I have some UIButtons within a UIScrollView, but I do not want to delay the button touches. However, as soon as the scroll view detects a drag/scroll, I want to cancel the UIButton touch and proceed with the scrolling of the UIScrollView.
I have included the following...
_scrollView.delaysContentTouches = NO;
...but (obviously) the button touch does not cancel when dragged. Does anyone have any suggestions as to how I can implement this functionality?
You can override this method of UIScrollView.
-(BOOL)touchesShouldCancelInContentView:(UIView *)view
{
return YES;
}
And in your UIButton, you should add different method for different control events.
show highlight effect for UIControlEventTouchDown.
trigger button for UIControlEventTouchUpInside | UIControlEventTouchUpOutside;
clear highlight effect for UIControlEventTouchCancel.
You could use scrollViewWillBeginDragging to fire off a notification and handle the button canceling by listening for it in your buttons' code. I think this is what you are trying to do, but I'm not sure if I have understood your question correctly.
Related
In my program I have placed a UIButton as a subview of a UIView, both of which have userInteractionEnabled set to true. When the button is tapped, an event is called to handle the button tap, which works as expected. However, the button's UIView superview also handles an event which should not be triggered in this case. Can anybody explain why the UIButton AND UIView are both triggering an event? Any help is appreciated.
Should you resign first responder after the button has done its duty so that the view that the button is in is no longer in control.
How about adding: bringSubviewtoFront:scrollview
to the end of your UIButton code. The idea here is to make your uiview the foremost view; which is what I think is happening when you touch the uiview and thus reactivating the triggering events
I have found a solution: I simply made the button a superview of the view which was handling unwanted events, rather than a subview.
I am working on a custom controller. I want to create a slider, to choose between more options. The problem is that when I touch the button I want to it doesn't call my touchesBegan method. But if I press in any other part of my view, it works. How can I get my button to move?
Thanks.
The UIButton is capturing the touch events. if you try this
myButton.userInteractionEnabled = NO;
Then it will no longer consume the touch events but it will also no longer fire the onTouchUpInside event. In this case you process all of the touches in the super view and position the slider button accordingly.
It should drag just fine. This will work for any UIView.
touchesBegan will not work on a UIButton .. for that to work you will have to subclass UIButton and implement touchesBegan
refer this answer for more info https://stackoverflow.com/a/4863734/919545
Why don't you create a custom UIView and avoid using the UIButton class? It is simplier that subclassing UIButto or to set
myButton.userInteractionEnabled = NO;
UIScrollView has a canceling mechanism, where it cancels the touch of subviews when it detects 'scrolling'.
I wonder if I can cancel a touch event (which already has begun) programmatically.
I have a draggable view inside a scroll view.
I can let the draggable view receive touches, but I'm wondering how to stop receiving touch events when I want and give touch events to the scroll view.
Have a look at cancelTrackingWithEvent:
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIControl_Class/index.html#//apple_ref/occ/instm/UIControl/cancelTrackingWithEvent%3A
You might want to have a look at the UITapGestureRecogniser class's cancelsTouchesInView method
Well I have had a similar problem.
I have solved it by disabling the scroll view when you receive touch event on its subview.
And when you think your event is complete you re-enable the scroll view.
If you do not do enable-disable the scroll view cancels your drag events automatically!
I have created a small UIView which contains two UIButtons. The view responds to UITapGesture events. The Buttons are supposed to respond to TouchUpInside, however when I tap the buttons the responder is the underlying view and the tap gesture selector is triggered. Looking for advice or suggestions.
You can modify the method that responds to the tap gesture in the orange view:
-(void) handleTapFrom:(UITapGestureRecognizer*) recognizer {
CGPoint location = [recognizer locationInView:orangeView];
UIView *hitView = [orangeView hitTest:location withEvent:nil];
if ([hitView isKindOfClass:[UIButton class]]) {
return;
}
//code that handle orange view tap
...
