移動端(手機端)頁面自適應解決方案—rem佈局篇
阿新 • • 發佈:2018-12-10
動端(手機端)頁面自適應解決方案—rem佈局
假設設計妹妹給我們的設計稿尺寸為750 * 1340。結合網易、淘寶移動端首頁html元素上的動態font-size屬性、設計稿尺寸、前端與設計之間協作流程一般分為下面兩種:
一、網易做法:
引入:頁面開頭處引入下面這段程式碼,用於動態計算font-size
(function(doc, win) { var docEl = doc.documentElement, isIOS = navigator.userAgent.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/), dpr = isIOS ? Math.min(win.devicePixelRatio, 3) : 1, dpr = window.top === window.self ? dpr : 1, //被iframe引用時,禁止縮放 dpr = 1, scale = 1 / dpr, resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize'; docEl.dataset.dpr = dpr; var metaEl = doc.createElement('meta'); metaEl.name = 'viewport'; metaEl.content = 'initial-scale=' + scale + ',maximum-scale=' + scale + ', minimum-scale=' + scale; docEl.firstElementChild.appendChild(metaEl); var recalc = function() { var width = docEl.clientWidth; if (width / dpr > 750) { width = 750 * dpr; } // 乘以100,px : rem = 100 : 1 docEl.style.fontSize = 100 * (width / 750) + 'px'; }; recalc() if (!doc.addEventListener) return; win.addEventListener(resizeEvt, recalc, false); })(document, window);
使用:
未引入前:
body {
width: 750px;
height: 640px;
}
引入後:除以100並將px換成rem
body {
width: 7.5rem;
height: 6.4rem;
}
換算的依據:
// 乘以100,px : rem = 100 : 1 var recalc = function() { var width = docEl.clientWidth; if (width / dpr > 750) { width = 750 * dpr; } // 乘以100,px : rem = 100 : 1 docEl.style.fontSize = 100 * (width / 750) + 'px'; };
二、淘寶做法(推薦做法,尤其是app內嵌頁面):
引入:頁面開頭處引入下面這段程式碼,用於動態計算font-size,或者單獨放入一個檔案,引入檔案也可以
; (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) { var match = metaEl.getAttribute('content').match(/initial\-scale=([\d\.]+)/); if (match) { scale = parseFloat(match[1]); dpr = parseInt(1 / scale); } } else if (flexibleEl) { 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,對於2和3的屏,用2倍的方案,其餘的用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 { // 其他裝置下,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; // 適配平板 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'] = {}));
使用:
未引入前:
body {
width: 750px;
height: 640px;
}
引入後:
@font-size-base: 75;
body {
width: 750rem/@font-size-base;
height: 640rem/@font-size-base;
}
換算依據:
function refreshRem() {
var width = docEl.getBoundingClientRect().width;
// 適配平板
if (width / dpr > 540) {
width = 540 * dpr;
}
var rem = width / 10;
docEl.style.fontSize = rem + 'px';
flexible.rem = win.rem = rem;
}
這邊是用的less,如果您沒有用less,就需要手動計算,當然也可以轉化為px : rem = 100 : 1。
如果想轉化為px : rem = 100 : 1,可以修改上面的refreshRem函式:
function refreshRem() {
var width = docEl.getBoundingClientRect().width
// 適配平板
if (width / dpr > 750) {
width = 750 * dpr
}
var rem = 100 * (width / 750)
docEl.style.fontSize = rem + 'px'
flexible.rem = win.rem = rem;
}
使用:
未引入前:
body {
width: 750px;
height: 640px;
}
引入後:除以100並將px換成rem
body {
width: 7.5rem;
height: 6.4rem;
}
換算依據就是上面修改的程式碼:
function refreshRem() {
var width = docEl.getBoundingClientRect().width
// 適配平板
if (width / dpr > 750) {
width = 750 * dpr
}
var rem = 100 * (width / 750)
docEl.style.fontSize = rem + 'px'
flexible.rem = win.rem = rem;
}