React Native 设置函数调用流程

Question

我写了这段代码

componentDidMount(){
    
    Geolocation.getCurrentPosition(info => {
        console.log(info.coords.latitude + "    " + info.coords.longitude)
        this.setState({coords: {latitude: info.coords.latitude, longitude: info.coords.longitude, latitudeDelta: this.LATITUDE_DELTA, longitudeDelta: this.LONGITUDE_DELTA}})
    }, error => Alert.alert('Error', JSON.stringify(error)),
    {enableHighAccuracy: true, timeout: 20000, maximumAge: 1000});
      
    console.log(this.state.coords.latitude + "    " + this.state.coords.longitude);

    region = getapi(this.state.coords.latitude, this.state.coords.longitude)
    this.setState({region})
    console.log("TEMP: " + region);
    hot = getHotBarb(this.state.region)
    this.setState({hot})
    rated = getRatedBarb(this.state.region)
    this.setState({rated})
    offer = getOfferBarb(this.state.region)
    this.setState({offer})

    this.setState({loading: false})

}

但是在日志控制台上，我首先看到 this.state.coords.latitude + " " + this.state.coords.longitude （未定义）的日志和 getCurrentPosition 调用中的日志（正确）。 问题是我不能调用函数 getapi 因为 this.state.coords.latitude, this.state.coords.longitude 结果未定义 我需要先设置this.state.coords.latitude和this.state.coords.longitude然后调用componentDidMount()的其他函数。

如何在其他函数之前调用 getCurrentPosition 函数上的 setState ？

Answer 1

试试这个方法

callApi(){

    console.log(this.state.coords.latitude + "    " + this.state.coords.longitude);

    region = getapi(this.state.coords.latitude, this.state.coords.longitude)
    this.setState({region})
    console.log("TEMP: " + region);
    hot = getHotBarb(this.state.region)
    this.setState({hot})
    rated = getRatedBarb(this.state.region)
    this.setState({rated})
    offer = getOfferBarb(this.state.region)
    this.setState({offer})

    this.setState({loading: false})
}


getCurrentPosition(){

    Geolocation.getCurrentPosition(info => {
        console.log(info.coords.latitude + "    " + info.coords.longitude);

        this.setState({coords: {latitude: info.coords.latitude, longitude: info.coords.longitude, latitudeDelta: this.LATITUDE_DELTA, longitudeDelta: this.LONGITUDE_DELTA}},
    () => this.callApi();  // call api here
    )

    }, error => Alert.alert('Error', JSON.stringify(error)),
    {enableHighAccuracy: true, timeout: 20000, maximumAge: 1000});
}


componentDidMount(){    
    this.getCurrentPosition();
}