好久没弄ReactNative了, 写个怎样实现闪屏(Splash)的文章吧.

注意:

(1) 怎样切换页面.

(2) 怎样使用计时器TimerMixin.

(3) 怎样使用动画效果.

(4) 怎样载入Android的项目资源(图片).

1. 准备

新建项目, 加入主模块index.android.js.

/* @flow */
/**
 * 測试
 * @author wangchenlong
 */
‘use strict‘;

var React = require(‘react-native‘);
var {
  AppRegistry,
  } = React;

var LearningRN = require(‘./main_modules/index.js‘);

AppRegistry.registerComponent(‘LearningRN‘, () => LearningRN);

/*@flow*/作为跳转和检查的注解. 參考.

2. 首页

主要包括闪屏和主页, 使用Navigator的栈, 用于加入额外的页面.

/* @flow*/
‘use strict‘;

var React = require(‘react-native‘);
var {
  Text,
  View,
  Navigator,
  BackAndroid,
} = React;

var styles = require(‘./styles‘); // 样式

var TimerMixin = require(‘react-timer-mixin‘); // RN的计时器

var SplashScreen = require(‘./splash_screen/index‘); // 飞屏

var MainScreen = require(‘./main_screen/index‘); // 主屏

var _navigator; // 页面管理器

// 后退button
BackAndroid.addEventListener(‘hardwareBackPress‘, function () {
  if (_navigator && _navigator.getCurrentRoutes().length > 1) {
    _navigator.pop();
    return true;
  }
  return false;
});

var LearningRN = React.createClass({

  mixins: [TimerMixin], // 延迟器

  // 初始化状态
  getInitialState: function () {
    return {
      splashed: true
    };
  },

  // 页面载入
  componentDidMount: function () {
    this.setTimeout(
      ()=> {
        this.setState({splashed: false});
      }, 2000);
    },

    // 线路映射
    routeMapper: function (route: Map, navigator: Navigator) {
      _navigator = navigator;

      if (route.name === ‘home‘) {
        return (
          <View style={styles.container}>
            <MainScreen/>
          </View>
        );
      }
    },

    render: function () {
      if (!this.state.splashed) {
        // 初始路径
        var initialRoute = {name: ‘home‘};

        return (
          <Navigator
          style={styles.container}
          initialRoute={initialRoute}
          configureScene={() => Navigator.SceneConfigs.FadeAndroid}
          renderScene={this.routeMapper}/>
        );
      } else {
        return (
          <SplashScreen/> /*飞屏*/
        );
      }
    }
  });

  module.exports = LearningRN;

后退button优先退出栈的页面, 最后作为结束.

闪屏显示两秒钟, 使用TimerMixin计时器, 再更新状态跳转主页.

在routeMapper中, 眼下主页, 以后再加入其它页面.

样式

/*@flow*/
/**
 * Created by wangchenlong on 15/11/29.
 */
‘use strict‘;

var React = require(‘react-native‘);

var {
  StyleSheet
  } = React;

var styles = StyleSheet.create({
  container: {
    flex: 1,
    flexDirection: ‘column‘
  },
});

module.exports = styles;

3. 闪屏

首页图片, 有个放大效果, 至1.2倍, 持续两秒(2000ms).

资源文件(uri)使用项目资源, 放在Android项目的drawable目录.

/* @flow*/
/**
 * 启动闪屏
 * @author C.L.Wang
 */
‘use strict‘;

var React = require(‘react-native‘);

var {
  View,
  Text,
  Image,
  Dimensions, // 尺寸
  Animated,   // 动画
  } = React;

var styles = require(‘./styles.js‘);

var WIDTH = Dimensions.get(‘window‘).width;

var SplashScreen = React.createClass({

  // 初始化状态
  getInitialState: function () {
    return {
      cover: {image: {uri: ‘splash‘}, text: ‘Girl\‘s Generation‘}, // 封面
      bounceValue: new Animated.Value(1) // 弹力值
    };
  },

  // 组件初始化
  componentDidMount: function () {
    Animated.timing(
      this.state.bounceValue, {toValue: 1.2, duration: 2000}
    ).start();
  },

  render: function () {
    return (
      <View style={styles.container}>
        <Animated.Image
          source={{uri: ‘splash‘}} // 混合资源
          style={{
            flex: 1,
            width: WIDTH,
            height: 1,
            transform: [{scale: this.state.bounceValue}]
          }}/>
        <Text style={styles.text}>
          {this.state.cover.text}
        </Text>
      </View>
    );
  }
});

module.exports = SplashScreen;

在Androidproject中放置图片资源, 改动时又一次编译打包, 适配屏幕尺寸.

在RNproject中放置, 改动时刷新就可以, 但无法适配. 使用时, 依据图片特点, 选择位置.

样式

/*@flow*/
/**
 * Created by C.L.Wang on 15/11/29.
 */
‘use strict‘;

var React = require(‘react-native‘);

var {
  StyleSheet
  } = React;

var styles = StyleSheet.create({
  container: {
    flex: 1,
    flexDirection: ‘column‘
  },
  text: {
    flex: 1,
    fontSize: 16,
    textAlign: ‘center‘,
    color: ‘#FF1493‘,
    position: ‘absolute‘,
    left: 0,
    right: 0,
    bottom: 10,
    backgroundColor: ‘transparent‘
  }
});

module.exports = styles;

Github下载地址

这次的比較简单. 我会再写一些复杂的页面.

OK, Enjoy it.

闪屏(Splash)