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使用 expo-location 获取不到位置信息 Location.getCurrentPositionAsync() 结果无打印

发布时间 2023-10-05 16:40:23作者: Li_pk

问题描述：

react native 中使用 expo-location 获取位置信息时，按照官方文档执行案例，获取不到位置结果。Location.requestForegroundPermissionsAsync() 执行后可以获取授权状态，但是执行到 Location.getCurrentPositionAsync() 时不会打印结果。

解决方法：

给 Location.getCurrentPositionAsync() 添加参数，如下

let location = await Location.getCurrentPositionAsync({
  accuracy: Location.Accuracy.Highest,
  maximumAge: 10000,
});
console.log("Location:", location);

官方文档：

expo-location文档地址

  1. 安装：
npx expo install expo-location
  1. 使用：
import React, { useState, useEffect } from 'react';
import { Platform, Text, View, StyleSheet } from 'react-native';
import Device from 'expo-device';
import * as Location from 'expo-location';

export default function App() {
  const [location, setLocation] = useState(null);
  const [errorMsg, setErrorMsg] = useState(null);

  useEffect(() => {
    (async () => {
      if (Platform.OS === 'android' && !Device.isDevice) {
        setErrorMsg(
          'Oops, this will not work on Snack in an Android Emulator. Try it on your device!'
        );
        return;
      }
      let { status } = await Location.requestForegroundPermissionsAsync();
      if (status !== 'granted') {
        setErrorMsg('Permission to access location was denied');
        return;
      }

      let location = await Location.getCurrentPositionAsync({});
      setLocation(location);
    })();
  }, []);

  let text = 'Waiting..';
  if (errorMsg) {
    text = errorMsg;
  } else if (location) {
    text = JSON.stringify(location);
  }

  return (
    <View style={styles.container}>
      <Text style={styles.paragraph}>{text}</Text>
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
    padding: 20,
  },
  paragraph: {
    fontSize: 18,
    textAlign: 'center',
  },
});

官方案例中 getCurrentPositionAsync 方法传参为空对象 {} ，这是打印不出结果的原因。
添加参数后便可以获取结果数据。