}
This way if you touch a UIButton, the tap will be ignored by the underlying view.
The right answer (which prevents the tabrecognizer from highjacking any taps and doesn't need you to implement a delegate etc) is found here. I got a lead to this answer via this post.
In short use:
tapRecognizer.cancelsTouchesInView = NO;
"Which prevents the tap recognizer to be the only one to catch all the
taps"
Each UIView has an 'exclusiveTouch' property. If it's set to YES the view won't pass the touch down the responder chain. Try setting this property on your UIButtons and see if that makes a difference.
How are the views ordered in the view hierarchy? Also, are you creating the interface in IB? If you hook up the connections properly, this shouldn't be an issue at all...
The problem with this design is that it's similar to embedding one button into another. While you may have a valid reason to do it, you should be more careful with the event flow.
What happens is the gesture recognizer intercepting touches before they reach subviews (the two buttons in your case). You should implement UIGestureRecognizerDelegate protocol, namely, gestureRecognizer:shouldReceiveTouch: method, and return NO if the touch is inside any of the two buttons. That will prevent the orange view from usurping touches intended for the buttons and the buttons will start to work as expected.
Check out this question.
uibutton-inside-a-view-that-has-a-uitapgesturerecognizer
I have a UIButton subview inside of a UITableViewCell.
When this button is touched, the user must hold the button for about a half second for the button's image to change to the UIControlStateHighlighted image.
This means that if the user just taps the button as is usually the case, the highlighted state is never shown.
Why does this occur and how can I fix it?
I just encountered this problem and saw that this issue hadn't been closed. After screwing around for a while I found a fix for it.
Now you can fix this by turning off delaysContentTouches or unchecking the "Delays content touches" box on the tableview.
The only negative side effect is that the user won't be able to tap down on a button and initiate a scrolling gesture. However, if the user tries to scroll starting from anywhere that doesn't itself accept touches, the behavior should be the same as before.
The problem is that your UIButton is inside a UITableView. This means that the table view has to determine whether your tap is going to be a swipe or if it's just a tap intended for the button. The table view has to delay sending a message to the UIButton until it knows that the user doesn't intend to swipe and therefore scroll the view instead of pressing the button.
If you don't need a table view, get rid of the UITableView.
Up for David Hodge's answer.
I just want to add a way to remove that "only negative side effect", already described by David: if you start scrolling inside a UIcontrol in a UIScrollView with delayContentTouches=NO, scrolling doesn't work.
SOLUTION
Subclass UIScrollView (or UITableView as the original question) and override:
-(BOOL) touchesShouldCancelInContentView:(UIView *)view {
return YES;
}
Your UIControls inside UIScrollView/UITableView will change their state immediately on tap and the scrollviews will be able to scroll even if the touch starts on some UIControl. Works like a charm.
I just change the image from within the target action method:
[sender setBackgroundImage:[UIImage imageNamed:#"highlighted-image.png"] forState:UIControlStateNormal];
It changes the background image instantly.
Edit: completely re-written following a misunderstanding of the question
One way of thinking of a UIButton is as a shorthand way of setting up an area of the screen that can respond to various instantaneous touch events the response it makes is defined by UIControl's Target-Action system for delivering messages to other objects.
UIControlEventTouchDown sounds like the one you need to respond to. It will be triggered as soon as someone touches inside your button - this is what the "Contact Info" button in SMS does.
UIButton* myButton = [[UIButton buttonWithType:UIButtonTypeRoundedRect];
// SEt up title, frame etc
[myButton addTarget:self action:#selector(myButtonWasPressed) forControlEvents: UIControlEventTouchDown];
[myMainView addSubView:myButton];
Will send a -(void)myButtonWasPressed message to the object this code runs from (ideally you view controller). In myButtonWasPressed you can then add a new view or take any action you like. The SMS app pushes a view controller to display the contact info using a navigation controller.
If this still doesn't solve your problem, you're going to have to post some code in order to get more insight into what's going wrong.