I see a lot of question about it on web, and particularly on StackOverflow.
I test many given answers but in my case, nothing works.
My class implements the protocol UIGestureRecognizerDelegate:
#interface CDMapViewController : CDViewController <UIGestureRecognizerDelegate>
The following method is wrote from xcode autocompletion in #implentation of my class
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldReceiveTouch:(UITouch *)touch {
NSLog(#"not called");
return NO;
}
I have correctly init the UIGestureRecognizer in first method which correctly call the second, third and fourth methods:
- (void)initGestureOnMap {
UIGestureRecognizer *gestureRecognizer = [[UIGestureRecognizer alloc] init];
gestureRecognizer.delegate = self;
[self.view addGestureRecognizer:gestureRecognizer];
}
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesBegan:touches withEvent:event];
gesture_dragging = NO;
}
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesMoved:touches withEvent:event];
gesture_dragging = YES;
}
- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesEnded:touches withEvent:event];
if (gesture_dragging || [touches count] != 1) return;
/* bla bla bla */
}
... It doesn't log – not called ... why ?
You need to call super implementations for the touches methods.
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesBegan:touches withEvent:event];
gesture_dragging = NO;
}
... and so on.
These methods need to be implemented on your view, and not your view controller.
Pick what kind of gesture you want. By itself, UIGestureRecognizer doesn't do much, so pick one like UITapGestureRecognizer. Next, implement your gesture recognizer with the designated initializer.
UITapGestureRecognizer *gestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(myMethod:)];
Finally, implement myMethod:.
-(void)myMethod:(UITapGestureRecognizer *)recognizer
{
// Whatever this does.
}
I am trying to detect double tap in a uiwebview. following is the code. when i debug, debugger comes to initwithcoder but never to touchesbegan nor to selector function. why so ?
I am putting a UIWebView in my xib file and setting identity inspector class to MyWebView
#import "MyWebView.h"
#implementation MyWebView
- (void) initTap {
UITapGestureRecognizer *singleFingerDoubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleSingleFingerDoubleTap:)];
singleFingerDoubleTap.numberOfTouchesRequired = 1;
singleFingerDoubleTap.numberOfTapsRequired = 2;
[self addGestureRecognizer:singleFingerDoubleTap];
[singleFingerDoubleTap release];
}
- (id)initWithCoder:(NSCoder*)coder
{
if (self = [super initWithCoder:coder]) {
// Initialization code.
[self initTap];
}
return self;
}
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
// Initialization code.
[self initTap];
}
return self;
}
-(void)handleSingleFingerDoubleTap:(id)sender {
NSLog(#"Doulble click detected !");
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
if (touch.tapCount == 2) {
//put you zooming action here
NSLog(#"Doulble click detected !");
}
}
- (void)dealloc {
[super dealloc];
}
#end
You just need to add delegate to the recognizer
singleFingerDoubleTap.delegate = self;
Then implement the following method to return YES.
#pragma mark Gesture recognizer delegate
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
Don't forget to add conform declaration to your class file.
Like this
#interface ORWebViewController : UIViewController<UIGestureRecognizerDelegate>
In case, you want to override the default zooming action on double tap, this will guide you.
UPDATE:
Please do not consider above mentioned reference as the author has moved it.
You can find the references from Disabling default zoom effect.
How do we detect a tap & hold on a UITableViewCell?
In iOS 3.2 or later you can use UILongPressGestureRecognizer
Here's the code lifted straight from my app. You should add these methods (and a boolean _cancelTouches member) to a class you derive from UITableViewCell.
-(void) tapNHoldFired {
self->_cancelTouches = YES;
// DO WHATEVER YOU LIKE HERE!!!
}
-(void) cancelTapNHold {
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:#selector(tapNHoldFired) object:nil];
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
self->_cancelTouches = NO;
[super touchesBegan:touches withEvent:event];
[self performSelector:#selector(tapNHoldFired) withObject:nil afterDelay:.7];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[self cancelTapNHold];
if (self->_cancelTouches)
return;
[super touchesEnded:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
[self cancelTapNHold];
[super touchesMoved:touches withEvent:event];
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
[self cancelTapNHold];
[super touchesCancelled:touches withEvent:event];
}
//Add gesture to a method where the view is being created. In this example long tap is added to tile (a subclass of UIView):
// Add long tap for the main tiles
UILongPressGestureRecognizer *longPressGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(longTap:)];
[tile addGestureRecognizer:longPressGesture];
[longPressGesture release];
-(void) longTap:(UILongPressGestureRecognizer *)gestureRecognizer{
NSLog(#"gestureRecognizer= %#",gestureRecognizer);
if ([gestureRecognizer state] == UIGestureRecognizerStateBegan) {
NSLog(#"longTap began");
}
}
You should probably handle the UIControlTouchDown event and depending on what you mean by "hold", fire a NSTimer that will count an interval since you initiated the touch and invalidate upon firing or releasing the touch (UIControlTouchUpInside and UIControlTouchUpOutside events). When the timer fires, you have your "tap & hold" detected.
