flexbox 工具的套件包管理网格栏的排版、对齐和特定尺寸。对于更复杂的表现则需要自订 CSS。
使用 display
通用类别来创建一个 flexbox 容器,并将 直属内元素 转换为 flex 属性。增加额外的 flex 属性,也能够进一步修改 flex 容器和属性。
<div class="d-flex p-2 bd-highlight">I'm a flexbox container!</div>
<div class="d-inline-flex p-2 bd-highlight">I'm an inline flexbox container!</div>
.d-flex
和 .d-inline-flex
也存在响应式设计。
.d-flex
.d-inline-flex
.d-sm-flex
.d-sm-inline-flex
.d-md-flex
.d-md-inline-flex
.d-lg-flex
.d-lg-inline-flex
.d-xl-flex
.d-xl-inline-flex
透过通用类别来设定 flex 容器与内层 flex 的方向,在大多的情况下你可以忽略水平的 class,因为浏览器预设值是 row
. 不过有些特定情境下需要设定这个值(比如在响应式环境下)。
使用 .flex-row
来设定水平的方向(浏览器预设值),或者使用 .flex-row-reverse
来作水平方向的反转。
<div class="d-flex flex-row bd-highlight mb-3">
<div class="p-2 bd-highlight">Flex item 1</div>
<div class="p-2 bd-highlight">Flex item 2</div>
<div class="p-2 bd-highlight">Flex item 3</div>
</div>
<div class="d-flex flex-row-reverse bd-highlight">
<div class="p-2 bd-highlight">Flex item 1</div>
<div class="p-2 bd-highlight">Flex item 2</div>
<div class="p-2 bd-highlight">Flex item 3</div>
</div>
使用 .flex-column
设置垂直方向,或使用 .flex-column-reverse
作垂直方向的反转。
<div class="d-flex flex-column bd-highlight mb-3">
<div class="p-2 bd-highlight">Flex item 1</div>
<div class="p-2 bd-highlight">Flex item 2</div>
<div class="p-2 bd-highlight">Flex item 3</div>
</div>
<div class="d-flex flex-column-reverse bd-highlight">
<div class="p-2 bd-highlight">Flex item 1</div>
<div class="p-2 bd-highlight">Flex item 2</div>
<div class="p-2 bd-highlight">Flex item 3</div>
</div>
flex-direction
的响应式属性。
.flex-row
.flex-row-reverse
.flex-column
.flex-column-reverse
.flex-sm-row
.flex-sm-row-reverse
.flex-sm-column
.flex-sm-column-reverse
.flex-md-row
.flex-md-row-reverse
.flex-md-column
.flex-md-column-reverse
.flex-lg-row
.flex-lg-row-reverse
.flex-lg-column
.flex-lg-column-reverse
.flex-xl-row
.flex-xl-row-reverse
.flex-xl-column
.flex-xl-column-reverse
使用 flexbox 容器上的 justify-content
通用类别改变 flex 物件在主轴上的对齐(x轴开始,如果 flex-direction: column
则为 y 轴)。从 start
浏览器预设)。 end
, center
, between
, 或 around
中选择。
<div class="d-flex justify-content-start">...</div>
<div class="d-flex justify-content-end">...</div>
<div class="d-flex justify-content-center">...</div>
<div class="d-flex justify-content-between">...</div>
<div class="d-flex justify-content-around">...</div>
justify-content
的响应式属性。
.justify-content-start
.justify-content-end
.justify-content-center
.justify-content-between
.justify-content-around
.justify-content-sm-start
.justify-content-sm-end
.justify-content-sm-center
.justify-content-sm-between
.justify-content-sm-around
.justify-content-md-start
.justify-content-md-end
.justify-content-md-center
.justify-content-md-between
.justify-content-md-around
.justify-content-lg-start
.justify-content-lg-end
.justify-content-lg-center
.justify-content-lg-between
.justify-content-lg-around
.justify-content-xl-start
.justify-content-xl-end
.justify-content-xl-center
.justify-content-xl-between
.justify-content-xl-around
在 flexbox 容器上使用 align-items
工具改变横轴上 flex 物件的对齐(y 轴开始,如果 flex-direction: column
则为 x 轴)。从 start
, end
, center
, baseline
, 或 stretch
(浏览器预设) 中选择。
<div class="d-flex align-items-start">...</div>
<div class="d-flex align-items-end">...</div>
<div class="d-flex align-items-center">...</div>
<div class="d-flex align-items-baseline">...</div>
<div class="d-flex align-items-stretch">...</div>
align-items
包含的响应式属性。
.align-items-start
.align-items-end
.align-items-center
.align-items-baseline
.align-items-stretch
.align-items-sm-start
.align-items-sm-end
.align-items-sm-center
.align-items-sm-baseline
.align-items-sm-stretch
.align-items-md-start
.align-items-md-end
.align-items-md-center
.align-items-md-baseline
.align-items-md-stretch
.align-items-lg-start
.align-items-lg-end
.align-items-lg-center
.align-items-lg-baseline
.align-items-lg-stretch
