Question

我已经创建了ListView这样的内容：

var data = [{id: 1, count: 1}, {id: 2, count: 1}];

var ds = new ListView.DataSource({
    rowHasChanged: function (row1, row2) { 
       console.log('changed');
       return true;
    }
});
var ListViewExample = React.createClass({
    getInitialState: function () {
        return {
            dataSource: ds.cloneWithRows(data)
        }
    },    
    componentDidMount: function() {
        setTimeout(()=>{
            console.log('changing...');
            data[0].count += 1;
            this.setState({
                dataSource: ds.cloneWithRows(data)
            });
        },3000);
    },
    render: function() {
        console.log('render')
      return (
        <ListView
          initialListSize={3}
          dataSource={this.state.dataSource}
          renderRow={(rowData) => <Text>{rowData.id}:{rowData.count}</Text>}
        />
      );
    }
});

运行此代码并显示日志：

[tid:com.facebook.React.JavaScript] 'Running application "mytest" with appParams: {"rootTag":1,"initialProps":{}}. __DEV__ === true, development-level warning are ON, performance optimizations are OFF'
2015-08-03 20:40:10.385 [info][tid:com.facebook.React.JavaScript] 'render'
2015-08-03 20:40:13.396 [info][tid:com.facebook.React.JavaScript] 'changing...'
2015-08-03 20:40:13.398 [info][tid:com.facebook.React.JavaScript] 'render'

当数据发生变化时，视图也发生了变化。

但为什么rowHasChanged没有被触发？（永远不会看到日志changed）

Answer 1

也许你应该看看这个：

https://stackoverflow.com/a/33871118/813675

简而言之，改变

this.setState({
  dataSource: ds.cloneWithRows(data)
});

到

this.setState({
  dataSource: this.state.dataSource.cloneWithRows(data)
});

希望得到帮助。

在什么情况下会在ListView上触发`rowHasChanged`？

1 个答案: