How does one get the current touch location from a GestureRecognizer?
I need to get the current touch location when the touch has begun as well as when the touch has ended.
What property is used to get this location?
Thanks
In your gesture recognizer handler:
CGPoint location = [gestureRecognizer locationInView:gestureRecognizer.view];
you could specify a different view, if you need it.
Related
Can I get the middle point coordinate of the UIRotationGestureRecognizer's two fingers? Or the location of each finger? Thank you.
You can get either.
The docs for UIRotationGestureRecognizer show the properties velocity and rotation.
This is specific to the rotation.
But you can use these methods from the UIGestureRecognizer...
Getting the Touches and Location of a Gesture
– locationInView:
– locationOfTouch:inView:
– numberOfTouches
To get the touches and locations.
From these you can easily calculate the mid point.
UIRotationGestureRecognizer extends UIGestureRecognizer which has the two methods: numberOfTouches and locationOfTouch:inView:. Use these to get the location of each finger. From there you can calculate a center.
In my iPhone application, I want to drop a pin at my current location using mapView and I also need to move another pin or a ball as my position changes. How can I do this?
To display user location, just add :
mapView.showsUserLocation = YES;
To get it, use the method userLocation which gives you a MKUserLocation.
You can then add a id<MKAnnotation> object with addAnnotation method to display another pin.
How do I get the co-ordinates of 2 touches on an iPhone? (both co-odiantes)??? This is killing me... any sample code would be great. Thanks.
If you are using touchesBegan:withEvent: and its siblings, you will be passed an NSSet object containing all the touches. You can get an NSArray using allObjects method on the set. You can retrieve individual UITouch objects using objectAtIndex: method. The UITouch object can give you coordinates based on any view's frame through the method locationInView:. The call will be on the lines of CGPoint point = [touch locationInView:self.view];. Do this for all the touches in the array.
If you are using gesture recognizers, the gesture recognizer object has a method numberOfTouches that gives you the number of touches and you can retrieve the location of each touch using locationOfTouch:inView:.
check touches began, touches moved, touches ended, and touches cancelled. here is the link for this UIResponder class reference
Ok what I would like to do is duplicate the controls of Space Invaders Evolution.
Begin a touch anywhere then drag around and the sprite moves 1:1 with your finger.
Sprite can not be moved of screen.
I have been using UIGestureRecognizer to handle dragging the sprite around the screen but im still pretty new to this and I have not been able to get this to work yet.
I don't know if you're unwilling to try this but it seems to me that this sort of thing could easily be done using ccTouchesBegan and ccTouchesMoved. I'd implement it by putting the following in my ccTouchesBegan and ccTouchesMoved methods (where sprite is the name of the sprite you're trying to move):
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInView:[touch view]];
location = [[CCDirector sharedDirector] convertToGL:location];
sprite.position = ccp(location.x, location.y);
Are you using Cocos2D or the Apple Frame-work?
In cocos2d you could use a layer (your scene for example) to detect the touch, which then moves the sprite. When the move is applied, check whether the sprite is still within screen boundaries, and move it back into screen boundaries if it's not.
There is example touch code in the cocos2d distribution. Not for your specific case, but general code, with text and explanation.
My app knows the current user position (CoreLocation.framework).
As soon as the user opens a new MapView his iPhone starts searching for the current position again.
Is it possible to skip that or to change the first user position for mkMapView?
Edit:
Is it possible to overwrite MKMapView and use an other LocationManager?
Yes, it is possible to have a separate location manager object and assign its value to the mapview (BTW, I'm using '=' below as list prefix to prevent the SO code-formatter from borking).
= In your UIViewController maintain two separate properties: one to a MKMapView and one to a CLLocationManager.
= Create a XIB file with the MKMapView and any other window chrome you want. Connect the outlets to the controller propeties. Make sure MKMapView does NOT follow user location.
