mdl-menu 不能与 max-width 一起正常工作

Question

如果我为 mdl-layout__header-row class 设置最大宽度属性，下拉菜单无法正常工作，它们未对齐。删除最大宽度属性一切正常。

代码：

<!doctype html>
<html>
    <head>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
        <title>Test Page</title>
        <link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
        <link rel="stylesheet" href="https://code.getmdl.io/1.3.0/material.red-light_blue.min.css" />
        <script src="https://code.getmdl.io/1.3.0/material.min.js"></script>
    </head>
    <body>
        <header class="mdl-layout__header">
            <div class="mdl-layout__header-row" style="max-width: 1200px;width: 100%;margin: auto;">
                <a href="/">
                    <img style="height: 60px;" src="http://www.vwshops.com/dummy-store-1/img/my-shop-logo-1452186152.jpg" />
                </a>
                <span>Logo</span>
                <button id="DROPDOWN_RIGHT" class="mdl-button mdl-js-button mdl-button--icon">
                    <i class="material-icons">arrow_drop_down</i>
                </button>
                <ul class="mdl-menu mdl-menu--bottom-right mdl-js-menu mdl-js-ripple-effect language-menu" for="DROPDOWN_RIGHT">
                    <li class="mdl-menu__item">One</li>
                    <li class="mdl-menu__item">Two</li>
                    <li class="mdl-menu__item">Three</li>
                </ul>
                <button style="margin-left: auto;" id="DROPDOWN_LEFT" class="mdl-button mdl-js-button mdl-button--icon">
                    <i class="material-icons">arrow_drop_down</i>
                </button>
                <ul class="mdl-menu mdl-menu--bottom-right mdl-js-menu mdl-js-ripple-effect language-menu" for="DROPDOWN_LEFT">
                    <li class="mdl-menu__item">One</li>
                    <li class="mdl-menu__item">Two</li>
                    <li class="mdl-menu__item">Three</li>
                </ul>
            </div>
        </header>
    </body>
</html>

Answer 1

添加position:relative。这会阻止定位元素偏离 .mdl-layout__header-row div 中的行。当使用绝对定位定位元素时，您需要设置一个父容器以将它们定位并通过为它们设置 position:relative 来实现 - 否则它将位于它们定位的最外层 html 元素/文档.

<!doctype html>
<html>
    <head>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
        <title>Test Page</title>
        <link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
        <link rel="stylesheet" href="https://code.getmdl.io/1.3.0/material.red-light_blue.min.css" />
        <script src="https://code.getmdl.io/1.3.0/material.min.js"></script>
    </head>
    <body>
        <header class="mdl-layout__header">
            <div class="mdl-layout__header-row" style="max-width: 1200px;width: 100%;margin: auto; position:relative;">
                <a href="/">
                    <img style="height: 60px;" src="http://www.vwshops.com/dummy-store-1/img/my-shop-logo-1452186152.jpg" />
                </a>
                <span>Logo</span>
                <button id="DROPDOWN_RIGHT" class="mdl-button mdl-js-button mdl-button--icon">
                    <i class="material-icons">arrow_drop_down</i>
                </button>
                <ul class="mdl-menu mdl-menu--bottom-right mdl-js-menu mdl-js-ripple-effect language-menu" for="DROPDOWN_RIGHT">
                    <li class="mdl-menu__item">One</li>
                    <li class="mdl-menu__item">Two</li>
                    <li class="mdl-menu__item">Three</li>
                </ul>
                <button style="margin-left: auto;" id="DROPDOWN_LEFT" class="mdl-button mdl-js-button mdl-button--icon">
                    <i class="material-icons">arrow_drop_down</i>
                </button>
                <ul class="mdl-menu mdl-menu--bottom-right mdl-js-menu mdl-js-ripple-effect language-menu" for="DROPDOWN_LEFT">
                    <li class="mdl-menu__item">One</li>
                    <li class="mdl-menu__item">Two</li>
                    <li class="mdl-menu__item">Three</li>
                </ul>
            </div>
        </header>
    </body>
</html>

mdl-menu 不能与 max-width 一起正常工作

mdl-menu not working properly with max-width

html

css

material-design-lite