How to move view back to its position?

Question

I have the following code to swipe a view out of the screen when swiped right

let gesture = UISwipeGestureRecognizer(target: self, action: #selector(swipedView(_:)))
gesture.direction = .right
centerView.addGestureRecognizer(gesture)

@objc func swipedView(_ sender: UISwipeGestureRecognizer) {
    UIView.animate(withDuration: 2.0, animations: {
        centerView.frame = centerView.frame.offsetBy(dx: self.view.frame.maxX-centerView.frame.minX, dy: 0)
    }) { completed in
    //Call API and if response failed move centerView to its original position
    } 
}

In animation's completion block I call an API. If the response is failed, I want to move centerView to its initial position. How can I do this without saving the starting frame in another variable?

What is the "response" here? Do you mean if the swipe gesture fails? — David Steppenbeck, Sep 12 '19 at 14:51
@DavidSteppenbeckPhD I call an API when the user swipes the view out of the screen. Think tinder app. When I like or dislike a card I call an API — iOSDev, Sep 13 '19 at 05:33
OK, I understand. And, is centerView always exactly centered horizontally in the view (before swiping)? — David Steppenbeck, Sep 13 '19 at 10:54

score 0 · Answer 1 · answered Sep 12 '19 at 14:09

0

Keep track of the original location before you move it.

var lastLocation: CGPoint?

// later
lastlocation = centerView.frame.origin
centerView.frame = centerView.frame.offsetBy(dx: self.view.frame.maxX-centerView.frame.minX, dy: 0)

Then whenever you would like to move it back just do the same again

UIView.animate(withDuration: 2.0) {
    if let point = self.lastLocation {
        self.centerView.frame.origin = point
    }
}

answered Sep 12 '19 at 14:09

Scriptable

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*How can I do this without saving the starting frame in another variable?* – えるまる Sep 12 '19 at 16:03
1

Well I don't think you can, you want to remember where it was to return to that point later unless it's starting position is already a known value. I.e. if your using auto layout for example and have a constraint constant starting out at zero, then you move it some amount, later you can just reset it back to zero – Scriptable Sep 13 '19 at 07:47

score 0 · Answer 2 · answered Sep 13 '19 at 11:08

As mentioned in the other answer, I'd use a var to record its initial position. However, if you insist to do it differently, then I guess it's possible, assuming that centerView is always supposed to be centered horizontally in self.view.

// Call API and if response failed move centerView to its original position
centerView.center.x = self.view.bounds.midX // y-value never changed so no need to change it here

How to move view back to its position?

2 Answers2