I have a UIScrollView with subclassed UIImageViews in it. When one of the imageviews are clicked, I'd like the parent UIView (contains the scrollview) to receive the event in its
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
I can tell if the imageview was clicked by
if(CGRectContainsPoint(myScrollView.frame, location) == YES){...}
Assuming the imageview and scrollview are the same size. Or is there a better way to to know a particular imageview within the scrollview was tapped? The imageviews are created dynamically.
The approach I've used for this in the past is to fire off a notification when a subview has been touched, with the subview as the object posted with the notification. You can then have your container view listen for the appropriate notification, and perform whatever action is needed based on the UIView instance that was selected.
You'd post the notification within the subview's -touchesEnded:withEvent: method as follows:
[[NSNotificationCenter defaultCenter] postNotificationName:#"MySubviewWasTouched" object:self];
To set up listening for this notification, you'd place code like the following somewhere in the initialization of your view or view controller:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(handleSubviewTouch:) name:#"MySubviewWasTouched" object:nil];
remembering to remove the observer in your teardown code for the the view or controller.
Finally, you'd need to implement the method that processes the receipt of the notification (-handleSubviewTouch: in the example above):
- (void)handleSubviewTouch:(NSNotification *)note;
{
UIView *subviewThatWasTouched = [note object];
// Your touch-handling logic here
}
Note that UIImageView ignores touches (or rather, lets them pass through to its superview) by default. Make sure you set your image views' userInteractionEnabled property to YES.
If the image views don't have any children, you can use the UIView method hitTest:withEvent:. It returns the farthest descendent of a UIView that contains a given touched point. So for example:
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
CGPoint location = [[touches anyObject] locationInView:myScrollView];
UIView *touchedView = [myScrollView hitTest:location withEvent:event];
// ...
}
Related
I have a UIScrollView with subviews and a UITapGestureRecognizer.
I create the recognizer like this:
UITapGestureRecognizer *tgr = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapGestureRecognized:)];
[self addGestureRecognizer:tgr];
The view property of UITapGestureRecognizer points to the scroll view itself even if the user touched a different view. I need to know if touch went down on the scroll view directly.
Paul's suggestions are good, but if you don't want (or can't) subclass or become the delegate of the recognizer, there's another way.
You can ask the gesture recognizer for its locationInView: and then retrieve the view which that point is on top of with your scrollView's hitTest:withEvent: method (defined on UIView). Something like:
CGPoint location = [recognizer locationInView:scrollView];
UIView *touchedView = [scrollView hitTest:location withEvent:nil];
You can become either subclass UITapGestureRecognizer and add a new ivar to hold this info by overriding the touchesBegan:withEvent: method something like this
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
/*
* If you wanted you could store a set of all the views to allow
* for multiple touches
*/
self.touchedView = [touches.anyObject view];
[super touchesBegan:touches withEvent:event];
}
Or if you like you can become the delegate for UITapGestureRecognizer and store the tapped view as a property in your class by implementing gestureRecognizer:shouldReceiveTouch:
Note: I already read some questions about the UIScrollView sending touches to the subviews (this included and although I have up voted, it's not working as I intended anymore).
What I have: I have a UIScrollView with a Custom UIView (let's call it A) inside which covers the entire UIScrollView. I am also allowed to put other custom UIViews inside the A.
On the code I am doing this:
[scrollView setDelaysContentTouches:YES];
scrollView.canCancelContentTouches = NO;
What is happening: At the moment my only issue is that, if I want to move a subview inside A, I have to touch it, wait, and then move it. Exactly as stated here:
Now, the behaviour changes depending on the "length in time" of the
first touch on the UIView. If it's short, then the relative dragging
is managed as it was a scroll for the UIScrollView. If it's long, then
I'm getting the touchesMoved: events inside my UIView.
What I want: The subviews inside A should always receive priority and I shouldn't have to touch and wait. If I touch A and not a subview of it, I want the UIScrollView to receive the touches, like panning and moving around (the contentSize is bigger than the frame).
Edit 1.0
The only reason for me to have this A view inside a generic UIScrollView, is because I want to be able to zoom in/out on the A view. So I am doing the following:
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return customView; // this is the A view
}
In the beginning I didn't had the A view inside the UIScrollView and the only thing I did was adding the A as a subView of my UIViewController's root view and everything went well. If there is another way to enable zoom in/out I will gladly accept the answer.
Note: Thank you all for your contributions, specially to Aaron Hayman.
