I would like to detect when a user makes a swipe gesture, and detect it's direction (left, right, up or down). I need to detect it not when the gesture is finished, but just when the iPhone knows the direction, even if it's not finished.
I am using XCode 5, and designing for iPhone 5 with iOS 7.
I would like to know the code that I have to paste to the .h, and to the .m, and if I have to drag and drop any item to the mainView.
If you want to know the direction when the gesture is not finished you would probably need the UIPanGestureRecognizer and detect the direction using the velocityInView: method.
in the *.h file:
#interface ViewController : UIViewController
#property (nonatomic, strong) UIPanGestureRecognizer *recognizer;
#end
in the *.m file:
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
self.recognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(panGesture:)];
[self.view addGestureRecognizer:self.recognizer];
}
-(void)panGesture:(UIPanGestureRecognizer *)sender
{
NSLog(#"Velocity: %#", NSStringFromCGPoint([sender velocityInView:self.view]));
// Here You need to determine the direction
}
#end
From Docs:
Gestures are either discrete or continuous. A discrete gesture, such
as a tap, occurs once. A continuous gesture, such as pinching, takes
place over a period of time. For discrete gestures, a gesture
recognizer sends its target a single action message. A gesture
recognizer for continuous gestures keeps sending action messages to
its target until the multitouch sequence ends,
So if you need to "detect it not when the gesture is finished, but just when the iphone knows the direction, even if it's not finished" you could not use UISwipeGestureRecognizer since it is a discrete one. You should use UIPanGestureRecognizer and analyse it is results to check is there a swipe gesture or not.
To have a good example how it works, you can download a sample code provided by Apple:
https://developer.apple.com/library/ios/samplecode/SimpleGestureRecognizers/Introduction/Intro.html#//apple_ref/doc/uid/DTS40009460
Hope that helps ;)
You can easily get using UISwipeGestureRecognizers property directions...
After :----
UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:#selector(swipeRight)];
swipeRight.direction = UISwipeGestureRecognizerDirectionRight;
[self.yourView addGestureRecognizer:swipeRight];
UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:#selector(swipeLeft)];
swipeRight.direction = UISwipeGestureRecognizerDirectionLeft;
[self.gifWebView addGestureRecognizer:swipeLeft];
-(void)swipeRight{
//Do whatever you want
}
-(void)swipeLeft{
//Do whatever you want
}
And For Before Swipe you can use UIPanGestureRecognizer
I hope it help you
Swipe gestures are very quick. Swipe gesture recognizers are designed to fire once, not continuously. I don't think you will be able to get information about a swipe gesture that is "in flight" very easily.
If this is urgent, you will probably have to create a custom subclass of swipe gesture recognizer and add additional logic and delegate messages that would notify the delegate once the gesture recognizer decides that it has detected a swipe. That is way beyond your current skill level however.
Related
I'm trying to add a very simple swipe up gesture to one of my views. The gesture does not work at all unless I apply an outward/opposite pinch gesture with two of my fingers. I am creating the gesture connections via IB. I have set up the gesture properties to Swipe: Down and Touches: 1. However it will only work with a 2 finger outward pinching motion? What is going on? Thanks.
Edit:
Ok, I've tried coding it out rather than using interface builder and I'm getting the same results. Here is the code I'm using
UISwipeGestureRecognizer *swipeUpOnVideoView = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:#selector(SwipeUp:)];
swipeUpOnVideoView.direction = UISwipeGestureRecognizerDirectionUp;
swipeUpOnVideoView.numberOfTouchesRequired = 1;
[self.playerView addGestureRecognizer:swipeUpOnVideoView];
As you can see I am specifically designating only 1 touch, however my SwipeUp: method will only execute if I use an outward pinching motion with two fingers???
check this it working proper in my application:
UISwipeGestureRecognizer *swipeUp = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(swipeUp:)];
[swipeUp setDirection:UISwipeGestureRecognizerDirectionUp ];
[self.view addGestureRecognizer:swipeUp];
- (IBAction)swipeUp:(UISwipeGestureRecognizer *)recognizer
{
// do you stuff here
}
May be it will help you.
