I am using SWRevealViewController from John-Lluch. I need to use pan gesture to view the sidebars and I am using swipe to view my previous and next articles. However, the pan gesture can only be detected.
UPDATED: My swipe gesture worked if I disable my pan gesture.
Pan Gesture
[self.view addGestureRecognizer:self.revealViewController.panGestureRecognizer];
Swipe gesture
UISwipeGestureRecognizer *left = [[[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(swipeLeft:)] autorelease];
left.direction = UISwipeGestureRecognizerDirectionLeft;
UISwipeGestureRecognizer *right = [[[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(swipeRight:)] autorelease];
right.direction = UISwipeGestureRecognizerDirectionRight;
[self.view addGestureRecognizer:left];
[self.view addGestureRecognizer:right];
[self.view addGestureRecognizer:self.revealViewController.panGestureRecognizer];
[self.view addGestureRecognizer:left];
Notice the difference? Implement the SwipeGesture as a property in your .h or make it in your .xib and link it to your .h
It is difficult to handle both pan and swipe gesture recognizer simultaneously. You will have handle the SWRevealViewController delegates for pan gesture and also swipe gesture for the current viewcontroller.
As apple suggests to differentiate the gesture you could use the following method
- (BOOL) gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}
Excerpt from the Apple Documentation:
This method is called when recognition of a gesture by either
gestureRecognizer or otherGestureRecognizer would block the other
gesture recognizer from recognizing its gesture. Note that returning
YES is guaranteed to allow simultaneous recognition; returning NO, on
the other hand, is not guaranteed to prevent simultaneous recognition
because the other gesture recognizer's delegate may 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 a ViewController with a vertically scrolling collection view that takes up the entire view. I want to be able to get swipe and pan gestures on the entire collection view (not just on cells) but I can't get any gestures. I have tried adding the gesture recognizer to the view and the collection view but neither seem to work.
Adding the gesture recognizer to the view
self.panEdgeGesture = [[UIScreenEdgePanGestureRecognizer alloc] initWithTarget:self action:#selector(handlePan:)];
self.panEdgeGesture.delegate = self;
[self.collectionView addGestureRecognizer:self.panEdgeGesture];
[self.panEdgeGesture setEdges:UIRectEdgeRight];
Then I added these functions:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldReceiveTouch:(UITouch *)touch{
return YES;
}
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
return YES;
}
- (void)handlePan:(UISwipeGestureRecognizer *)sender
{
DebugLog(#"Received pan gesture");
}
Could the collection view cells stop the gesture events from triggering? They have no gestures themselves.
Per UIScreenEdgePanGestureRecognizer's Class Reference:
After creating a screen edge pan gesture recognizer, assign an
appropriate value to the edges property before attaching the gesture
recognizer to your view. You use this property to specify from which
edges the gesture may start. This gesture recognizer ignores any
touches beyond the first touch.
So change you code to:
self.panEdgeGesture = [[UIScreenEdgePanGestureRecognizer alloc];
[self.panEdgeGesture setEdges:UIRectEdgeRight];
initWithTarget:self action:#selector(handlePan:)];
self.panEdgeGesture.delegate = self;
[self.collectionView addGestureRecognizer:self.panEdgeGesture];
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;
}
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 2d map that the user can zoom and pan using the gesture recognizers. While it works, i want the user to start panning immediately after a zoom once they have 1 finger lifted. Unfortunately, in the docs it says:
The gesture ends (UIGestureRecognizerStateEnded) when both fingers
lift from the view.
which is pretending me from going from a pinch zoom to a pan right away. What could i do to fix this?
This is possible, and easy! It involves being your gesture recognizer's delegate. Something no-one seems to know exists. In my view controller subclass I have declared both conforming to the protocol <UIGestureRecognizerDelegate> and two ivars:
UIPinchGestureRecognizer *myPinchGR;
UIPanGestureRecognizer *myPanGR;
These ivars are instantiated in view did load. Notice setting self as the delegate.
-(void)viewDidLoad{
[super viewDidLoad];
myPanGR = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(panTarget:)];
myPanGR.delegate = self;
[self.view addGestureRecognizer:myPanGR];
myPinchGR = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(pinchTarget:)];
myPinchGR.delegate = self;
[self.view addGestureRecognizer:myPinchGR];
}
One of the delegate calls made by a UIGestureRecognizer is shouldRecognizeSimultaneouslyWithGestureRecognizer: if I had more than two gesture recognizers then this function would have to contain some logic. But since there are only two I can just return YES.
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
return YES;
}
Now you do have to include a little (very little) extra logic in your action methods to screen for the appropriate conditions.
-(void)panTarget:(UIPanGestureRecognizer *)panGR{
if (panGR.numberOfTouches > 1) return;
NSLog(#"panny");
}
-(void)pinchTarget:(UIPinchGestureRecognizer *)pinchGR{
if (pinchGR.numberOfTouches < 2) return;
NSLog(#"pinchy");
}
Run this code an look at the logs. you will see when you move one finger you will see "panny" when you place a second finger down you will see "pinchy", and back and forth.
Use this code inside the gesture handling method.
if (gesture.numberOfTouches != 2) {
// code here to end pinching
}
As Gesture handling method will be called immediately when user lift a finger while 2 finger pinching.