版权声明：本文仅供个人学习。
CSS 中 Flex-Box 语法链接 http://www.ruanyifeng.com/blog/2015/07/flex-grammar.html
布局源码
import React, { Component } from 'react';
import {
Platform,
StyleSheet,
View,
Image,
} from 'react-native';
const instructions = Platform.select({
ios: 'Press Cmd+R to reload,\n' +
'Cmd+D or shake for dev menu',
android: 'Double tap R on your keyboard to reload,\n' +
'Shake or press menu button for dev menu',
});
export default class App extends Component {
render() {
return (
<View style={styles.container}>
<Image style={styles.image} source={require('./img/point.png')}/>
<Image style={styles.image} source={require('./img/point.png')}/>
<Image style={styles.image} source={require('./img/point.png')}/>
</View>
);
}
}水平布局（不设置朝向，则默认为竖直布局）
const styles = StyleSheet.create({
container: {
flexDirection: 'row',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});竖直布局（不设置朝向，则默认为竖直布局）
const styles = StyleSheet.create({
container: {
flexDirection: 'column',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});默认样式 顶部 水平居左/左上角
const styles = StyleSheet.create({
container: {
},
image: {
width: 40,
height: 40,
padding: 20,
background: '#00000033'
}
});或
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'flex-start',
},
image: {
width: 40,
height: 40,
padding: 20,
background: '#00000033'
}
});
顶部 水平居中
const styles = StyleSheet.create({
container: {
flex: 1,
alignItems: 'center',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});顶部 水平居右/右上角
const styles = StyleSheet.create({
container: {
flex: 1,
alignItems: 'flex-end',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});居左 竖直居中
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});水平且垂直居中（显示在屏幕中央）
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});居右 竖直居中
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'flex-end',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});底部 水平居左/左下角
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'flex-end',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});
底部 水平居中
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'flex-end',
alignItems: 'center',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});底部 水平居右/右下角
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'flex-end',
alignItems: 'flex-end',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});默认或设置为 flexDirection: column 时
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'flex-start',
alignItems: 'center',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});或
const styles = StyleSheet.create({
container: {
flex: 1,
flexDirection: 'column',
justifyContent: 'flex-start',
alignItems: 'center',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});设置为 flexDirection: row 时
const styles = StyleSheet.create({
container: {
flex: 1,
flexDirection: 'row',
justifyContent: 'flex-start',
alignItems: 'center',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});justifyContent 的属性值
下面的这两个属性值，可以搭配 alignItems 的 flex-start、flex-end、center 三个属性搭配使用‘space-between’：两端对齐，项目之间的间隔都相等
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'space-between'
},
image: {
width: 40,
height: 40,
padding: 20,
}
});‘space-around’：每个项目两侧的间隔相等。所以，项目之间的间隔比项目与边框的间隔大一倍
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'space-around'
},
image: {
width: 40,
height: 40,
padding: 20,
}
});alignItems 的属性值
下面的这两个属性值，可以搭配 justifyContent 的 flex-start、flex-end、center 三个属性搭配使用‘baseline’: 项目的第一行文字的基线对齐
//TODO 没看到效果呢
const styles = StyleSheet.create({
container: {
flex: 1,
alignItems: 'baseline'
},
image: {
width: 40,
height: 40,
padding: 20,
}
});‘stretch’（默认值）：如果项目未设置高度或设为auto，将占满整个容器的高度
//TODO 没看到效果呢
const styles = StyleSheet.create({
container: {
flex: 1,
alignItems: 'stretch'
},
image: {
width: 40,
height: 40,
padding: 20,
}
});flex-grow 的属性值：定义项目的放大比例
const styles = StyleSheet.create({
container: {
flex: 1,
},
image: {
flexGrow: 1,
width: 40,
height: 40,
padding: 20,
}
});const styles = StyleSheet.create({
container: {
flexDirection: 'row',
flex: 1,
},
image: {
flexGrow: 1,
width: 40,
height: 40,
padding: 20,
}
});flex-wrap 的属性值：如果一条轴线排不下，换行。默认情况下，项目都排在一条线上（又称”主轴线”）。flex-wrap 属性定义
有三个属性值：nowrap（默认）：不换行；wrap：换行、第一行在前；wrap-reverse：换行、第一行在后
const styles = StyleSheet.create({
container: {
flex: 1,
flexWrap: 'wrap',
},
image: {
width: 40,
height: 40,
padding: 20,
}
});