.align-items-xl-start
.align-items-xl-end
.align-items-xl-center
.align-items-xl-baseline
.align-items-xl-stretch
使用 flexbox 物件上的 align-self
通用类别单独改变在横轴上的对齐(y 轴开始,如果 flex-direction: column
则为 x 轴)。与 align-items 相同的选项中选择: align-items
: start
, end
, center
, baseline
, 或 stretch
(浏览器预设)。
<div class="align-self-start">Aligned flex item</div>
<div class="align-self-end">Aligned flex item</div>
<div class="align-self-center">Aligned flex item</div>
<div class="align-self-baseline">Aligned flex item</div>
<div class="align-self-stretch">Aligned flex item</div>
align-self
的响应式属性。
.align-self-start
.align-self-end
.align-self-center
.align-self-baseline
.align-self-stretch
.align-self-sm-start
.align-self-sm-end
.align-self-sm-center
.align-self-sm-baseline
.align-self-sm-stretch
.align-self-md-start
.align-self-md-end
.align-self-md-center
.align-self-md-baseline
.align-self-md-stretch
.align-self-lg-start
.align-self-lg-end
.align-self-lg-center
.align-self-lg-baseline
.align-self-lg-stretch
.align-self-xl-start
.align-self-xl-end
.align-self-xl-center
.align-self-xl-baseline
.align-self-xl-stretch
在相邻元素上使用 .flex-fill
来强制它们在相同的宽度上分配所有可用的水平空间。对于等宽导览特别有用。
<div class="d-flex bd-highlight">
<div class="p-2 flex-fill bd-highlight">Flex item</div>
<div class="p-2 flex-fill bd-highlight">Flex item</div>
<div class="p-2 flex-fill bd-highlight">Flex item</div>
</div>
flex-fill
同样包含响应式的组合。
.flex-fill
.flex-sm-fill
.flex-md-fill
.flex-lg-fill
.flex-xl-fill
使用 .flex-grow-*
通用类别来切换项目弹性增长以填充可用空间。在下面的范例中, .flex-grow-1
元素使用它可以使用的所有可用空间,同时允许剩余的两个 flex 物件保留必要的空间。
<div class="d-flex bd-highlight">
<div class="p-2 flex-grow-1 bd-highlight">Flex item</div>
<div class="p-2 bd-highlight">Flex item</div>
<div class="p-2 bd-highlight">Third flex item</div>
</div>
如果需要,使用 .flex-shrink-*
工具来切换调整项目的尺寸。 在下面的示例中,第二个带有 .flex-shrink-1
的弹性项目被强制将其内容包装到一个新行,“收缩”以允许更多空间用于上一个具有 .w-100
的弹性项目。
<div class="d-flex bd-highlight">
<div class="p-2 w-100 bd-highlight">Flex item</div>
<div class="p-2 flex-shrink-1 bd-highlight">Flex item</div>
</div>
flex-grow
和 flex-shrink
也具备响应式设计。
.flex-{grow|shrink}-0
.flex-{grow|shrink}-1
.flex-sm-{grow|shrink}-0
.flex-sm-{grow|shrink}-1
.flex-md-{grow|shrink}-0
.flex-md-{grow|shrink}-1
.flex-lg-{grow|shrink}-0
.flex-lg-{grow|shrink}-1
.flex-xl-{grow|shrink}-0
.flex-xl-{grow|shrink}-1
当你将 flex 对齐与 auto margin 混在一起的时候,flexbox 也能正常的运行。下面的范例是透过自动 margin 来控制 flex 物件的三个案例:预设(无 margin),向右推两个项目(.mr-auto
),并向左推两个项目(.ml-auto
)。
不幸的是,IE10 和 IE11 在父层 justify-content
value. 值并没有正确的表现,可以在搜索这个问题来了解更多细节。
<div class="d-flex bd-highlight mb-3">
<div class="p-2 bd-highlight">Flex item</div>
<div class="p-2 bd-highlight">Flex item</div>
<div class="p-2 bd-highlight">Flex item</div>
</div>
<div class="d-flex bd-highlight mb-3">
<div class="mr-auto p-2 bd-highlight">Flex item</div>
<div class="p-2 bd-highlight">Flex item</div>
<div class="p-2 bd-highlight">Flex item</div>
</div>
<div class="d-flex bd-highlight mb-3">
<div class="p-2 bd-highlight">Flex item</div>
<div class="p-2 bd-highlight">Flex item</div>
<div class="ml-auto p-2 bd-highlight">Flex item</div>
</div>
混合以下属性 align-items
, flex-direction: column
, 和 margin-top: auto
或 margin-bottom: auto
,会将一个 flex 物件移动到容器的顶部或底部。
<div class="d-flex align-items-start flex-column bd-highlight mb-3" style="height: 200px;">
<div class="mb-auto p-2 bd-highlight">Flex item</div>
<div class="p-2 bd-highlight">Flex item</div>
<div class="p-2 bd-highlight">Flex item</div>
</div>
<div class="d-flex align-items-end flex-column bd-highlight mb-3" style="height: 200px;">
<div class="p-2 bd-highlight">Flex item</div>
<div class="p-2 bd-highlight">Flex item</div>
<div class="mt-auto p-2 bd-highlight">Flex item</div>
</div>
改变 flex 物件在 flex 容器中的 Wrap。可设置 .flex-nowrap
, .flex-wrap
, .flex-wrap-reverse
这些属性。
<div class="d-flex flex-nowrap">
...
