Ios 地图套件缩放问题

我有一个应用程序，它有一个带有位置PIN的地图，但我想更改它，以便放大用户的位置

默认情况下，它从坐标0、0开始（离开非洲海岸），但现在它在英国上，但我不能把它放大到街道级别。当我调整

Delta

设置时，它没有任何区别

这是我正在使用的代码

#import "FirstViewController.h"
#import "MapPin.h"

@implementation FirstViewController

@synthesize map;
@synthesize locationManager , location;


-(void)addAnnotations{

    // Normally read the data for these from the file system or a Web service
    CLLocationCoordinate2D coordinate = {53.0670, -2.521};
    MapPin *pin = [[MapPin alloc]initWithCoordinates:coordinate
                                           placeName:@"Mr Shoe - Gents,Ladies,Kids"
                                         description:@"01270 626767, 123 Your Street, CW5 5NA"
                   ];

    [self.map addAnnotation:pin];

    [pin release];

    // Normally read the data for these from the file system or a Web service
    CLLocationCoordinate2D coordinate2 = {53.0659, -2.521};
    MapPin *pin2 = [[MapPin alloc]initWithCoordinates:coordinate2
                                            placeName:@"Veg-is-us - Fruit & veg"
                                          description:@"01270 626767, 123 Your Street, CW5 5NA"

                    ];

    [self.map addAnnotation:pin2];


    [pin2 release]; 

    CLLocationCoordinate2D coordinate3= {53.06879, -2.52195};
    MapPin *pin3= [[MapPin alloc]initWithCoordinates:coordinate3
                                            placeName:@"PC Centre Nantwich"
                                          description:@"01270 626767, 15c Beam street, CW5 5NA"

                    ];

    [self.map addAnnotation:pin3];


    [pin3 release]; 
}

// The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
/*
 - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
 self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
 if (self) {
 // Custom initialization.
 }
 return self;
 }
 */


// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {

    [[CLLocationManager alloc] init];
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;
    [locationManager startUpdatingLocation];
    [self addAnnotations];
        [self addAnnotations];


     [super viewDidLoad];
}
-(void) locationManager: (CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
    location = newLocation.coordinate;
    //One location is obtained.. just zoom to that location

    MKCoordinateRegion region;
    region.center=location;
    //Set Zoom level using Span
    MKCoordinateSpan span;
    span.latitudeDelta=0.4;
    span.longitudeDelta=0.4;
    region.span=span;
    NSLog(@"map=%@", map);
    [map setRegion:region animated:TRUE];

}

/*
 // Override to allow orientations other than the default portrait orientation.
 - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
 // Return YES for supported orientations.
 return (interfaceOrientation == UIInterfaceOrientationPortrait);
 }
 */

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc. that aren't in use.
}

- (void)viewDidUnload {
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


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


@end

---

在

viewDidLoad

中，此行没有任何作用：

[[CLLocationManager alloc] init];

编译器应该在该行给出警告，如“表达式结果未使用”

您需要将该代码的结果实际分配给

locationManager

变量，并且需要设置

delegate

，否则将不会调用delegate方法：

self.locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;

---

顺便说一下，在

viewDidLoad

中，您正在调用

[self addAnnotations]两次，我认为最好先调用
[super viewDidLoad]
而不是最后一次。
有人吗？这一定是一个简单的错误，但我看不出来，代码看起来不错。是否确定正在调用委托方法（在那里放置断点或NSLog）？在该委托方法中，就在setRegion行之前，放置
NSLog（@“map=%@”，map）并查看它打印的内容。你是否在你的应用程序的其他地方更新地图区域？@MDT这是我的代码，我试图输出到调试，但它似乎没有记录它，因为我升级了Xcode（旧的调试控制台工作正常），谢谢@Anna我整理了一下，它现在放大了，太棒了，非常感谢你帮我省去了更多的麻烦，然而，我现在已经失去了在地图上导航的能力，它是用橡皮筋拉回到中心的。有什么想法吗？每次用户位置更新时，didUpdateToLocation方法都会被调用，其中的代码会一直以用户为中心。要仅放大第一次更新，请调用
[manager stopUpdatengLocation]在该方法的末尾。