MKMapView zoom User Location and Annotation - objective-c

Question

I want my MKMapView to zoom 'User Location' and the Annotation as close as possible.
The map already show both, but is zoomed out to the whole country.
How can I do that?
And I don’t know why the Annotation and Pin are not animated.
My Code:
//Coords User
CLLocationCoordinate2D user_location;
user_location.latitude = mapView.userLocation.location.coordinate.latitude;
user_location.longitude = mapView.userLocation.location.coordinate.longitude;
//Coords Annotation
CLLocationCoordinate2D club_location;
club_location.latitude = [self.clubInfo.latitude doubleValue];
club_location.longitude = [self.clubInfo.longitude doubleValue];
MKMapPoint userPoint = MKMapPointForCoordinate(user_location);
MKMapPoint annotationPoint = MKMapPointForCoordinate(club_location);
MKMapRect userRect = MKMapRectMake(userPoint.x, userPoint.y, 0, 0);
MKMapRect annotationRect = MKMapRectMake(annotationPoint.x, annotationPoint.y, 0, 0);
MKMapRect unionRect = MKMapRectUnion(userRect, annotationRect);
MKMapRect unionRectThatFits = [mapView mapRectThatFits:unionRect];
[mapView setVisibleMapRect:unionRectThatFits animated:YES];
// Add an annotation
MKPointAnnotation *annotation = [[MKPointAnnotation alloc] init];
annotation.coordinate = club_location;
annotation.title = self.clubInfo.clubName;
annotation.subtitle = #"Pin!";
[mapView addAnnotation:annotation]; // This was missing
[mapView selectAnnotation:annotation animated:YES];
Logs:
userRect: {{134217728.0, 134217728.0}, {0.0, 0.0}}
annotationRect: {{99775488.0, 152579328.0}, {0.0, 0.0}}
unionRect: {{99775488.0, 134217728.0}, {34442240.0, 18361600.0}}
mapView.visibleMapRect: {{96025087.6, 116070015.1}, {41943040.7, 54657025.8}}

Answer 1

If I understand well, you want those two annotations to be visible with maximum possible zoom. I found this solution that does not reqire any calculations.
// You have coordinates
CLLocationCoordinate2D user = ...;
CLLocationCoordinate2D annotation = ...;
// Make map points
MKMapPoint userPoint = MKMapPointForCoordinate(user);
MKMapPoint annotationPoint = MKMapPointForCoordinate(annotation);
// Make map rects with 0 size
MKMapRect userRect = MKMapRectMake(userPoint.x, userPoint.y, 0, 0);
MKMapRect annotationRect = MKMapRectMake(annotationPoint.x, annotationPoint.y, 0, 0);
// Make union of those two rects
MKMapRect unionRect = MKMapRectUnion(userRect, annotationRect);
// You have the smallest possible rect containing both locations
MKMapRect unionRectThatFits = [mapView mapRectThatFits:unionRect];
[mapView setVisibleMapRect:unionRectThatFits animated:YES];
CoreLocation and MapKit structures are hell.

Answer 2

For anyone coming here later: The shortest way of doing this is (iOS7+) this:
Assuming you have a #property MKMapView *mapView, and an MKPointAnnotation *theAnnotation, call:
[self.mapView showAnnotations:#[theAnnotation, self.mapView.userLocation] animated:NO];
Now this could cause some problems if called too early (i.e. when self.mapView.userLocation is not yet set). If so, you can call in viewWillAppear:
[self.mapView.userLocation addObserver:self forKeyPath:#"location" options:0 context:NULL];
Then, implement:
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
if ([keyPath isEqualToString:#"location"]) {
[self.mapView showAnnotations:#[theAnnotation, self.mapView.userLocation] animated:NO];
}
}
That way you're sure it's set. Don't forget to remove the observer at viewWillDisappear:
[self.mapView.userLocation removeObserver:self forKeyPath:#"location"];

