Related
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
I want to be able to recognise ALL touches in an interface, no matter what was touched.
I've tried:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
.. but this just recognises when the user taps on something that doesn't respond to taps (uiimages for instance)
The reason i need this ability is that I want to kick in a slide show if the user doesn't touch the screen for 5 minutes, so I want to reset the timer whenever they touch. It seems wrong to put this reset code in each UI event individually.
There are several possible solutions, but as said #omz - overriding the sendEvent: it is the best one.
#interface YourWindow : UIWindow {
NSDate timeOfLastTouch;
}
#end
#implementation YourWindow
- (void)sendEvent:(UIEvent *)event {
[super sendEvent:event];
NSSet *touches = [event allTouches];
UITouch *touch = [touches anyObject];
if( touch.phase == UITouchPhaseEnded ){
timeOfLastTouch = [NSDate date];
}
}
#end
Do not forget replace UIWindow with YourWindow.
You could subclass UIWindow and override the sendEvent: method.
you could use a tap gesture
In your interface add the UIGestureRecognizerDelegate
#interface ViewController : UIViewController <UIGestureRecognizerDelegate> {
then in your viewDidLoad add this
UITapGestureRecognizer *tapped = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapMethod)];
tapped.delegate=self;
tapped.numberOfTapsRequired = 1;
[self.view addGestureRecognizer:tapped];
then do your timer code in the tapped method
-(void)tapped {
//timer code
}
Make sure you UI elements have setUserInteractionEnabled:YES
You can subclass the UIWindow and override the sendEvent: method like this:
- (void)sendEvent:(UIEvent *)event {
if (event.type == UIEventTypeTouches) {
// You got a touch, do whatever you like
};
[super sendEvent:event]; // Let the window do the propagation of the event
}
As #Alladinian said in one of the comments, iOS Reference Documentation mentions that subclassing UIApplication is the right application and thus, seems preferred to subclassing UIWindow. cf. https://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIApplication_Class/Reference/Reference.html :
You might decide to subclass UIApplication to override sendEvent: or
sendAction:to:from:forEvent: to implement custom event and action
dispatching.
I am handling touches for a couple of my UI components in my view controller (custom subclass of UIViewController). It has methods touchesBegan:withEvent:, touchesMoved:withEvent:, and touchesEnded:withEvent:. It was working fine. Then I added a scroll view (UIScrollView) as the top view in the hierarchy.
Now my touch handlers on the view controller don't work. They don't get called. The interesting thing is, I have various other UI components within the scroll view that do work. Some are buttons, some are custom views that define their own touchesBegan:withEvent:, etc. The only thing that doesn't work is the touch handlers on the view controller.
I thought maybe it's because the scroll view is intercepting those touches for its own purposes, but I subclassed UIScrollView and just to see if I could get it to work I am returning YES always from touchesShouldBegin:withEvent:inContentView: and NO always from touchesShouldCancelInContentView:. Still doesn't work.
If it makes a difference my view controller is within a tab bar controller, but I don't think it's relevant.
Has anyone had this problem and have a ready solution? My guess is the scroll view monkeys up the responder chain. Can I monkey it back? I guess if I can't figure anything else out I'll make the top level view under my scroll view be a custom view and forward the messages on to the view controller, but seems kludgy.
create a subclass of UIScrollView class and override the touchesBegan: and other touch methods as follows:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
// If not dragging, send event to next responder
if (!self.dragging){
[self.nextResponder touchesBegan: touches withEvent:event];
}
else{
[super touchesBegan: touches withEvent: event];
}
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
// If not dragging, send event to next responder
if (!self.dragging){
[self.nextResponder touchesMoved: touches withEvent:event];
}
else{
[super touchesMoved: touches withEvent: event];
}
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
// If not dragging, send event to next responder
if (!self.dragging){
[self.nextResponder touchesEnded: touches withEvent:event];
}
else{
[super touchesEnded: touches withEvent: event];
}
}
Well this worked, but I'm not sure I can "get away with it", since nextResponder is not one of the UIView methods you're "encouraged" to override in a subclass.
