九、响应式发:rem和less(适配移动端)
一、响应式开发
响应式开发优先适配移动端又兼容到pc端
官网:https://less.bootcss.com/usage/
教程:https://www.w3cschool.cn/less/
rem和em:https://blog.csdn.net/u010132177/article/details/103725945
参考:https://www.jianshu.com/p/58a061c6e9af
1.1安装less依赖
cnpm install less less-loader --save-dev
//记录到devDependencies中,因为这是我们在开发中使用的而非在生产中使用(当然,也可以不加--save-dev)
1.1.2 安装 style-loader、css-loader
cnpm install --save-dev style-loader css-loader
【待整理】=====================
1.2 添加配置到 build/webpack.base.conf.js
【配置】
,{ //加less配置开始
test: /\.less$/,
use: [
"style-loader",
"css-loader",
"less-loader"
]
}//加less配置结尾
'use strict'
const path = require('path')
const utils = require('./utils')
const config = require('../config')
const vueLoaderConfig = require('./vue-loader.conf')
function resolve (dir) {
return path.join(__dirname, '..', dir)
}
module.exports = {
context: path.resolve(__dirname, '../'),
entry: {
app: './src/main.js'
},
output: {
path: config.build.assetsRoot,
filename: '[name].js',
publicPath: process.env.NODE_ENV === 'production'
? config.build.assetsPublicPath
: config.dev.assetsPublicPath
},
resolve: {
extensions: ['.js', '.vue', '.json'],
alias: {
'vue$': 'vue/dist/vue.esm.js',
'@': resolve('src'),
}
},
module: {
rules: [
{
test: /\.vue$/,
loader: 'vue-loader',
options: vueLoaderConfig
},
{
test: /\.js$/,
loader: 'babel-loader',
include: [resolve('src'), resolve('test'), resolve('node_modules/webpack-dev-server/client')]
},
{
test: /\.(png|jpe?g|gif|svg)(\?.*)?$/,
loader: 'url-loader',
options: {
limit: 10000,
name: utils.assetsPath('img/[name].[hash:7].[ext]')
}
},
{
test: /\.(mp4|webm|ogg|mp3|wav|flac|aac)(\?.*)?$/,
loader: 'url-loader',
options: {
limit: 10000,
name: utils.assetsPath('media/[name].[hash:7].[ext]')
}
},
{
test: /\.(woff2?|eot|ttf|otf)(\?.*)?$/,
loader: 'url-loader',
options: {
limit: 10000,
name: utils.assetsPath('fonts/[name].[hash:7].[ext]')
}
}, {//【配置】加less配置开始
test: /\.less$/,
use: [
"style-loader",
"css-loader",
"less-loader"
]
}//加less配置结尾]
},
node: {
// prevent webpack from injecting useless setImmediate polyfill because Vue
// source contains it (although only uses it if it's native).
setImmediate: false,
// prevent webpack from injecting mocks to Node native modules
// that does not make sense for the client
dgram: 'empty',
fs: 'empty',
net: 'empty',
tls: 'empty',
child_process: 'empty'
}
}
1.3 在根目录 index.html下添加代码:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1.0">
<link href="https://cdn.jsdelivr.net/npm/animate.css@3.5.1" rel="stylesheet" type="text/css">
<title>hello_vue</title>
<script>
(function (doc, win) {
var docEl = doc.documentElement,
resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
recalc = function () {
var clientWidth = docEl.clientWidth;
if (!clientWidth) return;
if(clientWidth>=750){
docEl.style.fontSize = '100px';
}else{
docEl.style.fontSize = 100 * (clientWidth / 750) + 'px';
}
};
if (!doc.addEventListener) return;
win.addEventListener(resizeEvt, recalc, false);
doc.addEventListener('DOMContentLoaded', recalc, false);
})(document, window);
</script>
</head>
<body>
<div id="app"></div>
<!-- built files will be auto injected -->
</body>
</html>
代码解释:
<1>设置meta属性 <meta name="viewport" content="width=device-width,initial-scale=1.0">
<script>
<2>运用rem特性进行宽度适配
(function(){
let html = document.documentElement,
hWidth = html.getBoundingClientRect().width;
console.log(hWidth);
html.style.fontSize = hWidth/15 + "px";//1rem的长度
})()//根据设计图进行设计,所有的页面完成必须是基于同一个设备或者说是同一分辨率的设备,比如上面代码中的15是可以根据你所选设备的分辨率自行进行选择,最后让font-size为5的倍数,上面代码的核心是保证在不同的设备分辨率下可以动态的调整rem(1rem 就等于 html的font-size)
<3>使用less或者是sass进行css开发,我是基于vue库进行开发的,所以进行如下操作引入less编译器
npm install less less-loader --save//下载less编译器
{
test: /\.less$/,
loader: "style-loader!css-loader!less-loader",
}//在webpack.base.conf.js 中的module模块中加入这都代码
<4> vue中使用less
<style lange="less">
@rem:25rem //这个值是如何确定的?比如我一开始的屏幕分辨率是基于iphone6 其中宽度为375px,所以此时我设置的font-size :375/15,即此时1rem为25px,所以我此时设置这个变量为25,看下面我对css变量的设置
.main{
width:280/@rem;//此时如果换在iphone6上面,在设计图上该样式的宽度为280px,这个是固定宽度,不能进行适配,所以我需要将其转尺寸换为rem来表示 此时@rem代表的是你的font-size尺寸(全套页面必须基于同一个设备分辨率来完成)即1rem, 所以280px对应的rem为280/@rem?
}
</style>
<script>
//使用原生js进行设备的适配
(function flexible (window, document) {
var docEl = document.documentElement
var dpr = window.devicePixelRatio || 1
// adjust body font size
function setBodyFontSize () {
if (document.body) {
document.body.style.fontSize = (12 * dpr) + 'px'
}
else {
document.addEventListener('DOMContentLoaded', setBodyFontSize)
}
}
setBodyFontSize();
// set 1rem = viewWidth / 10
function setRemUnit () {
var rem = docEl.clientWidth / 10
docEl.style.fontSize = rem + 'px'
}
setRemUnit()
// reset rem unit on page resize
window.addEventListener('resize', setRemUnit)
window.addEventListener('pageshow', function (e) {
if (e.persisted) {
setRemUnit()
}
})
// detect 0.5px supports
if (dpr >= 2) {
var fakeBody = document.createElement('body')
var testElement = document.createElement('div')
testElement.style.border = '.5px solid transparent'
fakeBody.appendChild(testElement)
docEl.appendChild(fakeBody)
if (testElement.offsetHeight === 1) {
docEl.classList.add('hairlines')
}
docEl.removeChild(fakeBody)
}
}(window, document))
</script>