使用按钮在地图上放置 Pin 图——iOS

Question

虽然我的最终项目不是我在哪里停放应用程序。我认为这是一个很好地开始掌握MKMap 和Locations 的好地方。

好的，这样我就可以设置图钉，看到自己，并让我的当前位置显示在标签中。

我不能做的是：

A.按下按钮
1）存储用户当前位置。 2）在当前用户位置放置一个图钉（红色）。 （因此，即使用户（蓝色）移动，新引脚也会保留）

B.在单独的按钮按下 1) 清除掉地图上的用户pin（红色）的pin。

我似乎无法为按钮中的新图钉设置地图注释。数字会发生变化，并且地图不会刷新（我猜）以显示我的 pin 有或没有正确的坐标集。

这是我目前所拥有的。 （没有窃笑）：P

#import "Find_My_CarViewController.h"
#import "MapAnnotation.h"

@implementation Find_My_CarViewController

@synthesize CLController;
@synthesize hereIamLat;
@synthesize hereIamLong;
@synthesize mapView;

- (void)dealloc
{
    [hereIamLat release];
    [hereIamLong release];
    [CLController release];
    [super dealloc];
}

- (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.
}

#pragma mark - View lifecycle


// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
    [super viewDidLoad];
    CLController = [[CoreLocationController alloc] init];
    CLController.delegate = self;
    [CLController.locMgr startUpdatingLocation];  
}

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

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

-(void)viewWillAppear:(BOOL)animated
{
    MKCoordinateRegion region;
    region.center.latitude =40.798356;
    region.center.longitude= -81.411158;
    region.span.longitudeDelta=0.3;
    region.span.latitudeDelta =0.3;
    [mapView setRegion:region animated:YES];   
}

- (void)locationUpdate:(CLLocation *)location
{
    latitudeLabel.text = [NSString stringWithFormat:@"LATITUDE: %f", location.coordinate.latitude];
    longitudeLabel.text = [NSString stringWithFormat:@"LONGITUDE: %f", location.coordinate.longitude];

    //hereIamLat = [NSString stringWithFormat:@"%g", location.coordinate.latitude];
    //hereIamLong = [NSString stringWithFormat:@"%g", location.coordinate.longitude];   
}

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

-(IBAction)PushToMark
{
    NSScanner *strLat = [NSScanner scannerWithString:latitudeLabel.text];
    double dblLat;
    [strLat scanDouble:&dblLat];
    NSScanner *strLong = [NSScanner scannerWithString:longitudeLabel.text];
    double dblLong;
    [strLong scanDouble:&dblLong];

    NSLog(@"lat: %f",dblLat);
    NSLog(@"long: %f",dblLong);
    MKCoordinateRegion location1;
    location1.center.latitude =dblLat;
    location1.center.longitude= dblLong;
    location1.span.longitudeDelta=0.1;
    location1.span.latitudeDelta =0.1;

    MapAnnotation *ann1 =[[[MapAnnotation alloc] init] autorelease];
    ann1.title=@"Here";
    ann1.subtitle=@"I AM";
    ann1.coordinate= location1.center;
    [mapView addAnnotation:ann1];
}

@end

编辑： 好的，所以我走了这条路谢谢。

#import "LocationTestViewController.h"
#import "CoreLocation/CoreLocation.h"
#import "MapAnnotation.h"

@implementation LocationTestViewController
@synthesize locationManager;
@synthesize mapView;

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

- (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.
}

#pragma mark - View lifecycle

/*
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
 [super viewDidLoad];
}
*/

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

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

- (IBAction)getLocation:(id)sender {


locationManager = [[CLLocationManager alloc] init];
locationManager.distanceFilter=kCLDistanceFilterNone;
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
[locationManager startUpdatingLocation];

[mapView setMapType:MKMapTypeStandard];
[mapView setZoomEnabled:YES];
[mapView setScrollEnabled:YES];
MKCoordinateRegion region = {{0.0,0.0},{0.0,0.0}};
region.center.latitude = locationManager.location.coordinate.latitude;
region.center.longitude = locationManager.location.coordinate.longitude;
region.span.longitudeDelta = 0.005f;
region.span.latitudeDelta = 0.005f;
[mapView setRegion:region animated:YES];
[mapView setDelegate:sender];

MKCoordinateRegion location1;
location1.center.latitude =locationManager.location.coordinate.latitude;
location1.center.longitude= locationManager.location.coordinate.longitude;
location1.span.longitudeDelta=0.1;
location1.span.latitudeDelta =0.1;

MapAnnotation *ann1 =[[[MapAnnotation alloc] init] autorelease];
ann1.title=@"You Parked Here";
ann1.subtitle=@"";
ann1.coordinate= location1.center;
[mapView addAnnotation:ann1];

}
@end

Answer 1

当您收到委托回调 - (void)locationUpdate:(CLLocation *)location 时，为什么不使用 CLLocationCoordinate2D 来存储您的当前位置？没有真正的理由使用MKCoordinateRegion 和NSScanner。

改为这样做：

- (void)locationUpdate:(CLLocation *)location
{
    latitudeLabel.text = [NSString stringWithFormat:@"LATITUDE: %f", location.coordinate.latitude];
    longitudeLabel.text = [NSString stringWithFormat:@"LONGITUDE: %f", location.coordinate.longitude];

    self.myLocation = location; // a property that stores the current location
}

然后在您的- (IBAction)pushToMark 中，您可以使用self.myLocation 作为坐标属性创建和添加注释。

至于删除注释 - 请参阅 Mundi 的答案。

Answer 2

将您创建的注释的引用存储在视图控制器的@property 中。要删除，请使用

[mapView removeAnnotation:self.ann1];
self.ann1 = nil;

此外，您扫描标签中的字符串以找出坐标的策略也很奇怪。为什么不只使用位置，您也可以将其存储在变量中？