Happy coding...:)
It turned out I had a number of other UITapGestureRecognizers that were on my Xib file. Even though I wasn't calling them in the code anywhere they were associated with views on my page via the connections inspector. For some reason this interference made it so that my single finger swipeGesture would only register if I used a two finger pinching motion.
Deleting multiple UITapGestureRecognizers from my xib and then writing the code for the UISwipeGestureRecognizer programmatically fixed the problem for me.
I am developing an app and I want to scroll through different UIViewControllers with a UISwipeGestureRecognizer.
Everything works, but there is one thing where I couldn't find a solution for.
I add the UIGestureRecognizers like this
- (void)viewDidLoad {
[super viewDidLoad];
UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(swipeLeft)];
[swipeLeft setDirection:UISwipeGestureRecognizerDirectionLeft];
[self.view addGestureRecognizer:swipeLeft];
UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(swipeRight)];
[swipeRight setDirection:UISwipeGestureRecognizerDirectionRight];
[self.view addGestureRecognizer:swipeRight];
}
Now I want to know if it is possible to except a part of the self.view where it is possible to swipe to a different view.
I want to do this around a UISwitch.
Can someone please help me?
Best regards,
Lukas Goes
You can use another UIView and add it to self.view. Those UISwipeGestureRecognizer won't work inside that UIView.
Add another UISwipeGestureRecognizer to the switch, and, on your original swipe gesture recognisers, call requireGestureRecognizerToFail: on the switch's new recognizer.
Hope that makes sense, it's such a verbose class... :\
I suggest you to use the delegate method of a gesture recognizer : gestureRecognizer:shouldReceiveTouch:.
In the touch parameter, you have many information, like the position in the screen. You can use this position and test if it is above the switch frame. Return yes or no depending of if you want to trigger the selector associated to the gesture recognizer or not.
Which gesture am I looking to capture if I want to detect when the user slides his/her finger upwards (think of scrubbing through a song, that kind of motion, but up) and adjust a setting as a result (I don't want to use a UISlider).
What would you guys recommend for this? Is that a pan gesture recognizer or a swipe?
Try this:
UISwipeGestureRecognizer *swipeRecognizer =
[[UISwipeGestureRecognizer alloc]
initWithTarget:self
action:#selector(swipeDetected)];
swipeRecognizer.direction = UISwipeGestureRecognizerDirectionUp;
[self.view addGestureRecognizer:swipeRecognizer];
A swipe is one-time simple motion; observe that it happened, and you respond afterwards. A pan gesture is a continuous movement that you want to able to track while it happens. Which of those do you want?
I'd like to code my own tap gesture recognizer, to detect the number of taps and number of touches (I don't want to use the iOS tap gesture recognizer because I want to extend it later in various other manners) ;
I tried the following : use the first motionBegin number of touches as the numberOfTouches of the tap, increment the numberOfTaps, and start the tap detection timer to detect the tap gesture if no new taps has been seen in a while
The problem is that one quickly realises that when doing a double-touch tap gesture, iOS either correctly detects one motionBegin with a double touch, or two quick one touch events. I guess a correct implementation should try to detect those quick one touch events that happen closely, but I'm wondering if there is a better way to implement the gesture recognizer.
Someone knows how the iOS tap gesture is implemented?
1. Add UIGestureRecognizerDelegate in your .h file. like
#interface finalScreenViewController : UIViewController <UIGestureRecognizerDelegate>
{
// do your stuff
}
2. Create a view in your viewDidLoad method (or any other method) you wanna to add the gesture in your .m file
ex
UIView * myView=[[UIView alloc]init];
myView.frame=CGRectMake(0,0.self.view.frame.size.width,self.view.frame.size.height);
[self.view addSubView: myView];
UITapGestureRecognizer *letterTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapMethod:)];
letterTapRecognizer.numberOfTapsRequired = 1;
[myView addGestureRecognizer:letterTapRecognizer];
3. you can get view by
- (void) tapMethod:(UITapGestureRecognizer*)sender {
UIView *view = sender.view;
NSLog(#"%d", view.tag);//By tag, you can find out where you had tapped.
}
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.