我下面的快捷代码应具有2个按钮,即开始和暂停按钮。现在,我的代码在文本字段上接受一个int并将其倒计数并显示在标签lblTime上。当点击暂停按钮时,标签计时器停止。再次点击时,计时器会下降1秒钟,应该像点击启动按钮时一样倒计时。随着计时器从标签上的位置向下移动。我希望倒数到零,而不是只倒数一秒。查看功能暂停。
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
let MAX_LENGTH_PHONENUMBER = 2
let ACCEPTABLE_NUMBERS = "0123456789"
var enterTime = UITextField()
var lblTime = UILabel()
var startBTN = UIButton()
var timer = Timer()
var counter = 0
var pauseBTN = UIButton()
var jake = 0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
[enterTime,lblTime,startBTN,pauseBTN].forEach{
$0.backgroundColor = .systemRed
view.addSubview($0)
$0.translatesAutoresizingMaskIntoConstraints = false
}
enterTime.frame = CGRect(x: view.center.x-115, y: view.center.y-200, width: 60, height: 50)
lblTime.frame = CGRect(x: view.center.x-115, y: view.center.y, width: 60, height: 50)
pauseBTN.frame = CGRect(x: view.center.x-115, y: view.center.y+90, width: 60, height: 50)
startBTN.frame = CGRect(x: view.center.x-115, y: view.center.y+200, width: 60, height: 50)
startBTN.addTarget(self, action: #selector(startHit), for: .touchDown)
pauseBTN.addTarget(self, action: #selector(pause), for: .touchDown)
enterTime.placeholder = String("MM:SS")
enterTime.delegate = self
enterTime.addTarget(self, action: #selector(self.textFieldDidChange), for: UIControl.Event.editingChanged)
pauseBTN.setTitle("pause", for: .normal)
startBTN.setTitle("Start", for: .normal)
}
@objc func pause() {
if jake == 0 {
timer.invalidate()
pauseBTN.setTitle("go", for: .normal)
}
else {
timer.fire()
pauseBTN.setTitle("pause", for: .normal)
counter -= 1
lblTime.text = formatSeconds(counter)
if ( counter == 0 ) {
timer.invalidate()}
}
jake += 1
}
@objc func startHit() {
timer.invalidate()
counter = convertToSeconds(from: enterTime.text!)
lblTime.text = formatSeconds(counter)
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(timerAction), userInfo: nil, repeats: true)
}
@objc func timerAction() {
counter -= 1
lblTime.text = formatSeconds(counter)
if ( counter == 0 ) {
timer.invalidate()
}
}
func convertToSeconds(from timeString: String) -> Int {
let components = timeString.components(separatedBy: ":")
if components.count == 2 {
let minutes = Int(components[0]) ?? 0
let seconds = Int(components[1]) ?? 0
return (minutes * 60) + seconds
} else if components.count == 3 {
let hours = Int(components[0]) ?? 0
let minutes = Int(components[1]) ?? 0
let seconds = Int(components[2]) ?? 0
return (hours * 60 * 60) + (minutes * 60) + seconds
} else {
return 0
}
}
func formatSeconds(_ totalSeconds: Int) -> String {
let formatter = DateComponentsFormatter()
formatter.unitsStyle = .positional
formatter.allowedUnits = [.minute, .second]
formatter.zeroFormattingBehavior = .pad
return formatter.string(from: TimeInterval(totalSeconds))!
