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.
Related
I have two UIButtons that I added to my view
[self.view addSubview:button1];
[self.view addSubview:button2];
These buttons have a selector and in the selector is a menu where the user can choose an option and this option can vary in string size for the button so I decided to remove the buttons from the view and reload them again with different string size and button size. I have am getting the information from an API call so there is where I set the buttons up to my view. I tried to do this:
[button1 removeFromSuperview];
Also tried:
[self.button1 removeFromSuperView];
Now, for the UILabel I have it inside a table view cell because the string is long and covers my detailTextLabel. I am using UITableViewCellStyleValue1 for the cells. I have tried to use NSLineBreakByWordWrapping and set the numberOfLines to 0 as well as 5 so I then decided to add the UILabel inside the table view cell so I can control how far the string goes and I can also wrap that around. Since the cell was writing over and over the label every time the cell with the table view was hidden, I decided to create the label inside the if(cell == nil) statement.Like the button, this label also gets refreshed when the buttons are pressed and a menu option is chosen so I have to remove it from the view, the same way i did the buttons. For some reason it isn't working. Anyone have any thoughts/ideas/suggestions?
I also NSLog(#"%#",[button1 superview]) after I removed it to make sure that the button was indeed (null) as well as the label, and they do show up on the terminal as null but the buttons overlap each other, in fact you can still click the old button and you can see it underneath the new button. Same goes with the label. If you need any code let me know, this problem is frustrating me so much!
Also, I am on iOS7 and for some reason my device isn't displaying the status bar. I've tried to change it inside the info.plist -> status bar style. I've tried the 3 options it has but none of them seem to work. I checked all my xib files and checked for any hidden keywords in my .m files. Thanks in advance.
Since you mentioned the button was making an API call I am guessing you may be threading that section of code. If that's the case then the reason its not working is likely because you are not allowed to update the UI in a background thread.
Try replacing:
[button1 removeFromSuperview];
with this:
[button1 performSelectorOnMainThread:#selector(removeFromSuperview) withObject:nil waitUntilDone:NO];
I deeply suggest using storyboards, they make working with the UI a lot easier! They also allow you to play with constraints to see how your UI elements react to longer text or to the screen rotating, etc...
That apple tutorial:
https://developer.apple.com/library/ios/documentation/iPhone/Conceptual/SecondiOSAppTutorial/Introduction/Introduction.html
goes through a simple app with storyboards!
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.
I have a toolbar with 5 buttons.
4 of them are regular bar button items and one of them is a custom one (A 'UIButton' inside a 'UIBarButtonItem').
I noticed that when I click between the regular buttons (not exactly on them), one of them (the closest one) still recieves the click event and is being highlighted (which is what I want).
But the custom bar button item does not show this behaviour.
When I tap between it and one of the regular buttons neither of the 2 receives the touch event. This probably because the UIButton is the one the gets the click event. Is there a way to add a touch event the containing bar button item as well? Or perhaps another way to solve this?
Thanks!
button.userInteractionEnabled = YES; I believe is the answer.
One solution might be that you create image of same as bar button item and assign to UIButton as background image, this will solve your issue.
Hope this helps you....
Solved it!
I added another UIView to the UIBarButtonItem and then I added the UIButton to the UIView.
I added a touch gesture to the UIView (And also kept the original touch event of the UIButton) that expanded the area that you can touch the button which solved the problem.
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.
Take a look at this method:
[textButton addTarget:self action:#selector(articleModalWillAppear:) forControlEvents:UIControlEventTouchDown];
When the button is touched, it calls articleModalWillAppear:. That works well. The problem is the button also calls the action when it is dragged. (The button is big and contains a text paragraph)
I put six such buttons as subviews of UIScrollView (with UIPageControl). It works well when dragging UIScrollView horizontally. But it pops up modal views when dragging vertically because when a finger dragging across a button, the button considers it as a touch, and the touch calls articleModalWillAppear:.
If you still don't understand my problem, think about the New York Times iPad app. You can drag the pages horizontally. You can touch an article description to go to the full article view. But nothing happens when you drag vertically inside an article description. How to achieve this?
Use a different event e.g.:
[textButton addTarget:self action:#selector(articleModalWillAppear:) forControlEvents:UIControlEventTouchUpInside];
UIControlEventTouchUpInside is the most generally used in this case.
use forControlEvents:UIControlEventTouchUpInside
That only registers a click event when a user touches down inside the button and then touches up in the same button, and ignores drags.