I was able to figure it out by doing the following on the UIScrollView sub-class I had:
-(BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
CGPoint pointOfContact = [gestureRecognizer locationInView:self];
// The view with a tag of 200 is my A view.
return (![[self hitTest:pointOfContact withEvent:nil] isEqual:[self viewWithTag:200]]);
}
I haven't tested this, but I believe how you are handling the touch events in View A (or it's subviews) will determine how touch events are passed on. Specifically, if you're trying to use the methods: touchesBegan, touchesMoves, touchesEnded, etc instead of a UIGestureRecognizer you won't receive the touches in the way you want. Apple design the UIGestureRecognizer to handle problems like the one you're facing. Specifically, the UIScrollView uses UIPanGestureRecognizer to handle the scrolling. If you add a UIPanGestureRecognizer to each of the subviews of View A any "panning" that occurs on one of those subviews should be sent to that subview instead of the UIScrollView. However, if you're simply using the "raw" touches methods, the UIPanGestureRecognizer in UIScrollView will never be cancelled.
In general, it's almost always best to use a UIGestureRecognizer instead of processing the touches directly in the view. If you need touches processed in a way that no standard UIGestureRecognizer can provide, subclass UIGestureRecognizer and process the touches there. That way you get all the the functionality of a UIGestureRecognizer along with your own custom touch processing. I really think Apple intended for UIGestureRecognizer to replace most (if not all) of the custom touch processing code that developers use on UIView. It allows for code-reuse and it's a lot easier to deal with when mitigating what code processes what touch event.
Jacky, I needed a similar thing: Within a building plan (your A, in my case a subclass of UIScrollView), let the user place and resize objects (call them Bs). Here's a sketch of what it took me to get at this behavior:
In the superview's (A) initWithFrame: method, set these two:
self.canCancelContentTouches = YES;
self.delaysContentTouches = NO;
This will ensure taps on B are immediately routed to the Bs.
In the embedded B, stop the superview A from cancelling taps, so it does not interfere with a gesture started on the B.
In the touchesBegan: method, search the view hierarchy upwards (using superview property of the views) until you find a UIScrollView, and set its canCancelContentTouches to NO. Remember the superview you changed, and restore this property in the touchesEnded and touchesCancelled methods of B.
I'd be interested whether this works for you as well. Good Luck!
nobi
I think you had better use "touchesBegan,touchesMoved,touchesEnded" to pass the event.
you can do like this:
you should make a mainView . It has 2 property. One is yourScrollView A , and One is yourCustomView.
`[yourScrollView addSubviews:yourCustomView];
[mainView addSubviews:yourScrollView];`
and then write your touches method in the mainView.m like this (ignor the scrollView statment)
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *mytouch=[[touches allObjects] objectAtIndex:0];
if ([[touches allObjects] isKindOfClass:[yourCustomView class]])
{
//do whatever you want
}
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *mytouch=[[touches allObjects] objectAtIndex:0];
if ([[touches allObjects] isKindOfClass:[yourCustomView class]])
{
//do whatever you want
}
}
The last step: pass the event to the subview of the scrollView(your A).
#import "yourScrollView.h"
#implementation yourScrollView
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
// Initialization code.
}
return self;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
[super touchesBegan:touches withEvent:event];
if(!self.dragging)
[[self nextResponder] touchesBegan:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
[super touchesMoved:touches withEvent:event];
if(!self.dragging)
[[self nextResponder] touchesMoved:touches withEvent:event];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
[super touchesEnded:touches withEvent:event];
if(!self.dragging)
[[self nextResponder] touchesEnded:touches withEvent:event];
}
- (void)dealloc {
[super dealloc];
}
#end
wish to help you
hello
i put some uitextfield in uiscrollview,and connect them in interface builder to event "touch down" to a method,the problem his that when the uitexttfield is inside uiscrollview the method doesn't called and when the textfield is not in the uiscroll view the method doesn't called.
UIScrollView is special because of all the touch events it needs to process itself. Try sub-classing UIScrollView and add:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"you should see this for touch events on your scroll view");
}
set the class name in IB to your UIScrollView subclass.
I do have a view that has a UIScrollView and over it there is a view that display some text.
When the user swipes over this view that contains text the UIScrollView won't scroll. How to make this view transparent in a way it relays the swipe gesture to UIScrollView.
Thanks
You can just set
myTextView.userInteractionEnabled = NO;
Or, if you're creating your view with Interface Builder, there's a check box there called 'User interaction enabled', just uncheck that.
