It is similar to this question:
iPhone iOS how to add a UILongPressGestureRecognizer and UITapGestureRecognizer to the same control and prevent conflict?
but my problem is more complex.
I want to implement the same behavior you see in iOS 8 on iPad. I mean page grid in Safari.
The problem: one view should respond to both long press and tap gesture recognizers. The following things should work:
1)close button accepts clicks
2)when the tap begins the selected view should perform scale animation
3)on long press the selected view becomes draggable
If I don't use (requireGestureRecognizerToFail:) then tap gesture doesn't work. If I use this method then everything works but the long press events take place with huge delays.
How to solve this issue.
You need to use the requireGestureRecognizerToFail method.
//Single tap
UITapGestureRecognizer *tapDouble = [[UITapGestureRecognizer alloc]
initWithTarget:self
action:#selector(handleTapGestureForSearch:)];
tapDouble.numberOfTapsRequired = 1;
tapDouble.delegate = self;
[self addGestureRecognizer:tapDouble];
//long press
UILongPressGestureRecognizer *longPressGestureRecognizer=[[UILongPressGestureRecognizer alloc]initWithTarget:self action:#selector(handleLongPressRecognizer:)];
longPressGestureRecognizer.numberOfTouchesRequired=1;
longPressGestureRecognizer.minimumPressDuration = 0.5f;
[longPressGestureRecognizer requireGestureRecognizerToFail:tapDouble];
longPressGestureRecognizer.delegate = self;
[self addGestureRecognizer:longPressGestureRecognizer];
This means Long press gesture wait for the single Tap.
You can add time to the long press gesture.
UILongPressGestureRecognizer *longPressGesture=[[UILongPressGestureRecognizer alloc]initWithTarget:self action:#selector(ontappLongPressGesture:)];
longPressGesture.minimumPressDuration=0.6;
longPressGesture.delegate=self;
[cell.view addGestureRecognizer:longPressGesture];
UITapGestureRecognizer *gesture=[[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(cellSelected:)];
//[gesture requireGestureRecognizerToFail:longPressGesture];
gesture.delegate=self;
[cell.view addGestureRecognizer:gesture];
also you need to set this delegate to work both gesture together
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
Related
I've a scrollview on which one button is added, now I want to give action as well as double tap gesture to the button.
If the button is on UIView, both action of the button and double tap gesture methods work perfectly. But if the button is present on UIScrollView then action gets called followed by double tap gesture method.
Any help will be appreciated.
The scroll view needs a fair amount of touch logic to track, and that must be getting confused with the button's touch logic and your gesture recognizer.
Without investigating that further, I'd get around this by handling the button's taps via two gesture recognizers that you control, which should work no matter the parent view.
Do not give the button a target/action as you normally would in IB or in code
Create a single tap gesture recognizer to handle the button action.
Create a double tap gr as you probably do already. Add both to the button.
// for your current target-action behavior
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(singleTap:)];
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(doubleTap:)];
singleTap.numberOfTapsRequired = 1;
doubleTap.numberOfTapsRequired = 2;
[singleTap requireGestureRecognizerToFail:doubleTap];
[button addGestureRecognizer:singleTap];
[button addGestureRecognizer:doubleTap];
Then, instead of your IBAction method...
- (void)singleTap:(UIGestureRecognizer *)gr {
if (gr.state == UIGestureRecognizerStateRecognized) {
// target-action behavior here
NSLog(#"single tapped");
}
}
- (void)doubleTapped:(UIGestureRecognizer *)gr {
if (gr.state == UIGestureRecognizerStateRecognized) {
NSLog(#"double tapped");
}
}
I have set two UITapGestureRecognizers in my xib on a UIImageView. I have also set their IBAction in the associated header file.
For the single tap gesture recognizer, I set taps and touches to 1, state to Enabled, and delayed touches ended to YES in the Attributes inspector.
For the double tap gesture recognizer, I set taps and touches to 2, state to Enabled, cancel touches in view to YES and delay touches ended to YES.
When I double tap on the UIImageView, it only triggers the IBAction method for the single tap. So, I decided to print the imageview.gestureRecognizer and it shows the UITapGestureRecognizer for single tap's state as Ended and the UITapGestureRecognizer for double tap's state as Possible.
I have been stuck on this for a couple hours. I found ways to do it programatically but I was wondering how I can do it by setting it in the xib itself.
Any help would be great! Thank you in advance for your responses!
