UIPanGestureRecognizer not works on button - iphone

Question

I am facing problem with UIPanGestureRecognizer. suppose i am adding 10 button dynamicaly using diffrent tags when i add first button the try to drag it to other place then its works fine. and then if i add other button then try to drag that second button then even its works fine but if then i would lyk to drag first button then it not being draged and. and message shown in log is Ignoring call to [UIPanGestureRecognizer setTranslation:inView:] since gesture recognizer is not active.
gesture is working only on recently added button. below is the code that i am using
Here is code to add buttons
NSUInteger counter = 1;
if([ButtonArray count] !=0 ){
NSLog(#"%d",[ButtonArray count]);
NSLog(#"hi");
counter = [ButtonArray count] + 1;
}
[ButtonArray addObject:[NSString stringWithFormat:#"%d",counter]];
NSLog(#"%d",1);
UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[btn setTag:counter];
btn.frame = CGRectMake(80.0, 210.0, 160.0, 40.0);
//[btn addTarget:self action:#selector(Dragged:withEvent:) forControlEvents:UIControlEventTouchDragInside];
//[self.view addSubview:btn];
btn.userInteractionEnabled = YES;
gesture = [[UIPanGestureRecognizer alloc]
initWithTarget:self
action:#selector(labelDragged:)];
[btn addGestureRecognizer:gesture];
// add it
[self.view addSubview:btn];
here is code for gesture
UIButton *button = (UIButton *)gesture.view;
CGPoint translation = [gesture translationInView:button];
// move button
button.center = CGPointMake(button.center.x + translation.x,
button.center.y + translation.y);
// reset translation
[gesture setTranslation:CGPointZero inView:button];

Answer 1

I suspect the problem comes down to this:
gesture = [[UIPanGestureRecognizer alloc]
initWithTarget:self
action:#selector(labelDragged:)];
I tend to think from your code that gesture is some property in your class. In this case you are constantly overriding the old gesture when you create a new one. That would also explain the behavior you describe.
EDIT:
you do not strictly need to store your gesture recognizers in a property; it would be enough to do:
UIPanGestureRecognizer* localgesture = [[UIPanGestureRecognizer alloc]
initWithTarget:self
action:#selector(labelDragged:)];
[btn addGestureRecognizer:localgesture];
then, when the labelDragged method is called, you can use its recognizer argument to know which gesture recognizers fired:
- (void)labelDragged:(UIGestureRecognizer *)gestureRecognizer;