Check out the UIView hitTest Method
Returns the farthest descendant of the receiver in the view hierarchy (including itself) that contains a specified point.
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
Inside the -touchesXXXX:withEvent: methods of your custom view, call their super methods to forward touch events.
For example:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
// forward touchesBegan to super class
[super touchesBegan:touches withEvent:event];
...
// process touchesBegan for this view
}
Do the same things for touchesMoved, touchesEnded, and touchesCancelled.
I'm trying to handle touches on a iPhone's UITextView. I successfully managed to handle taps and other touch events by creating a subclass of UIImageViews for example and implementing the touchesBegan method...however that doesn't work with the UITextView apparently :(
The UITextView has user interaction and multi touch enabled, just to be sure...no no joy. Anyone managed to handle this?
UITextView (subclass of UIScrollView) includes a lot of event processing. It handles copy and paste and data detectors. That said, it is probably a bug that it does not pass unhandled events on.
There is a simple solution: you can subclass UITextView and impement your own touchesEnded (and other event handling messages) in your own versions, you should call[super touchesBegan:touches withEvent:event]; inside every touch handling method.
#import "MyTextView.h" //MyTextView:UITextView
#implementation MyTextView
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
NSLog(#"touchesBegan");
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
[super touchesBegan:touches withEvent:event];
NSLog(#"touchesMoved");
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
NSLog(#"****touchesEnded");
[self.nextResponder touchesEnded: touches withEvent:event];
NSLog(#"****touchesEnded");
[super touchesEnded:touches withEvent:event];
NSLog(#"****touchesEnded");
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event{
[super touches... etc];
NSLog(#"touchesCancelled");
}
If you want to handle single/double/triple tap on UITextView, you can delegate UIGestureRecongnizer and add gesture recognizers on your textview.
Heres sameple code (in viewDidLoad):
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleSingleTap)];
//modify this number to recognizer number of tap
[singleTap setNumberOfTapsRequired:1];
[self.textView addGestureRecognizer:singleTap];
[singleTap release];
and
-(void)handleSingleTap{
//handle tap in here
NSLog(#"Single tap on view");
}
Hope this help :D
Better solution (Without swizzling anything or using any Private API :D )
As explained below, adding new UITapGestureRecognizers to the textview does not have the expected results, handler methods are never called. That is because the UITextView has some tap gesture recognizer setup already and I think their delegate does not allow my gesture recognizer to work properly and changing their delegate could lead to even worse results, I believe.
Luckily the UITextView has the gesture recognizer I want already setup, the problem is that it changes according to the state of the view (i.e.: set of gesture recognizers are different when inputing Japanese than when inputing English and also when not being in editing mode).
I solved this by overriding these in a subclass of UITextView:
- (void)addGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
{
[super addGestureRecognizer:gestureRecognizer];
// Check the new gesture recognizer is the same kind as the one we want to implement
// Note:
// This works because `UITextTapRecognizer` is a subclass of `UITapGestureRecognizer`
// and the text view has some `UITextTapRecognizer` added :)
if ([gestureRecognizer isKindOfClass:[UITapGestureRecognizer class]]) {
UITapGestureRecognizer *tgr = (UITapGestureRecognizer *)gestureRecognizer;
if ([tgr numberOfTapsRequired] == 1 &&
[tgr numberOfTouchesRequired] == 1) {
// If found then add self to its targets/actions
[tgr addTarget:self action:#selector(_handleOneFingerTap:)];
}
}
}
- (void)removeGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
{
// Check the new gesture recognizer is the same kind as the one we want to implement
// Read above note
if ([gestureRecognizer isKindOfClass:[UITapGestureRecognizer class]]) {
UITapGestureRecognizer *tgr = (UITapGestureRecognizer *)gestureRecognizer;
if ([tgr numberOfTapsRequired] == 1 &&
[tgr numberOfTouchesRequired] == 1) {
// If found then remove self from its targets/actions
[tgr removeTarget:self action:#selector(_handleOneFingerTap:)];
}
}
[super removeGestureRecognizer:gestureRecognizer];
}
- (void)_handleOneFingerTap:(UITapGestureRecognizer *)tgr
{
NSDictionary *userInfo = [NSDictionary dictionaryWithObject:tgr forKey:#"UITapGestureRecognizer"];
[[NSNotificationCenter defaultCenter] postNotificationName:#"TextViewOneFingerTapNotification" object:self userInfo:userInfo];
// Or I could have handled the action here directly ...
