Android浏览器默认预览模式浏览 会缩小页面 WebView中则会以原始大小显示
Android浏览器和WebView默认为mdpi。hdpi相当于mdpi的1.5倍 ldpi相当于0.75倍
三种解决方式:1 viewport属性 2 CSS控制 3 JS控制
1 viewport属性放在HTML的<meta>中
Html代码
<SPAN style="FONT-SIZE: x-small"> <head> <title>Exmaple</title> <meta name=”viewport” content=”width=device-width,user-scalable=no”/> </head> </SPAN>
meta中viewport的属性如下
Html代码
<SPAN style="FONT-SIZE: x-small"> <meta name="viewport" content=" height = [pixel_value | device-height] , width = [pixel_value | device-width ] , initial-scale = float_value , minimum-scale = float_value , maximum-scale = float_value , user-scalable = [yes | no] , target-densitydpi = [dpi_value | device-dpi | high-dpi | medium-dpi | low-dpi] " /> </SPAN>
2 CSS控制设备密度
为每种密度创建独立的样式表(注意其中的webkit-device-pixel-ratio 3个数值对应3种分辨率)
Html代码
<link rel="stylesheet" media="screen and (-webkit-device-pixel-ratio: 1.5)" href="hdpi.css" /> <link rel="stylesheet" media="screen and (-webkit-device-pixel-ratio: 1.0)" href="mdpi.css" /> <link rel="stylesheet" media="screen and (-webkit-device-pixel-ratio: 0.75)" href="ldpi.css" />
在一个样式表中,指定不同的样式
Html代码
#header { <SPAN style="WHITE-SPACE: pre"></SPAN> background:url(medium-density-image.png); } @media screen and (-webkit-device-pixel-ratio: 1.5) { // CSS for high-density screens #header { background:url(high-density-image.png); } } @media screen and (-webkit-device-pixel-ratio: 0.75) { // CSS for low-density screens #header { background:url(low-density-image.png); } }
Html代码
<meta name="viewport" content="target-densitydpi=device-dpi, width=device-width" />
3 JS控制
Android浏览器和WebView支持查询当前设别密度的DOM特性
window.devicePixelRatio 同样值有3个(0.75,1,1.5对应3种分辨率)
JS中查询设备密度的方法
Js代码
if (window.devicePixelRatio == 1.5) { alert("This is a high-density screen"); } else if (window.devicePixelRation == 0.75) { alert("This is a low-density screen"); }