React Native 应用程序不会更新状态，直到我离开应用程序然后返回它

Question

在我的 react native 应用程序中，我有它，因此用户可以为特定事件设置本地通知（通过点击按钮）。但是，用户可能会在 iOS 设置中关闭/打开通知，当用户这样做并返回应用程序时，状态不会生效。它生效的唯一方式是当用户退出应用程序然后重新进入时。

export default class Bell extends React.Component {
  constructor() {
    super();
    this.state = {
      appState: AppState.currentState,
      isNotifActive: true,
      isBellActive: false,
      alertBody:"",
      fireDate: "",
      LaunchStatus: "",
      notificationPermission: ""

    };
  }

  componentDidMount(){
    this.setState({
        alertBody: this.props.alertBody,
        fireDate:this.props.fireDate,
        LaunchStatus: this.props.LaunchStatus
    }) 
    AppState.addEventListener('change', (state) => {
      if (state === 'active') {
        Permissions.check('notification').then(response => { // Response is one of: 'authorized', 'denied', 'restricted', or 'undetermined'
          this.setState({ notificationPermission: response })
        })
        if(this.state.notificationPermission == 'authorized') this.setState({isNotifActive:true}) //problem
        else if(this.state.notificationPermission != 'authorized') this.setState({isNotifActive:false})

      }
      if (state === 'background') {
        Permissions.check('notification').then(response => { // Response is one of: 'authorized', 'denied', 'restricted', or 'undetermined'
          this.setState({ notificationPermission: response })
        })
        if(this.state.notificationPermission == 'authorized') this.setState({isNotifActive:true}) //problem?
        else if(this.state.notificationPermission != 'authorized') this.setState({isNotifActive:false}) 
      }
    })
  }

  render() {
    let LaunchStatus = this.state.LaunchStatus
    return (

      <Ionicons
        name={this.state.isBellActive? "md-notifications":"md-notifications-off"}
        color={"white"}
        size={30}
        style={styles.NotifIcon}
        onPress={() => {
            Vibration.vibrate()
            if(this.state.isNotifActive == true){
              if(LaunchStatus == 2){
                Alert.alert(
                  'No Notification Made',
                  'No launch time is available at the moment, you may toggle a notification when a launch time is made.',
                  [
                    {text: 'OK'},
                  ]
                );
              }
              else{
                if(this.state.isBellActive){
                  PushNotificationIOS.scheduleLocalNotification({
                      alertTitle: "Launching Soon:",
                      alertBody: this.state.alertBody,
                      fireDate: this.state.fireDate // in 30 mins
                  });
                  this.setState({NotifIcon : "md-notifications"});
                  this.setState({isBellActive : false});
                  }
                  else if(this.state.isBellActive != true){
                      PushNotificationIOS.cancelLocalNotifications();
                      this.setState({NotifIcon : "md-notifications-off"}); 
                      this.setState({isBellActive : true});
                  }
                }
            }
            else if(this.state.isNotifActive == false){
              PushNotificationIOS.cancelAllLocalNotifications();
              this.setState({NotifIcon : "md-notifications-off"});
              }
            }}
        />
    );
  }  
}

上面的代码所做的是检查应用程序是处于活动状态还是在后台，然后检查 iOS 上的通知权限状态。如果未切换通知，则用户不应在应用程序中切换通知，反之亦然。它可以工作，但是只有在用户关闭/打开通知后 -> 进入应用程序 -> 退出应用程序 -> 然后返回应用程序

Answer 1

解决方案： 我拿走了 componentDidMount 中的 eventListener 而是安装了 firebase 只是为了添加：

  firebase.messaging().hasPermission()
    .then(enabled => {
      if (enabled) {
        this.setState({isNotifActive: true})
      } else {
        this.setState({isNotifActive: false})
    } 
    });

在“Let Launches......”语句之后的渲染中。