}
By doing this way, no matter when the textview changes its gesture recognizers, we will always catch the tap gesture recognizer we want → Hence, our handler method will be called accordingly :)
Conclusion:
If you want to add a gesture recognizers to the UITextView, you have to check the text view does not have it already.
If it does not have it, just do the regular way. (Create your gesture recognizer, set it up, and add it to the text view) and you are done!.
If it does have it, then you probably need to do something similar as above.
Old Answer
I came up with this answer by swizzling a private method because previous answers have cons and they don't work as expected. Here, rather than modifying the tapping behavior of the UITextView, I just intercept the called method and then call the original method.
Further Explanation
UITextView has a bunch of specialized UIGestureRecognizers, each of these has a target and a action but their target is not the UITextView itself, it's an object of the forward class UITextInteractionAssistant. (This assistant is a #package ivar of UITextView but is forward definition is in the public header: UITextField.h).
UITextTapRecognizer recognizes taps and calls oneFingerTap: on the UITextInteractionAssistant so we want to intercept that call :)
#import <objc/runtime.h>
// Prototype and declaration of method that is going be swizzled
// When called: self and sender are supposed to be UITextInteractionAssistant and UITextTapRecognizer objects respectively
void proxy_oneFingerTap(id self, SEL _cmd, id sender);
void proxy_oneFingerTap(id self, SEL _cmd, id sender){
[[NSNotificationCenter defaultCenter] postNotificationName:#"TextViewOneFinderTap" object:self userInfo:nil];
if ([self respondsToSelector:#selector(proxy_oneFingerTap:)]) {
[self performSelector:#selector(proxy_oneFingerTap:) withObject:sender];
}
}
...
// subclass of UITextView
// Add above method and swizzle it with.
- (void)doTrickForCatchingTaps
{
Class class = [UITextInteractionAssistant class]; // or below line to avoid ugly warnings
//Class class = NSClassFromString(#"UITextInteractionAssistant");
SEL new_selector = #selector(proxy_oneFingerTap:);
SEL orig_selector = #selector(oneFingerTap:);
// Add method dynamically because UITextInteractionAssistant is a private class
BOOL success = class_addMethod(class, new_selector, (IMP)proxy_oneFingerTap, "v#:#");
if (success) {
Method originalMethod = class_getInstanceMethod(class, orig_selector);
Method newMethod = class_getInstanceMethod(class, new_selector);
if ((originalMethod != nil) && (newMethod != nil)){
method_exchangeImplementations(originalMethod, newMethod); // Method swizzle
}
}
}
//... And in the UIViewController, let's say
[textView doTrickForCatchingTaps];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(textViewWasTapped:) name:#"TextViewOneFinderTap" object:nil];
- (void)textViewWasTapped:(NSNotification *)noti{
NSLog(#"%#", NSStringFromSelector:#selector(_cmd));
}
You need to assign the UITextView instance.delegate = self (assuming you want to take care of the events in the same controller)
And make sure to implement the UITextViewDelegate protocol in the interface... ex:
#interface myController : UIViewController <UITextViewDelegate>{
}
Then you can implement any of the following
- (BOOL)textViewShouldBeginEditing:(UITextView *)textView;
- (BOOL)textViewShouldEndEditing:(UITextView *)textView;
- (void)textViewDidBeginEditing:(UITextView *)textView;
- (void)textViewDidEndEditing:(UITextView *)textView;
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text;
- (void)textViewDidChange:(UITextView *)textView;
- (void)textViewDidChangeSelection:(UITextView *)textView;
I'm using a textview as a subview of a larger view. I need the user to be able to scroll the textview, but not edit it. I want to detect a single tap on the textview's superview, including on the textview itself.
Of course, I ran into the problem that the textview swallows up the touches that begin on it. Disabling user interaction would fix this, but then the user won't be able to scroll the textview.
My solution was to make the textview editable and use the textview's shouldBeginEditing delegate method to detect a tap in the textview. I simply return NO, thereby preventing editing, but now I know that the textview (and thus the superview) has been tapped. Between this method and the superview's touchesEnded method I have what I need.
I know that this won't work for people who want to get access to the actual touches, but if all you want to do is detect a tap, this approach works!
How about make a UIScrollView and [scrollView addSubview: textview] which makes it possible to scroll textview?
You can also send a Touch Down event. Wire-up this event through the Interface Builder.
Then add code in your event handler
- (IBAction)onAppIDTap:(id)sender {
//Your code
}