I need to add several swipe gestures to my scene on a game. From what I know, this can only be done programmatically, unfortunately I have never added gestures in this way, I have always used IB. I know I need to initialize a gesture recognizer, using initWithTarget:action: and I know how to set its properties, what I don't know is how to make this gesture do stuff. I assume it is through the action parameter #selector but this seems to never get called. Am I doing this wrong? here is what I have:
UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self
action:#selector(animateSwipeRightLeft)];
[self.view addGestureRecognizer:swipeRight];
and for the selector I have:
-(void)animateSwipeRightLeft {
//do stuff...
}
so it comes down to a few related questions: am I setting this up correctly? if so, why is my selector not being called? and if I am wrong about not being able to do this with IB, how?
also, if it helps, my gestures are set up in the initWithSize method for my scene.
You should add gesture recognizers in SKScene's didMoveToView method.
- (void)didMoveToView:(SKView *)view {
UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self
action:#selector(animateSwipeRightLeft)];
[self.view addGestureRecognizer:swipeRight];
}
self.view is nil inside init methods
Related
I have a UIView that already has a UIPanGesture implemented that works when a user drags the UIView half way up causing some action. As of now, it works just fine. Now, within the same UIView I want to implement a a UISwipeGesture so when the user swipes up, some other method would be called. I've been reading about the UIGestureRecognizerDelegate methods and I'm thinking I need to use gestureRecognizer:shouldRequireFailureOfGestureRecognizer: but I'm not sure.
I implemented the following in my viewDidLoad and got an error saying "invalid argument. Unrecognized selector sent to instance"
UIPanGestureRecognizer * panRec = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(handlePan:)];
panRec.delegate = self;
[panedView addGestureRecognizer:panRec];
UISwipeGestureRecognizer * swipeRec = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(handleSwipe:)];
swipeRec.direction = UISwipeGestureRecognizerDirectionUp;
swipeRec.delegate=self;
[panedView addGestureRecognizer:swipeRec];
[self gestureRecognizer:swipeRec shouldRequireFailureOfGestureRecognizer: panRec];
gestureRecognizer:shouldRequireFailureOfGestureRecognizer: is a delegate of the the UIGestureRecognizer. Meaning , you will implement the method , and when a gesture happens this method will be called automatically . To enable the gesture recognisers calling this method you need to set the gesture recogniser delegate to self, this can be done in viewDidLoad.
I have a UIView called myView on myViewController. I have a UIGestureRecognizer called swipeLeft (code below) that detects when a user swipes left on it.
The problem is: myViewController recognises the same gesture on the whole screen and performs another action. So I would like my app to perform myMethod when you swipeLeft in this particular area of myViewController, the area being myView.
UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self
action:#selector(myMethod:)];
swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
swipeLeft.delaysTouchesBegan = YES;
[self.myView addGestureRecognizer:swipeLeft];
More details: I am using RESideMenu and myViewController is the right menu, so when it is visible, the whole view of myViewController recognises swipes in all directions. I would like to change the recogniser in this particular UIView myView.
Thanks!
First you will need to add the swipe gesture to your view controllers header file.
#property (strong, nonatomic) UISwipeGestureRecognizer *swipeLeft;
If you look in DEMORootViewController.m, you will see this call:
self.rightMenuViewController = [self.storyboard instantiateViewControllerWithIdentifier:#"rightMenuViewController"];
This will call your awakeFromNib, and it's your first chance to do something. In here you will create that swipe gesture. You can not add it to your view yet though, because your outlets are not set at this point. The first time they are set is in viewDidLoad, so that's where you will add the gesture to your view. So add this to your view controllers implementation file
- (void)awakeFromNib
{
self.swipeLeft = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:#selector(myMethod:)];
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self.swipeView addGestureRecognizer:self.swipeLeft];
}
- (void)myMethod:(UISwipeGestureRecognizer *)swipe
{
NSLog(#"Did swipe") ;
}
Finally you will need to tell the pan gesture in RESideMenu.m to fail whenever our swipeLeft gesture occurs. The way to do that is to add the following code to RESideMenu.m at line 220. That's at the end of the viewDidLoad method.
if ([self.rightMenuViewController isKindOfClass:[DEMOVC class]]) {
DEMOVC *rightVC = (DEMOVC *)self.rightMenuViewController;
if (rightVC.swipeLeft) {
[panGestureRecognizer requireGestureRecognizerToFail:rightVC.swipeGesture];
} } }
This is assuming your custom VC is called DEMOVC. You will also need to import your custom VC to RESideMenu.m like this:
#import "DEMOVC.h"
Please let me know if this worked out for you, and if there's something else I can help you with.