It's a very good question. If you add gestures to code like this
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget: self action:#selector(singleTap)];
singleTap.numberOfTapsRequired = 1;
[self.view addGestureRecognizer:singleTap];
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget: self action:#selector(doubleTap)] ;
doubleTap.numberOfTapsRequired = 2;
[self.view addGestureRecognizer:doubleTap];
[singleTap requireGestureRecognizerToFail:doubleTap];
And all works fine because you canceled first gesture here
[singleTap requireGestureRecognizerToFail:doubleTap];
If you add two gestures in xib you always should cancel single tap if there was a double tap. And you always need to use 2 properties for gestures and use
[self.firstGestureProperty requireGestureRecognizerToFail:self.secondGestureOroperty];
For single tap:
For double tap:
Source code:
And everything works fine.
I am trying to have a UISwipeGestureRecognizer that is attached to a webview. This works, but I need to also be able to scroll up and down the web view.
Here is my code:
UISwipeGestureRecognizer *upSwipeGesture = [[UISwipeGestureRecognizer alloc]
initWithTarget:self action:#selector(tapAction)];
upSwipeGesture.direction = UISwipeGestureRecognizerDirectionUp;
upSwipeGesture.cancelsTouchesInView = NO;
[self.view addGestureRecognizer:upSwipeGesture];
[webView.scrollView.panGestureRecognizer requireGestureRecognizerToFail:upSwipeGesture];
If I comment out the last line, then the webview scrolls but the gesture is not recognized. If I do not comment out the last line, then the gesture is recognized but the webview does not scroll.
I would like to be able to scroll and have the gesture be recognized. Any ideas? Thanks!
UIWebView has its own private views, which also has gesture recognizers attached. Hence, precedence rules keep any gesture recognizers added to a UIWebView from working properly.
One option is to implement the UIGestureRecognizerDelegate protocol and implement the method gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer. Return YES from this method for other tap gestures.
This way you'll get your tap handler called, and the web view will still get its called.
Try this,
UISwipeGestureRecognizer *upSwipeGesture = [[UISwipeGestureRecognizer alloc]
initWithTarget:self action:#selector(tapAction)];
upSwipeGesture.direction = UISwipeGestureRecognizerDirectionUp;
upSwipeGesture.cancelsTouchesInView = NO;
upSwipeGesture.delegate=self;
[self.view addGestureRecognizer:upSwipeGesture];
ind implement this delegate method,
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
return YES;
}
I have a uiwebview inside the uipageviewcontroller, I want to be able to select some text in the view so I have userInteractionEnabled set to YES, but when I do that I loose the option of turning the page by tapping, although swiping still works fine.
What's the best way to trap the UITapReconizer on the UIWebview and pass it on to the UIPageviewController?
Thanks.
UIPageviewController has a gestureRecognizers property
My guess is that one if its gesture recognizer and yours - if your using one - can't act simultaneously.
You could handle that through the gestures' methods, see question for handling multiple UITapGestureRecognizers, requiring your webView tap recognizer to fail for pageViewController's tap to succeed.
Like this (not tested)
UILongPressGestureRecognizer *yourTapGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(handleLongPress:)];
for(UIGesture *gesture in yourPageController.gestureRecognizers){
[gesture requireGestureRecognizerToFail:yourTapGesture];
}
[pageControllerTap requireGestureRecognizerToFail:yourTapGesture];
Also, I don't understand why you need userInteractionEnabled, is your UIWebView taking all space ? You could attach the gesture to webView's superview, and test webView-hit with locationInView: method.
I've sorted it.
I've added a gesture recogniser to the controller generating the uiwebview:
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc]
initWithTarget:self action:#selector(handleGesture:)];
tapRecognizer.numberOfTapsRequired = 1;
tapRecognizer.delegate = self;
[webView addGestureRecognizer:tapRecognizer];
With
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
return NO;
}
And adding in the pageviewController:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}
I'm displaying a document in a UIWebView. I want to place a hotspot over the document to trigger an action when it is tapped, but I also want to maintain the default UIWebView behavior of auto-zooming the document when it is double-tapped. I can't figure out how to respond to the single-taps while letting the UIWebView respond to the double-taps.
