UILongPressGestureRecognizer gets called twice when pressing down

I am detecting if the user has pressed down for 2 seconds:


UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc]
initWithTarget:self
action:@selector(handleLongPress:)];
longPress.minimumPressDuration = 2.0;
[self addGestureRecognizer:longPress];
[longPress release];

This is how I handle the long press:

-(void)handleLongPress:(UILongPressGestureRecognizer*)recognizer{
NSLog(@"double oo");
}

The text "double oo" gets printed twice when I press down for longer than 2 seconds. Why is this? How can I fix?

your gesture handler receives call for each state of gesture. so you need to put a check for each state and put your code in required state.

One must prefer using switch-case over if-else :

UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc]
initWithTarget:self
action:@selector(handleLongPress:)];
longPress.minimumPressDuration = 1.0;
[myView addGestureRecognizer:longPress];
[longPress release];

------------

-(void)handleLongPress:(UILongPressGestureRecognizer *)gesture {
switch(gesture.state){
case UIGestureRecognizerStateBegan:
NSLog(@"State Began");
break;
case UIGestureRecognizerStateChanged:
NSLog(@"State changed");
break;
case UIGestureRecognizerStateEnded:
NSLog(@"State End");
break;
default:
break;
}
}

Here's how to handle it in Swift:

func longPress(sender:UILongPressGestureRecognizer!) {

if (sender.state == UIGestureRecognizerState.Ended) {
println("Long press Ended");
} else if (sender.state == UIGestureRecognizerState.Began) {
println("Long press detected.");
}
}

UILongPressGestureRecognizer is a continuous event recognizer. You have to look at the state to see if this is the start, middle or end of the event and act accordingly. i.e. you can throw away all events after the start, or only look at movement as you need. From the [Class Reference][1]:

> Long-press gestures are continuous. The gesture begins (UIGestureRecognizerStateBegan) when the number of allowable fingers (numberOfTouchesRequired) have been pressed for the specified period (minimumPressDuration) and the touches do not move beyond the allowable range of movement (allowableMovement). The gesture recognizer transitions to the Change state whenever a finger moves, and it ends (UIGestureRecognizerStateEnded) when any of the fingers are lifted.


[1]:

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Now You Can Track The State Like This

- (void)handleLongPress:(UILongPressGestureRecognizer*)sender {
if (sender.state == UIGestureRecognizerStateEnded) {
NSLog(@"UIGestureRecognizerStateEnded");
//Do Whatever You want on End of Gesture
}
else if (sender.state == UIGestureRecognizerStateBegan){
NSLog(@"UIGestureRecognizerStateBegan.");
//Do Whatever You want on Began of Gesture
}
}

<h2>Just try this:</h2>

**Objective-C**

- (void)handleLongPress:(UILongPressGestureRecognizer*)sender {
if (sender.state == UIGestureRecognizerStateEnded) {
NSLog(@"Long press Ended");
} else if (sender.state == UIGestureRecognizerStateBegan) {
NSLog(@"Long press detected.");
}
}

**Swift 2.2:**

func handleLongPress(sender:UILongPressGestureRecognizer) {

if (sender.state == UIGestureRecognizerState.Ended) {
print("Long press Ended");
} else if (sender.state == UIGestureRecognizerState.Began) {
print("Long press detected.");
}
}

To check the state of the UILongPressGestureRecognizer just add an if statement on the selector method:

- (void)handleLongPress:(UILongPressGestureRecognizer *)sender {
if (sender.state == UIGestureRecognizerStateEnded) {
NSLog(@"Long press Ended");
} else if (sender.state == UIGestureRecognizerStateBegan) {
NSLog(@"Long press detected.");
}
}

Swift 3.0:

func handleLongPress(sender: UILongPressGestureRecognizer) {

if sender.state == .ended {
print("Long press Ended")
} else if sender.state == .began {
print("Long press detected")
}

You need to check the correct state, since there are different behaviors for each state. Most likely you're going to need the `UIGestureRecognizerStateBegan` state with the `UILongPressGestureRecognizer`.

UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc]
initWithTarget:self
action:@selector(handleLongPress:)];
longPress.minimumPressDuration = 1.0;
[myView addGestureRecognizer:longPress];
[longPress release];

...

- (void)handleLongPress:(UILongPressGestureRecognizer *)gesture {
if(UIGestureRecognizerStateBegan == gesture.state) {
// Called on start of gesture, do work here
}

if(UIGestureRecognizerStateChanged == gesture.state) {
// Do repeated work here (repeats continuously) while finger is down
}

if(UIGestureRecognizerStateEnded == gesture.state) {
// Do end work here when finger is lifted
}
}