学习flex布局，并用flex模仿php中文网首页，听老师讲的时候感觉是会了，当自己动手的时候还真的费劲了，真是看花容易绣花难啊。先看看示例：
实例
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>php中文网手机端-首页</title>
<style>
body {
margin: 0 auto;
background: #edeff0;
overflow-y: initial;
position: relative;
/*不要出现水平滚动条*/
overflow-x: hidden;
/*设置点击链接跳转时出现高亮,设置为透明: ios / ipad*/
-webkit-tap-highlight-color: transparent;
}
.top {
position: fixed;
top: 0;
width: 100%;
height: 42px;
background-color: #444444;
left: 50%;
-webkit-transform: translateX(-50%);
transform: translateX(-50%);
}
.top {
display: flex;
}
.top img:first-of-type,
.top img:last-of-type {
width: 25px;
height: 25px;
margin-top: 8px;
}
.top img:first-of-type {
border-radius: 50%;
margin-left: 5px;
}
.top .logo {
text-align: center;
flex: 1;
}
.top .logo img {
width: 94px;
height: 45px;
margin-top: -2px;
}
/*轮播图*/
.banner {
display: flex;
margin-top: 40px;
}
.banner img {
width: 100%;
height: 160px;
}
/*导航区*/
.nav {
height: 170px;
background-color: white;
box-sizing: border-box;
}
.nav ul {
margin: 0;
padding: 6px;
}
.nav ul li {
list-style-type: none;
text-align: center;
height: 75px;
}
.nav ul li img {
width: 45px;
height: 45px;
}
.nav ul li a {
text-align: center;
color: gray;
text-decoration: none;
}
.nav ul {
display: flex;
}
.nav ul li {
flex: 1;
}
/*推荐课程区*/
h3 {
color: gray;
padding-left: 10px;
}
.courses {
height: 326px;
color: gray;
}
.courses ul {
margin: 0;
padding: 0;
list-style: none;
/*flex布局*/
display: flex;
}
.courses ul li {
padding: 5px;
flex: 1;
}
.courses ul img {
width: 100%;
height: 90px;
}
.courses div {
background-color: white;
padding: 10px;
margin-top: 10px;
height: 90px;
/*flex布局*/
display: flex;
justify-content: flex-start;
}
.courses div img {
width: 100%;
height: 90px;
}
.courses div a {
text-decoration: none;
color: gray;
flex: 0.45;
}
.courses div p {
flex: .55;
margin-left: 15px;
}
.courses div p span:first-of-type {
font-size: 0.8rem;
background-color: black;
color: white;
border-radius: 30%;
padding: 0 2px;
}
.courses div p span:last-of-type {
font-size: 0.7rem;
}
/* 最新更新 **************/
.news-container {
height: 226px;
color: gray;
}
.news-container ul {
margin: 0;
padding: 0;
list-style: none;
/*flex布局*/
display: flex;
}
.nenews-containerws ul li {
padding: 5px;
flex: 1;
}
.news-container ul img {
width: 100%;
height: 90px;
}
.news-container div {
background-color: white;
padding: 10px;
margin-top: 10px;
height: 90px;
/*flex布局*/
display: flex;
justify-content: flex-start;
}
.news-container div img {
width: 100%;
height: 90px;
}
.news-container div a {
text-decoration: none;
color: gray;
flex: 0.45;
}
.news-container div p {
flex: .55;
margin-left: 15px;
}
.news-container div p span:nth-of-type(2) {
font-size: 0.8rem;
background-color: black;
color: white;
border-radius: 30%;
padding: 0 2px;
}
.news-container div p span:nth-of-type(1) {
display: block;
/*内联对象需加*/
overflow: hidden;
white-space: nowrap;
text-overflow: ellipsis;
width: 300px;
}
.news-container div p span:last-of-type {
font-size: 0.7rem;
}
h3.news {
margin-top: 49px;
padding-left: 10px;
}
.news_span {
float: right;
padding: 12px;
}
/* **********************最新文章 **************/
.wenz-container {
height: 326px;
color: gray;
margin-bottom: 20em;
}
.wenz-container ul {
margin: 0;
padding: 0;
list-style: none;
/*flex布局*/
display: flex;
}
.wenz-containerws ul li {
padding: 5px;
flex: 1;
}
.wenz-container ul img {
width: 100%;
height: 90px;
}
.wenz-container div {
background-color: white;
padding: 10px;
margin-top: 10px;
height: 90px;
/*flex布局*/
display: flex;
flex-direction: row-reverse;
justify-content: flex-start;
}
.wenz-container div img {
width: 100%;
height: 90px;
}
.wenz-container div a {
text-decoration: none;
color: gray;
flex: 0.45;
}
.wenz-container div p {
flex: .55;
margin-left: 15px;
}
.wenz-container div p span:nth-of-type(2) {
font-size: 0.8rem;
background-color: black;
color: white;
border-radius: 30%;
padding: 0 2px;
}
.wenz-container div p span:nth-of-type(1) {
padding: 9px;
}
.wenz-container div p span:last-of-type {
font-size: 0.7rem;
}
h3.wenz {
margin-top: 23px;
padding-left: 10px;
}
.wenz_span {
float: right;
padding: 12px;
}
/*底部样式*/
.footer {
position: fixed;
bottom: 0;
width: 100%;
height: 42px;
background: #eee;
}
.footer ul {
display: flex;
margin: 0;
padding: 0;
list-style-type: none;
text-align: center;
}
.footer ul li img {
