viewDidLayoutSubviews for Custom UITableViewCell

Question

I want to animate a subview of a custom TableViewCell. To perform this animation, the cell needs the width of this subview, which is laid out by an auto-layout-constraint.

However, when I use the animation-function in the cellForRowAtIndex function (mycell.animate()), the width is 0, because the subviews are not laid out yet and the animation will not work.

In a regular view, I would use viewDidLayoutSubviews(), because then the view is laid out, I can get the width and perform the animation. However, what's the equivalent function for a custom UITableViewCell?

I tried the willDisplay delegate function of the TableView, but when I print out the width of the cells subview, it still says 0...

Theiss

You probably have to create a subclass of UITableViewCell and then go from there. – Scull

hmm I actually have, sorry if that's been unclear – Theiss

I know this is probably deeper than that but, have you tried assigning the width to the table cell in cellForRow:at:? cell.frame.size.width = tableView.frame.size.width – Blowbyblow

layoutSubviews inside the cell subclass might do the trick. – Scull

lol thanks @lu2302, it really works! Didn't think it can be that easy :) – Theiss

Answer 1

The correct place is inside layoutSubviews:

class MyCell : UITableViewCell {
    override func layoutSubviews() {
        super.layoutSubviews()
        // do your thing
    }
}

Scull

Hi, I'm trying to use this approach while adding a gradient to a custom UITableViewCell. I call my applyGradient() function inside of layoutSubviews() My problem is that when the table loads, I see no gradient, but after I click the cell, the gradient will show. Any idea of why the gradient won't show before clicking? I've tried calling layoutSubviews() from different places in my code with no luck. @Scull – Illuviation

@Illuviation i've had your issue and the code above did it without the need to call the function, just put the gradient code within the function above in tableViewCell class :) – Amateurism

I've had a similar problem while setting shadow for a subview. Apparently, the layoutSubviews method doesn't get called after the view has been laid out by autolayout. (or it is returning 0 for some reason) – Corri

layoutSubviews() did not work in my case. After reuse of the cell, gradient frame was wrong, even though i removed gradient and apply it again in reuse. Updating frame inside draw(_ rect: CGRect) solved my problem – Ladylove

dropping shadow also worked only from draw(_ rect: CGRect) – Binni

Answer 2

It will work if you animate your view inside draw function in tableViewCell

override func draw(_ rect: CGRect) {
    super.draw(rect)

    //Your code here
}

Curly