RXSwift實現(xiàn)

import UIKit
import RxSwift
import RxCocoa

let countDownSeconds: Int = 60

class ViewController: UIViewController {

    let disposeBag = DisposeBag()
    
    @IBOutlet weak var sendCodeButton: UIButton!
    
    override func viewDidLoad() {
        super.viewDidLoad()
  
        let timer = Observable<Int>.timer(0, period: 1, scheduler: MainScheduler.instance)
           .map{countDownSeconds - $0}
           .filter{ $0 >= 0 }
           .asDriver(onErrorJustReturn: 0)
        
        let second = sendCodeButton.rx.tap
            .flatMapLatest { _ -> Driver<Int> in
                return timer
        }
        let sendCodeButtonText = second.map { $0 == 0 ? "發(fā)送驗證碼":"再次發(fā)送(\($0)s)"}
        let sendButtonEnable = second.map{$0 == 0 ? true : false}
        
        sendCodeButtonText
            .bind(to: sendCodeButton.rx.title(for: .normal))
            .disposed(by: disposeBag)
        
        sendButtonEnable
            .bind(to: sendCodeButton.rx.isEnabled)
            .disposed(by: disposeBag)
    }
 }

喜歡就請點個贊～