React Native 通告消息竖向轮播组件的封装

本文实例为大家分享了React Native通告消息竖向轮播组件的封装代码，供大家参考，具体内容如下

import React, {Component} from 'react'
import {
 Text,
 View,
 Animated,
 Easing,
 StyleSheet,
} from 'react-native'

export default class ScrollVertical extends Component {
 static defaultProps = {
  enableAnimation: true,
 };

 constructor(props) {
  super(props)
  let translatevalue= new Animated.ValueXY({x: 0, y: 0})
  translatevalue.addListener(({x,y})=>{
   // Log('value',x,y)
  })
  this.state = {
   translatevalue: translatevalue,
   // 滚屏高度
   scrollHeight: this.props.scrollHeight || 32,
   // 滚屏内容
   kb_content: [],
   // Animated.View 滚动到的 y轴坐标
   kb_tempValue: 0,
   // 最大偏移量
   kb_contentOffsetY: 0,
   // 每一次滚动切换之前延迟的时间
   delay: this.props.delay || 500,
   // 每一次滚动切换的持续时间
   duration: this.props.duration || 500,
   enableAnimation: true,
  }
 }

 render() {
  return (
   
    {
     this.state.kb_content.length !== 0 ?
      
{this.state.kb_content.map(this._createKbItem.bind(this))}
       : null
    }
   
  )
 }

 componentWillReceiveProps(nextProps) {
  Log('componentWillReceiveProps', nextProps)
   this.setState({
     enableAnimation: nextProps.enableAnimation?true:false
    }, () => {
     this.startAnimation();
    }
   )
 }

 componentDidMount() {
  Log('componentDidMount')
  let content = this.props.data || []
  if (content.length !== 0) {
   let h = (content.length + 1) * this.state.scrollHeight
   this.setState({
    kb_content: content.concat(content[0]),
    kb_contentOffsetY: h
   })

   // 开始动画
   // this._startAnimation()
   this.startAnimation();
  }
 }


 _createKbItem(kbItem, index) {
  return (
   
    {kbItem.content}
   
  )
 }

 startAnimation = () => {
  if (this.state.enableAnimation) {
   if(!this.animation){
    this.animation = setTimeout(() => {
     this.animation=null;
     this._startAnimation();
    }, this.state.delay);
   }

  }

 }

 componentWillUnmount() {
  if (this.animation) {
   clearTimeout(this.animation);
  }
  if(this.state.translatevalue){
   this.state.translatevalue.removeAllListeners();
  }
 }

 _startAnimation = () => {
  this.state.kb_tempValue -= this.state.scrollHeight;
  if (this.props.onChange) {
   let index = Math.abs(this.state.kb_tempValue) / (this.state.scrollHeight);
   this.props.onChange(index {
    // 无缝切换
    // Log('end')
    if (this.state.kb_tempValue - this.state.scrollHeight === -this.state.kb_contentOffsetY) {
     // 快速拉回到初始状态
     this.state.translatevalue.setValue({x: 0, y: 0});
     this.state.kb_tempValue = 0;
    }
    this.startAnimation();



   })
 }
}

const styles = StyleSheet.create({
 kbContainer: {
  // 必须要有一个背景或者一个border，否则本身高度将不起作用
  backgroundColor: 'transparent',
  overflow: 'hidden'
 },
 kb_text_c: {
  fontSize: 18,
  color: '#181818',
 }

使用

import React, {Component} from 'react';
import {
 StyleSheet,
 View,
 TouchableOpacity,
 alert,
 ScrollView,
 ART,
 TouchableHighlight,
 ListView,
 Dimensions,
 Text
} from 'react-native';

import ScrollVertical from '../../app-widget/scroll-vertical'


const dataArray = [
 {
  title: '降价了',
 },
 {
  title: '全场五折',
 },
 {
  title: '打到骨折',
 }
]
export default class extends React.Component {

 render() {
  let array = [{ content: '' }];
  if (dataArray && dataArray.length > 0) {
   array = [];
   for (let item of dataArray) {
    array.push({ content: item.title});
   }
  }
  return (
   
     {
     if (dataArray && dataArray.length > 0) {
      Log(dataArray[this.index].title)
     }
    }} style={{ flexDirection: 'row', backgroundColor: "#FFFFFF", alignItems: 'center', borderRadius: 8, paddingLeft: 5, paddingRight: 5 }}>
     公告
     
      新
     
     
       {
 this.index = index;
})}
enableAnimation={true}
data={array}
delay={2500}
duration={1000}
scrollHeight={34}
scrollStyle={{ alignItems: 'flex-start' }}
textStyle={{ color: Constant.colorTxtContent, fontSize: Constant.fontSizeSmall }} />
     
     
     查看
    
   
  );

 }
};

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。