I have a UIButton connected to an IBAction in Interface Builder.
The Problem:
The action firing and the de-highlight of the button both take a little bit to happen.
The Facts:
View structure:
View
10 Buttons (connected via UIControlEventTouchUpInside to the IBAction
View (Subview)
Gesture recognizer
Text Field
The Subview has a UITapGestureRecognizer, which delaysTouchesBegan and delaysTouchesEnded both are set to NO
The action is happening in the main thread.
Testing a simple button (with no images or title, and only a simple NSLog), the result is the same
The Question:
Why are firing and the de-highlight delayed?
In the end, I added somewhere some UIGestureRecognizer, and forgot to set delaysTouchesBegan to NO =(
Ok I think that because of the UITapGestureRecognizer .. try to do the following :
connect an IBOutlet to your button.
2.assing the UITapGestureRecognizer delegate to your ViewController.
3.Implement this gesture delegate method in yourViewController
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldReceiveTouch:(UITouch *)touch {
return (! [yourButton pointInside:[touch locationInView:yourButton] withEvent:nil]);
}
This will make the tap to be recognized to your button not to the recognizer.
Make sure your touch event is set the first contact of the button which would be the touch down event otherwise there will be a delay in the action until whichever other event you chose gets completed (i.e. touch up inside, touch up outside, etc).
In my case, there was a delay on IBAction for a button that was in a custom CalloutView of an MKAnnotationView.
In the same way there is a ~0.5sec delay between pressing the MKAnnotationView and the MKAnnotationView actually being selected, there is also a delay between any other user interactions you might add as a subview of the MKAnnotationView.
The solution is to disable the native UIGestureRecognizer within MapView that is causing the delay of any MKAnnotation view selections.
This can be done with the solution on this post:
Set isZoomEnabled = false within a gesture recognizer attached to the mapview on any tap, then set isZoomEnabled = false within a 0.5sec async dispatch.
Related
uitableviewdidselect cancel outs tap gesture action
there is an UIImageView in cell.contentView and there is a tap gesture to enlarge the image the control is not going to the Tap Gesture action its passing to the tableview didselect delegate ? I am using UITableView class for my table already did userInteractionEnabled=YES & cancelsTouchesInView = NO
Make sure you set
tapGestureRecognizer.cancelsTouchesInView = NO;
It won't work because table view can't take two user interactions at a time. First it will give priority to didSelectRowAtIndexPath. You need to disable user interaction on cells. So that tap gesture will be called. Make sure that user interaction enabled for imageView.
I have an image and in the storyboard I've dragged a Tap Gesture Recognizer on top of this image and changed the settings:
For my TGR:
For my image:
How do I hook this up to my controller now? I want a method to fire off when the double tap happens. Is there some sort of protocol I have to conform to? Do people normally do this from the storyboard or programmatically in viewDidLoad? I don't mind doing it another way if that's the general trend of things.
connect the gesture recognizer as a outlet to your ViewController and in your viewDidLoad :
[self.yourGesture addTarget:self action:#selector(didTapOnImage:)] ;
and then declare your method didTapOnImage method :
-(void)didTapOnImage:(UIGestureRecognizer*) recognizer
{
//do your work here
}
I have added UIPanGestureRecognizer on the view of my UIViewController.
In this view (a calculator) are some UIButton triggered by the event .TouchUpInside.
The problem comes if I tap on the button and make a small pan at the same time (which might happen if you tap quickly a button and are moving to the next one at the same time). Then the pan gesture is triggered. I would like to avoid it when there is a tap on a button. But I would like to allow it if the tap takes too long (let say 0.3s is enough to trigger the pan gesture).
How can I achieve that?
Set the property cancelsTouchesInView of your gesture recognizer to NO.
Then your button should work properly.
You can use the delegate method like this-
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
if ([touch.view isKindOfClass:[UIButton class]]) {
return NO;
}
return YES;
}
There is a dirty solution. You can just grab it in a UIScrollView
UITapGestureRecognizer is applied to both UIImageView and its subview (UITextView). However, when I tap on subview, the receiver becomes subview and its parent view (i.e. UIImageView + UITextView). It should however be only subview because that was the one I tapped. I was assuming nested gestures would react first but apparently parent receives the fist tap and then it goes to child.
So, there are different solutions out there for various scenarios (not similar to mine but rather buttons inside scroll view conflict). How can I easily fix my issue without possible subclassing and for iOS 6+ support? I tried delaying touch on start for UIGestureRecognizer on UIImageView and I tried setting cancelsTouchesInView to NO - all with no luck.
