How do own Gesture Recognizer Swipe - ios

Question

I've a question.. I would like to do my own gesture recognizer with swipe and that you drag (or swipe) down with two fingers but I don't now how..
This is my code of GestureSwipe.h:
#import <UIKit/UIKit.h>
#interface GestureSwipe : UIGestureRecognizer
#property CGPoint startTouchPosition;
#property(nonatomic) NSUInteger numberOfTouchesRequired;
#property(nonatomic) UISwipeGestureRecognizerDirection direction;
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;
#end
This is my code of GestureSwipe.m:
#define VERT_SWIPE_DRAG_MAX 7
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *aTouch = [touches anyObject];
// startTouchPosition is a property
self.startTouchPosition = [aTouch locationInView:self.view];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *aTouch = [touches anyObject];
CGPoint currentTouchPosition = [aTouch locationInView:self.view];
// Check if direction of touch is horizontal and long enough
if (fabsf(self.startTouchPosition.y - currentTouchPosition.y) <=
VERT_SWIPE_DRAG_MAX)
{
// If touch appears to be a swipe
if (self.startTouchPosition.y < currentTouchPosition.y) {
[self myProcessDownSwipe:touches withEvent:event];
}
self.startTouchPosition = CGPointZero;
}
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
self.startTouchPosition = CGPointZero;
}
-(void)myProcessDownSwipe:(NSSet *)touches withEvent:(UIEvent *)event {
}
How should I do to do swipe down with two fingers?
Then I have other VC where recognize my own gesture:
HelloViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
//newGesture = [[GestureSwipe alloc] init];
newGesture = [[GestureSwipe alloc] initWithTarget:self action:#selector(showImage:)];
newGesture.numberOfTouchesRequired = 2;
}

Answer 1

In HelloViewController you'd add something like this:
UISwipeGestureRecognizer *recognizer;
recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(handleSwipe:)];
// Set the acceptable swipe direction and number of touches required to do the gesture
[recognizer setDirection:(UISwipeGestureRecognizerDirectionDown)];
recognizer.numberOfTouchesRequired = 2;
// Add the gesture recogizer to the view
[self.view addGestureRecognizer:recognizer];
Then you would create a custom method (I called my one handleSwipe:, but this can be whatever suits you best) and do what you need to do.
EDIT: So your viewDidLoad method would look like this
- (void)viewDidLoad
{
[super viewDidLoad];
UISwipeGestureRecognizer *recognizer;
recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(handleSwipe:)];
// Set the acceptable swipe direction and number of touches required to do the gesture
[recognizer setDirection:(UISwipeGestureRecognizerDirectionDown)];
recognizer.numberOfTouchesRequired = 2;
// Add the gesture recogizer to the view
[self.view addGestureRecognizer:recognizer];
}
And the handleSwipe: method could be like this:
-(void)handleSwipe:(id)sender{
// Do something
}

Answer 2

There is no need to create your own recognizer. You can handle this with a standard recognizer and just state how many touches is required.
A good example can be found here: Capture only UIView 2 finger UIPanGestureRecognizer