摘要：安裝插件在終端執行在中配置使用適配倍屏，倍屏的封裝的將根據已有的標簽來設置縮放比例下，對于和的屏，用倍的方案，其余的用倍方案其他設備下，仍舊使用倍的方案在入口文件中引入在中就可以愉快的編寫啦，使用，下面上傳

1.安裝插件postcss-px2rem
在終端執行：npm install postcss-px2rem --save
2.在build/vue-loader.conf.js 中配置使用postcss-px2rem

module.exports = {
  loaders: utils.cssLoaders({
    sourceMap: isProduction
      ? config.build.productionSourceMap
      : config.dev.cssSourceMap,
    extract: isProduction
  }),
  postcss: [
    require("autoprefixer")({browsers: ["iOS >= 7", "Android >= 4.1"]}),
    require("postcss-px2rem")({remUnit: 75, "baseDpr":2})

  ],
  transformToRequire: {
    video: "src",
    source: "src",
    img: "src",
    image: "xlink:href"
  }
}

3.適配2倍屏，3倍屏的封裝的flex.js

;
(function(win, lib) {
    var doc = win.document;
    var docEl = doc.documentElement;
    var metaEl = doc.querySelector("meta[name="viewport"]");
    var flexibleEl = doc.querySelector("meta[name="flexible"]");
    var dpr = 0;
    var scale = 0;
    var tid;
    var flexible = lib.flexible || (lib.flexible = {});

    if (metaEl) {
        //console.warn("將根據已有的meta標簽來設置縮放比例");
        var match = metaEl.getAttribute("content").match(/initial-scale=([d.]+)/);
        if (match) {
            scale = parseFloat(match[1]);
            dpr = parseInt(1 / scale);
        }
        var content = flexibleEl.getAttribute("content");
        if (content) {
            var initialDpr = content.match(/initial-dpr=([d.]+)/);
            var 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) {
        var isAndroid = win.navigator.appVersion.match(/android/gi);
        var isIPhone = win.navigator.appVersion.match(/iphone/gi);
        var devicePixelRatio = win.devicePixelRatio;
        if (isIPhone) {
            // iOS下，對于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 {
            // 其他設備下，仍舊使用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 {
            var wrap = doc.createElement("div");
            wrap.appendChild(metaEl);
            doc.write(wrap.innerHTML);
        }
    }

    function refreshRem() {
        var width = docEl.getBoundingClientRect().width;
        if (width / dpr > 540) {
            width = 540 * dpr;
        }
        var 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(e) {
            doc.body.style.fontSize = 12 * dpr + "px";
        }, false);
    }


    refreshRem();

    flexible.dpr = win.dpr = dpr;
    flexible.refreshRem = refreshRem;
    flexible.rem2px = function(d) {
        var val = parseFloat(d) * this.rem;
        if (typeof d === "string" && d.match(/rem$/)) {
            val += "px";
        }
        return val;
    }
    flexible.px2rem = function(d) {
        var val = parseFloat(d) / this.rem;
        if (typeof d === "string" && d.match(/px$/)) {
            val += "rem";
        }
        return val;
    }

})(window, window["lib"] || (window["lib"] = {}));

4.在入口文件main.js中引入flex.js

import "@/assets/js/flex.js";
import Vue from "vue";

import App from "./App";

Vue.config.productionTip = false

/* eslint-disable no-new */
new Vue({
  el: "#app",
  render: h => h(App)
})

5.在css 中就可以愉快的編寫css啦，使用px ，下面上傳使用代碼；

#app {
  width: 200px;
  height: 400px;
  background: red;
}

職場小白south Joe，望各位大神批評指正，祝大家學習愉快！