Try the following code:
conform the <UIGestureRecognizerDelegate> to your class.
set yourGesture.delegate = self;
then add this delegate Method:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
// return YES (the default) to allow the gesture recognizer to examine the touch object, NO to prevent the gesture recognizer from seeing this touch object.
if([touch.view isKindOfClass: [UITextView class]] == YES)] {
return YES;
}
else {
return NO;
}
}
Hope it will solve your issue. Enjoy Coding..!!!!
That's exactly what is it supposed to do.
View hierarchy is like a tree structure and its traversal during a touch gesture starts from the root node. It is very likely for your parent view to receive gesture first and then its subviews. The traversal skips the nodes for which
userInteractionEnabled = NO.
since, you don't have any code I can't help you to play with this flag. A more general solution is to always set gesture only for your parentView and in the gesture delegates check the coordinates if it belongs to any one of the subview and if yes then call your gesture method for your subview.
Not a clean approach but works. !!
you should implement the UIGestureRecognizer delegate methods and apply the correct policy to the gesture, when multiple gesture are recognized
I have UIViewController on my simple storyboard IPad project which contains UIScrollView which is placed over entire surface (1024 x 768). I have created 3 XIB files which are UIViews which my application loads on start in viewDidLoad and add them into UIScrollView. Each of these 3 XIB files contains only one UIButton.
This is hierarchy:
~ UIViewController (UIViewControllerClass is class for this
UIViewController)
~~ UIScrollView (contains 3 identical UIViews)
~~~ UIView (UIViewClass is File's Owner for this XIB file)
~~~~ UIButton
I would like that my UIViewControllerClass becomes aware of both: touch anywhere on UIScrollView component AND if UIScrollView is touched, if UIButton inside of UIView in UIScrollView is touched, to have information that exactly that button is touched.
I made IBAction inside UIViewClass for touch on UIButton inside UIView in UIScrollView and when I set User Interaction Enabled = YES on all elements (UIViewController, UIView and UIScrollView) this method is called as it should.
But at this point my UIViewControllerClass isn't aware that touch occurred inside UIScrollView on that UIButton. I made touch recognizer like this:
UITapGestureRecognizer *touch = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleTouch)];
touch.numberOfTouchesRequired = 1;
and added it to UIScrollView component. In this way I am able to detect touch event on UIScrollView component in UIViewControllerClass, but touch event handler for UIButton in UIView which is inside UIScrollView isn't called anymore.
So, I need to have these two informations in UIViewControllerClass:
Touch on UIScrollView component was made
Touch on UIButton in UIView which is inside UIScrollView (if this button was touched) was made
I suppose that attaching touch event recognizer to entire UIScrollView component isn't solution, since it disables all touch event handlers I wrote inside UIViewClass.
I think solution is that somehow touches which are made on components in UIView inside UIScrollView should be sent up to UIViewControllerClass, but I didn't found a way to do this.
If anyone can help me, I'd be very grateful. Thanks in advance.
[edit #1: ANSWER by Zheng]
Tap gesture must have cancelsTouchesInView option set to NO!
For my case above, this line solves everything:
touch.cancelsTouchesInView = NO;
Many thanks to Zheng.
I don't know if this works for you or not, but I've given an answer about touch events for views inside scrollview here:
Dismissing the keyboard in a UIScrollView
The idea is to tell the scrollView not to swallow up all tap gestures within the scroll view area.
I'll paste the code here anyways, hopefully it fixes your problem:
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(hideKeyboard)];
// prevents the scroll view from swallowing up the touch event of child buttons
tapGesture.cancelsTouchesInView = NO;
[pageScrollView addGestureRecognizer:tapGesture];
[tapGesture release];
...
// method to hide keyboard when user taps on a scrollview
-(void)hideKeyboard
{
[myTextFieldInScrollView resignFirstResponder];
}
You can subclass your UIScrollView and override the method - hitTest:withEvent: which is called by the system to determine which view will handle the event. Whenever it is called, you can assume that a touch event occurred inside the scroll view, and by calling the super implementation, you can get the view which would normally process the event.
you can capture any kind of gestures in the UIscrollView. Make sure you also handle some of the default properties as well like set cancelsTouchesInView property to false, it is true by default. Also give some tag nos to your sub views to distinguish in selectors. & also enable their User interaction to true.
let tap = UITapGestureRecognizer(target: self, action:
selector(didTapByUser(_:)))