#interface ResponderRedirectingView : UIView {
IBOutlet UIResponder *newNextResponder;
}
#property (nonatomic, assign) IBOutlet UIResponder *newNextResponder;
#end
#implementation ResponderRedirectingView
#synthesize newNextResponder;
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
- (UIResponder *)nextResponder {
return self.newNextResponder;
}
- (void)dealloc
{
[super dealloc];
}
#end
Then in Interface Builder I made the direct subview of the scroll view one of these, and hooked up its newNextResponder to skip the scrollview and point directly to the view controller.
This works too, replacing the override of nextResponder with these overrides:
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[self.newNextResponder touchesBegan:touches withEvent:event];
}
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
[self.newNextResponder touchesMoved:touches withEvent:event];
}
- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[self.newNextResponder touchesEnded:touches withEvent:event];
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
[self.newNextResponder touchesCancelled:touches withEvent:event];
}
"It was working fine. Then I added a scroll view (UIScrollView) as the top view in the hierarchy."
is your scrollview on top of your contentview that contains items?
all your components should be in the scrollview and not the view behind the scrollview
user1085093's answer worked for me. Once you move the touch more than a small amount, however, it then gets interpreted as a Pan Gesture.
I overcame this by altering the behaviour of the Pan Gesture recogniser so it requires two fingers:
-(void)awakeFromNib
{
NSArray *gestureRecognizers = self.gestureRecognizers;
UIGestureRecognizer *gestureRecognizer;
for (gestureRecognizer in gestureRecognizers) {
if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {
UIPanGestureRecognizer *pgRecognizer = (UIPanGestureRecognizer*)gestureRecognizer;
pgRecognizer.minimumNumberOfTouches = 2;
}
}
}
The touchesBegan: etc methods will NEVER be called in a UIScrollView because it is a subclass of UIView and overrides these methods. check out the different UIScrollView methods available here. The work-around will depend on what you want to implement.
Is it possible to handle touch events in the key UIWindow in the app Delegate or anywhere else?
Any help would be appreciated please.
There is a handy catch-all method in UIWindow called sendEvent: which sees every event near the start of the event-handling pipeline. If you want to do any non-standard additional event handling, this is a good place to put it. Something like this:
- (void)sendEvent:(UIEvent *)event {
if ([self eventIsNoteworthy:event]) [self extraEventHandling:event];
[super sendEvent:event]; // Apple says you must always call this!
}
Docs: UIWindow class reference | iOS event delivery docs
This blog post also mentions how to override hitTest:withEvent: to catch some events before they're bound to the target leaf subview in the view hierarchy. You can also override that method on your UIWindow object if you want.
You will have to subclass UIWindow with your own class and override sendEvent: method. But remember that the method gets other types of events - not only touches so you have to check for event type (event.type == UIEventTypeTouches). Also since you get set of touches you might want to check which ones just began, which ones ended, moved etc. To do that you have to iterate through allTouches and check the phase property of every UITouch.
#implementation TouchWindow
- (void)sendEvent:(UIEvent *)event {
if (event.type == UIEventTypeTouches) {
for(UITouch * t in [event allTouches]) {
if(t.phase == UITouchPhaseBegan) {
/*
Paste your code here.
Inform objects that some touch has occurred.
It's your choice if you want to perform method/selector directly,
use protocols/delegates, notification center or sth else.
*/
}
}
}
[super sendEvent:event];
}
#end
Of course TouchWindow is subclass of UIWindow
#interface TouchWindow : UIWindow
#end
And you will probably have to change that class in your .xib file in XCode
UIWindow is a subclass of UIView, so you simply subclass it and use it in you AppDelegate:
self.window = [[MyWindow alloc] initWithFrame:CGRectMake(0,0,320,480)]; // Sorry for hard-coded frame size!
and in MyWindow you override -hitTest:withEvent: and/or -pointInside:withEvent:
UIWindow is a subclass of UIResponder, which has APIs for handling touch events (e.g., touchesBegan:withEvent:). It is possible then for you to subclass UIWindow, override the touch event handling APIs, and manage the touch events yourself.
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
}