React Native Tutorial摘要（二）

###组件的宽和高 基本跟CSS同样使用，但要注意是放在style中的对象中，即{{}}。

import React, { Component } from 'react';
import { AppRegistry, View } from 'react-native';

class FixedDimensionsBasics extends Component {
  render() {
    return (
      <View>
        <View style={{width: 50, height: 50, backgroundColor: 'powderblue'}} />
        <View style={{width: 100, height: 100, backgroundColor: 'skyblue'}} />
        <View style={{width: 150, height: 150, backgroundColor: 'steelblue'}} />
      </View>
    );
  }
};

AppRegistry.registerComponent('AwesomeProject', () => FixedDimensionsBasics);

同时提供了动态的比例模式，尽可能填充可用区域。flex: 1
基于父节点大小使用。若是父节点大小为0，则没法使用。

import React, { Component } from 'react';
import { AppRegistry, View } from 'react-native';

class FlexDimensionsBasics extends Component {
  render() {
    return (
      // Try removing the `flex: 1` on the parent View.
      // The parent will not have dimensions, so the children can't expand.
      // What if you add `height: 300` instead of `flex: 1`?
      <View style={{flex: 1}}>
        <View style={{flex: 1, backgroundColor: 'powderblue'}} />
        <View style={{flex: 2, backgroundColor: 'skyblue'}} />
        <View style={{flex: 3, backgroundColor: 'steelblue'}} />
      </View>
    );
  }
};

AppRegistry.registerComponent('AwesomeProject', () => FlexDimensionsBasics);

###伸缩布局 主要是_flexDirection_，alignItems，_justifyContent_的组合使用。
flexDirection ： row，column
justifyContent： flex-start，center，flex-end，space-around，space-between
alignment：flex-start, center, flex-end, stretch（这个还没明白是如何拉伸）

import React, { Component } from 'react';
import { AppRegistry, View } from 'react-native';

class AlignItemsBasics {
  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', () => AlignItemsBasics);