Flex

flexbox 通用類別的套件包管理網格欄的排版、對齊和特定尺寸。對於更複雜的表現則需要自訂 CSS。

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啟用 flex

使用 display 通用類別來創建一個 flexbox 容器,並將 直屬內元素 轉換為 flex 屬性。增加額外的 flex 屬性,也能夠進一步修改 flex 容器和屬性。

I'm a flexbox container!
<div class="d-flex p-2">I'm a flexbox container!</div>
I'm an inline flexbox container!
<div class="d-inline-flex p-2">I'm an inline flexbox container!</div>

.d-flex.d-inline-flex 也包含響應式的屬性。

  • .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

方向性

透過通用類別來設定 flex 容器與內層 flex 的方向,在大多的情況下你可以忽略水平的 class,因為瀏覽器預設值是 row,不過有些特定情境下需要設定這個值(像是響應式情境)。

使用 .flex-row 來設定水平的方向(瀏覽器預設值喔),或者使用 .flex-row-reverse來作水平方向的反轉。

Flex item 1
Flex item 2
Flex item 3
Flex item 1
Flex item 2
Flex item 3
<div class="d-flex flex-row">
  <div class="p-2">Flex item 1</div>
  <div class="p-2">Flex item 2</div>
  <div class="p-2">Flex item 3</div>
</div>
<div class="d-flex flex-row-reverse">
  <div class="p-2">Flex item 1</div>
  <div class="p-2">Flex item 2</div>
  <div class="p-2">Flex item 3</div>
</div>

使用 .flex-column 設置垂直方向,或使用.flex-column-reverse 作垂直方向的反轉。

Flex item 1
Flex item 2
Flex item 3
Flex item 1
Flex item 2
Flex item 3
<div class="d-flex flex-column">
  <div class="p-2">Flex item 1</div>
  <div class="p-2">Flex item 2</div>
  <div class="p-2">Flex item 3</div>
</div>
<div class="d-flex flex-column-reverse">
  <div class="p-2">Flex item 1</div>
  <div class="p-2">Flex item 2</div>
  <div class="p-2">Flex item 3</div>
</div>

flex-direction 的響應式屬性。

  • .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

調整內容

使用 flexbox 容器上的 justify-content 通用類別改變 flex 物件在主軸上的對齊(x軸開始,如果 flex-direction: column,則為 y 軸)。從 start(瀏覽器預設)、 endcenterbetween、或 around 中選擇。

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<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 的響應式屬性。

  • .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

對齊物件

在 flexbox 容器上使用 align-items 工具改變橫軸上 flex 物件的對齊(y 軸開始,如果 flex-direction: column,則為 x 軸)。從startendcenterbaseline、 或 stretch (瀏覽器預設) 中選擇。

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<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 包含的響應式屬性

  • .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

自身對齊

使用 flexbox 物件上的 align-self 通用類別單獨改變在橫軸上的對齊(y 軸開始,如果 flex-direction: column,則為 x 軸)。與 align-items 相同的選項中選擇:startendcenterbaseline、 或 stretch (瀏覽器預設)。

Flex item
Aligned flex item
Flex item
Flex item
Aligned flex item
Flex item
Flex item
Aligned flex item
Flex item
Flex item
Aligned flex item
Flex item
Flex item
Aligned flex item
Flex item
<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 的響應式屬性。

  • .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

自動的 margins

當你將 flex 對齊與 auto margin 混在一起的時候,flexbox 也能正常的運行。下面的範例是透過自動 margin 來控制 flex 物件的三個案例:預設(無 margin),向右推兩個項目(.mr-auto),並向左推兩個項目(.ml-auto)。

不幸的是,IE10 和 IE11 在父層 justify-content 值並沒有正確的支援自動 margin 在 flex 元件上看 StackOverflow 答案 了解更多細節。

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex">
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
</div>

<div class="d-flex">
  <div class="mr-auto p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
</div>

<div class="d-flex">
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="ml-auto p-2">Flex item</div>
</div>

搭配 align-items

混合以下屬性 align-items, flex-direction: column, 和 margin-top: automargin-bottom: auto,會將一個 flex 物件移動到容器的頂部或底部。

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex align-items-start flex-column" style="height: 200px;">
  <div class="mb-auto p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
</div>

<div class="d-flex align-items-end flex-column" style="height: 200px;">
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="mt-auto p-2">Flex item</div>
</div>

Wrap (Flex 的 Wrap 屬性)

改變 flex 物件在 flex 容器中的 Wrap。可設置 .flex-nowrap.flex-wrap.flex-wrap-reverse 這些屬性。

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex flex-nowrap">
  ...
</div>
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex flex-wrap">
  ...
</div>
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex flex-wrap-reverse">
  ...
</div>

flex-wrap 也包含響應式屬性。

  • .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

排序

使用 order 通用類別改變特定 flex 物件的 顯示 排序。我們僅提供將一個物件排在第一個或最後一個,以及重置使用 DOM 次序。由於 order 只能使用整數值(例如,5),對需要的任何額外值需要自定義 CSS。

First flex item
Second flex item
Third flex item
<div class="d-flex flex-nowrap">
  <div class="order-3 p-2">First flex item</div>
  <div class="order-2 p-2">Second flex item</div>
  <div class="order-1 p-2">Third flex item</div>
</div>

order 也包含的響應式屬性。

  • .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-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-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-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-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

對齊內容

使用 flexbox 容器上的 align-content 工具將 flex 物件於橫軸上 一起 對齊。從start (瀏覽器預設), end, center, between, around, 或 stretch中選擇。為了呈現這通用類別的效果,我們加入了 flex-wrap: wrap,及增加了flex項的數量。

注意! 此特性對於單行的 flex 無作用。

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex align-content-start flex-wrap">
  ...
</div>
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex align-content-end flex-wrap">...</div>
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex align-content-center flex-wrap">...</div>
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex align-content-between flex-wrap">...</div>
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex align-content-around flex-wrap">...</div>
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
<div class="d-flex align-content-stretch flex-wrap">...</div>

align-content 也包含響應式屬性。

  • .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