说说vue-cli中使用flexible和px2rem-loader

待我称王封你为后i 2022-03-06 02:40 217阅读 1赞

**1.下载lib-flexible**

npm i lib-flexible --save
    或
    yarn add lib-flexible

**2.在项目中引入lib-flexible 一般情况在(main.js中引入lib-flexible)**

import 'lib-flexible/flexible'

**3.设置meta标签(视情况而定)**

**4.安装px2rem-loader**

npm install px2rem-loader   --save
    或
    yarn add px2rem-loader

**5.在webpack中配置px2rem-loader**

1，在项目build文件中找到util.js，将px2rem-loader添加到cssLoaders中，  
2，px2rem-loader 下的 remUnit 根据设计稿而定  
具体如下：

exports.cssLoaders = function (options) {
      options = options || {}
    
      const cssLoader = {
        loader: 'css-loader',
        options: {
          minimize: process.env.NODE_ENV === 'production',
          sourceMap: options.sourceMap
        }
      }
      //rem编译（新加px2）
      const px2remLoader = {
        loader: 'px2rem-loader',
        options: {
          remUnit: 75 // 由于设计稿是750
        }
      }
    
      function generateLoaders (loader, loaderOptions) {
        var loaders = [cssLoader,px2remLoader]//添加到loader里面
        省略.....
      }
    }

**6.项目中使用**

假设设计稿width和font-size分别是200px，50px  
具体代码：(按照设计稿写即可)

.demo{
        width: 200px;
        font-size: 50px;
    }

**7.单独使用flexible可直接添加一个rem.js文件，具体如下：**

1，配合less，sass和stylus来做px转换rem  
2，具体可参看[css编译][css]

/*
    ** 移动端自适应方案  FROM 手淘
    */
    export const setViewport = (()=>{//此处是单独使用
        const win = window
        const lib = window.lib || (window.lib = {})
    //;(function(win, lib) {//此处是直接使用
        let doc = win.document;
        let docEl = doc.documentElement;
        let metaEl = doc.querySelector('meta[name="viewport"]');
        let flexibleEl = doc.querySelector('meta[name="flexible"]');
        let dpr = 0;
        let scale = 0;
        let tid;
        let flexible = lib.flexible || (lib.flexible = {});
        
        if (metaEl) {
            //console.warn('将根据已有的meta标签来设置缩放比例');
            let match = metaEl.getAttribute('content').match(/initial\-scale=([\d\.]+)/);
            if (match) {
                scale = parseFloat(match[1]);
                dpr = parseInt(1 / scale);
            }
        } else if (flexibleEl) {
            let content = flexibleEl.getAttribute('content');
            if (content) {
                let initialDpr = content.match(/initial\-dpr=([\d\.]+)/);
                let maximumDpr = content.match(/maximum\-dpr=([\d\.]+)/);
                if (initialDpr) {
                    dpr = parseFloat(initialDpr[1]);
                    scale = parseFloat((1 / dpr).toFixed(2));
                }
                if (maximumDpr) {
                    dpr = parseFloat(maximumDpr[1]);
                    scale = parseFloat((1 / dpr).toFixed(2));
                }
            }
        }
    
        if (!dpr && !scale) {
            //let isAndroid = win.navigator.appVersion.match(/android/gi);
            let isIPhone = win.navigator.appVersion.match(/iphone/gi);
            let devicePixelRatio = win.devicePixelRatio;
            if (isIPhone) {
                // iOS下，对于2和3的屏，用2倍的方案，其余的用1倍方案
                if (devicePixelRatio >= 3 && (!dpr || dpr >= 3)) {                
                    dpr = 3;
                } else if (devicePixelRatio >= 2 && (!dpr || dpr >= 2)){
                    dpr = 2;
                } else {
                    dpr = 1;
                }
            } else {
                // 其他设备下，仍旧使用1倍的方案
                dpr = 1;
            }
            scale = 1 / dpr;
        }
    
        docEl.setAttribute('data-dpr', dpr);
        if (!metaEl) {
            metaEl = doc.createElement('meta');
            metaEl.setAttribute('name', 'viewport');
            metaEl.setAttribute('content', 'initial-scale=' + scale + ', maximum-scale=' + scale + ', minimum-scale=' + scale + ', user-scalable=no');
            if (docEl.firstElementChild) {
                docEl.firstElementChild.appendChild(metaEl);
            } else {
                let wrap = doc.createElement('div');
                wrap.appendChild(metaEl);
                doc.write(wrap.innerHTML);
            }
        }
    
        function refreshRem(){
            let width = docEl.getBoundingClientRect().width;
            if (width / dpr > 540) {
                width = 540 * dpr;
            }
            let rem = width / 10;
            docEl.style.fontSize = rem + 'px';
            flexible.rem = win.rem = rem;
        }
    
        win.addEventListener('resize', function() {
            clearTimeout(tid);
            tid = setTimeout(refreshRem, 300);
        }, false);
        win.addEventListener('pageshow', function(e) {
            if (e.persisted) {
                clearTimeout(tid);
                tid = setTimeout(refreshRem, 300);
            }
        }, false);
    
        if (doc.readyState === 'complete') {
            doc.body.style.fontSize = 12 * dpr + 'px';
        } else {
            doc.addEventListener('DOMContentLoaded', function() {
                doc.body.style.fontSize = 12 * dpr + 'px';
            }, false);
        }
    
        refreshRem();
    
        flexible.dpr = win.dpr = dpr;
        flexible.refreshRem = refreshRem;
        flexible.rem2px = function(d) {
            let val = parseFloat(d) * this.rem;
            if (typeof d === 'string' && d.match(/rem$/)) {
                val += 'px';
            }
            return val;
        };
        flexible.px2rem = function(d) {
            let val = parseFloat(d) / this.rem;
            if (typeof d === 'string' && d.match(/px$/)) {
                val += 'rem';
            }
            return val;
        };
    
    });
    //})(window, window.lib || (window.lib = {}));

[css]: https://segmentfault.com/a/1190000018306810