</div>
<div class="d-flex flex-wrap">
...
</div>
<div class="d-flex flex-wrap-reverse">
...
</div>
flex-wrap
也包含响应式属性。
.flex-nowrap
.flex-wrap
.flex-wrap-reverse
.flex-sm-nowrap
.flex-sm-wrap
.flex-sm-wrap-reverse
.flex-md-nowrap
.flex-md-wrap
.flex-md-wrap-reverse
.flex-lg-nowrap
.flex-lg-wrap
.flex-lg-wrap-reverse
.flex-xl-nowrap
.flex-xl-wrap
.flex-xl-wrap-reverse
使用 order
通用类别改变特定 flex 物件的 显示 排序。我们仅提供将一个物件排在第一个或最后一个,以及重置使用 DOM 次序。由于 order
只能使用整数值(例如,5),对需要的任何额外值需要自定义 CSS。
<div class="d-flex flex-nowrap bd-highlight">
<div class="order-3 p-2 bd-highlight">First flex item</div>
<div class="order-2 p-2 bd-highlight">Second flex item</div>
<div class="order-1 p-2 bd-highlight">Third flex item</div>
</div>
order
也包含响应式设计。
.order-0
.order-1
.order-2
.order-3
.order-4
.order-5
.order-6
.order-7
.order-8
.order-9
.order-10
.order-11
.order-12
.order-sm-0
.order-sm-1
.order-sm-2
.order-sm-3
.order-sm-4
.order-sm-5
.order-sm-6
.order-sm-7
.order-sm-8
.order-sm-9
.order-sm-10
.order-sm-11
.order-sm-12
.order-md-0
.order-md-1
.order-md-2
.order-md-3
.order-md-4
.order-md-5
.order-md-6
.order-md-7
.order-md-8
.order-md-9
.order-md-10
.order-md-11
.order-md-12
.order-lg-0
.order-lg-1
.order-lg-2
.order-lg-3
.order-lg-4
.order-lg-5
.order-lg-6
.order-lg-7
.order-lg-8
.order-lg-9
.order-lg-10
.order-lg-11
.order-lg-12
.order-xl-0
.order-xl-1
.order-xl-2
.order-xl-3
.order-xl-4
.order-xl-5
.order-xl-6
.order-xl-7
.order-xl-8
.order-xl-9
.order-xl-10
.order-xl-11
.order-xl-12
使用 flexbox 容器上的 align-content
工具将 flex 物件于横轴上一起对齐。从 start
浏览器预设), end
, center
, between
, around
, or stretch
中选择。为了呈现这通用类别的效果,我们加入了 flex-wrap: wrap
及增加了flex项的数量。
注意!此特性对于单行的 flex 无作用。
<div class="d-flex align-content-start flex-wrap">
...
</div>
<div class="d-flex align-content-end flex-wrap">...</div>
<div class="d-flex align-content-center flex-wrap">...</div>
<div class="d-flex align-content-between flex-wrap">...</div>
<div class="d-flex align-content-around flex-wrap">...</div>
<div class="d-flex align-content-stretch flex-wrap">...</div>
align-content
也包含响应式设计。
.align-content-start
.align-content-end
.align-content-center
.align-content-around
.align-content-stretch
.align-content-sm-start
.align-content-sm-end
.align-content-sm-center
.align-content-sm-around
.align-content-sm-stretch
.align-content-md-start
.align-content-md-end
.align-content-md-center
.align-content-md-around
.align-content-md-stretch
.align-content-lg-start
.align-content-lg-end
.align-content-lg-center
.align-content-lg-around
.align-content-lg-stretch
.align-content-xl-start
.align-content-xl-end
.align-content-xl-center
.align-content-xl-around
.align-content-xl-stretch