NSTimer inside custom tableViewCell

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臣服心动
臣服心动 2021-01-24 16:45

I\'m activating a function in my custom cell class from a viewController. The custom cell class looks like this:

import UIKit

class TableViewCell: UITableViewCe         


        
2条回答
  •  走了就别回头了
    2021-01-24 17:40

    Alright, so your problem is that you are calling a class method on the TableView class rather than an instance function. You want to get a handle on an actual cell instance, not just the class. So first, your TableCell class with the proper signatures (i.e. remove the class prefix):

    class TableViewCell: UITableViewCell {
    
        var counter = 10
    
        // No longer class functions! :)
        func timerStarted(){
            var timer = NSTimer()
    
            timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "update", userInfo: nil, repeats: true)
        }
    
        func update() {
            // Update counter
            counter-- // <-- performs the actual decrement for you
            println(counter)
        }
    }
    

    Then just update your long press to activate the timer on an actual cell, not just the cell's class:

    func longPressActive(gestureRecognizer:UIGestureRecognizer) {
        if (gestureRecognizer.state == UIGestureRecognizerState.Began) {
            var point = gestureRecognizer.locationInView(self.tv)
            if let indexPath = self.tv.indexPathForRowAtPoint(point) {
                // Check to make sure it is the correct subclass
                if let cell = self.tv.cellForRowAtIndexPath(indexPath: indexPath) as? TableViewCell {
                    // Starting the timer on the actual cell, not just the cell class
                    cell.timerStarted();
                }
            }
        }
    }
    

    Also, I want to make a comment about your timerStarted() function. You first create a new timer and assign it to timer and then you create a second timer and assign that to timer as well, redundant. Also, since you are not saving the timer outside that method there is no need to create a variable (to keep your same functionality). So the function could be:

    func timerStarted(){
        NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "update", userInfo: nil, repeats: true)
    }
    

    But there is a good chance you will want to cancel this at some point, so I would probably store it as an instance variable:

    private var timer: NSTimer
    
    func timerStarted(){
        self.timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "update", userInfo: nil, repeats: true)
    }
    

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