UILongPressGestureRecognizer on UISwitch does not fire - ios

Today I tried to add an additional UILongPressGestureRecognizer to an UISwitch, which did not really work. My code is the following:
UILongPressGestureRecognizer *lpgr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(doSomething:)];
[lpgr setDelaysTouchesBegan:YES];
[lpgr setDelaysTouchesEnded:YES];
[lpgr setCancelsTouchesInView:YES];
[self.switcher addGestureRecognizer:lpgr];
in the viewDidLoad method of the viewController that is the parent viewController of that switch. (the switcher is an instance variable, set through a storyboard. The IBOutlet is set properly from the UISwitch to the switcherProperty of its viewController).
On a couple of other controls (like a UIButton, UISlider, UIStepper and so on) this works, even without the touches cancelled or delayed, and perfectly triggers the target method. However, with my switch, it refuses that behavior.
I have tried removing any other gestureRecognizer on the UISwitch by iterating through all gestureRecognizers on that switch and calling [switcher removeGestureRecognizer: ... ], I´ve also set all of them to require my longPressGestureRecognizer to fail. Other types of gestureRecognizers don´t fire as well.
As far as I understand, GestureRecognizers will receive touches, before the view or control, which they belong to, receives them. Thus, setCancelsTouchesInView:YES and setDelaysTouchesInView:YES should enable the gestureRecognizer to handle every single gesture until it fails or succeeds, without the view knowing, right?
--------------EDIT------------------
The whole content of my method:
- (void)viewDidLoad
{
[super viewDidLoad];
UIGestureRecognizer *lpgr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(edit:)];
[self.view addGestureRecognizer:lpgr];
lpgr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(edit:)];
[self.button addGestureRecognizer:lpgr];
lpgr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(edit:)];
[self.slider addGestureRecognizer:lpgr];
lpgr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(edit:)];
[self.segmentedControl addGestureRecognizer:lpgr];
lpgr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(edit:)];
[self.switcher addGestureRecognizer:lpgr];
lpgr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(edit:)];
[self.stepper addGestureRecognizer:lpgr];
}
As I said, for the other controls this is working, only the switch does not want to work

try with it
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
// Disallow recognition of tap gestures in the segmented control.
if ((touch.view == yourSwitch)) {//change it to your condition
return NO;
}
return YES;
}
make sure you confirm UIGestureRecognizerDelegate for it to work.

Related

Setting conditions on number of Tap gesture in ios

I have a UILabel and when i double tap on it ,it should assign value of Label to the other view's UITextView otherwise next view's textview should be empty.
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapped:)];
[tapRecognizer setNumberOfTapsRequired:1];
[tapRecognizer setDelegate:self];
[holderView addGestureRecognizer:tapRecognizer];
tapRecognizer = nil;
UITapGestureRecognizer *doubleTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(LaunchText)];
[doubleTapRecognizer setNumberOfTapsRequired:2];
[doubleTapRecognizer setDelegate:self];
[holderView addGestureRecognizer:doubleTapRecognizer];
holderView.userInteractionEnabled=YES;
[tapRecognizer requireGestureRecognizerToFail:doubleTapRecognizer];
/*n=[SingleTon getInstance];
n.Name=textLabel.text;*/
if (doubleTapRecognizer.numberOfTapsRequired==2) {
n.Name=#"hi";
}
/* if (doubleTapRecognizer.numberOfTapsRequired==2) {
n.Name=textLabel.text;
}*/
else{
//n.Name=textLabel.text;
n.Name=#"hellow";
}
-(void) LaunchText
{
[self performSegueWithIdentifier:#"textAdd" sender:self];
}
I am always getting if condition, else part never runs, What is the issue with my code?
Please try below code.
//first add single tap
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(singleT:)];
[tapRecognizer setNumberOfTapsRequired:1];
[holderView addGestureRecognizer:tapRecognizer];
//now add double tap
UITapGestureRecognizer *doubleTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(doubleT:)];
[doubleTapRecognizer setNumberOfTapsRequired:2];
[holderView addGestureRecognizer:doubleTapRecognizer];
holderView.userInteractionEnabled=YES;
[tapRecognizer requireGestureRecognizerToFail:doubleTapRecognizer];
Now Implement Single Tap and Double Tap Method
-(void)singleT:(UITapGestureRecognizer *)gest
{
NSLog(#"Single");
}
-(void)doubleT:(UITapGestureRecognizer *)gest
{
NSLog(#"double");
}
Maybe this will help you.
doubleTapRecognizer.numberOfTapsRequired==2 is the value you set to how many times the user has to tap to set off the gesture recognizer. it you want to allow for single and double taps you can keep a count on the gesture recognizer target and see how many times they've tapped over a giving time, like 0.2 secs or whatever time you want. I'm not 100% sure but you could also try to add two gestures to the label one for numberOfTapsRequired = 1 and numberOfTapsRequired = 2 and have them both perform different functions. Again i'm not sure on the two recognizers but you could give it a try and try the other method otherwise.

