react-native - null 不是 React Native 组件中的对象(评估 'internalInstance.getHostNode' )

Question

我的 React Native 应用程序有一个应该显示可滚动列表的组件。我也在用 React Native Elements ，尽管忽略它似乎没有什么大的不同。

我的组件如下所示:

export class MyComponent extends React.Component {
    constructor(props) {
        super(props);

        const ds = new ListView.DataSource({ rowHasChanged: (r1, r2) => r1 !== r2 });
        this.state = { ds: ds.cloneWithRows(this.props.myItems) };
    }

    render() {
        return (
            <View>
                <Text>Some text here</Text>
                <List>
                    <ListView dataSource={ this.state.ds } renderRow={ renderRow } />
                </List>
            </View>
        );
    }
};

哪里 renderRow在类之外声明，因为它不需要它的状态，如:

const renderRow = (rowData, sectionId) => {
    return (
        <ListItem
            key={ sectionId }
            title={ rowData.myProp }
            subtitle={ rowData.myOtherProp }
        />
    );
};

此外，删除 <List>与它的 children 似乎也没有什么不同。

从日志记录(不包含在代码中，为简洁起见)我可以看到组件 constructor运行没有问题。 render但是没有调用方法。在 adb logcat输出(我使用的是 Android 模拟器)我看到以下内容:

10-16 14:02:34.507 10161 10205 W ReactNativeJS: Possible Unhandled Promise Rejection (id: 0):
10-16 14:02:34.507 10161 10205 W ReactNativeJS: null is not an object (evaluating 'internalInstance.getHostNode')
10-16 14:02:34.507 10161 10205 W ReactNativeJS: getHostNode@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:16594:24
10-16 14:02:34.507 10161 10205 W ReactNativeJS: getHostNode@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18320:35
10-16 14:02:34.507 10161 10205 W ReactNativeJS: getHostNode@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:16594:36
10-16 14:02:34.507 10161 10205 W ReactNativeJS: getHostNode@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18320:35
10-16 14:02:34.507 10161 10205 W ReactNativeJS: getHostNode@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:16594:36
10-16 14:02:34.507 10161 10205 W ReactNativeJS: getHostNode@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18320:35
10-16 14:02:34.507 10161 10205 W ReactNativeJS: getHostNode@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:16594:36
10-16 14:02:34.507 10161 10205 W ReactNativeJS: getHostNode@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18320:35
10-16 14:02:34.507 10161 10205 W ReactNativeJS: getHostNode@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:16594:36
10-16 14:02:34.507 10161 10205 W ReactNativeJS: updateChildren@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:17792:47
10-16 14:02:34.507 10161 10205 W ReactNativeJS: _reconcilerUpdateChildren@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:17341:36
10-16 14:02:34.507 10161 10205 W ReactNativeJS: _updateChildren@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:17445:48
10-16 14:02:34.507 10161 10205 W ReactNativeJS: updateChildren@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:17432:21
10-16 14:02:34.507 10161 10205 W ReactNativeJS: receiveComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:14715:20
10-16 14:02:34.507 10161 10205 W ReactNativeJS: receiveComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:16656:34
10-16 14:02:34.507 10161 10205 W ReactNativeJS: _updateRenderedComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18688:33
10-16 14:02:34.507 10161 10205 W ReactNativeJS: _performComponentUpdate@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18658:30
10-16 14:02:34.507 10161 10205 W ReactNativeJS: updateComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18579:29
10-16 14:02:34.507 10161 10205 W ReactNativeJS: receiveComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18481:21
10-16 14:02:34.507 10161 10205 W ReactNativeJS: receiveComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:16656:34
10-16 14:02:34.507 10161 10205 W ReactNativeJS: _updateRenderedComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18688:33
10-16 14:02:34.507 10161 10205 W ReactNativeJS: _performComponentUpdate@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18658:30
10-16 14:02:34.507 10161 10205 W ReactNativeJS: updateComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18579:29
10-16 14:02:34.507 10161 10205 W ReactNativeJS: receiveComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18481:21
10-16 14:02:34.507 10161 10205 W ReactNativeJS: receiveComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:16656:34
10-16 14:02:34.507 10161 10205 W ReactNativeJS: _updateRenderedComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18688:33
10-16 14:02:34.507 10161 10205 W ReactNativeJS: _performComponentUpdate@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18658:30
10-16 14:02:34.507 10161 10205 W ReactNativeJS: updateComponent@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18579:29
10-16 14:02:34.507 10161 10205 W ReactNativeJS: performUpdateIfNecessary@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:18495:21
10-16 14:02:34.507 10161 10205 W ReactNativeJS: performUpdateIfNecessary@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:16688:42
10-16 14:02:34.507 10161 10205 W ReactNativeJS: runBatchedUpdates@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:16299:41
10-16 14:02:34.507 10161 10205 W ReactNativeJS: perform@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:17035:16
10-16 14:02:34.507 10161 10205 W ReactNativeJS: perform@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:17035:16
10-16 14:02:34.507 10161 10205 W ReactNativeJS: perform@http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&m
10-16 14:02:34.527 10161 10205 W ReactNativeJS: Warning: performUpdateIfNecessary: Unexpected batch number (current 17, pending 15)
10-16 14:02:34.800 10161 10205 W ReactNativeJS: Warning: performUpdateIfNecessary: Unexpected batch number (current 21, pending 15)
10-16 14:02:34.801 10161 10205 W ReactNativeJS: Warning: performUpdateIfNecessary: Unexpected batch number (current 22, pending 20)
10-16 14:02:34.905 10161 10205 W ReactNativeJS: Warning: performUpdateIfNecessary: Unexpected batch number (current 26, pending 15)
10-16 14:02:34.908 10161 10205 W ReactNativeJS: Warning: performUpdateIfNecessary: Unexpected batch number (current 27, pending 20)
10-16 14:02:35.191 10161 10205 W ReactNativeJS: Warning: performUpdateIfNecessary: Unexpected batch number (current 31, pending 15)
10-16 14:02:35.191 10161 10205 W ReactNativeJS: Warning: performUpdateIfNecessary: Unexpected batch number (current 32, pending 20)
10-16 14:02:35.192 10161 10205 W ReactNativeJS: Warning: performUpdateIfNecessary: Unexpected batch number (current 33, pending 30)

我正在使用

react 15.3.2

react 原生 0.35.0

react 原生元素 0.6.2

我的问题有两个方面:我如何解决发生的问题(例如，为什么我的 render() 方法没有被调用)以及我在这里做错了什么？

Answer 1

原来，实际的解决方案不在ListView的使用中或 List . render() 中的一些日志语句导致 render()失败的方法 - 默默地。 RN 然后尝试重新渲染组件，这导致问题中显示的日志消息不断重新出现，直到应用程序被杀死。