react-native/docs/Basics-Layout.md
Devin Abbott 6c5f532591 Add docs pages for basics: Dimensions and Layout
Summary:
These pages should sufficiently give a beginner enough information to make most layouts in React Native. They should go after the basics-style page, whenever that is ready.

Having a single page for Layout was too much, so I split it into two: Dimensions and Layout.

![dimensions react native a framework for building native apps using react](https://cloud.githubusercontent.com/assets/1198882/16311045/c6918b64-3923-11e6-8cc9-daeda9eb40e6.png)

![layout react native a framework for building native apps using react](https://cloud.githubusercontent.com/assets/1198882/16310233/9a66405a-3920-11e6-9ef6-1594f7228e83.png)

lacker
Closes https://github.com/facebook/react-native/pull/8364

Differential Revision: D3477147

Pulled By: lacker

fbshipit-source-id: 1ef31ac0a64e43166a7581b38fa8263282672eeb
2016-06-23 11:58:54 -07:00

105 lines
4.0 KiB
Markdown

---
id: basics-layout
title: Layout
layout: docs
category: The Basics
permalink: docs/basics-layout.html
next: basics-network
---
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.
You will normally use a combination of `flexDirection`, `alignItems`, and `justifyContent` to achieve the right layout.
> Flexbox works the same way in React Native as it does in CSS on the web, with a few exceptions. The most notable one: the defaults are different, with `flexDirection` defaulting to `column` instead of `row`, and `alignItems` defaulting to `stretch` instead of `flex-start`.
#### Flex Direction
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`.
```ReactNativeWebPlayer
import React from 'react';
import { AppRegistry, View } from 'react-native';
class AwesomeProject {
render() {
return (
// Try setting `flexDirection` to `column`.
<View style={{flex: 1, flexDirection: 'row'}}>
<View style={{width: 50, height: 50, backgroundColor: 'powderblue'}} />
<View style={{width: 50, height: 50, backgroundColor: 'skyblue'}} />
<View style={{width: 50, height: 50, backgroundColor: 'steelblue'}} />
</View>
);
}
};
AppRegistry.registerComponent('AwesomeProject', () => AwesomeProject);
```
#### Justify Content
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`.
```ReactNativeWebPlayer
import React from 'react';
import { AppRegistry, View } from 'react-native';
class AwesomeProject {
render() {
return (
// Try setting `justifyContent` to `center`.
// Try setting `flexDirection` to `row`.
<View style={{
flex: 1,
flexDirection: 'column',
justifyContent: 'space-between',
}}>
<View style={{width: 50, height: 50, backgroundColor: 'powderblue'}} />
<View style={{width: 50, height: 50, backgroundColor: 'skyblue'}} />
<View style={{width: 50, height: 50, backgroundColor: 'steelblue'}} />
</View>
);
}
};
AppRegistry.registerComponent('AwesomeProject', () => AwesomeProject);
```
#### Align Items
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`.
> 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.
```ReactNativeWebPlayer
import React from 'react';
import { AppRegistry, View } from 'react-native';
class AwesomeProject {
render() {
return (
// Try setting `alignItems` to 'flex-start'
// Try setting `justifyContent` to `flex-end`.
// Try setting `flexDirection` to `row`.
<View style={{
flex: 1,
flexDirection: 'column',
justifyContent: 'center',
alignItems: 'center',
}}>
<View style={{width: 50, height: 50, backgroundColor: 'powderblue'}} />
<View style={{width: 50, height: 50, backgroundColor: 'skyblue'}} />
<View style={{width: 50, height: 50, backgroundColor: 'steelblue'}} />
</View>
);
}
};
AppRegistry.registerComponent('AwesomeProject', () => AwesomeProject);
```
#### API Reference
We've covered the basics, but there are many other styles you may need for layouts. The full list is available [here](./docs/flexbox.html).