I'm not sure what I am doing wrong but I try to catch touches on a MKMapView object. I subclassed it by creating the following class :
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#interface MapViewWithTouches : MKMapView {
}
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *) event;
#end
And the implementation :
#import "MapViewWithTouches.h"
#implementation MapViewWithTouches
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *) event {
NSLog(#"hello");
//[super touchesBegan:touches withEvent:event];
}
#end
But it looks like when I use this class, I see nothing on the Console :
MapViewWithTouches *mapView = [[MapViewWithTouches alloc] initWithFrame:self.view.frame];
[self.view insertSubview:mapView atIndex:0];
Any idea what I'm doing wrong?
The best way I have found to achieve this is with a Gesture Recognizer. Other ways turn out to involve a lot of hackish programming that imperfectly duplicates Apple's code, especially in the case of multitouch.
Here's what I do: Implement a gesture recognizer that cannot be prevented and that cannot prevent other gesture recognizers. Add it to the map view, and then use the gestureRecognizer's touchesBegan, touchesMoved, etc. to your fancy.
How to detect any tap inside an MKMapView (sans tricks)
WildcardGestureRecognizer * tapInterceptor = [[WildcardGestureRecognizer alloc] init];
tapInterceptor.touchesBeganCallback = ^(NSSet * touches, UIEvent * event) {
self.lockedOnUserLocation = NO;
};
[mapView addGestureRecognizer:tapInterceptor];
WildcardGestureRecognizer.h
//
// WildcardGestureRecognizer.h
// Copyright 2010 Floatopian LLC. All rights reserved.
//
#import <Foundation/Foundation.h>
typedef void (^TouchesEventBlock)(NSSet * touches, UIEvent * event);
#interface WildcardGestureRecognizer : UIGestureRecognizer {
TouchesEventBlock touchesBeganCallback;
}
#property(copy) TouchesEventBlock touchesBeganCallback;
#end
WildcardGestureRecognizer.m
//
// WildcardGestureRecognizer.m
// Created by Raymond Daly on 10/31/10.
// Copyright 2010 Floatopian LLC. All rights reserved.
//
#import "WildcardGestureRecognizer.h"
#implementation WildcardGestureRecognizer
#synthesize touchesBeganCallback;
-(id) init{
if (self = [super init])
{
self.cancelsTouchesInView = NO;
}
return self;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
if (touchesBeganCallback)
touchesBeganCallback(touches, event);
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
}
- (void)reset
{
}
- (void)ignoreTouch:(UITouch *)touch forEvent:(UIEvent *)event
{
}
- (BOOL)canBePreventedByGestureRecognizer:(UIGestureRecognizer *)preventingGestureRecognizer
{
return NO;
}
- (BOOL)canPreventGestureRecognizer:(UIGestureRecognizer *)preventedGestureRecognizer
{
return NO;
}
#end
SWIFT 3
let tapInterceptor = WildCardGestureRecognizer(target: nil, action: nil)
tapInterceptor.touchesBeganCallback = {
_, _ in
self.lockedOnUserLocation = false
}
mapView.addGestureRecognizer(tapInterceptor)
WildCardGestureRecognizer.swift
import UIKit.UIGestureRecognizerSubclass
class WildCardGestureRecognizer: UIGestureRecognizer {
var touchesBeganCallback: ((Set<UITouch>, UIEvent) -> Void)?
override init(target: Any?, action: Selector?) {
super.init(target: target, action: action)
self.cancelsTouchesInView = false
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
super.touchesBegan(touches, with: event)
touchesBeganCallback?(touches, event)
}
override func canPrevent(_ preventedGestureRecognizer: UIGestureRecognizer) -> Bool {
return false
}
override func canBePrevented(by preventingGestureRecognizer: UIGestureRecognizer) -> Bool {
return false
}
}
After a day of pizzas, screamings, I finally found the solution! Very neat!
