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
			<span class="nx">s</span> <span class="o">=</span> <span class="nx">calcRato</span><span class="p">(</span><span class="nx">sw</span><span class="p">);</span>
			<span class="nx">t</span><span class="p">.</span><span class="nx">content</span> <span class="o">=</span> <span class="s1">'width='</span> <span class="o">+</span> <span class="mi">100</span> <span class="o">/</span> <span class="nx">s</span> <span class="o">+</span> <span class="s1">'%, user-scalable=no, initial-scale='</span> <span class="o">+</span> <span class="nx">s</span><span class="p">;</span>
		<span class="p">}</span>
	<span class="p">}</span>
<span class="p">}</span>

<span class="kd">function</span> <span class="nx">calcRato</span><span class="p">(</span><span class="nx">sw</span><span class="p">)</span> <span class="p">{</span>
	<span class="c1">//离散放大级别</span>
	<span class="kd">var</span> <span class="nx">step</span> <span class="o">=</span> <span class="mf">0.125</span><span class="p">;</span>
	<span class="c1">//基准宽度为320px</span>
	<span class="kd">var</span> <span class="nx">zoom</span> <span class="o">=</span> <span class="nx">sw</span> <span class="o">/</span> <span class="mi">320</span><span class="p">;</span>
	<span class="c1">//放大时不使用线性算法</span>
	<span class="k">if</span> <span class="p">(</span><span class="nx">zoom</span> <span class="o">></span> <span class="mi">1</span><span class="p">)</span> <span class="p">{</span>
		<span class="nx">zoom</span> <span class="o">=</span> <span class="nb">Math</span><span class="p">.</span><span class="nx">floor</span><span class="p">(</span><span class="nb">Math</span><span class="p">.</span><span class="nx">sqrt</span><span class="p">(</span><span class="nx">zoom</span><span class="p">)</span> <span class="o">/</span> <span class="nx">step</span><span class="p">)</span> <span class="o">*</span> <span class="nx">step</span><span class="p">;</span>
	<span class="p">}</span>
	<span class="k">return</span> <span class="nx">zoom</span><span class="p">;</span>
<span class="p">}</span>
</code>
对,我也是用这种方法比较方便。不过由于宽高等比缩放后,在元素定位布局时很多手机的屏幕就不够高,因此还是得媒体查询做些细节上的调节 用过这种代码写hybrid app效果还行,核心区别就在于它没有媒体查询,手机,平板都长一个样,等比缩放不仔细看效果也不差(毕竟会变形),如果你只需要开发个大部分机型适配的页面,我觉得这么写挺好
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