WeUI是微信Web服务开发的UI套件, 目前包含12个模块 (Button, Cell, Toast, Dialog, Progress, Msg, Article, ActionSheet, Icons, Panel, Tab, SearchBar).
Demo页面: https://weui.io
Github页面: https://github.com/weui/weui
下面讲一讲我从WeUI中学到的CSS技巧.
从这里我开始注意到, WeUI的实现中, 很多边框都是用:before,:after绘制的.
.weui_btn:after { content: " "; width: 200%; height: 200%; position: absolute; top: 0; left: 0; border: 1px solid rgba(0, 0, 0, 0.2); -webkit-transform: scale(0.5); transform: scale(0.5); -webkit-transform-origin: 0 0; transform-origin: 0 0; box-sizing: border-box; border-radius: 10px; }
这么做是为了在Retina屏(视网膜屏)上确保1px真的是1pixel.
.weui_cell { padding: 10px 15px; position: relative; display: -webkit-box; display: -webkit-flex; display: -ms-flexbox; display: flex; -webkit-box-align: center; -webkit-align-items: center; -ms-flex-align: center; align-items: center; }
看到这里发现WeUI大量使用了flex布局方式.
之前一直比较困惑如何实现列表项之间的, 左边有些空缺的边框. border属性又不支持只显示一条边上的一部分, 难道要插入
WeUI的实现方式是: 利用.weui_cells:before.
.weui_cell:before { content: " "; position: absolute; left: 15px; top: 0; width: 100%; height: 1px; border-top: 1px solid #D9D9D9; color: #D9D9D9; -webkit-transform-origin: 0 0; transform-origin: 0 0; -webkit-transform: scaleY(0.5); transform: scaleY(0.5); }
left: 15px(左边的空缺)配合上.weui_cells_title的overflow: hidden(隐藏右边超出的部分)就可以显示有空缺的边框了.
列表项末尾的右箭头的实现方式竟然是weui_cell_ft::after的旋转了45度的border. 我本以为会用iconfont.
.weui_cells_access .weui_cell_ft:after { content: " "; display: inline-block; -webkit-transform: rotate(45deg); transform: rotate(45deg); height: 6px; width: 6px; border-width: 2px 2px 0 0; border-color: #C8C8CD; border-style: solid; position: relative; top: -2px; top: -1px; margin-left: .3em; }
在每个行内部嵌入了一个隐藏的
<input type="radio" class="weui_check" name="radio1">
隐藏的方式是:
.weui_check { position: absolute; left: -9999em; }
在每个input.weui_check的后面放置了一个用于显示对勾的span.input.weui_check和.weui_icon_checked是兄弟关系.
<span class="weui_icon_checked"></span>
.weui_cells_radio .weui_check:checked + .weui_icon_checked:before { display: block; content: '\EA08'; color: #09BB07; font-size: 16px;}
复选框如上面的单选框一样被隐藏了.
<input type="checkbox" class="weui_check" name="checkbox1">
比较出乎我意料的是选中和未被选中的效果都是用iconfont实现的. 本以为未被选中的效果是用border实现, 选中效果用一个check的iconfont配合水平竖直居中定位.
/* 选中效果 */.weui_cells_checkbox .weui_check:checked + .weui_icon_checked:before { content: '\EA06'; color: #09BB07;}/* 未选中效果 */.weui_cells_checkbox .weui_icon_checked:before { content: '\EA01'; color: #C9C9C9; font-size: 23px; display: block;}
<input class="weui_switch" type="checkbox">
之前觉得这个效果很难做啊, 看了weui的实现竟然只用css就行了!
.weui_switch { -webkit-appearance: none; -moz-appearance: none; appearance: none; position: relative; width: 52px; height: 32px; border: 1px solid #DFDFDF; outline: 0; border-radius: 16px; box-sizing: border-box; background: #DFDFDF;}.weui_switch:checked { border-color: #04BE02; background-color: #04BE02;}.weui_switch:before { content: " "; position: absolute; top: 0; left: 0; width: 50px; height: 30px; border-radius: 15px; border-top-left-radius: 15px; border-top-right-radius: 15px; border-bottom-right-radius: 15px; border-bottom-left-radius: 15px; background-color: #FDFDFD; -webkit-transition: -webkit-transform .3s; transition: -webkit-transform .3s; transition: transform .3s; transition: transform .3s, -webkit-transform .3s;}.weui_switch:checked:before { -webkit-transform: scale(0); transform: scale(0);}.weui_switch:after { content: " "; position: absolute; top: 0; left: 0; width: 30px; height: 30px; border-radius: 15px; background-color: #FFFFFF; box-shadow: 0 1px 3px rgba(0, 0, 0, 0.4); -webkit-transition: -webkit-transform .3s; transition: -webkit-transform .3s; transition: transform .3s; transition: transform .3s, -webkit-transform .3s;}.weui_switch:checked:after { -webkit-transform: translateX(20px); transform: translateX(20px);}
其中,.weui_switch提供了边框, 未选中时背景色#DFDFDF(深灰), 选中时#04BE02(绿色).