Peter, I used your trick above and tweaked it a little bit to finally have a solution which work perfectly with MKMapView and should work also with UIWebView
MKTouchAppDelegate.h
#import <UIKit/UIKit.h>
#class UIViewTouch;
#class MKMapView;
#interface MKTouchAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
UIViewTouch *viewTouch;
MKMapView *mapView;
}
#property (nonatomic, retain) UIViewTouch *viewTouch;
#property (nonatomic, retain) MKMapView *mapView;
#property (nonatomic, retain) IBOutlet UIWindow *window;
#end
MKTouchAppDelegate.m
#import "MKTouchAppDelegate.h"
#import "UIViewTouch.h"
#import <MapKit/MapKit.h>
#implementation MKTouchAppDelegate
#synthesize window;
#synthesize viewTouch;
#synthesize mapView;
- (void)applicationDidFinishLaunching:(UIApplication *)application {
//We create a view wich will catch Events as they occured and Log them in the Console
viewTouch = [[UIViewTouch alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
//Next we create the MKMapView object, which will be added as a subview of viewTouch
mapView = [[MKMapView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
[viewTouch addSubview:mapView];
//And we display everything!
[window addSubview:viewTouch];
[window makeKeyAndVisible];
}
- (void)dealloc {
[window release];
[super dealloc];
}
#end
UIViewTouch.h
#import <UIKit/UIKit.h>
#class UIView;
#interface UIViewTouch : UIView {
UIView *viewTouched;
}
#property (nonatomic, retain) UIView * viewTouched;
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event;
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;
#end
UIViewTouch.m
#import "UIViewTouch.h"
#import <MapKit/MapKit.h>
#implementation UIViewTouch
#synthesize viewTouched;
//The basic idea here is to intercept the view which is sent back as the firstresponder in hitTest.
//We keep it preciously in the property viewTouched and we return our view as the firstresponder.
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
NSLog(#"Hit Test");
viewTouched = [super hitTest:point withEvent:event];
return self;
}
//Then, when an event is fired, we log this one and then send it back to the viewTouched we kept, and voilà!!! :)
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch Began");
[viewTouched touchesBegan:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch Moved");
[viewTouched touchesMoved:touches withEvent:event];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch Ended");
[viewTouched touchesEnded:touches withEvent:event];
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch Cancelled");
}
#end
I hope that will help some of you!
Cheers
UITapGestureRecognizer *tgr = [[UITapGestureRecognizer alloc]initWithTarget:self action:#selector(handleGesture:)];
tgr.numberOfTapsRequired = 2;
tgr.numberOfTouchesRequired = 1;
[mapView addGestureRecognizer:tgr];
[tgr release];
- (void)handleGesture:(UIGestureRecognizer *)gestureRecognizer
{
if (gestureRecognizer.state != UIGestureRecognizerStateEnded)
return;
CGPoint touchPoint = [gestureRecognizer locationInView:mapView];
CLLocationCoordinate2D touchMapCoordinate = [mapView convertPoint:touchPoint toCoordinateFromView:mapView];
//.............
}
For a MKMapView the real working solution is with gesture recognization !
Me I wanted to stop updating the center of the map on my location when I drag the map or pinch to zoom.
So, create and add your gesture recognizer to the mapView :
- (void)viewDidLoad {
...
// Add gesture recognizer for map hoding
UILongPressGestureRecognizer *longPressGesture = [[[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(handleLongPressAndPinchGesture:)] autorelease];
longPressGesture.delegate = self;
longPressGesture.minimumPressDuration = 0; // In order to detect the map touching directly (Default was 0.5)
[self.mapView addGestureRecognizer:longPressGesture];
// Add gesture recognizer for map pinching
UIPinchGestureRecognizer *pinchGesture = [[[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(handleLongPressAndPinchGesture:)] autorelease];
pinchGesture.delegate = self;
[self.mapView addGestureRecognizer:pinchGesture];
// Add gesture recognizer for map dragging
UIPanGestureRecognizer *panGesture = [[[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(handlePanGesture:)] autorelease];
panGesture.delegate = self;
panGesture.maximumNumberOfTouches = 1; // In order to discard dragging when pinching
[self.mapView addGestureRecognizer:panGesture];
}
Look the UIGestureRecognizer Class Reference to see all available gesture recognizer.