= Have the UIViewController implement the CLLocationManagerDelegate protocol--especially the locationManager:didUpdateToLocation:fromLocation: method which will be called whenever a new location value is available. We'll be setting the controller as the delegate for the location manager.
= In the viewController's loadView method, load the NIB with the MKMapView in it. To give user feedback you may want to put up a UIActivityIndicatorView spinner and set it to startAnimating. Then you start with:
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
self.locationManager.desiredAccuracy = kCLLocationAccuracyKilometer;
self.locationManager.distanceFilter = 10; // or whatever
[self.locationManager startUpdatingLocation];
= In locationManager:didUpdateToLocation:fromLocation: check to see if the event was updated since the last N seconds. Then tell the location manager to stop updating, the spinner to stop animating, and get the lat/long data and assign it to the map view along with a view span and region so it zooms and centers to the right place.
= Now here's the tricky part: the blue marble 'throbber' is a feature of the mapview tracking user location. You'll have to momentarily 'fake it' until the real one kicks in (or just use a separate marker for the current location and maintain its position yourself). Personally I'd go with the blue marble that the user is familiar with.
= To make it so it shows right at startup you will need to create a custom MKAnnotationView with just the blue marble graphic added at the location returned by the location manager. This means taking a snapshot of a Mapview with the location showing, then photoshopping just the blue marble out and using it as the image for a custom annotation view.
= If you want it to actively follow the map, you can enable the userlocation tracking of the mapview and when it gets the actual data, you hide your previously set marker and let the mapview do the updating. The other option is to allow the existing location manager to continue receiving updates every second or so and update the position of the blue marble annotation yourself.
= To let the mapview's own userLocation do the updating add to viewDidLoad:
[self.map.userLocation addObserver:self
forKeyPath:#"location"
options:(NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld)
context:NULL];
self.map.showsUserLocation = YES; // starts updating user location
= Implement observeValueForKeyPath. It gets called when the location attribute of the mapview's userlocation has a value:
-(void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
{
if ([self.map isUserLocationVisible]) {
[self.locationManager stopUpdatingLocation];
self.ownBlueMarble.hidden = YES;
}
// The current location is in self.map.userLocation.coordinate
}
= To avoid the warm-up delay in showing current location, keep a reference to the viewController containing the map and the location manager so it doesn't go away (it's a bit of a memory hog but if you release it you'll have to wait again until MapView loads the tiles and is ready to go).
= In viewWillLoad you can stuff the last known location into the custom bluemarble annotation and show it. Toggle on/off the userLocation tracking and when you get the notification the same hide-the-annotation-show-the-real-marble trick will work. The mapview's own location manager kicks in and when it has the data, you can make your annotation marker disappear.
= You might want to implement the viewController's viewWillDisappear method and manually turn off userLocation tracking on the mapview so it's off by default the next time the view is brought up. You'll also want to get the last known userLocation and save it for the next get-go. That way, you can do all the positioning marker-juggling in the viewWillAppear method and not have to worry about userLocation interfering until you're ready for it.
Good luck.
In your controller:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
CLLocationCoordinate2D coord = {latitude: 37.423617, longitude: -122.220154};
MKCoordinateSpan span = {latitudeDelta: 1, longitudeDelta: 1};
MKCoordinateRegion region = {coord, span};
[mapView setRegion:region];
}
When map appears it's going to be centered close to Palo Alto
Try setting the showUserLocation property to false on initialisation and then restore the region the map view previously had (you will obviously have to store this before the previous map is destroyed).
Is this what you wanted?
You don't need to use another Location Manager, you can add whatever points you want to the map and update them via whatever other logic you want.
Let's say you had a socket connection to a remote control car, and that car send back socket data containing geo-location information in the payload. You could parse that out, and update the location of the thumbnail on your map in real time. The "userLocation" property is not needed for that, but you could show it if you wanted to.
The location of the user is read-only, you can use it or not. That doesn't mean you need another location manager to do anything you might need to do. It sounds like your app doesn't really need that feature, but I could be misunderstanding your question.