Answer 3

Use these 4 classes - it works like a charm!
//MapViewController.h file
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#interface MapViewController : UIViewController <CLLocationManagerDelegate> {
IBOutlet UIButton *buttonBack;
IBOutlet MKMapView *mapView;
IBOutlet UILabel *labelTitle;
NSString *lon,*lat,*nickName;
BOOL isFirstLaunch;
}
#property(nonatomic,retain) NSString *lon,*lat,*nickName;
#property(nonatomic,retain) IBOutlet UIButton *buttonBack;
#property(nonatomic,retain) IBOutlet UILabel *labelTitle;
#property(nonatomic,retain) IBOutlet MKMapView *mapView;
-(IBAction)buttonBackAction:(UIButton *)_btn;
-(void)zoomToFitMapAnnotations;
#end
//
// MapViewController.m
//
#import "MapViewController.h"
#import "Annotation.h"
#implementation MapViewController
#synthesize buttonBack,mapView,labelTitle;
#synthesize lon,lat,nickName;
// 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;
}
*/
-(IBAction)buttonBackAction:(UIButton *)_btn{
[self.navigationController popViewControllerAnimated:1];
}
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
CLLocationManager* locationManager = [[CLLocationManager alloc] init];
[locationManager setDelegate:self];
[locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
[locationManager startUpdatingLocation];
NSLog(#"MapViewController");
labelTitle.text = #"anscacorona.blogspot.in"
CLLocationCoordinate2D location;
location.latitude = [self.lat floatValue];
location.longitude = [self.lon floatValue];
Annotation *annotation = [[Annotation alloc] init];
annotation.theCoordinate = location;
annotation.theTitle = [NSString stringWithFormat:#"%#",labelTitle.text];
[mapView addAnnotation:annotation];
[annotation release];
mapView.showsUserLocation = 1;
[self zoomToFitMapAnnotations];
[super viewDidLoad];
}
// Shows the location of both users. called when the device location changes to move the map accordinly. necessary ONLY once when the window is opened. afterwards the user can move the map as he choises.
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
if (isFirstLaunch) {
CLLocationCoordinate2D topLeftCoord;
CLLocationCoordinate2D bottomRightCoord;
topLeftCoord.longitude = fmin([self.lon floatValue], newLocation.coordinate.longitude);
topLeftCoord.latitude = fmax([self.lat floatValue], newLocation.coordinate.latitude);
bottomRightCoord.longitude = fmax([self.lon floatValue], newLocation.coordinate.longitude);
bottomRightCoord.latitude = fmin([self.lat floatValue], newLocation.coordinate.latitude);
MKCoordinateRegion region;
region.center.latitude = topLeftCoord.latitude - (topLeftCoord.latitude - bottomRightCoord.latitude) * 0.5;
region.center.longitude = topLeftCoord.longitude + (bottomRightCoord.longitude - topLeftCoord.longitude) * 0.5;
region.span.latitudeDelta = fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.5; // Add a little extra space on the sides
region.span.longitudeDelta = fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.5; // Add a little extra space on the sides
region = [mapView regionThatFits:region];
[mapView setRegion:region animated:YES];
isFirstLaunch = NO;
}
}
-(void)zoomToFitMapAnnotations
{
if([mapView.annotations count] == 0)
return;
CLLocationCoordinate2D topLeftCoord;
CLLocationCoordinate2D bottomRightCoord;
topLeftCoord.longitude = fmin(mapView.userLocation.location.coordinate.longitude, [self.lon floatValue]);
topLeftCoord.latitude = fmax(mapView.userLocation.location.coordinate.latitude, [self.lat floatValue]);
bottomRightCoord.longitude = fmax(mapView.userLocation.location.coordinate.longitude, [self.lon floatValue]);
bottomRightCoord.latitude = fmin(mapView.userLocation.location.coordinate.latitude, [self.lat floatValue]);
MKCoordinateRegion region = { {0.0, 0.0 }, { 0.0, 0.0 } };
CLLocationCoordinate2D userCoord = {[self.lat floatValue],[self.lon floatValue]};
region.center = userCoord;
region.span.latitudeDelta = 0.05f;//fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.1; // Add a little extra space on the sides
region.span.longitudeDelta = 0.05f;//fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.1; // Add a little extra space on the sides
[mapView setRegion:region animated:YES];
[mapView regionThatFits:region];
}
/*
// 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.
}
#pragma mark - View Lifecycle
-(void)viewWillAppear:(BOOL)animated{
isFirstLaunch=YES;
}
- (void)viewDidUnload {
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)dealloc {
[super dealloc];
}
#end
//anotation classes- Annotation.h
#import <MapKit/MapKit.h>
#interface Annotation : NSObject <MKAnnotation>{
CLLocationCoordinate2D theCoordinate;
NSString *theTitle;
NSString *restId;
NSString *theSubtitle;
}
#property(nonatomic,retain) NSString *restId;
#property(nonatomic,retain) NSString *theTitle;
#property(nonatomic,retain) NSString *theSubtitle;
#property CLLocationCoordinate2D theCoordinate;
#end
//Annotation.m
#import "Annotation.h"
#implementation Annotation
#synthesize theCoordinate,theTitle,theSubtitle,restId;
- (CLLocationCoordinate2D)coordinate;
{
return theCoordinate;
}
// required if you set the MKPinAnnotationView's "canShowCallout" property to YES
- (NSString *)title
{
return theTitle;
}
// optional
- (NSString *)subtitle
{
return theSubtitle;
}
- (void)dealloc
{
[super dealloc];
}
#end