布局属性

More detailed examples about those properties can be found on the Layout with Flexbox page.

示例

The following example shows how different properties can affect or shape a React Native layout. You can try for example to add or remove squares from the UI while changing the values of the property flexWrap.

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文档

属性

alignContent

alignContent controls how rows align in the cross direction, overriding the alignContent of the parent. 访问 https://developer.mozilla.org/en-US/docs/Web/CSS/align-content 来进一步了解。

Type	必需
enum('flex-start', 'flex-end', 'center', 'stretch', 'space-between', 'space-around', 'space-evenly')	否

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alignItems

alignItems aligns children in the cross direction. For example, if children are flowing vertically, alignItems controls how they align horizontally. It works like align-items in CSS (default: stretch). See https://developer.mozilla.org/en-US/docs/Web/CSS/align-items for more details.

Type	Required
enum('flex-start', 'flex-end', 'center', 'stretch', 'baseline')	No

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alignSelf

alignSelf controls how a child aligns in the cross direction, overriding the alignItems of the parent. It works like align-self in CSS (default: auto). See https://developer.mozilla.org/en-US/docs/Web/CSS/align-self for more details.

Type	Required
enum('auto', 'flex-start', 'flex-end', 'center', 'stretch', 'baseline')	No

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aspectRatio

Aspect ratio controls the size of the undefined dimension of a node. See https://developer.mozilla.org/en-US/docs/Web/CSS/aspect-ratio for more details.

• On a node with a set width/height, aspect ratio controls the size of the unset dimension
• On a node with a set flex basis, aspect ratio controls the size of the node in the cross axis if unset
• On a node with a measure function, aspect ratio works as though the measure function measures the flex basis
• On a node with flex grow/shrink, aspect ratio controls the size of the node in the cross axis if unset
• Aspect ratio takes min/max dimensions into account

Type	Required
number, string	No

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borderBottomWidth

borderBottomWidth works like border-bottom-width in CSS. See https://developer.mozilla.org/en-US/docs/Web/CSS/border-bottom-width for more details.

Type	Required
number	No

---

borderEndWidth

When direction is ltr, borderEndWidth is equivalent to borderRightWidth. When direction is rtl, borderEndWidth is equivalent to borderLeftWidth.

Type	Required
number	No

---

borderLeftWidth

borderLeftWidth works like border-left-width in CSS. See https://developer.mozilla.org/en-US/docs/Web/CSS/border-left-width for more details.

Type	Required
number	No

---

borderRightWidth

borderRightWidth works like border-right-width in CSS. See https://developer.mozilla.org/en-US/docs/Web/CSS/border-right-width for more details.

Type	Required
number	No

---

borderStartWidth

When direction is ltr, borderStartWidth is equivalent to borderLeftWidth. When direction is rtl, borderStartWidth is equivalent to borderRightWidth.

Type	Required
number	No

---

borderTopWidth

borderTopWidth works like border-top-width in CSS. See https://developer.mozilla.org/en-US/docs/Web/CSS/border-top-width for more details.

Type	Required
number	No

---

borderWidth

borderWidth works like border-width in CSS. See https://developer.mozilla.org/en-US/docs/Web/CSS/border-width for more details.

Type	Required
number	No

---

bottom

bottom is the number of logical pixels to offset the bottom edge of this component.

It works similarly to bottom in CSS, but in React Native you must use points or percentages. Ems and other units are not supported.

See https://developer.mozilla.org/en-US/docs/Web/CSS/bottom for more details of how bottom affects layout.

Type	Required
number, string	No

---

columnGap

columnGap works like column-gap in CSS. Only pixel units are supported in React Native. See https://developer.mozilla.org/en-US/docs/Web/CSS/column-gap for more details.

Type	Required
number	No

---

direction

direction指定了用户界面的阅读顺序。ltr表示 left to right，即从左往右阅读。反之rtl为从右往左阅读。默认值为inherit，但根节点的值会根据用户所在地的不同而不同。访问 https://yogalayout.com/docs/layout-direction 来进一步了解。

类型	必需	平台
enum('inherit', 'ltr', 'rtl')	否	iOS

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display

display设置组件的显示类型。可用于元素的显示和隐藏。

它的表现和 CSS 上的display类似，但目前只支持'flex'和'none'两个值。默认值是'flex'。

类型	必需
enum('none', 'flex')	否

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end

当direction设置为ltr时，end等同于right。当direction设置为rtl，end等同于left。

此样式的优先级高于left和right。

类型	必需
number, string	否

---

flex

在 React Native 中flex的表现和 CSS 有些区别。flex在 RN 中只能为整数值，其具体表现请参考yoga布局引擎的文档，其地址为 https://github.com/facebook/yoga

当flex为一个正整数时，组件尺寸会具有弹性，并根据具体的 flex 值来按比例分配。比如两个组件在同一个父容器中，一个flex为 2，另一个flex为 1，则两者的尺寸比为 2：1。 flex: <positive number> equates to flexGrow: <positive number>, flexShrink: 1, flexBasis: 0.

当flex为 0 时，组件尺寸由width和height决定，此时不再具有弹性。

当flex为-1 时，组件尺寸一般还是由width和height决定。但是当空间不够时，组件尺寸会收缩到minWidth和minHeight所设定的值。

flexGrow、flexShrink、flexBasis和在 CSS 上表现一致。

类型	必需
number	否

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flexBasis

flexBasis is an axis-independent way of providing the default size of an item along the main axis. Setting the flexBasis of a child is similar to setting the width of that child if its parent is a container with flexDirection: row or setting the height of a child if its parent is a container with flexDirection: column. The flexBasis of an item is the default size of that item, the size of the item before any flexGrow and flexShrink calculations are performed.

类型	必需
number, string	否

---

flexDirection

flexDirection controls which directions children of a container go. row goes left to right, column goes top to bottom, and you may be able to guess what the other two do. It works like flex-direction in CSS, except the default is column. 访问 https://developer.mozilla.org/en-US/docs/Web/CSS/flex-direction 来进一步了解。

类型	必需
enum('row', 'row-reverse', 'column', 'column-reverse')	否

---

flexGrow

flexGrow describes how any space within a container should be distributed among its children along the main axis. After laying out its children, a container will distribute any remaining space according to the flex grow values specified by its children.

flexGrow accepts any floating point value >= 0, with 0 being the default value. A container will distribute any remaining space among its children weighted by the children’s flexGrow values.

类型	必需
number	否

---

flexShrink

flexShrink describes how to shrink children along the main axis in the case in which the total size of the children overflows the size of the container on the main axis. flexShrink is very similar to flexGrow and can be thought of in the same way if any overflowing size is considered to be negative remaining space. These two properties also work well together by allowing children to grow and shrink as needed.

flexShrink accepts any floating point value >= 0, with 0 being the default value. A container will shrink its children weighted by the children’s flexShrink values.

类型	必需
number	否

---

flexWrap

flexWrap controls whether children can wrap around after they hit the end of a flex container. It works like flex-wrap in CSS (default: nowrap). 访问 https://developer.mozilla.org/en-US/docs/Web/CSS/flex-wrap 来进一步了解。Note it does not work anymore with alignItems: stretch (the default), so you may want to use alignItems: flex-start for example (breaking change details: https://github.com/facebook/react-native/releases/tag/v0.28.0).

类型	必需
enum('wrap', 'nowrap', 'wrap-reverse')	否

---

gap

gap works like gap in CSS. Only pixel units are supported in React Native. See https://developer.mozilla.org/en-US/docs/Web/CSS/gap for more details.

Type	Required
number	No

---

height

height用于设置组件的高度。

它的表现和 CSS 上的height类似， but in React Native 只能使用逻辑像素值（数字单位）或百分比，而不能使用 em 或是任何其他单位。 访问 https://developer.mozilla.org/en-US/docs/Web/CSS/height 来进一步了解。

类型	必需
number, string	否

---

justifyContent

justifyContent aligns children in the main direction. For example, if children are flowing vertically, justifyContent controls how they align vertically. It works like justify-content in CSS (default: flex-start). 访问 https://developer.mozilla.org/en-US/docs/Web/CSS/justify-content 来进一步了解。

类型	必需
enum('flex-start', 'flex-end', 'center', 'space-between', 'space-around', 'space-evenly')	否

---

left

left值是指将本组件定位到距离左边多少个逻辑像素（左边的定义取决于position属性）。

它的表现和 CSS 上的left类似， but in React Native 只能使用逻辑像素值（数字单位）或百分比，而不能使用 em 或是任何其他单位。

访问 https://developer.mozilla.org/en-US/docs/Web/CSS/left for more details of how left affects layout.

类型	必需
number, string	否

---

margin

设置margin相同于同时设置marginTop、marginLeft、marginBottom以及marginRight。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/margin 来进一步了解。

类型	必需
number, string	否

---

marginBottom

marginBottom和 CSS 上的margin-bottom表现一致。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/margin-bottom 来进一步了解。

类型	必需
number, string	否

---

marginEnd

When direction is ltr, marginEnd is equivalent to marginRight. When direction is rtl, marginEnd is equivalent to marginLeft.

类型	必需
number, string	否

---

marginHorizontal

设置marginHorizontal相同于同时设置marginLeft和marginRight。

类型	必需
number, string	否

---

marginLeft

marginLeft和 CSS 上的margin-left表现一致。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/margin-left 来进一步了解。

类型	必需
number, string	否

---

marginRight

marginRight和 CSS 上的margin-right表现一致。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/margin-right 来进一步了解。

类型	必需
number, string	否

---

marginStart

When direction is ltr, marginStart is equivalent to marginLeft. When direction is rtl, marginStart is equivalent to marginRight.

类型	必需
number, string	否

---

marginTop

marginTop和 CSS 上的margin-top表现一致。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/margin-top 来进一步了解。

类型	必需
number, string	否

---

marginVertical

设置marginVertical相同于同时设置marginTop和marginBottom。

类型	必需
number, string	否

---

maxHeight

maxHeight is the maximum height for this component, in logical pixels.

它的表现和 CSS 上的max-height类似，但是在 React Native 上只能使用逻辑像素值（数字单位）或百分比，而不能使用 em 或是任何其他单位。

访问 https://developer.mozilla.org/en-US/docs/Web/CSS/max-height 来进一步了解。

类型	必需
number, string	否

---

maxWidth

maxWidth is the maximum width for this component, in logical pixels.

它的表现和 CSS 上的max-width类似，但是在 React Native 上只能使用逻辑像素值（数字单位）或百分比，而不能使用 em 或是任何其他单位。

访问 https://developer.mozilla.org/en-US/docs/Web/CSS/max-width 来进一步了解。

类型	必需
number, string	否

---

minHeight

minHeight is the minimum height for this component, in logical pixels.

它的表现和 CSS 上的min-height类似，但是在 React Native 上只能使用逻辑像素值（数字单位）或百分比，而不能使用 em 或是任何其他单位。

访问 https://developer.mozilla.org/en-US/docs/Web/CSS/min-height 来进一步了解。

类型	必需
number, string	否

---

minWidth

minWidth is the minimum width for this component, in logical pixels.

它的表现和 CSS 上的min-width类似，但是在 React Native 上只能使用逻辑像素值（数字单位）或百分比，而不能使用 em 或是任何其他单位。

访问 https://developer.mozilla.org/en-US/docs/Web/CSS/min-width 来进一步了解。

类型	必需
number, string	否

---

overflow

overflow controls how children are measured and displayed. overflow: hidden causes views to be clipped while overflow: scroll causes views to be measured independently of their parents main axis. It works like overflow in CSS (default: visible). 访问 https://developer.mozilla.org/en/docs/Web/CSS/overflow 来进一步了解。

类型	必需
enum('visible', 'hidden', 'scroll')	否

---

padding

设置padding相同于同时设置paddingTop、paddingBottom、paddingLeft以及paddingRight。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/padding 来进一步了解。

类型	必需
number, string	否

---

paddingBottom

paddingBottom和 CSS 上的padding-bottom表现一致。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/padding-bottom 来进一步了解。

类型	必需
number, string	否

---

paddingEnd

When direction is ltr, paddingEnd is equivalent to paddingRight. When direction is rtl, paddingEnd is equivalent to paddingLeft.

类型	必需
number, string	否

---

paddingHorizontal

设置paddingHorizontal相同于同时设置paddingLeft和paddingRight。

类型	必需
number, string	否

---

paddingLeft

paddingLeft和 CSS 上的padding-left表现一致。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/padding-left 来进一步了解。

类型	必需
number, string	否

---

paddingRight

paddingRight和 CSS 上的padding-right表现一致。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/padding-right 来进一步了解。

类型	必需
number, string	否

---

paddingStart

When direction is ltr, paddingStart is equivalent to paddingLeft. When direction is rtl, paddingStart is equivalent to paddingRight.

类型	必需
number, string	否

---

paddingTop

paddingTop和 CSS 上的padding-top表现一致。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/padding-top 来进一步了解。

类型	必需
number, string	否

---

paddingVertical

设置paddingVertical相同于同时设置paddingTop和paddingBottom。

类型	必需
number, string	否

---

position

position in React Native is similar to regular CSS, but everything is set to relative by default, so absolute positioning is always relative to the parent.

If you want to position a child using specific numbers of logical pixels relative to its parent, set the child to have absolute position.

If you want to position a child relative to something that is not its parent, don't use styles for that. Use the component tree.

See https://github.com/facebook/yoga for more details on how position differs between React Native and CSS.

类型	必需
enum('absolute', 'relative')	否

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right

right值是指将本组件定位到距离右边多少个逻辑像素（右边的定义取决于position属性）。

它的表现和 CSS 上的right类似，但是在 React Native 上只能使用逻辑像素值（数字单位）或百分比，而不能使用 em 或是任何其他单位。

访问 https://developer.mozilla.org/en-US/docs/Web/CSS/right for more details of how right affects layout.

类型	必需
number, string	否

---

rowGap

rowGap works like row-gap in CSS. Only pixel units are supported in React Native. See https://developer.mozilla.org/en-US/docs/Web/CSS/row-gap for more details.

Type	Required
number	No

---

start

当direction设置为ltr时，start等同于left。当direction设置为rtl，start等同于right。

此样式的优先级高于left、right和end。

类型	必需
number, string	否

---

top

top值是指将本组件定位到距离顶部多少个逻辑像素（顶部的定义取决于position属性）。

它的表现和 CSS 上的top类似，但是在 React Native 上只能使用逻辑像素值（数字单位）或百分比，而不能使用 em 或是任何其他单位。

访问 https://developer.mozilla.org/en-US/docs/Web/CSS/top for more details of how top affects layout.

类型	必需
number, string	否

---

width

width设置组件的宽度。

它的表现和 CSS 上的width类似，但是在 React Native 上只能使用逻辑像素值（数字单位）或百分比，而不能使用 em 或是任何其他单位。 访问 https://developer.mozilla.org/en-US/docs/Web/CSS/width 来进一步了解。

类型	必需
number, string	否

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zIndex

zIndex控制着组件的堆叠覆盖顺序。多数情况下你不会用到此样式。默认情况下组件按其在文档树的顺序依次渲染，所以在代码结构上靠后的组件会覆盖前面的组件（如果它们在布局上有重叠的部分）。有时候在写一些动画或者自定义的模态窗口时，你可能会需要设置zIndex样式来改变层叠覆盖顺序。

它的表现和 CSS 上的z-index一致——zIndex大的在上面。这里面的z意味着三维空间中的z轴，你可以想象成垂直于手机屏幕指向你的眼睛的坐标轴。访问 https://developer.mozilla.org/en-US/docs/Web/CSS/z-index 来进一步了解。

在 iOS 上，使用zIndex可能需要View彼此为兄弟节点才能生效。

类型	必需
number	否

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