Question

我下载了this教程的源代码，并对其进行了一些操作。一切正常。

现在我想创建自己的项目来实现位置和标题。但写完之后，它不起作用。我甚至没有在顶部看到GPS指示。

当我运行其他应用程序时，它很好。 Xcode不会给出任何错误或警告。

我的代码：（它没有改变AppDelegate中的任何内容。）

LocationAndHeadingTestViewController.h

#import <UIKit/UIKit.h>
#import "LocationController.h"

@interface LocationAndHeadingTestViewController : UIViewController <LocationControllerDelegate>
{
    LocationController *_locationController;

    IBOutlet UILabel *_errorLabel;

    //Location
    IBOutlet UILabel *_locationTimeLabel;
    IBOutlet UILabel *_latitudeLabel;
    IBOutlet UILabel *_longitudeLabel;
    IBOutlet UILabel *_altitudeLabel;

    //Heading
    IBOutlet UILabel *_headingTimeLabel;
    IBOutlet UILabel *_trueHeadingLabel;
    IBOutlet UILabel *_magneticHeadingLabel;
    IBOutlet UILabel *_headingAccuracyLabel;

    IBOutlet UIImageView *_compass;
}

@property (nonatomic, retain) LocationController *locationController;

@end

LocationAndHeadingTestViewController.m

#import "LocationAndHeadingTestViewController.h"

@implementation LocationAndHeadingTestViewController

@synthesize locationController = _locationController;

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];

    _locationController = [LocationController new];
    _locationController.delegate = self;
    [_locationController.locationManager startUpdatingLocation];
    [_locationController.locationManager startUpdatingHeading];
}


- (void)locationUpdate:(CLLocation *)location 
{
    [_locationTimeLabel setText:[NSString stringWithFormat:@"%@", location.timestamp]];
    [_latitudeLabel setText:[NSString stringWithFormat:@"%f", location.coordinate.latitude]];
    [_longitudeLabel setText:[NSString stringWithFormat:@"%f", location.coordinate.longitude]];
    [_altitudeLabel setText:[NSString stringWithFormat:@"%f", [location altitude]]];
}

- (void)headingUpdate:(CLHeading *)heading
{
    [_headingTimeLabel setText:[NSString stringWithFormat:@"%@", heading.timestamp]];
    [_trueHeadingLabel setText:[NSString stringWithFormat:@"%f", heading.trueHeading]];
    [_magneticHeadingLabel setText:[NSString stringWithFormat:@"%f", heading.magneticHeading]];
    [_headingAccuracyLabel setText:[NSString stringWithFormat:@"%f", heading.headingAccuracy]];
}

- (void)locationError:(NSError *)error 
{
    _errorLabel.text = [error description];
}

- (void)didReceiveMemoryWarning 
{
    [super didReceiveMemoryWarning];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

- (void)viewDidUnload 
{
    [super viewDidUnload];
}

- (void)dealloc 
{
    [_locationController release];
    [super dealloc];
}

@end

LocationController.h

#import <CoreLocation/CoreLocation.h>

@protocol LocationControllerDelegate
@required

- (void)locationUpdate:(CLLocation *)location;
- (void)headingUpdate:(CLHeading *)heading;
- (void)locationError:(NSError *)error;

@end

@interface LocationController : NSObject <CLLocationManagerDelegate>
{
    CLLocationManager *_locationManager;
    id _delegate;
}

@property (nonatomic, retain) CLLocationManager *locationManager;
@property (nonatomic, assign) id delegate;

@end

LocationController.m

#import <CoreLocation/CoreLocation.h>
#import "LocationController.h"

@implementation LocationController

@synthesize locationManager = _locationManager, delegate = _delegate;

- (id)init
{
    if(self = [super init]) 
    {
        _locationManager = [[CLLocationManager new] autorelease];
        _locationManager.desiredAccuracy = kCLLocationAccuracyBest;
        _locationManager.delegate = self;
    }

    return self;
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation 
{
    if([self.delegate conformsToProtocol:@protocol(LocationControllerDelegate)]) 
    {
        [self.delegate locationUpdate:newLocation];
    }
}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error 
{
    if([self.delegate conformsToProtocol:@protocol(LocationControllerDelegate)]) 
    {
        [_delegate locationError:error];
    }
}

- (void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading
{
    if([self.delegate conformsToProtocol:@protocol(LocationControllerDelegate)]) 
    {
        [_delegate headingUpdate:newHeading];
    }
}

- (void)dealloc 
{
    [_locationManager release];
    [super dealloc];
}

@end

这很简单，但我认为我真的忽视了一些事情。

聚苯乙烯。我会将id委托更改为id＆lt; ..＆gt;代表

Answer 1

您不应该自动释放CLLocationManager对象：

_locationManager = [[CLLocationManager new] autorelease];

这是一个“保留”财产。您需要删除自动释放，您将在dealloc中释放它。你只能发布一次。

如果您使用setter分配了它，那么setter会为您保留它。这样就可以了：

self.locationManager = [[CLLocationManager new] autorelease];

Answer 2

您的应用是否已在iPhone设置中启用了位置服务？

位置服务（全局访问）可以打开，但位置服务设置中的特定应用也可能同时被拒绝访问位置。

位置和标题不起作用

2 个答案: