Detect when UITableViewCell did load

问题

I need to be able to detect when my custom UITableViewCell has been loaded on screen, so that I can programmatically do stuff to the view inside it. The only code I could get working was implementing layoutSubviews() inside the custom UITableViewCell, but this is bad practice because layoutSubviews() is called more than one time. Also, putting my code in awakeFromNib() doesn't work because I need to call a delegate property, which hasn't been set at that point. How can I achieve this?

回答1:

There are two different ways you could do it.

In your UITableViewDelegate you can implement the delegate method that is called when a cell is about to be displayed.

func tableView(_ tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
    // Update the cell
}

Or in your UITableViewCell subclass you could implement didMoveToSuperView.

override func didMoveToSuperview() {
    super.didMoveToSuperview()
    if superview != nil {
        // Update the cell
    }
}

回答2:

The most obvious place IMHO would be in tableView:cellForRowAtIndexPath:, just after having dequeued an instance and done the relevant init there, just add a call to a custom method of your custom cell.

回答3:

You can easily use the functions below to track the tableViewCell:-

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// return n ( n = number of rows required )
// If n > 0, the function below will get called n times
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Identifier", forIndexPath: indexPath) as UITableViewCell!
//Create views, labels, buttons whatever you want and wherever you want.
//Add them to the cell by using cell.addSubview("Your view/label")
return cell
}

来源：https://stackoverflow.com/questions/35559352/detect-when-uitableviewcell-did-load

标签

ios

swift

uitableview