CSS Flexbox 项目


目录

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子元素(项目)

Flex 容器的直接子元素自动成为柔性 (flex) 项目。

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上面的元素代表灰色弹性容器内的四个蓝色弹性项目。

例子

<div class="flex-container">
  <div>1</div>
  
  <div>2</div>
  <div>3</div> 
  
  <div>4</div>
</div>

自己尝试一下 →

<!DOCTYPE html>
<html>
<head>
<style>
.flex-container {
  display: flex;
  background-color: #f1f1f1;
}

.flex-container > div {
  background-color: DodgerBlue;
  color: white;
  width: 100px;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;
}
</style>
</head>
<body>

<h1>Flexible Items</h1>

<div class="flex-container">
  <div>1</div>
  <div>2</div>
  <div>3</div> 
  <div>4</div>
</div>

<p>All direct children of a flexible container becomes flexible items.</p>

</body>
</html>


弹性项目属性是:

  • order
  • flex-grow
  • flex-shrink
  • flex-basis
  • flex
  • align-self

订单属性

order 属性指定 Flex 项目的顺序。

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代码中的第一个 Flex 项目不必显示为布局中的第一个项目。

订单值必须是数字,默认值为 0。

例子

order 属性可以更改弹性项目的顺序:

<div class="flex-container">
  <div style="order: 3">1</div>
  
  <div style="order: 2">2</div>
  <div style="order: 4">3</div> 
  
  <div style="order: 1">4</div>
</div>

自己尝试一下 →

<!DOCTYPE html>
<html>
<head>
<style>
.flex-container {
  display: flex;
  align-items: stretch;
  background-color: #f1f1f1;
}

.flex-container>div {
  background-color: DodgerBlue;
  color: white;
  width: 100px;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;
}
</style>
</head>
<body>

<h1>The order Property</h1>

<p>Use the order property to sort the flex items as you like:</p>

<div class="flex-container">
  <div style="order: 3">1</div>
  <div style="order: 2">2</div>
  <div style="order: 4">3</div> 
  <div style="order: 1">4</div>
</div>

</body>
</html>



flex-grow 属性

flex-grow 属性指定 Flex 项目相对于其余 Flex 项目的增长量。

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该值必须是数字,默认值为 0。

例子

使第三个弹性项目的增长速度比其他弹性项目快八倍:

<div class="flex-container">
  <div style="flex-grow: 1">1</div>
  
  <div style="flex-grow: 1">2</div>
  <div style="flex-grow: 
  8">3</div> 
</div>

自己尝试一下→

<!DOCTYPE html>
<html>
<head>
<style>
.flex-container {
  display: flex;
  align-items: stretch;
  background-color: #f1f1f1;
}

.flex-container > div {
  background-color: DodgerBlue;
  color: white;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;
}
</style>
</head>
<body>

<h1>The flex-grow Property</h1>

<p>Make the third flex item grow eight times faster than the other flex items:</p>

<div class="flex-container">
  <div style="flex-grow: 1">1</div>
  <div style="flex-grow: 1">2</div>
  <div style="flex-grow: 8">3</div>
</div>

</body>
</html>




flex-shrink 属性

flex-shrink 属性指定 Flex 项目相对于其余 Flex 项目收缩的程度。

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该值必须是数字,默认值为 1。

例子

不要让第三个 Flex 项目像其他 Flex 项目一样收缩:

<div class="flex-container">
  <div>1</div>
  <div>2</div>
  <div style="flex-shrink: 
  0">3</div>
    <div>4</div>
  <div>5</div>
  <div>6</div>
  
  <div>7</div>
  <div>8</div>
  <div>9</div>
  
  <div>10</div>
</div>

自己尝试一下 →

<!DOCTYPE html>
<html>
<head>
<style>
.flex-container {
  display: flex;
  align-items: stretch;
  background-color: #f1f1f1;
}

.flex-container>div {
  background-color: DodgerBlue;
  color: white;
  width: 100px;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;
}
</style>
</head>
<body>

<h1>The flex-shrink Property</h1>

<p>Do not let the third flex item shrink as much as the other flex items:</p>

<div class="flex-container">
  <div>1</div>
  <div>2</div>
  <div style="flex-shrink: 0">3</div>
  <div>4</div>
  <div>5</div>
  <div>6</div>
  <div>7</div>
  <div>8</div>
  <div>9</div>
  <div>10</div>
</div>

</body>
</html>



flex-basis 属性

flex-basis 属性指定 Flex 项目的初始长度。

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例子

将第三个 Flex 项目的初始长度设置为 200 像素:

