react-native setState issue

index.ios.js

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

var React = require('react-native');
var fs = require('NativeModules').FileSystem;
var {
  AppRegistry,
  StyleSheet,
  Text,
  TouchableHighlight,
  ListView,
  View,
  AlertIOS
} = React;
var README_URL = 'https://coding.net/u/levi/p/imouto-host/git/raw/master/README.md';
var MAP = {'Acrylated':'AcrylicHosts','Hosts-ä': 'Hosts-a'};
var BASE_URL = 'https://coding.net/u/levi/p/imouto-host/git/raw/master/';
var GOOGLE_HOSTS_URL = 'https://raw.githubusercontent.com/txthinking/google-hosts/master/hosts';

var aHostsApp = React.createClass({
	getInitialState: function () {
		var ds = new ListView.DataSource({
				rowHasChanged:(r1,r2) => r1 !== r2
			});
		return {
			dataSource: ds.cloneWithRows(['row 1', 'row 2']),
			pressTest: 0,
			loaded: false,
			updatePressed: false
		};
	},
	getData: function () {
		var that = this;
		fetch(README_URL)
			.then((response) => response.text())
			.then(function (res) {
				var f = res.match(/\- (.+)/g);

				f = f.map(function(line, idx) {
					var l = line.replace(/^\s?-\s?/, '') + '\n';
					var a = l.split(/\s?\:\s?/); 
					return {
						title: a.shift(),
						desc: a.join(':').split(' ').shift()
					};
				});
				f.push({
					title: 'google-hosts',
					desc: '每天2:00-3:00'
				});
				var _ds = JSON.parse(JSON.stringify(f)); // clone datasorce, force renderRow update
				
				that.setState({
					dataSource: that.state.dataSource.cloneWithRows(_ds),
					loaded: true
				});
			})
			.done();
	},
	componentDidMount: function () {
		this.getData();
	},
	render: function() {
		if (!this.state.loaded) {
			return this.renderLoadingView();
		}
		return this.renderList();
	},
	renderLoadingView: function() {
	    return (
	      <View style={styles.loading}>
	        <Text>
	          Loading ...
	        </Text>
	      </View>
	    );
	},
	renderList: function () {
		return (
			<View style={styles.container}>
				<Text style={styles.title}>aHostsApp{this.state.pressTest.toString()}</Text>
				<View style={styles.separator} />
				<ListView
					style={styles.listGroup}
					dataSource={this.state.dataSource}
					renderRow= {this.renderRow} />
			</View>
		);
	},
	renderRow: function (rowData, sectionID, rowID) {
		return (
			<View style={styles.listItem} id={rowID}>
				<View style={styles.itemContent}>
				<Text style={styles.itemTitle}>{rowData.title}</Text>
				<Text style={styles.itemDesc}>更新时间：{rowData.desc}</Text>
				</View>
				<TouchableHighlight style={[styles.buttonSmall, this.state.pressTest == 2 && styles.updatePressed]} onPress={()=> this.onItemPress(rowData)} underlayColor="#06f">
					<Text style={[styles.buttonSmallText, this.state.pressTest == 2 && styles.lightGrayText]}>{this.state.pressTest.toString()}更新</Text>
				</TouchableHighlight>
			</View>
		);
	},
	onItemPress: function (rowData) {
		var that = this;
		var title = rowData.title;
		var url;

		title = MAP[title] || title;
		if ( this.state.updatePressed ) {return;}
		
		if (title === 'google-hosts') {
			url = GOOGLE_HOSTS_URL;
		} else {
			url = encodeURI(BASE_URL + title + '/hosts');
		}
		// that.setState({updatePressed: true});
		that.setState({pressTest: 2});
		console.log('pressTest::::2' ,this.state.pressTest.toString() ); // get 0
		setTimeout(function(){
			console.log( that.state.pressTest ) // get 2
		}, 10);
		// fetch host
		fetch(url)
			.then((res) => res.text())
			.then(function (res) {
				fs.writeFile('/etc/hosts', res, function (res) {
					that.setState({pressTest: 0});
					// that.setState({updatePressed: false});
					console.log('pressTest::::0' ,that.state.pressTest.toString() ); // get 2
					if (res) {
						console.log('success');
						// AlertIOS.alert('alert','success');
					} else {
						// AlertIOS.alert('alert','failed');
						console.log('failed');
					}
				});
			});
	}
});

var styles = StyleSheet.create({
  container: {
    flex: 1,
    // justifyContent: 'center',
    // alignItems: 'center',
    backgroundColor: '#F5F5F5',
  },
  loading: {
  	height: 36,
  	flex: 1,
  	alignItems: 'center',
  	alignSelf: 'stretch',
  	justifyContent: 'center'
  },
  title: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
    marginTop: 20
  },
  lightGrayText: {
  	color: '#666'
  },
  buttonSmall: {
  	borderRadius: 4,
    alignSelf: 'center',
    alignItems: 'center',
    justifyContent: 'center',
    borderWidth: 1,
    borderColor: '#3385ff',
    paddingTop: 4,
    paddingBottom: 4,
    paddingLeft: 9,
    paddingRight: 9,
    marginRight: 6
  },
  buttonSmallText: {
  	fontSize: 12,
    color: '#3385ff'
  },
  listTitle: {
  	paddingLeft: 6,
  	marginBottom: 10
  },
  listGroup: {
  },
  listItem: {
  	flex: 1,
  	flexDirection: 'row',
  	paddingLeft: 6,
  	paddingRight: 6,
  	paddingTop: 10,
  	paddingBottom: 10,
  	borderWidth: 1,
  	borderColor: '#ddd',
  	marginTop: -1,
  	backgroundColor: '#fff'
  },
  itemContent: {
  	flex: 1,
  	paddingLeft: 10
  },
  itemTitle: {
  	fontSize: 16,
  	marginBottom: 6
  },
  itemDesc: {
  	fontSize: 12,
  	color: '#333'
  },
  separator: {
  	height: 1,
  	backgroundColor: '#eee'
  },
  updatePressed: {
  	backgroundColor: '#eee',
  	borderColor: '#eee'
  }
});

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