Message Sent To Deallocated Instance on UIButton inside iCarousel

I have implemented iCarousel (https://github.com/nicklockwood/iCarousel) into my Xcode project and now have a scrolling carousel of views. Inside each view I have a UIButton, which I have added a UILongPressGestureRecogniser to, like this:
UILongPressGestureRecognizer *lpgr = [[UILongPressGestureRecognizer alloc] init];
[lpgr setMinimumPressDuration:1.5];
[lpgr addTarget:self action:#selector(testAction)];
[self.demoButton addGestureRecognizer:lpgr];
However, when I tap for 1.5 seconds, the following error is displayed in the console:
2014-07-01 09:50:08.002 ExampleApp[3117:892602] -[ExampleVC testAction]: message sent to deallocated instance 0x15cd7bd20
(lldb)*
I haven't seen any section of the code which is releasing the views, so very confused. Why is this and how can I fix it?
I think there can be a problem like this:
UILongPressGestureRecognizer *lpgr = [[UILongPressGestureRecognizer alloc] init];
[lpgr setMinimumPressDuration:1.5];
[lpgr addTarget:self action:#selector(testAction)];
[self.demoButton addGestureRecognizer:lpgr];
You forgot to release lpgr after these lines.
[lpgr release];
And if you miss this line, and demo button is released by iCarussel because of memory optimization, your gestureRecognizer won't be released and will send a message to the deallocated demoButton.
And use the LongPress like this:
[[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(handleLongPress:)];
and handle:
- (void)handleLongPress:(UILongPressGestureRecognizer *)gesture{
if (gesture.state == UIGestureRecognizerStateEnded) {
//Do Whatever You want on End of Gesture
}
else if (gesture.state == UIGestureRecognizerStateBegan){
//Do Whatever You want on Began of Gesture
}
}
and don't forget to implement <UIGestureRecognizerDelegate>
Update:
Inside each view I have a UIButton
You have a button inside each view, but about your code I see that you have a class variable demobutton. So when you initialize a view add your demo button like this:
UIView* yourView ...
UIButton* demoButton = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];
[yourView addSubview:demoButton];
UILongPressGestureRecognizer *lpgr = [[UILongPressGestureRecognizer alloc] init];
[lpgr setMinimumPressDuration:1.5];
[lpgr addTarget:self action:#selector(testAction:)];
[demoButton addGestureRecognizer:lpgr];
[demoButton release];
[lpgr release];

Single Tap TapGestureRecognizer

I am trying to use this code for a tap gesture recognizer, it works fine when number of taps required is set to 2, but when I set the number of taps required to 1 it stop functioning. I appreciate any help in getting this to work.
UITapGestureRecognizer *doubleTap =
[[UITapGestureRecognizer alloc]
initWithTarget:self
action:#selector(tapDetected:)];
[doubleTap setNumberOfTapsRequired : 1];
[doubleTap setDelaysTouchesBegan : YES];
[self.view addGestureRecognizer:doubleTap];
You try this:-
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget: self action:#selector(tapDetected:)];
singleTap.numberOfTapsRequired = 1;
[self.view addGestureRecognizer:singleTap];
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget: self action:#selector(tapDetected:)];
doubleTap.numberOfTapsRequired = 2;
[self.view addGestureRecognizer:doubleTap];
[singleTap requireGestureRecognizerToFail:doubleTap];
This works for me.
If You only want the receiver to respond to one/first touch then setDelaysTouchesBegan:NO Since this is used for processing touches in UITouchPhaseBegan so it is analyzed and is prevented from being delivered. Property discussion from documentation:
When the value of this property is NO (the default), views analyze touch events in UITouchPhaseBegan and UITouchPhaseMoved in parallel with the receiver. When the value of the property is YES, the window suspends delivery of touch objects in the UITouchPhaseBegan phase to the view. If the gesture recognizer subsequently recognizes its gesture, these touch objects are discarded. If the gesture recognizer, however, does not recognize its gesture, the window delivers these objects to the view in a touchesBegan:withEvent: message (and possibly a follow-up touchesMoved:withEvent: message to inform it of the touches’ current locations). Set this property to YES to prevent views from processing any touches in the UITouchPhaseBegan phase that may be recognized as part of this gesture.
It looks to me like you are simply failing to set the delegate of your GestureRecognizer. Are you sure the double tap was firing successfully? When I placed your code into my project I see the same behavior but setting the delegate properly and using shouldRecognizeSimultaneouslyWithGestureRecognizer causes it to recognize the single tap properly.
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self
action:#selector(tapDetected:)];
[doubleTap setDelegate:self];
[doubleTap setNumberOfTapsRequired : 1];
[doubleTap setDelaysTouchesBegan : YES];
[picker addGestureRecognizer:doubleTap];
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
if ([gestureRecognizer isKindOfClass:UITapGestureRecognizer.class] &&
[otherGestureRecognizer isKindOfClass:UITapGestureRecognizer.class])
{
return YES;
}
else
{
return NO;
}
}