I am trying to use Gestures in a game that I am working on and when I use the following code it is giving me the above error.
UISwipeGestureRecognizer* up = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(swipeUp)];
[up setDirection:(UISwipeGestureRecognizerDirectionUp)];
[self addGestureRecognizer:up];
Please help.
You can only add Gesture Recognizers to views.
The last line in your code should be changed to:
[self.view addGestureRecognizer:up];
I'm making a sidebar on my app so that when you swipe right it opens, I am using this code in the object I made called sidebar:
_swipeRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self.superview action:#selector(swiped)];
[_swipeRecognizer setDirection: UISwipeGestureRecognizerDirectionRight];
[self.superview addGestureRecognizer:_swipeRecognizer];
And this of course crashes and throws the error:
[UIView swiped]: unrecognized selector sent to instance 0x1fdbd0c0
because it's looking for the "swiped" method on self.superview when I want it to look for the method on self, but I want the gesture to be detected on self.superview.
I'm also confused, if I set initWithTarget then why do I have to do addGestureRecognizer? What's the difference between those two things?
Change this:
_swipeRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self.superview action:#selector(swiped)];
to:
_swipeRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(swiped)];
The call to initWithTarget:action: specifies the class that gets told about the gesture events. The "target" must implement the "action" method.
The call to addGestureRecognizer: specifies which view the gesture must happen on.
In many cases these are the same but in your case they are different.
if you want to handle the gesture recognized in self, at first line, you should set self as the the receiver, not self.superview:
_swipeRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(swiped)];
then implement the swiped action:
-(void)swiped:(UIGestureRecognizer *)gestureRecognizer {
//enter code here
}
Simply I want to add a tap gesture for a UIImageView that when the user touches, calls a method that is implemented in another class (not the same class that contains the UIImageView).
Can I do this and if so how can i do it ?
You can do that. But you need the instance of the target class (class in which method is going to execute) as delegate or something in the gesture adding class.
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self.delegate action:#selector(doSomething)];
Here delegate will be the instance of the target class that you have to set before going to that class.
Edit
I will explain a little more. Suppose you have two view controller classes VCA and VCB. you want to call a method in VCA from VCB through a tap gesture.
in VCB.h
#property (nonatomic,assign)VCA *delegate;
in VCB.m
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self.delegate action:#selector(doSomething)];
in VCA.m
You will present/ push VCB
VCB * viewController = [[VCB alloc]init];
viewController.delegate = self;
// push or present viewController
Declare recognizer selector on init
UITapGestureRecognizer *recognizer =
[UITapGestureRecognizer
initWithTarget:objectOfAnotherClass
action:#selector(methodImplementedOnObjectOfAnotherClass:)];
dont forget about defining number of taps (numberOfTapsRequired) and optional gesture recognizer required to fail (requireGestureRecognizerToFail:)
Link to article about selector.
One straightforward approach is calling the method of another class from the selector method of tapGesture ie.
Add UITapGestureRecogniser to the imageview
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:#selector(tapRecognised)];
[imageView addGestureRecognizer:tapGesture];
Dont forget to enable the userInteraction of the UIImageView, because by default for imageview userInteraction is disabled.
you can do this like below.
imageView.userInteractionEnabled = YES;
Then in the selector of tapGestureRecogniser call the method of another class
- (void)tapRecognised
{
[next tappedOnImage];
}
Here next is the object of another class. You can use delegation also to call the method.
Hope this will help you.
here self.desired view is the view in which you want to add gesture and you should add gesture in following way
and "webViewTapped.delegate = self" means you want to call a function of the same class when user tap and you can change it to your desired function by using delegate like self.delegate
UITapGestureRecognizer *viewTapped = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapAction:)];
webViewTapped.numberOfTapsRequired = 1;
webViewTapped.delegate = self;
[self.desiredView addGestureRecognizer:viewTapped];
- (void)tapAction:(UITapGestureRecognizer *)sender;
{
// do your stuff here
}