Because we've defined the delegate to self, we have to implement the protocole UIGestureRecognizerDelegate :
typedef enum {
MapModeStateFree, // Map is free
MapModeStateGeolocalised, // Map centred on our location
MapModeStateGeolocalisedWithHeading // Map centred on our location and oriented with the compass
} MapModeState;
#interface MapViewController : UIViewController <CLLocationManagerDelegate, UIGestureRecognizerDelegate> {
MapModeState mapMode;
}
#property (nonatomic, retain) IBOutlet MKMapView *mapView;
...
And override the methode gestureRecognizer:gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer: in order to allow recognize multiple gestures simultaneously, if I understood right :
// Allow to recognize multiple gestures simultaneously (Implementation of the protocole UIGestureRecognizerDelegate)
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}
Now write the methodes which will be called by our gesture recognizers :
// On map holding or pinching pause localise and heading
- (void)handleLongPressAndPinchGesture:(UIGestureRecognizer *)sender {
// Stop to localise and/or heading
if (sender.state == UIGestureRecognizerStateBegan && mapMode != MapModeStateFree) {
[locationManager stopUpdatingLocation];
if (mapMode == MapModeStateGeolocalisedWithHeading) [locationManager stopUpdatingHeading];
}
// Restart to localise and/or heading
if (sender.state == UIGestureRecognizerStateEnded && mapMode != MapModeStateFree) {
[locationManager startUpdatingLocation];
if (mapMode == MapModeStateGeolocalisedWithHeading) [locationManager startUpdatingHeading];
}
}
// On dragging gesture put map in free mode
- (void)handlePanGesture:(UIGestureRecognizer *)sender {
if (sender.state == UIGestureRecognizerStateBegan && mapMode != MapModeStateFree) [self setMapInFreeModePushedBy:sender];
}
Just in case somebody is trying to do the same like me: I wanted to create an annotation at the point where the user taps. For that I used the UITapGestureRecognizer solution:
UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(didTapOnMap:)];
[self.mapView addGestureRecognizer:tapGestureRecognizer];
[tapGestureRecognizer setDelegate:self];
- (void)didTapOnMap:(UITapGestureRecognizer *)gestureRecognizer
{
CGPoint point = [gestureRecognizer locationInView:self.mapView];
CLLocationCoordinate2D coordinate = [self.mapView convertPoint:point toCoordinateFromView:self.mapView];
.......
}
However, didTapOnMap: was also called when I tapped on the annotation and a new one would be created. The solution is to implement the UIGestureRecognizerDelegate:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
if ([touch.view isKindOfClass:[MKAnnotationView class]])
{
return NO;
}
return YES;
}
You probably will need to overlay a transparent view to catch the touches just like is done so often with UIWebView-based controls. The Map View already does a bunch of special things with a touch in order to allow the map to be moved, centered, zoomed, etc... that the messages are not getting bubbled up to your app.
Two other (UNTESTED) options I can think of:
1) Resign the first responder via IB and set it to "File's Owner" to allow file's Owner to respond to the touches. I an dubious that this will work because MKMapView extends NSObject, not UIView ans a result the touch events still may not get propagated up to you.
2) If you want to trap when the Map state changes (such as on a zoom) just implement the MKMapViewDelegate protocol to listen for particular events. My hunch is this is your best shot at trapping some interaction easily (short of implementing the transparent View over the Map). Do not forget to set the View Controller housing the MKMapView as the map's delegate (map.delegate = self).
Good Luck.
I haven't experimented, but there's a good chance MapKit is based around a class cluster, and therefore subclassing it is difficult and ineffective.
I'd suggest making the MapKit view a subview of a custom view, which should allow you to intercept touch events before they reach it.
So after half a day of messing around with this I found the following:
As everyone else found, pinching doesn't work. I tried both subclassing MKMapView and the method described above (intercepting it). And the result is the same.
In the Stanford iPhone videos, a guy from Apple says that many of the UIKit things will
cause alot of errors if you "transfer" the touch requests (aka the two methods described above), and you probably won't get it to work.
THE SOLUTION: is described here: Intercepting/Hijacking iPhone Touch Events for MKMapView. Basically you "catch" the event before any responder gets it, and interpret it there.
In Swift 3.0
import UIKit
import MapKit
class CoordinatesPickerViewController: UIViewController {
#IBOutlet var mapView: MKMapView!
override func viewDidLoad() {
super.viewDidLoad()
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(clickOnMap))
mapView.addGestureRecognizer(tapGestureRecognizer)
}
#objc func clickOnMap(_ sender: UITapGestureRecognizer) {
if sender.state != UIGestureRecognizerState.ended { return }
let touchLocation = sender.location(in: mapView)
let locationCoordinate = mapView.convert(touchLocation, toCoordinateFrom: mapView)
print("Tapped at lat: \(locationCoordinate.latitude) long: \(locationCoordinate.longitude)")
}
}
Make the MKMapView a subview of a custom view and implement
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
in the custom view to return self instead of the subview.
