当应用程序在本机中处于前台或后台时如何调用函数?

问题描述

当我的本机应用程序转到后台或前台时，我遇到问题.当应用在后台或前台但无法找到任何解决方案时，我试图在设定的时间间隔内调用操作.

I have a problem when react native app goes to background or foreground. I am trying to call my action in a set interval when app in background or foreground but unable to find any solution.

在我的应用程序中，当用户单击开始导航"按钮并将其重定向到手机的默认地图"应用程序时.当应用未激活时，我需要在一定时间间隔内更新数据库.

In my app when user click on start navigation button and it redirect user to the Default map application of phone. I need to update my Database in a time interval when app not active.

我已使用Appstate来检查应用程序何时未激活.并将setInterval函数设置为在一组时间间隔内调用操作.

I have used Appstate to check when app is not active. And set setInterval function to call action in a set of time interval.

componentDidMount() {
    AppState.addEventListener('change', this._handleAppStateChange);
  }

  componentWillUnmount() {
    AppState.removeEventListener('change', this._handleAppStateChange);
  }

  _handleAppStateChange = (nextAppState) => {
    if (
      this.state.appState.match(/inactive|background/) &&
      nextAppState === 'active'
    ) {
      console.log('App has come to the foreground!');

this._interval = setInterval( () => {
      console.log('check');
    }, 5000);

      if(global.routeName && global.routeName != '' && global.routeName == "OrderDetail"){
        this.props.navigation.navigate("OrderDetail",{orderId: global.orderId});
      }
    }else{
this._interval = setInterval( () => {
      console.log('check 2');
    }, 5000);
}
    this.setState({appState: nextAppState});
  };

我希望当应用程序进入后台或前台时，setInterval应该在一组间隔中调用，但实际上我无法获取我的输出.

I expected when app goes to background or foreground setInterval should be call in a set of interval, but the actual i'm unable to get my output.

推荐答案

当应用程序在后台运行时，"setInterval"将无法运行.您可以使用 react-native-background-timer

示例代码

BackgroundTimer.runBackgroundTimer(() => {
//code that will be called every 3 seconds
},
3000);
//rest of code will be performing for iOS on background too

BackgroundTimer.stopBackgroundTimer(); //after this call all code on background stop run.

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