Question

App.js

  render() {
return (
  <View style={{ flex: 1, marginTop: 20 }}>
    <Button
      title="Learn More"
      color="#841584"
      accessibilityLabel="Learn more about this purple button"
      onPress={() => {
        (this.state.dadda = '2017-09-07');
       }}
    />
    <EventCalendar
      eventTapped={this._eventTapped.bind(this)}
      events={this.state.events}
      width={width}
      initDate={this.state.dadda}
      scrollToFirst={false}
     />
  </View>
); }

这是我的父组件，我想将initDate传递给事件日历组件，我想在按下按钮时更新日期？

Answer 1

您不应通过直接将值分配给state变量来变异 state ，而应使用setState来实现

<Button
  title="Learn More"
  color="#841584"
  accessibilityLabel="Learn more about this purple button"
  onPress={() => this.setState({dadda: '2017-09-07'})}
/>

Answer 2

将dadaa设置为状态的方式不正确，请改用this.setState函数，看看doc。

将onPress处理程序更改为

...
< Button
  title = "Learn More"
  color = "#841584"
  accessibilityLabel = "Learn more about this purple button"
  onPress = {
    () => {
      this.setState({
        dadda:'2017-09-07'
      });
    }
  }
/>
...

此外，不要在render内部声明函数，而应将其保持在类级别，例如

onPressHandler = () => {
  this.setState({
    dadaa: 'aaaa'
  });
}

render() {
  return (
    ...
    <
    Button
      ...
      onPress = {this.onPressHandler}
      ...
    />
    ...
  );
}

希望这会有所帮助！

将值动态传递给子组件进行本机反应

2 个答案: