按下按钮即可在地图上放置Pin——iOS

Question

虽然我的最终项目不是另一个，但我把应用程序停在了哪里。我认为这将是一个很好的开始，以更好地掌握MKMap和Locations。

好的，这样我就可以设置pin，查看自己，并将我的当前位置显示在标签中。

我不能做的是：

A。按下按钮
1） 将用户存储在当前位置。2） 在当前用户位置放置一个pin（红色）。（因此，即使用户（蓝色）移动，新引脚也会保留）

B。单独按下按钮1） 清除用户从地图上掉下来的pin（红色）。

我似乎无法在按钮中设置新接点的地图注释。数字改变了，地图不会刷新（我猜）来显示我的密码，里面有或没有正确的密码。

这就是我目前所拥有的。（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

获得委托回调- (void)locationUpdate:(CLLocation *)location时，为什么不使用CLLocationCoordinate2D来存储当前位置？没有真正的理由使用MKCoordinateRegion和NSScanner。

改为：

- (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- (IBAction)pushToMark中，可以使用self.myLocation作为坐标特性创建和添加注释。

至于删除注释，请参见Mundi的答案。

Answer 2

将对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，扫描标签中的字符串以找出坐标的策略也相当奇怪。为什么不直接使用位置，也可以将其存储在变量中？