CODEWITHSUNDEEP
iosobjective-cgestureuipangesturerecognizerpan
user3403733
user3403733

Reputation: 79

How to use Pan Gestures

Im a beginner programmer with Xcode 5 and was attempting to write code to allow a user to move a image with input from the users touch.

So far, I believe that my code is correct but i believe I'm missing something as the UIImage refuses move. Although when attempt to test it with NSLog I don't get a response which shows it working. My guess it that I have to make a custom class for the image and if so would I do this and how would I link it.

For example

  @implementation StartPage
  - (IBAction)HandlePan:(UIGestureRecognizer *)sender; {
  NSLog(@"panning"); //Testing to check if the image moves when touched by user.

  CGPoint NetTranslation ;
  CGPoint Translation =
 [(UIPanGestureRecognizer *) sender translationInView: _Imageview ];

  sender.view.transform=CGAffineTransformMakeTranslation (

  NetTranslation.x += Translation.x,
  NetTranslation.y += Translation.y);
  enter code here
  if(sender.state == UIGestureRecognizerStateEnded)
  {
   NetTranslation.x += Translation.x;
   NetTranslation.y += Translation.y;
  }

}

Upvotes: 1

Views: 3066

Answers (3)

Mr.Javed Multani
Mr.Javed Multani

Reputation: 13294

For swift language we can do like this:

Take a view and set IBOutlet:

@IBOutlet weak var viewDrag: UIView!

var panGesture = UIPanGestureRecognizer()

Write this pretty code on viewDidLoad()

 panGesture = UIPanGestureRecognizer(target: self, action: #selector(self.draggedView(_:)))
    viewDrag.isUserInteractionEnabled = true
    viewDrag.addGestureRecognizer(panGesture)

This is method which is calling while gesture recognized

 @objc func draggedView(_ sender:UIPanGestureRecognizer){
    self.view.bringSubviewToFront(viewDrag)
    let translation = sender.translation(in: self.view)
    viewDrag.center = CGPoint(x: viewDrag.center.x + translation.x, y: viewDrag.center.y + translation.y)
    sender.setTranslation(CGPoint.zero, in: self.view)
}

100% working and tested

Upvotes: 0

Learning Programming
Learning Programming

Reputation: 476

While using any Gesture you should use following steps,

Now you are using pan gesture so i am giving following steps to add pan gesture,

  1. Add delegate like to your header file [ .h file ]

    @interface ViewName : UIView <UIGestureRecognizerDelegate>

  2. Declare that gesture

    @property (nonatomic,strong) UIPanGestureRecognizer *pan;

  3. Allocate that gesture

    pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(handlePan:)];

  4. Mention where these delegate methods are present

    pan.delegate = self;

  5. Adding that gesture to the view like

    [self.view addGestureRecognizer:pan];

  6. Defining the handlePan method like as

    - (void)handlePan:(UIPanGestureRecognizer *)recognizer
{ 
   // code for pan gesture here
}

I think you missed to do something... Hope this will solve your problem, check whether you added UIGestureRecognizer in header file or not...

Upvotes: 4

Avt
Avt

Reputation: 17053

If your HandlePan method is not called check that your _Imageview has user interactions enabled:

_Imageview.userInteractionEnabled = YES

Upvotes: 1

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