UIPanGestureRecognizer always move from location (0, 0) - ios

Question

I'd like to drag customView.
But, when I drag the customView, it always move from location (0, 0).
Please look at following image.
the red parts is the customView, and when I drag it, it move to the location.
How do I fix it to make move customView correctly?
I have this code.
labelview is the customView(subclass of UIView).
- (void)viewDidLoad
{
[super viewDidLoad];
_labelView = [[LabelView alloc]initWithFrame:CGRectMake(20, 60, 200, 100)];
UIPanGestureRecognizer* pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:#selector(panAction:)];
[_labelView addGestureRecognizer:pan];
[self.view addSubview:_labelView];
}
- (void)panAction:(UIPanGestureRecognizer *)sender
{
CGPoint p = [sender translationInView:self.view];
CGPoint movedPoint = CGPointMake(_labelView.center.x + p.x, _labelView.center.y + p.y);
sender.view.center = movedPoint;
[sender setTranslation:movedPoint inView:self.view];
}

Answer 1

While the other two answers are technically correct, they are not ideal solutions because when you add a gesture recognizer to self.view then anytime you drag anywhere in self.view you will drag your LabelView, but I imagine you only want to drag it when you actually have your finger on the LabelView itself.
So, just keep what you have, but change this one line:
[sender setTranslation:movedPoint inView:self.view];
to
[sender setTranslation:CGPointZero inView:self.view];

Answer 2

You have implemented the logic upside down. It has to be exactly other way around. Set the ´UIPanGestureRecognizer´ to UIViewController's view and set the center of your custom view.
- (void)viewDidLoad
{
[super viewDidLoad];
_labelView = [[LabelView alloc]initWithFrame:CGRectMake(20, 60, 200, 100)];
UIPanGestureRecognizer* pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:#selector(panAction:)];
// [_labelView addGestureRecognizer:pan]; must be removed
[self.view addGestureRecognizer:pan]; // must be added
[self.view addSubview:_labelView];
}
- (void)panAction:(UIPanGestureRecognizer *)sender
{
CGPoint p = [sender translationInView:self.view];
CGPoint movedPoint = CGPointMake(_labelView.center.x + p.x, _labelView.center.y + p.y);
[_labelView setCenter:movedPoint];
}

Answer 3

I solved by writing following code.
Thank you for answers.
- (void)viewDidLoad
{
[super viewDidLoad];
_labelView = [[LabelView alloc]initWithFrame:CGRectMake(20, 60, 200, 100)];
UIPanGestureRecognizer* pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:#selector(panAction:)];
[_labelView addGestureRecognizer:pan];
[self.view addSubview:_labelView];
}
- (void)panAction:(UIPanGestureRecognizer *)sender
{
CGPoint p = [sender translationInView:sender.view];
CGPoint movedPoint = CGPointMake(sender.view.center.x + p.x, sender.view.center.y + p.y);
sender.view.center = movedPoint;
[sender setTranslation:CGPointZero inView:sender.view];
}