每次移动超过50米时，我如何用一个新位置更新我的委托?

So I need my delegate updated with a new location when ever the device has moved 50 metres or more. This is part of an end of chapter quiz in a book I'm learning with.

因此，当设备移动50米或以上时，我需要我的委托更新一个新的位置。这是我正在学习的一本书的期末考试的一部分。

Here is my code:

这是我的代码:

- (id)initWithCoder:(NSCoder *)aDecoder //we're overriding the superclasses (UIViewController) initialiser
{

    self = [super initWithCoder:aDecoder];

    if (self){
        //create location manager object
        locationManager = [[CLLocationManager alloc] init];

        //there will be a warning from this line of code
        [locationManager setDelegate:self];

        //and we want it to be as accurate as possible
        //regardless of how much time/power it takes
        [locationManager setDesiredAccuracy:kCLLocationAccuracyBest];

        //set the amount of metres travelled before location update is made
        [locationManager setDistanceFilter:50];

        //tell our manager to start looking for its location immediately
        [locationManager startMonitoringSignificantLocationChanges];

    }

    return self;
}

- (void)locationManager:(CLLocationManager *)manager
    didUpdateLocations:(NSArray *)locations
{
    NSLog(@"%@", [locations lastObject]);
}

I have set the distance filter to 50 (I hope that corresponds to 50 metres). Then when printing to console I've called the last object in the array which I hope would be the most recently updated location.

我将距离滤波器设置为50(我希望它对应50米)。当打印到控制台时，我调用了数组中的最后一个对象，我希望这是最近更新的位置。

I then build and run and the initial location is printed to console. I then click debug > location > city run in my iOS simulator menu. I guess this takes the location passt 50 metres as a city run would definitely be more than 50 metres. The location is updated again. I try to update the location again by clicking freeway drive and nothing happens.

然后，我构建并运行并将初始位置打印到控制台。然后在iOS模拟器菜单中单击debug >位置>。我想这大概要花50米的距离，因为一个城市的跑步肯定会超过50米。位置再次更新。我尝试通过点击高速公路来更新位置，但是什么也没有发生。

In the docs it states: "It does not rely on the value in the distanceFilter property to generate events. Calling this method several times in succession does not automatically result in new events being generated"

在文档中，它声明:“它不依赖于远程筛选器属性的值来生成事件。连续多次调用此方法不会自动生成新的事件。

This is exactly what I'm experiencing. I can change location once and have the new location printed to console.. however changing the location again results in no changes.

这正是我正在经历的。我可以更改位置一次，并将新的位置打印到控制台。但是，更改位置将不会导致任何更改。

I thought the -locationManager:didUpdateLocations: updates console with the new location every time it's updated. Do I need to do this some other way?

我认为-locationManager:didUpdateLocations:每次更新时都使用新位置更新控制台。我还需要用别的方法吗?

Hope you can help Kind regards

希望你能帮个忙。

1 个解决方案

#1

You forgot to call: startUpdatingLocation like this:

你忘了打电话:startUpdatingLocation:

if ([CLLocationManager locationServicesEnabled]) {
    [self.locationManager startUpdatingLocation];
}