RN 遇到的一点问题 - V2EX
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boyxy120
V2EX    React

RN 遇到的一点问题

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  •   boyxy120 Sep 18, 2017 2743 views
    This topic created in 3146 days ago, the information mentioned may be changed or developed.

    就是第一次加载时能加载出相应的数据,在后来加载更多的时候,状态机里的 dataArray 改变了,但是页面不会动态刷新,一般要怎么做才行,刚接触 RN 还不是很懂这个机制

    render 代码

     renderData() { return ( <View> {this.state.dataArray.length !== 0 ? <SectionList renderItem={this.renderItemView} renderSectiOnHeader={this.renderListHeaderView} showsVerticalScrollIndicator={false} sectiOns={this.state.dataArray} /> : <View/>} </View> ); } render() { return this.renderData(); } 

    调用代码

     loadHome() { const {navigate} = this.props.navigation; if (!this.state.isRefreshing) { return ( <View> {/* 将 this 对象传过去 */} <ScrollImage navigate={navigate} _home={this}/> <NewsView navigate={navigate} _home={this}/> </View> ) } else { return ( <View/> ) } } render() { const {navigate} = this.props.navigation; return ( <ScrollView ref='ScrollView' style={{backgroundColor: '#F3F3F3'}} OnScroll={this._onScroll.bind(this)} scrollEventThrottle={50} refreshCOntrol={ <RefreshControl refreshing={this.state.isRefreshing} OnRefresh={this._onRefresh.bind(this)} colors={['#00A2ED']} progressBackgroundColor="#ffffff"/> }> {this.loadHome()} </ScrollView> ); } 
    Daemon1993
        1
    Daemon1993  
       Sep 18, 2017   1
    在接受新数据的时候 setState({}) 来改变数组
    我前面用 redux 是在 componentWillReceiveProps 页面接受新数据
    建议看看 RN 组件的生命周期
    https://www.race604.com/react-native-component-lifecycle/
    boyxy120
        2
    boyxy120  
    OP
       Sep 18, 2017
    @Daemon1993
    似乎是 SectionList 这个组件的坑,不是生命周期的问题
    本组件继承自 PureComponent 而非通常的 Component,这意味着如果其 props 在浅比较中是相等的,则不会重新渲染。所以请先检查你的 renderItem 函数所依赖的 props 数据(包括 data 属性以及可能用到的父组件的 state ),如果是一个引用类型( Object 或者数组都是引用类型),则需要先修改其引用地址(比如先复制到一个新的 Object 或者数组中),然后再修改其值,否则界面很可能不会刷新。(译注:这一段不了解的朋友建议先学习下 js 中的基本类型和引用类型。)
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