React Native Infinite Scroll [英] React Native Infinite Scroll

问题描述

我试图得到一个无限滚动的最小例子。
所以我有这个：

I've tried to get a minimal example of infinite scroll. So I have this:

var React = require('react-native');

var {
    StyleSheet,
    View,
    Image,
    ListView,
    } = React;

var data = [
    {
        "id": 1,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    },
    {
        "id": 2,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    },
    {
        "id": 3,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    },
    {
        "id": 4,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    },
    {
        "id": 5,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    },
    {
        "id": 6,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    }

];

var InfiniteScreen = React.createClass({
    getInitialState: function () {
        return {
            isLoadingTail: false,
            dataSource: new ListView.DataSource({
                rowHasChanged: (row1, row2) => row1 !== row2,
            })
        };
    },
    componentDidMount: function () {
        this.setState({
            dataSource: this.getDataSource(data)
        });
    },
    renderRow: function (item) {
        return (
            <View>
                <Image style={{width: 80, height: 80}} source={{uri: 'http:' + item.profile_picture.href}}/>
            </View>
        );
    },
    onEndReached: function () {
        console.log('onEndReached', this.state.isLoadingTail);
        if (this.state.isLoadingTail) {
            // We're already fetching
            return;
        }
        this.setState({
            isLoadingTail: true
        });

        this.setState({
            isLoadingTail: false,
            dataSource: this.getDataSource(data)
        });
    },
    getDataSource: function (users):ListView.DataSource {
        return this.state.dataSource.cloneWithRows(users);
    },
    render: function () {
        return (
            <View>
                <ListView
                    dataSource={this.state.dataSource}
                    renderRow={this.renderRow}
                    onEndReached={this.onEndReached}
                />
            </View>);
    }
});

如果我滚动到最底部，则触发onEndReached（），但新数据不会出现。任何想法？

If I scroll to the very bottom, onEndReached() is fired, but the new data doesn't appear. Any ideas?

推荐答案

您始终使用相同的数据克隆数据源，因此不会出现任何新内容。这是一个工作示例（通过 concat 添加新数据）：

You always clone your data source with the same data, so nothing new appears. Here is a working example (add new data via concat):

var React = require('react-native');

var {
    StyleSheet,
    View,
    Image,
    ListView,
    } = React;

var data = [
    {
        "id": 1,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    },
    {
        "id": 2,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    },
    {
        "id": 3,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    },
    {
        "id": 4,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    },
    {
        "id": 5,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    },
    {
        "id": 6,
        "profile_picture": {
            "href": "//like1.r.worldssl.net/ui_big/1305634.jpg"
        }
    }

];

var InfiniteScreen = React.createClass({
    getInitialState: function () {
        return {
            isLoadingTail: false,
            dataSource: new ListView.DataSource({
                rowHasChanged: (row1, row2) => row1 !== row2,
            })
        };
    },
    componentDidMount: function () {
        this._data = [];
        this.setState({
            dataSource: this.getDataSource(data)
        });
    },
    renderRow: function (item) {
        return (
            <View>
                <Image style={{width: 80, height: 80}} source={{uri: 'http:' + item.profile_picture.href}}/>
            </View>
        );
    },
    onEndReached: function () {
        console.log('onEndReached', this.state.isLoadingTail);
        if (this.state.isLoadingTail) {
            // We're already fetching
            return;
        }
        this.setState({
            isLoadingTail: true
        });

        this.setState({
            isLoadingTail: false,
            dataSource: this.getDataSource(data)
        });
    },
    getDataSource: function (users):ListView.DataSource {
        this._data = this._data.concat(users);
        return this.state.dataSource.cloneWithRows(this._data);
    },
    render: function () {
        return (
            <View style={styles.container}>
                <ListView
                    dataSource={this.state.dataSource}
                    renderRow={this.renderRow}
                    onEndReached={this.onEndReached}
                />
            </View>);
    }
});

var styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    backgroundColor: '#F5FCFF',
  },
});

这篇关于React Native Infinite Scroll的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！