.weui_switch:before提供了边框内部的浅灰色#FDFDFD. 被选中时scale(0)缩小消失.
.weui_switch:after提供了圆形按键. 被选中时向右边移动20px.
效果如下:
<input class="weui_input" type="number" pattern="[0-9]*" placeholder="请输入qq号">
input的pattern="[0-9]*限制了输入只能是0-9的数字(pattern的值是正则表达式).
input[type="number"]在Chrome上默认会在最右边显示上下箭头. WeUI通过下面的代码禁用了箭头, 这段代码在Chrome的Dev Tool里面是看不到的, 只能从CSS里面看, 害我找了半天.
.weui_input::-webkit-outer-spin-button,.weui_input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0;}
点选input[type="number"]在iOS上会自动打开数字键盘.
WeUI用下面这个简单的方法实现了图片前面的灰层.absolute定位加上top:0; right:0; bottom:0; left:0;就会让元素被抻开到父元素的边界.
.weui_uploader_status:before { content: " "; position: absolute; top: 0; right: 0; bottom: 0; left: 0; background-color: rgba(0, 0, 0, 0.5);}
图片上传状态用了一个经典的(水平+垂直)居中方式, 利用top: 50%(让元素的上边界定位到父元素的50%位置)和transform: translateY(-50%)(让元素往上移动元素自身高度的50%).
.weui_uploader_status .weui_uploader_status_content { position: absolute; top: 50%; left: 50%; -webkit-transform: translate(-50%, -50%); transform: translate(-50%, -50%); color: #FFFFFF;}
我平时常用的垂直居中方式如下. 水平居中类似.
.vertical-center { position: relative; top: 50%; transform: translateY(-50%);}
最后的上传按钮:
<p class="weui_uploader_input_wrp"> <input class="weui_uploader_input" type="file" accept="image/jpg,image/jpeg,image/png,image/gif" multiple=""> </p>
input[type="file"]在iOS上会自动触发选择"拍照"还是"照片"的菜单.
方框是用.weui_uploader_input_wrp画出来的, 而加号是用.weui_uploader_input_wrp:before和:after.
真正的input利用opacity:0隐藏起来了.
.weui_uploader_input_wrp:before { width: 2px; height: 39.5px; } .weui_uploader_input_wrp:after { width: 39.5px; height: 2px; } .weui_uploader_input_wrp:before, .weui_uploader_input_wrp:after { content: " "; position: absolute; top: 50%; left: 50%; -webkit-transform: translate(-50%, -50%); transform: translate(-50%, -50%); background-color: #D9D9D9; } .weui_uploader_input { position: absolute; z-index: 1; top: 0; left: 0; width: 100%; height: 100%; opacity: 0; -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
<input class="weui_input" type="date" value=""> <input class="weui_input" type="datetime-local" value="" placeholder="">
在iOS上, 点选input[type="date"]会出现"年-月-日"的选择框, 点选input[type="datetime-local"]会出现"月-日-上午/下午-时-分"的选择框.
电话号码+86位置的右箭头和分割线是用:before和:after绘制的.
<p id="toast" style="display:none"> <p class="weui_mask_transparent"></p> <p class="weui_toast"> <i class="weui_icon_toast"></i> <p class="weui_toast_content">已完成</p> </p> </p>
.weui_mask_transparent就是一个position:fixed占满全屏的透明幕布, 让用户无法操作界面.
.weui_toast才是页面中间的黑块.
竟然是纯用HTML+CSS(animation+transition)实现的.
