SwiftUI视图在@ObservedObject变更时未更新问题排查

你的核心问题在于：视图通过@EnvironmentObject监听MyViewModel的变化，但MyViewModel中locationManager的属性更新无法传递到视图层面。以下是具体原因和修复步骤：

问题根源 #

MyViewModel作为ObservableObject，其内部用@ObservedObject修饰的locationManager，当locationManager的@Published属性变化时，只会通知MyViewModel本身，不会触发MyViewModel的objectWillChange事件，因此视图无法感知到这些更新。你之前尝试用@Published修饰locationManager无效，大概率是因为MyViewModel没有正确声明为ObservableObject。

修复步骤 #

1. 确保MyViewModel是ObservableObject #

必须显式让MyViewModel遵循ObservableObject协议，这样视图才能监听它的变化：

class MyViewModel: ObservableObject {
    // 其他属性与方法
}

2. 用@Published修饰MyViewModel中的locationManager #

@Published会自动监听locationManager的objectWillChange事件，并将变化转发给视图：

class MyViewModel: ObservableObject {
    @Published var locationManager: LocationManager

    init() {
        self.locationManager = LocationManager()
    }
}

3. 补全LocationManager的首次位置更新逻辑（可选） #

当前代码中首次获取位置时，仅设置了location但未更新locationData和totalDistance，会导致视图首次加载时显示空值或默认值，建议补充：

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    guard let latestLocation = locations.last else { return }
    DispatchQueue.main.async {
        if let currentLocation = self.location {
            let distance = latestLocation.distance(from: currentLocation)
            self.totalDistance += distance
            self.location = latestLocation
            self.locationData = String(format: "%.5f", latestLocation.coordinate.latitude) + ", " + String(format: "%.5f", latestLocation.coordinate.longitude)
            print("location: \(self.locationData), distance: \(self.totalDistance)")
        } else {
            self.location = latestLocation
            // 补充首次位置的UI数据初始化
            self.totalDistance = 0
            self.locationData = String(format: "%.5f", latestLocation.coordinate.latitude) + ", " + String(format: "%.5f", latestLocation.coordinate.longitude)
        }
    }
}

4. 确认LocationManager初始化时设置了代理 #

在LocationManager的构造方法中，必须将自身设置为CLLocationManager的代理，否则无法接收位置更新回调：

init() {
    self.authorizationStatus = .notDetermined
    self.totalDistance = 0
    self.locationData = ""
    self.locationManager = CLLocationManager()
    super.init()
    self.locationManager.delegate = self
    // 按需添加权限请求和位置更新启动代码
    self.locationManager.requestWhenInUseAuthorization()
    self.locationManager.startUpdatingLocation()
}

内容的提问来源于stack exchange，提问作者soleil