width: 20px;
height: 20px;
}
.footer ul li a {
color: gray;
text-decoration: none;
}
.footer ul li {
flex: 1;
}
</style>
</head>
<body>
<!--布局原则: 宽宽自适应, 高度是固定-->
<!--固定定位: 顶部-->
<div class="top">
<img src="http://hzone.4008691117.com/static/images/user-pic.jpeg" alt="">
<div class="logo">
<img src="http://hzone.4008691117.com/static/images/logo.png" alt="">
</div>
<img src="http://hzone.4008691117.com/static/images/user-nav.jpg" alt="">
</div>
<!--banner轮播图,这里用图片暂时代替-->
<div class="banner">
<img src="http://hzone.4008691117.com/static/images/banner.jpg" alt="">
</div>
<!--导航区-->
<div class="nav">
<ul>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/images/html.png" alt=""><br>HTML/CSS</a>
</li>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/images/JavaScript.png" alt=""><br>JavaScript</a>
</li>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/images/code.png" alt=""><br>服务端</a>
</li>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/images/sql.png" alt=""><br>数据库</a>
</li>
</ul>
<ul>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/images/app.png" alt=""><br>移动端</a>
</li>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/images/manual.png" alt=""><br>手册</a>
</li>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/images/tool2.png" alt=""><br>工具</a>
</li>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/images/live.png" alt=""><br>直播</a>
</li>
</ul>
</div>
<!--课程区-->
<h3>推荐课程</h3>
<div class="courses">
<ul>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc1.jpg" alt=""></a>
</li>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc2.jpg" alt=""></a>
</li>
</ul>
<div>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc3.jpg" alt=""></a>
<p>
<a href="">CI框架30分钟极速入门</a>
<br>
<span>中级</span><span>49748次播放</span>
</p>
</div>
<div>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc4.jpg" alt=""></a>
<p>
<a href="">2018前端入门_HTML5</a>
<br>
<span>初级</span><span>210066次播放</span>
</p>
</div>
</div>
<!-- 最新更新 -->
<h3 class="news">最新更新</h3>
<div class="news-container">
<div>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc3.jpg" alt="图片区"></a>
<p>
<a href="">Laravel 5.8 中文文档手册</a>
<br>
<span>《Laravel 5.1/5.8速查表：https://www.php.cn/phpkj/laravel/cheatsheet5</span>
<span>中级</span><span class="news_span">49748次播放</span>
</p>
</div>
<div>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc4.jpg" alt="图片区"></a>
<p>
<a href="">2018前端入门_HTML5</a>
<br>
<span>《Laravel 5.1/5.8速查表：https://www.php.cn/phpkj/laravel/cheatsheet5</span>
<span>初级</span><span class="news_span">210066次播放</span>
</p>
</div>
</div>
<!-- 最新文章 -->
<h3 class="wenz">最新文章</h3>
<div class="wenz-container">
<div>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc3.jpg" alt=""></a>
<p>
<a href="">百度站长主动推送php怎么弄</a>
<br>
<span>发布时间：2019.9.11</span>
</p>
</div>
<div>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc4.jpg" alt=""></a>
<p>
<a href="">宝塔phpmyadmin无法打开</a>
<br>
<span>发布时间：2019.9.11</span>
</p>
</div>
<div>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc4.jpg" alt=""></a>
<p>
<a href="">宝塔phpmyadmin无法打开</a>
<br>
<span>发布时间：2019.9.11</span>
</p>
</div>
<div>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc4.jpg" alt=""></a>
<p>
<a href="">宝塔phpmyadmin无法打开</a>
<br>
<span>发布时间：2019.9.11</span>
</p>
</div>
<div>
<a href=""><img src="http://hzone.4008691117.com/static/images/tjkc4.jpg" alt=""></a>
<p>
<a href="">宝塔phpmyadmin无法打开</a>
<br>
<span>发布时间：2019.9.11</span>
</p>
</div>
</div>
<!--底部-->
<div class="footer">
<ul>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/font-icon/zhuye.png" alt=""><br><span>主页</span></a>
</li>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/font-icon/video.png" alt=""><br><span>视频</span></a>
</li>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/font-icon/luntan.png" alt=""><br><span>社区</span></a>
</li>
<li>
<a href=""><img src="http://hzone.4008691117.com/static/font-icon/geren.png" alt=""><br><span>我的</span></a>
</li>
</ul>
</div>
</body>
</html>运行实例 »
点击 "运行实例" 按钮查看在线实例
【问题】
老师您好，在实际处理中，有以下几点问题请教您：
1、 课堂上讲的页面采用 min-width: 320px max-width:768px ，我在处理时候，尝试了去掉，直接用 width: 100%
发现也能够用，这两者的区别在哪里呢？
2、当用底部或者头部固定元素的时候，会将其他元素遮挡显示不全，为了让挡住的元素显示，我采用给靠近底部元素增加了margin-bottom 属性， 当我采用 像素（px）的时候，发现不怎么起作用，后来改用 em 的时候效果明显。老师，在移动端 页面布局元素大小是不是最好用 em ?
3、老师，并不是所以的地方都需要采用 flex 布局对吧？要根据实际场景来。
老师，您辛苦了~~