Thanks for the pizza and screamings - you saved me lots of time.
multipletouchenabled will work sporadically.
viewTouch.multipleTouchEnabled = TRUE;
In the end, I switched out the views when I needed to capture the touch (different point in time than needing pinchzooms):
[mapView removeFromSuperview];
[viewTouch addSubview:mapView];
[self.view insertSubview:viewTouch atIndex:0];
I notice that you can track the number and location of touches, and get the location of each in a view:
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch Moved %d", [[event allTouches] count]);
NSEnumerator *enumerator = [touches objectEnumerator];
id value;
while ((value = [enumerator nextObject])) {
NSLog(#"touch description %f", [value locationInView:mapView].x);
}
[viewTouched touchesMoved:touches withEvent:event];
}
Has anyone else tried using these values to update the map's zoom level? It would be a matter of recording the start positions, and then the finish locations, calculating the relative difference and updating the map.
I'm playing with the basic code provided by Martin, and this looks like it will work...
Here's what I put together, that does allow pinch zooms in the simulator (haven't tried on a real iPhone), but I think would be fine:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch Began %d", [touches count]);
reportTrackingPoints = NO;
startTrackingPoints = YES;
[viewTouched touchesBegan:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
if ([[event allTouches] count] == 2) {
reportTrackingPoints = YES;
if (startTrackingPoints == YES) {
BOOL setA = NO;
NSEnumerator *enumerator = [[event allTouches] objectEnumerator];
id value;
while ((value = [enumerator nextObject])) {
if (! setA) {
startPointA = [value locationInView:mapView];
setA = YES;
} else {
startPointB = [value locationInView:mapView];
}
}
startTrackingPoints = NO;
} else {
BOOL setA = NO;
NSEnumerator *enumerator = [[event allTouches] objectEnumerator];
id value;
while ((value = [enumerator nextObject])) {
if (! setA) {
endPointA = [value locationInView:mapView];
setA = YES;
} else {
endPointB = [value locationInView:mapView];
}
}
}
}
//NSLog(#"Touch Moved %d", [[event allTouches] count]);
[viewTouched touchesMoved:touches withEvent:event];
}
- (void) updateMapFromTrackingPoints {
float startLenA = (startPointA.x - startPointB.x);
float startLenB = (startPointA.y - startPointB.y);
float len1 = sqrt((startLenA * startLenA) + (startLenB * startLenB));
float endLenA = (endPointA.x - endPointB.x);
float endLenB = (endPointA.y - endPointB.y);
float len2 = sqrt((endLenA * endLenA) + (endLenB * endLenB));
MKCoordinateRegion region = mapView.region;
region.span.latitudeDelta = region.span.latitudeDelta * len1/len2;
region.span.longitudeDelta = region.span.longitudeDelta * len1/len2;
[mapView setRegion:region animated:YES];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
if (reportTrackingPoints) {
[self updateMapFromTrackingPoints];
reportTrackingPoints = NO;
}
[viewTouched touchesEnded:touches withEvent:event];
}
The main idea is that if the user is using two fingers, you track the values. I record the starting and ending points in startPoints A and B. Then I record the current tracking points, and when I'm done, on touchesEnded, I can call a routine to calculate the relative lengths of the line between the points I start with, and the line between the point I end with using simple hypotenuse calc. The ratio between them is the zoom amount: I multiply the region span by that amount.
Hope it's useful to someone.
I took the idea of an "overlay" transparent view, from MystikSpiral's answer, and it worked perfectly for what I was trying to achieve; quick, and clean solution.
In short, I had a custom UITableViewCell (designed in IB) with a MKMapView on the left-hand-side and some UILabels on the right. I wanted to make the custom cell so you could touch it anywhere and this would push a new view controller. However touching the map didn't pass touches 'up' to the UITableViewCell until I simply added a UIView of the same size as the map view right on top of it (in IB) and made it's background the 'clear color' in code (don't think you can set clearColor in IB??):
dummyView.backgroundColor = [UIColor clearColor];
Thought it might help someone else; certainly if you want to achieve the same behaviour for a table view cell.
I don't understand why other answers are so complicated. The solution is really just one line:
mapView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(mapTapped)))
#objc func mapTapped() {}