I first set up the hotspot as a transparent UIButton with an action, but double-tapping the hotspot resulted in the hotspot action being called twice. So I removed the action from the button and attached a single-tap gesture instead:
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(singleTapAction:)];
singleTap.numberOfTapsRequired = 1;
singleTap.delegate = self;
[self.hotspot addGestureRecognizer:singleTap];
[singleTap release];
This works the same as the normal button action. But then I created a double-tap gesture, and configured it to block the single-tap gesture with requireGestureRecognizerToFail:
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(zoomWebView:)];
doubleTap.numberOfTapsRequired = 2;
doubleTap.delegate = self;
[self.hotspot addGestureRecognizer:doubleTap];
[doubleTap release];
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(singleTapAction:)];
singleTap.numberOfTapsRequired = 1;
[singleTap requireGestureRecognizerToFail:doubleTap];
singleTap.delegate = self;
[self.hotspot addGestureRecognizer:singleTap];
[singleTap release];
- (void)zoomWebView:(UITapGestureRecognizer *)gesture {
NSLog(#"double tap");
}
With this setup, a single-tap on the hotspot calls singleTapAction and a double-tap on the hotspot calls zoomWebView (a custom method). This is good because singleTapAction is no longer called twice, but bad because the UIWebView no longer responds to the double-tap.
I tried forwarding the double-tap event from my doubleTap gesture to the UIWebView by subclassing UITapGestureRecognizer, overriding the touchesBegan and touchesEnded methods, and sending their arguments on to the corresponding methods of the UIWebView. When I did that, I could see that my subclass was receiving the events, but the UIWebView didn't respond to the forwarded events. This is to be expected because the Event Handling Guide for iOS says that we can only forward events to custom subclasses of UIView, not to UIKit framework objects.
Is there a way to prevent my single-tap gesture from responding to double-taps that doesn't divert the double-tap events? This seems like a basic requirement, but I can't see a straightforward way to do it. I read about and experimented with UIGestureRecognizer's touch delivery properties, but no combination of values stopped the single-tap gesture from consuming the double-tap gesture.
By the way, the relationship between the hotspot and the UIWebView in my view hierarchy is that of "cousins" -- they are subviews of two sibling views. If I add the gesture recognizers to hotspot view, the web view or their "grandparent" view, I get the same results.
Okay, I found a solution in two parts:
1) I had to add my gestures to a parent view of the UIWebView. Unmatched events don't travel through overlapping objects in a view from layer to layer as I was imagining. Instead, they travel through the hierarchy of views from child to parent. So as long as I was adding my double-tap gesture to a sibling or "cousin" view of the UIWebView, it was never going to proceed on to the web view. This means that I can't use buttons or views laid out in Interface Builder to determine multiple hotspot areas. Instead, I have to redirect all single-tap events to one method and then look at the touch positions to determine what action to trigger.
2) I had to add the gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer: method to my view controller (the delegate of my gestures) and return YES. This allows my single-tap gesture to respond even when I'm displaying HTML, text or image content in the UIWebView, which implements its own gesture for these content types. I learned this part from this answer.
With these changes, I understand the hierarchy of events to be:
Single-tap web view: my single-tap gesture on the web view's parent view responds; the web view's single-tap gesture also responds if applicable because simultaneous gestures are enabled
Double-tap web view: my double-tap gesture on the web view's parent view responds (but doesn't do anything); my single-tap gesture does not respond because it is configured to only respond if the double-tap fails; the web view's double-tap event also responds because it is part of the view hierarchy (it seems that the double-tap functionality of the web view does not use a gesture because otherwise it would have take precedence over my own gesture in my original setup)
With that explanation out of the way, here's some working code:
- (void)viewDidLoad {
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(doubleTapWebView:)];
doubleTap.numberOfTapsRequired = 2;
doubleTap.delegate = self;
[self.webViewParent addGestureRecognizer:doubleTap];
[doubleTap release];
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(singleTapWebView:)];
singleTap.numberOfTapsRequired = 1;
[singleTap requireGestureRecognizerToFail:doubleTap];
singleTap.delegate = self;
[self.webViewParent addGestureRecognizer:singleTap];
[singleTap release];
}
- (void)doubleTapWebView:(UITapGestureRecognizer *)gesture {
NSLog(#"double-tap");
// nothing to do here
}
- (void)singleTapWebView:(UITapGestureRecognizer *)gesture {
NSLog(#"single-tap");
CGPoint touchLocation = [gesture locationInView:self.webViewParent];
float x = touchLocation.x;
float y = touchLocation.y;
CGRect frame = self.webViewParent.frame;
if (y < frame.size.height * .33) {
NSLog(#"top");
} else if (y > frame.size.height * .67) {
NSLog(#"bottom");
} else if (x < frame.size.width * .33) {
NSLog(#"left");
} else if (x > frame.size.width * .67) {
NSLog(#"right");
} else {
NSLog(#"center");
}
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}
Always been a problem with mouse clicks since event handling began.
It's impossible at the instance of a single click, for any software to determine that a double click is about to happen.
So, if you want to handle single clicking and double clicking, you'll have to do your own double click handling.
Time the instances of single click, and generate a double click event of your own.
Hopefully that can transfer to tapping in your context.