<p id="loadingToast" class="weui_loading_toast" style="/* display: none; */"> <p class="weui_mask_transparent"></p> <p class="weui_toast"> <p class="weui_loading"> <p class="weui_loading_leaf weui_loading_leaf_0"></p> <p class="weui_loading_leaf weui_loading_leaf_1"></p> <p class="weui_loading_leaf weui_loading_leaf_2"></p> <p class="weui_loading_leaf weui_loading_leaf_3"></p> <p class="weui_loading_leaf weui_loading_leaf_4"></p> <p class="weui_loading_leaf weui_loading_leaf_5"></p> <p class="weui_loading_leaf weui_loading_leaf_6"></p> <p class="weui_loading_leaf weui_loading_leaf_7"></p> <p class="weui_loading_leaf weui_loading_leaf_8"></p> <p class="weui_loading_leaf weui_loading_leaf_9"></p> <p class="weui_loading_leaf weui_loading_leaf_10"></p> <p class="weui_loading_leaf weui_loading_leaf_11"></p> </p> <p class="weui_toast_content">数据加载中</p> </p></p>
.weui_loading_leaf { position: absolute; top: -1px; opacity: 0.25;}.weui_loading_leaf:before { content: " "; position: absolute; width: 8.14px; height: 3.08px; background: #d1d1d5; box-shadow: rgba(0, 0, 0, 0.0980392) 0px 0px 1px; border-radius: 1px; -webkit-transform-origin: left 50% 0px; transform-origin: left 50% 0px;}.weui_loading_leaf_0 { -webkit-animation: opacity-60-25-0-12 1.25s linear infinite; animation: opacity-60-25-0-12 1.25s linear infinite;}.weui_loading_leaf_0:before { -webkit-transform: rotate(0deg) translate(7.92px, 0px); transform: rotate(0deg) translate(7.92px, 0px);}/* ... */.weui_loading_leaf_11 { -webkit-animation: opacity-60-25-11-12 1.25s linear infinite; animation: opacity-60-25-11-12 1.25s linear infinite;}.weui_loading_leaf_11:before { -webkit-transform: rotate(330deg) translate(7.92px, 0px); transform: rotate(330deg) translate(7.92px, 0px);}@-webkit-keyframes opacity-60-25-0-12 { 0% { opacity: 0.25; } 0.01% { opacity: 0.25; } 0.02% { opacity: 1; } 60.01% { opacity: 0.25; } 100% { opacity: 0.25; }}/* ... */@-webkit-keyframes opacity-60-25-11-12 { 0% { opacity: 0.895958333333333; } 91.6767% { opacity: 0.25; } 91.6867% { opacity: 1; } 51.6767% { opacity: 0.25; } 100% { opacity: 0.895958333333333; }}
<p class="weui_dialog_confirm" id="dialog1"> <p class="weui_mask"></p> <p class="weui_dialog"> <p class="weui_dialog_hd"><strong class="weui_dialog_title">弹窗标题</strong></p> <p class="weui_dialog_bd">自定义弹窗内容,居左对齐显示,告知需要确认的信息等</p> <p class="weui_dialog_ft"> <a href="javascript:;" class="weui_btn_dialog default">取消</a> <a href="javascript:;" class="weui_btn_dialog primary">确定</a> </p> </p></p>
你能看到的边框都是用:after实现的.
略. ( *・ω・)✄╰ひ╯
略. ( *・ω・)✄╰ひ╯
略. ( *・ω・)✄╰ひ╯
<p id="actionSheet_wrap"> <p class="weui_mask_transition" id="mask" style="display: none;"></p> <p class="weui_actionsheet" id="weui_actionsheet"> <p class="weui_actionsheet_menu"> <p class="weui_actionsheet_cell">示例菜单</p> <p class="weui_actionsheet_cell">示例菜单</p> <p class="weui_actionsheet_cell">示例菜单</p> <p class="weui_actionsheet_cell">示例菜单</p> </p> <p class="weui_actionsheet_action"> <p class="weui_actionsheet_cell" id="actionsheet_cancel">取消</p> </p> </p> </p>
值得一提的是, 页面下方的ActionSheet始终是显示的, 只不过平时通过transform: translateY(100%)隐藏了起来, 显示时用translateY(0). 这方法无需JS就可以自适应任意高度的ActionSheet.
.weui_actionsheet { position: fixed; left: 0; bottom: 0; -webkit-transform: translate(0, 100%); transform: translate(0, 100%); -webkit-backface-visibility: hidden; backface-visibility: hidden; z-index: 2; width: 100%; background-color: #EFEFF4; -webkit-transition: -webkit-transform .3s; transition: -webkit-transform .3s; transition: transform .3s; transition: transform .3s, -webkit-transform .3s; } .weui_actionsheet_toggle { -webkit-transform: translate(0, 0); transform: translate(0, 0); }
一堆iconfont. ( *・ω・)✄╰ひ╯
略. ( *・ω・)✄╰ひ╯
Navbar:
TabBar:
略. ( *・ω・)✄╰ひ╯
无焦点状态:
有焦点状态:
<p class="weui_search_bar weui_search_focusing" id="search_bar"> <form class="weui_search_outer"> <!-- 搜索框有焦点时的搜索图标, 搜索框和清空按钮 --> <p class="weui_search_inner"> <i class="weui_icon_search"></i> <input type="search" class="weui_search_input" id="search_input" placeholder="搜索" required=""> <a href="javascript:" class="weui_icon_clear" id="search_clear"></a> </p> <!-- 搜索框没有焦点时的显示 --> <label for="search_input" class="weui_search_text" id="search_text"> <i class="weui_icon_search"></i> <span>搜索</span> </label> </form> <!-- 搜索框有焦点时的取消键 --> <a href="javascript:" class="weui_search_cancel" id="search_cancel">取消</a> </p>
这里我最好奇的是, 当用户点击搜索框时, 弹出的键盘上右下角的按键是"搜索"而不是"换行".
我测试的效果是, 在微信中点击搜索框时键盘显示"搜索"按键, 在Safari中打开时则显示"换行".
这就很诡异了, 说明微信做了什么手脚. 难道与JS有关?
但是我在网上搜索了下, 发现只要确保input[type="search"]被form包围, 且form有action属性即可. 示例:
<form action=""> <input type="search" name="search" placeholder="search"> </form>
但是WeUI的实现中,form并没有action属性, 所以暂时不知道WeUI是如何做的.
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