React Native 0.20官方入门教程

最近对React Native比较有兴趣，简单把官网的入门例子做了一下，发现了很多坑，特别是watchman版本过低的问题，导致总是运行不起来。所以 这里特别下载了最新的watchman，进行了源码编译。希望本文对刚学习的新人有用。

安装Rect Native

安装必要的依赖watchman

cd watchman-4.5.0
./autogen.sh
./configure --prefix=/usr/local/Cellar/watchman/2.9.8 --with-pcre
make
make install

安装Rect Native开发工具

npm install -g react-native-cli
react-native init <APP_NAME>

IOS版本的项目文件用XCODE打开<APP_NAME>/ios/<APP_NAME>.xcodeproj，运行?+R即可

此时通过修改index.ios.js 运行?+R查看视图变化

模拟数据

通常在index.ios.js或index.android.js 顶部增加

var MOCKED_MOVIES_DATA = [
  {title: 'Title',year: '2015',posters: {thumbnail: 'http://i.imgur.com/UePbdph.jpg'}},];

修改代码,增加Image组件支持

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

修改render

render() {
      var movie = MOCKED_MOVIES_DATA[0];
    return (
      <View style={styles.container}>
        <Text>{movie.title}</Text>
        <Text>{movie.year}</Text>
        <Image 
          source={{uri: movie.posters.thumbnail}}
          style={styles.thumbnail} />
      </View>
    );
  }

更新样式代码

const styles = StyleSheet.create({
  container: {
    flex: 1,justifyContent: 'center',alignItems: 'center',backgroundColor: '#F5FCFF',},thumbnail: {
      width: 53,height: 81,}
});

Xcode中?+R重新载入，即看到视图已载入我们的模拟数据。

重新布局

使用FlexBox布局
改变结构代码

render() {
    var movie = MOCKED_MOVIES_DATA[0];
    return (
      <View style={styles.container}>
        <Image 
          source={{uri: movie.posters.thumbnail}}
          style={styles.thumbnail} />
        <View style={styles.rightContainer}>
          <Text style={styles.title}>{movie.title}</Text>
          <Text style={styles.year}>{movie.year}</Text>
        </View>
      </View>
    );
  }

更新样式

const styles = StyleSheet.create({
  container: {
    flex: 1,flexDirection: 'row',rightContainer: {
      flex: 1,title: {
      fontSize: 20,marginBottom: 8,textAlign: 'center',year: {
      textAlign: 'center',}
});

获取真实的数据

添加API数据地址

var REQUEST_URL = 'https://raw.githubusercontent.com/facebook/react-native/master/docs/MoviesExample.json';

完整代码

'use strict';

import React,View
} from 'react-native';

var REQUEST_URL = 'https://raw.githubusercontent.com/facebook/react-native/master/docs/MoviesExample.json';

class FaceMash extends Component {
  constructor(props){
    super(props);
    this.state = {
      movies: null,};
  }
  
  componentDidMount(){
    this.fetchData();
  }
  
  fetchData(){
      fetch(REQUEST_URL)
      .then((response)=>response.json())
      .then((responseData)=>{
          this.setState({
              movies: responseData.movies,});
      })
      .done();
  }
  
  render() {
      if(!this.state.movies){
          return this.renderLoadingView();
      }
      var movie = this.state.movies[0];
      return this.renderMovie(movie);
  }
  
  renderLoadingView(){
      return (
          <View style={styles.container}>
              <Text>
                  Loading movies...
              </Text>
          </View>
      );
  }
  
  renderMovie(movie){
      return (
        <View style={styles.container}>
          <Image 
            source={{uri: movie.posters.thumbnail}}
            style={styles.thumbnail} />
          <View style={styles.rightContainer}>
            <Text style={styles.title}>{movie.title}</Text>
            <Text style={styles.year}>{movie.year}</Text>
          </View>
        </View>
      );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,}
});

AppRegistry.registerComponent('FaceMash',() => FaceMash);

显示列表

/**
 * Sample React Native App
 * https://github.com/facebook/react-native
 */
'use strict';

import React,ListView,View
} from 'react-native';

var API_KEY='7waqfqbprs7pajbz28mqf6vz';
var API_URL = 'http://api.rottentomatoes.com/api/public/v1.0/lists/movies/in_theaters.json';
var PAGE_SIZE = 25;
var PARAMS = '?apikey='+API_KEY+'&page_limit='+PAGE_SIZE;
var REQUEST_URL = API_URL+PARAMS;

class FaceMash extends Component {
  constructor(props){
    super(props);
    this.state = {
        dataSource: new ListView.DataSource({
            rowHasChanged: (row1,row2) => row1 !== row2,}),loaded: false,};
  }
  
  componentDidMount(){
    this.fetchData();
  }
  
  fetchData(){
      fetch(REQUEST_URL)
      .then((response)=>response.json())
      .then((responseData)=>{
          this.setState({
              dataSource: this.state.dataSource.cloneWithRows(responseData.movies),loaded: true,});
      })
      .done();
  }
  
  render() {
      if(!this.state.loaded){
          return this.renderLoadingView();
      }
      return (
          <ListView
          dataSource={this.state.dataSource}
          renderRow={this.renderMovie}
          style={styles.listView}>
        </ListView>
         
      );
  }
  
  renderLoadingView(){
      return (
          <View style={styles.container}>
              <Text>
                  Loading movies...
              </Text>
          </View>
      );
  }
  
  renderMovie(movie){
      return (
        <View style={styles.container}>
          <Image 
            source={{uri: movie.posters.thumbnail}}
            style={styles.thumbnail} />
          <View style={styles.rightContainer}>
            <Text style={styles.title}>{movie.title}</Text>
            <Text style={styles.year}>{movie.year}</Text>
          </View>
        </View>
      );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,listView: {
      paddingTop: 20,() => FaceMash);

（编辑：李大同）

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