<div class="flex-container">
  <div>1</div>
  <div>2</div>
  <div style="flex-basis: 200px">3</div>
    <div>4</div>
</div>

自己尝试一下→

<!DOCTYPE html>
<html>
<head>
<style>
.flex-container {
  display: flex;
  align-items: stretch;
  background-color: #f1f1f1;
}

.flex-container > div {
  background-color: DodgerBlue;
  color: white;
  width: 100px;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;
}
</style>
</head>
<body>

<h1>The flex-basis Property</h1>

<p>Set the initial length of the third flex item to 200 pixels:</p>

<div class="flex-container">
  <div>1</div>
  <div>2</div>
  <div style="flex-basis:200px">3</div>
  <div>4</div>
</div>

</body>
</html>



弹性属性

flex 属性是 的简写属性 flex-growflex-shrinkflex-basis 属性。

例子

使第三个 Flex 项目不可增长 (0)、不可收缩 (0),并且具有 初始长度为 200 像素:

<div class="flex-container">
  <div>1</div>
  <div>2</div>
  <div style="flex: 
  0 0 200px">3</div>
    <div>4</div>
</div>

自己尝试一下 →

<!DOCTYPE html>
<html>
<head>
<style>
.flex-container {
  display: flex;
  align-items: stretch;
  background-color: #f1f1f1;
}

.flex-container>div {
  background-color: DodgerBlue;
  color: white;
  width: 100px;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;
}
</style>
</head>
<body>

<h1>The flex Property</h1>

<p>Make the third flex item not growable (0), not shrinkable (0), and with an initial length of 200 pixels:</p>

<div class="flex-container">
  <div>1</div>
  <div>2</div>
  <div style="flex: 0 0 200px">3</div>
  <div>4</div>
</div>

</body>
</html>



自我对齐属性

align-self 属性指定灵活容器内所选项目的对齐方式。

align-self 属性会覆盖容器的 align-items 属性设置的默认对齐方式。

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在这些示例中,我们使用 200 像素高的容器,以更好地演示 对齐自我属性:

例子

将第三个 Flex 项目对齐在容器的中间:

<div class="flex-container">
  <div>1</div>
  <div>2</div>
  <div style="align-self: 
  center">3</div>
    <div>4</div>
</div>

自己尝试一下 →

<!DOCTYPE html>
<html>
<head>
<style>
.flex-container {
  display: flex;
  height: 200px;
  background-color: #f1f1f1;
}

.flex-container > div {
  background-color: DodgerBlue;
  color: white;
  width: 100px;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;
}
</style>
</head>
<body>

<h1>The align-self Property</h1>

<p>The "align-self: center;" aligns the selected flex item in the middle of the container:</p>

<div class="flex-container">
  <div>1</div>
  <div>2</div>
  <div style="align-self: center">3</div>
  <div>4</div>
</div>

<p>The align-self property overrides the align-items property of the container.</p>

</body>
</html>


例子

将第二个 Flex 项目与容器顶部对齐,将第三个 Flex 项目与容器顶部对齐 容器底部:

<div class="flex-container">
  <div>1</div>
  <div style="align-self: 
  flex-start">2</div>
    <div style="align-self: 
  flex-end">3</div>
    <div>4</div>
</div>

自己尝试一下 →

<!DOCTYPE html>
<html>
<head>
<style>
.flex-container {
  display: flex;
  height: 200px;
  background-color: #f1f1f1;
}

.flex-container > div {
  background-color: DodgerBlue;
  color: white;
  width: 100px;
  margin: 10px;
  text-align: center;
  line-height: 75px;
  font-size: 30px;
}
</style>
</head>
<body>

<h1>The align-self Property</h1>

<p>The "align-self: flex-start;" aligns the selected flex item at the top of the container.</p>
<p>The "align-self: flex-end;" aligns the selected flex item at the bottom of the container.</p>

<div class="flex-container">
  <div>1</div>
  <div style="align-self: flex-start">2</div>
  <div style="align-self: flex-end">3</div>
  <div>4</div>
</div>

<p>The align-self property overrides the align-items property of the container.</p>

</body>
</html>



CSS Flexbox 项目属性

下表列出了所有 CSS Flexbox 项目属性:

align-self

指定 Flex 项目的对齐方式(覆盖 Flex 容器的align-items 属性)

flex

flex-grow、flex-shrink 和 flex-basis 的简写属性 特性

flex-basis

指定弹性项目的初始长度

flex-grow

指定 Flex 项目相对于同一容器内其余 Flex 项目的增长量

flex-shrink

指定 Flex 项目相对于同一容器内的其余 Flex 项目收缩的程度

order

指定同一容器内弹性项目的顺序