Is it possible to add two gestures in a view?

As the title of this question said, I need to create a view where it needs to have action when one tap it or hold it. That means I have to add UITapGestureRecognizer and a UILongPressGestureRecognizer. I have already tried it. Somehow it redirect me to the screen where I needed to go, but it has affected it's back button. Affected by in the sense of it goes back to default text which is "Item" and it cannot perform it's assigned action.
Yes you can add these two gestures in one view. See the below code
UITapGestureRecognizer *singleTapRecognizer = [[UITapGestureRecognizer alloc]initWithTarget:self action:#selector(didTap:)];
singleTapRecognizer.numberOfTapsRequired = 1;
singleTapRecognizer.delegate = self;
[self.view addGestureRecognizer:singleTapRecognizer];
UILongPressGestureRecognizer *longPressRecognizer = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:#selector(didLongPress:)];
[longPressRecognizer setDelegate:self];
longPressRecognizer.allowableMovement = 1.0f;
longPressRecognizer.minimumPressDuration = 2.0;
[self.view addGestureRecognizer:longPressRecognizer];
As i mentioned in my comment you can do so,here is some piece of code to help you out.
UITapGestureRecognizer * recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleTap:)];
recognizer.delegate = self;
[view addGestureRecognizer:recognizer];
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc]
initWithTarget:self
action:#selector(handleLongPress:)];
longPress.minimumPressDuration = 2.0;
[view addGestureRecognizer:longPress];
and here are are some links too for your better understanding:-
https://developer.apple.com/library/ios/documentation/uikit/reference/UILongPressGestureRecognizer_Class/Reference/Reference.html
https://developer.apple.com/library/ios/documentation/uikit/reference/UITapGestureRecognizer_Class/Reference/Reference.html
Hope this will help you out.

IBAction does not fire when I add viewDidLoad

I have several IBActions attached to UIButtons. The IBActions work fine until I add the following code:
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(#"View Did Load");
[self addGestureRecognizersToView:drawImage];
}
After I add that chunk of code the IBActions do not fire. The UIButtons highlight when I touch them, but none of the IBAction code gets hit.
Here is my addGestureRecognizers code:
- (void)addGestureRecognizersToView:(UIImageView *)theView {
UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(handlePan:)];
[panGesture setMaximumNumberOfTouches:2];
[panGesture setMinimumNumberOfTouches:1];
//panGesture.delegate = drawImage;
[theView addGestureRecognizer:panGesture];
[panGesture release];
UITapGestureRecognizer *doubleFingerTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleDoubleTap:)];
[doubleFingerTap setNumberOfTapsRequired:2];
[self.view addGestureRecognizer:doubleFingerTap];
[doubleFingerTap release];
UITapGestureRecognizer *singleFingerTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleSingleTap:)];
[singleFingerTap setNumberOfTapsRequired:1];
[self.view addGestureRecognizer:singleFingerTap];
[singleFingerTap release];
}
If I comment out the singleFingerTap code it works. I'm guessing I should not be using alloc since I have already alloced that once before in doubleFingerTap?
Any ideas on what I might be missing here?
You single finger tap is hindering with the normal behavior of the button. You will have to make sure the touches get through unhindered.
[singleFingerTap setCancelsTouchesInView:NO];
It sounds like the UITapGestureRecognizer is intercepting the taps that would otherwise have been handled by the UIButtons.
You can use gestureRecognizer:shouldReceiveTouch::
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
return (touch.view != self.button1 &&
touch.view != self.button2);
}
Alternatively, you could hack the responder chain.

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