Question

在Bootstrap 3中我使用了这个：

.something {
    padding: 5px;
    @media screen and (min-width: $screen-sm-min) { 
        padding: 20px;
    }
    @media screen and (min-width: $screen-md-min) { 
        padding: 40px;
    }
}

如何在Boostrap 4-alpha中做同样的事情？我在他们的文档中找不到一个例子。这是变量.scss

$grid-breakpoints: (
  xs: 0,
  sm: 576px,
  md: 768px,
  lg: 992px,
  xl: 1200px
) !default;
@include _assert-ascending($grid-breakpoints, "$grid-breakpoints");
@include _assert-starts-at-zero($grid-breakpoints);

Answer 1

使用这样的断点mixins：

@include media-breakpoint-up(xs) { ... }
@include media-breakpoint-up(sm) { ... }
@include media-breakpoint-up(md) { ... }
@include media-breakpoint-up(lg) { ... }
@include media-breakpoint-up(xl) { ... }

v4 breakpoints reference

v4 alpha6 breakpoints reference

低于完整选项和值。

断点＆amp; up（切换值及以上）：

// Extra small devices (portrait phones, less than 576px)
// No media query since this is the default in Bootstrap

// Small devices (landscape phones, 576px and up)
@media (min-width: 576px) { ... }

// Medium devices (tablets, 768px and up)
@media (min-width: 768px) { ... }

// Large devices (desktops, 992px and up)
@media (min-width: 992px) { ... }

// Extra large devices (large desktops, 1200px and up)
@media (min-width: 1200px) { ... }

断点＆amp;值：

@include media-breakpoint-down(xs) { ... }
@include media-breakpoint-down(sm) { ... }
@include media-breakpoint-down(md) { ... }
@include media-breakpoint-down(lg) { ... }

断点＆amp;向下（切换值和向下）：

// Extra small devices (portrait phones, less than 576px)
@media (max-width: 575px) { ... }

// Small devices (landscape phones, less than 768px)
@media (max-width: 767px) { ... }

// Medium devices (tablets, less than 992px)
@media (max-width: 991px) { ... }

// Large devices (desktops, less than 1200px)
@media (max-width: 1199px) { ... }

// Extra large devices (large desktops)
// No media query since the extra-large breakpoint has no upper bound on its width

断点＆amp;下降值：

@include media-breakpoint-only(xs) { ... }
@include media-breakpoint-only(sm) { ... }
@include media-breakpoint-only(md) { ... }
@include media-breakpoint-only(lg) { ... }
@include media-breakpoint-only(xl) { ... }

仅限断点：

// Extra small devices (portrait phones, less than 576px)
@media (max-width: 575px) { ... }

// Small devices (landscape phones, 576px and up)
@media (min-width: 576px) and (max-width: 767px) { ... }

// Medium devices (tablets, 768px and up)
@media (min-width: 768px) and (max-width: 991px) { ... }

// Large devices (desktops, 992px and up)
@media (min-width: 992px) and (max-width: 1199px) { ... }

// Extra large devices (large desktops, 1200px and up)
@media (min-width: 1200px) { ... }

仅限断点值（仅在值之间切换）：

si projectco --nolock

Answer 2

我回答了similar question here

正如@Syden所说，mixins会起作用。另一种选择是像这样使用SASS map-get ..

@media (min-width: map-get($grid-breakpoints, sm)){
  .something {
    padding: 10px;
   }
}

@media (min-width: map-get($grid-breakpoints, md)){
  .something {
    padding: 20px;
   }
}

http://www.codeply.com/go/0TU586QNlV

Bootstrap 4 Breakpoints demo

Answer 3

Bootstrap提供了一种使用媒体查询为不同站点定义不同任务的方法。它使用四个断点。

我们有超小的屏幕尺寸，小于576像素，这意味着尺寸从576到768像素。

中型屏幕尺寸占用768像素到992像素的屏幕尺寸大屏幕，从992像素到1200像素。

例如小文本

这意味着在576px和768px之间的小屏幕上，文本居中对于中型屏幕，将“ sm”更改为“ md”，大“ lg”更改为

Answer 4

除上述之外，如果您想在模块级样式表中使用引导媒体断点（例如在 create-react-app 组件中），默认情况下它们将是未定义的，您需要导入 mixins 和将其依赖项分别放入每个模块中。

您可以在每个文件的顶部导入它们：

@import 'bootstrap/scss/_functions';
@import 'bootstrap/scss/_variables';
@import 'bootstrap/scss/mixins/_breakpoints';

或者你可以在你的 scss 文件夹中创建一个 _mixins.scss 文件，包含上面的行，然后将该文件导入模块。

注意，当你在文件名前包含“_”时，它不会被生成到 CSS 中，它会被作为一个部分文件处理，只被编译器导入并忽略。

在Bootstrap 4-alpha中使用媒体断点

4 个答案: