108 lines
4.4 KiB
Markdown
108 lines
4.4 KiB
Markdown
---
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id: flexbox
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title: Layout with Flexbox
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layout: docs
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category: The Basics
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permalink: docs/flexbox.html
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next: handling-text-input
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previous: height-and-width
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---
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A component can specify the layout of its children using the flexbox algorithm. Flexbox is designed to provide a consistent layout on different screen sizes.
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You will normally use a combination of `flexDirection`, `alignItems`, and `justifyContent` to achieve the right layout.
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> Flexbox works the same way in React Native as it does in CSS on the web, with a few exceptions. The defaults are different, with `flexDirection` defaulting to `column` instead of `row`, and the `flex` parameter only supporting a single number.
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#### Flex Direction
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Adding `flexDirection` to a component's `style` determines the **primary axis** of its layout. Should the children be organized horizontally (`row`) or vertically (`column`)? The default is `column`.
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```ReactNativeWebPlayer
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import React, { Component } from 'react';
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import { AppRegistry, View } from 'react-native';
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class FlexDirectionBasics extends Component {
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render() {
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return (
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// Try setting `flexDirection` to `column`.
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<View style={{flex: 1, flexDirection: 'row'}}>
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<View style={{width: 50, height: 50, backgroundColor: 'powderblue'}} />
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<View style={{width: 50, height: 50, backgroundColor: 'skyblue'}} />
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<View style={{width: 50, height: 50, backgroundColor: 'steelblue'}} />
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</View>
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);
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}
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};
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AppRegistry.registerComponent('AwesomeProject', () => FlexDirectionBasics);
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```
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#### Justify Content
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Adding `justifyContent` to a component's style determines the **distribution** of children along the **primary axis**. Should children be distributed at the start, the center, the end, or spaced evenly? Available options are `flex-start`, `center`, `flex-end`, `space-around`, and `space-between`.
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```ReactNativeWebPlayer
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import React, { Component } from 'react';
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import { AppRegistry, View } from 'react-native';
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class JustifyContentBasics extends Component {
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render() {
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return (
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// Try setting `justifyContent` to `center`.
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// Try setting `flexDirection` to `row`.
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<View style={{
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flex: 1,
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flexDirection: 'column',
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justifyContent: 'space-between',
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}}>
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<View style={{width: 50, height: 50, backgroundColor: 'powderblue'}} />
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<View style={{width: 50, height: 50, backgroundColor: 'skyblue'}} />
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<View style={{width: 50, height: 50, backgroundColor: 'steelblue'}} />
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</View>
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);
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}
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};
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AppRegistry.registerComponent('AwesomeProject', () => JustifyContentBasics);
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```
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#### Align Items
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Adding `alignItems` to a component's style determines the **alignment** of children along the **secondary axis** (if the primary axis is `row`, then the secondary is `column`, and vice versa). Should children be aligned at the start, the center, the end, or stretched to fill? Available options are `flex-start`, `center`, `flex-end`, and `stretch`.
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> For `stretch` to have an effect, children must not have a fixed dimension along the secondary axis. In the following example, setting `alignItems: stretch` does nothing until the `width: 50` is removed from the children.
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```ReactNativeWebPlayer
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import React, { Component } from 'react';
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import { AppRegistry, View } from 'react-native';
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class AlignItemsBasics extends Component {
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render() {
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return (
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// Try setting `alignItems` to 'flex-start'
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// Try setting `justifyContent` to `flex-end`.
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// Try setting `flexDirection` to `row`.
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<View style={{
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flex: 1,
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flexDirection: 'column',
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justifyContent: 'center',
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alignItems: 'center',
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}}>
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<View style={{width: 50, height: 50, backgroundColor: 'powderblue'}} />
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<View style={{width: 50, height: 50, backgroundColor: 'skyblue'}} />
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<View style={{width: 50, height: 50, backgroundColor: 'steelblue'}} />
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</View>
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);
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}
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};
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AppRegistry.registerComponent('AwesomeProject', () => AlignItemsBasics);
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```
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#### Going Deeper
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We've covered the basics, but there are many other styles you may need for layouts. The full list of props that control layout is documented [here](./docs/layout-props.html).
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We're getting close to being able to build a real application. One thing we are still missing is a way to take user input, so let's move on to [learn how to handle text input with the TextInput component](docs/handling-text-input.html).
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