<p>Modal是模态视图，它的作用是可以用来覆盖 React Native中根视图的原生视图，Modal模态视图是一种覆盖包围当前内容视图的一个简单方法。</p>    <p>注意：如果你需要如何在您的应用程序的其余部分呈现模态的更多控制，那么可以考虑使用顶级导航（top-level Navigator）。</p>    <h3>Modal 属性</h3>    <p>照例，我想大家都知道我的习惯了，毕竟官网也是这个顺序，那就是在用人之前，先要了解人，毕竟疑人不用，用人不疑嘛，要想相信一个人，首先得了解一个人嘛。来，看看 Modal 的相关属性。</p>    <ul>     <li>animated bool 是否有动画效果，不过这个属性已经被抛弃了，取之代替的是：animationType</li>     <li> <p>animationType ([‘none’, ‘slide’, ‘fade’]) 这个animationType属性作用就是如何控制模态动画，有一下三个类型：</p>      <ul>       <li>none 出现的时候不带动画效果</li>       <li>fade 带有淡入动画的效果</li>       <li>slide 从底部滑动出来的动画效果</li>      </ul> </li>     <li> <p>onRequestClose Platform.OS === ‘android’ ? PropTypes.func.isRequired : PropTypes.func 这是一个 Android 平台需要的属性，它的作用是当这个模态视图取消或者关闭消失的时候回调这个函数</p> </li>     <li>onShow function 当模态视图显示的时候调用此函数</li>     <li>transparent bool 布尔值，是否透明，true 将使得在一个透明背景的模式</li>     <li>visible bool 布尔值，是否可见</li>     <li>onOrientationChange func ios 当在显示模态的方向变化时回调此函数</li>     <li>supportedOrientations ios ([‘portrait’, ‘portrait-upside-down’, ‘landscape’, ‘landscape-left’, ‘landscape-right’]))</li>    </ul>    <h3>实例演示</h3>    <p>来，我们大家一起看看这个效果的实现，看完效果就更加直观的能够感受到这个组件的作用和功能了。动态效果图如下：</p>    <p style="text-align:center"><img src="https://simg.open-open.com/show/d053fd3ffc1b17d0043b62330c9a2d5a.gif"></p>    <p>实例代码</p>    <pre>  <code class="language-javascript">import React, { Component } from 'react';  import {    AppRegistry,    StyleSheet,    Modal,    Picker,    Switch,    TouchableHighlight,    Text,    View  } from 'react-native';    classButtonextendsComponent{    state = {   active: false,    };      _onHighlight = ()=> {   this.setState({active: true});    };      _onUnhighlight = ()=> {   this.setState({active: false});    };      render() {   var colorStyle = {     color: this.state.active ? '#fff' : '#000',   };   return (     <TouchableHighlight    onHideUnderlay={this._onUnhighlight}    onPress={this.props.onPress}    onShowUnderlay={this._onHighlight}    style={[styles.button, this.props.style]}    underlayColor="#a9d9d4">      <Textstyle={[styles.buttonText,colorStyle]}>{this.props.children}</Text>     </TouchableHighlight>   );    }  }    export default classModalDemoextendsComponent{    state = {   animationType: 'none',   modalVisible: false,   transparent: false,    };      _setModalVisible = (visible) => {   this.setState({modalVisible: visible});    };      _setAnimationType = (type) => {   this.setState({animationType: type});    };      _toggleTransparent = ()=> {   this.setState({transparent: !this.state.transparent});    };    render() {    var modalBackgroundStyle = {     backgroundColor: this.state.transparent ? 'rgba(0, 0, 0, 0.5)' : '#f5fcff',   };   var innerContainerTransparentStyle = this.state.transparent     ? {backgroundColor: '#fff', padding: 20}     : null;   var activeButtonStyle = {     backgroundColor: '#ddd'   };   return (      <View>    <Modal      animationType={this.state.animationType}      transparent={this.state.transparent}      visible={this.state.modalVisible}      onRequestClose={() => this._setModalVisible(false)}      >      <Viewstyle={[styles.container,modalBackgroundStyle]}>     <Viewstyle={[styles.innerContainer,innerContainerTransparentStyle]}>       <Text>This modal was presented {this.state.animationType === 'none' ? 'without' : 'with'} animation.</Text>       <Button      onPress={this._setModalVisible.bind(this, false)}      style={styles.modalButton}>      Close       </Button>     </View>      </View>    </Modal>    <Viewstyle={styles.row}>      <Textstyle={styles.rowTitle}>Animation Type</Text>      <ButtononPress={this._setAnimationType.bind(this,'none')}style={this.state.animationType==='none'?activeButtonStyle:{}}>     none      </Button>      <ButtononPress={this._setAnimationType.bind(this,'slide')}style={this.state.animationType==='slide'?activeButtonStyle:{}}>     slide      </Button>      <ButtononPress={this._setAnimationType.bind(this,'fade')}style={this.state.animationType==='fade'?activeButtonStyle:{}}>     fade      </Button>    </View>      <Viewstyle={{marginTop:50,flexDirection:'row',alignItems:'center',justifyContent:'center'}}>      <Textstyle={{color:'grey',fontWeight:'bold',marginRight:20}}>Transparent</Text>      <Switchvalue={this.state.transparent}onValueChange={this._toggleTransparent}/>    </View>      <ButtononPress={this._setModalVisible.bind(this,true)}>      Present    </Button>     </View>   );    }  }    const styles = StyleSheet.create({   container: {   flex: 1,   justifyContent: 'center',   padding: 20,    },    innerContainer: {   borderRadius: 10,   alignItems: 'center',    },    row: {   alignItems: 'center',   flex: 1,   flexDirection: 'row',   marginBottom: 20,    },    rowTitle: {   flex: 1,   fontWeight: 'bold',    },    button: {   borderRadius: 5,   flex: 1,   height: 44,   alignSelf: 'stretch',   justifyContent: 'center',   overflow: 'hidden',    },    buttonText: {   fontSize: 18,   margin: 5,   textAlign: 'center',    },    modalButton: {   marginTop: 10,    },    pickerItem: {   fontSize: 16,    },  });    AppRegistry.registerComponent('ModalDemo', () => ModalDemo);  </code></pre>    <p>这个例子内容比较多，大家仔细看看，最好动手实践一下，这样才能掌握的更加熟练。</p>    <p> </p>    <p>来自：http://godcoder.me/2017/01/04/基础篇章：关于 React Native 之 Modal 组件的讲解/</p>    <p> </p>