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let newLength: Int = textField.text!.count + string.count - range.length
let numberOnly = NSCharacterSet.init(charactersIn: ACCEPTABLE_NUMBERS).inverted
let strValid = string.rangeOfCharacter(from: numberOnly) == nil
return (strValid && (newLength <= MAX_LENGTH_PHONENUMBER))
}
@objc func textFieldDidChange(_ textField: UITextField) {
if textField.text!.count == 2 {
textField.text = textField.text! + ":00"
}
}
}
您可以在ViewController中使用isPaused一个变量字段来跟踪您的暂停状态。并且在您的pause()函数中,您可以检查该状态并更新计时器状态。如果尚未暂停,则使计时器无效,否则再次重新创建计时器。您的暂停功能可能看起来像下面的代码段。
@objc func pause() {
if !isPaused {
timer.invalidate()
pauseBTN.setTitle("go", for: .normal)
}
else {
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(timerAction), userInfo: nil, repeats: true)
pauseBTN.setTitle("pause", for: .normal)
}
isPaused = !isPaused
}
要暂停/停止计时器,请同时使用timer.invalidate()
和timer = nil
,因为在计时器启动时,它总是在创建新实例。
class ViewController: UIViewController, UITextFieldDelegate {
let MAX_LENGTH_PHONENUMBER = 2
let ACCEPTABLE_NUMBERS = "0123456789"
var enterTime = UITextField()
var lblTime = UILabel()
var startBTN = UIButton()
var timer:Timer? = Timer()
var counter = 0
var pauseBTN = UIButton()
var isPaused = false
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
[enterTime,lblTime,startBTN,pauseBTN].forEach{
$0.backgroundColor = .systemRed
view.addSubview($0)
$0.translatesAutoresizingMaskIntoConstraints = false
}
enterTime.frame = CGRect(x: view.center.x-115, y: view.center.y-200, width: 60, height: 50)
lblTime.frame = CGRect(x: view.center.x-115, y: view.center.y, width: 60, height: 50)
pauseBTN.frame = CGRect(x: view.center.x-115, y: view.center.y+90, width: 60, height: 50)
startBTN.frame = CGRect(x: view.center.x-115, y: view.center.y+200, width: 60, height: 50)
startBTN.addTarget(self, action: #selector(startHit), for: .touchDown)
pauseBTN.addTarget(self, action: #selector(pause), for: .touchDown)
enterTime.placeholder = String("MM:SS")
enterTime.delegate = self
enterTime.addTarget(self, action: #selector(self.textFieldDidChange), for: UIControl.Event.editingChanged)
pauseBTN.setTitle("pause", for: .normal)
startBTN.setTitle("Start", for: .normal)
}
@objc func pause() {
if !isPaused {
timer?.invalidate()
timer = nil
pauseBTN.setTitle("go", for: .normal)
}
else {
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(timerAction), userInfo: nil, repeats: true)
pauseBTN.setTitle("pause", for: .normal)
}
isPaused = !isPaused
}
@objc func startHit() {
isPaused = false
timer?.invalidate()
counter = convertToSeconds(from: enterTime.text ?? "")
lblTime.text = formatSeconds(counter)
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(timerAction), userInfo: nil, repeats: true)
}
@objc func timerAction() {
if ( counter == 0 ) {
timer?.invalidate()
timer = nil
return
}
counter -= 1
lblTime.text = formatSeconds(counter)
}
func convertToSeconds(from timeString: String) -> Int {
let components = timeString.components(separatedBy: ":")
if components.count == 1 {
let minutes = Int(components[0]) ?? 0
return minutes * 60
} else if components.count == 2 {
let minutes = Int(components[0]) ?? 0
let seconds = Int(components[1]) ?? 0
return (minutes * 60) + seconds
} else if components.count == 3 {
let hours = Int(components[0]) ?? 0
let minutes = Int(components[1]) ?? 0
let seconds = Int(components[2]) ?? 0
return (hours * 60 * 60) + (minutes * 60) + seconds
} else {
return 0
}
}
func formatSeconds(_ totalSeconds: Int) -> String {
let formatter = DateComponentsFormatter()
formatter.unitsStyle = .positional
formatter.allowedUnits = [.minute, .second]
formatter.zeroFormattingBehavior = .pad
return formatter.string(from: TimeInterval(totalSeconds)) ?? ""
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let newLength: Int = (textField.text?.count ?? 0) + string.count - range.length
let numberOnly = NSCharacterSet.init(charactersIn: ACCEPTABLE_NUMBERS).inverted
let strValid = string.rangeOfCharacter(from: numberOnly) == nil
return (strValid && (newLength <= MAX_LENGTH_PHONENUMBER))
}
@objc func textFieldDidChange(_ textField: UITextField) {
if let text = textField.text, text.count == 2 {
textField.text = text + ":00"
}
}
}