如何使用 NSTimer 进行倒计时?
How can I make a countdown with NSTimer?
如何使用 Swift 使用 NSTimer
进行倒计时?
问题 1:
@IBOutlet var countDownLabel: UILabel!
var count = 10
override func viewDidLoad() {
super.viewDidLoad()
var timer = Timer.scheduledTimer(timeInterval: 0.4, target: self, selector: #selector(UIMenuController.update), userInfo: nil, repeats: true)
}
func update() {
if(count > 0) {
countDownLabel.text = String(count--)
}
}
问题 2:
两者都可以。 SpriteKit 是用于场景、动作等的 SDK。Simple View Application 是项目模板。他们不应该冲突
计时器的变量
var timer = 60
以 1.0 为间隔的 NSTimer
var clock = NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, selector: "countdown", userInfo: nil, repeats: true)
在这里你可以减少定时器
func countdown() {
timer--
}
在 Swift 5.1 中,这将起作用:
var counter = 30
override func viewDidLoad() {
super.viewDidLoad()
Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)
}
@objc func updateCounter() {
//example functionality
if counter > 0 {
print("\(counter) seconds to the end of the world")
counter -= 1
}
}
制作倒计时应用 Xcode 8.1,Swift 3
import UIKit
import Foundation
class ViewController: UIViewController, UITextFieldDelegate {
var timerCount = 0
var timerRunning = false
@IBOutlet weak var timerLabel: UILabel! //ADD Label
@IBOutlet weak var textField: UITextField! //Add TextField /Enter any number to Countdown
override func viewDidLoad() {
super.viewDidLoad()
//Reset
timerLabel.text = ""
if timerCount == 0 {
timerRunning = false
}
}
//Figure out Count method
func Counting() {
if timerCount > 0 {
timerLabel.text = "\(timerCount)"
timerCount -= 1
} else {
timerLabel.text = "GO!"
}
}
//ADD Action Button
@IBAction func startButton(sender: UIButton) {
//Figure out timer
if timerRunning == false {
_ = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(ViewController.Counting), userInfo: nil, repeats: true)
timerRunning = true
}
//unwrap textField and Display result
if let countebleNumber = Int(textField.text!) {
timerCount = countebleNumber
textField.text = "" //Clean Up TextField
} else {
timerCount = 3 //Defoult Number to Countdown if TextField is nil
textField.text = "" //Clean Up TextField
}
}
//Dismiss keyboard
func keyboardDismiss() {
textField.resignFirstResponder()
}
//ADD Gesture Recignizer to Dismiss keyboard then view tapped
@IBAction func viewTapped(_ sender: AnyObject) {
keyboardDismiss()
}
//Dismiss keyboard using Return Key (Done) Button
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
keyboardDismiss()
return true
}
}
Swift 3
private let NUMBER_COUNT_DOWN = 3
var countDownLabel = UILabel()
var countDown = NUMBER_COUNT_DOWN
var timer:Timer?
private func countDown(time: Double)
{
countDownLabel.frame = CGRect(x: 0, y: 0, width: 300, height: 300)
countDownLabel.font = UIFont.systemFont(ofSize: 300)
countDownLabel.textColor = .black
countDownLabel.center = CGPoint(x: self.view.frame.width / 2, y: self.view.frame.height / 2)
countDownLabel.textAlignment = .center
self.view.addSubview(countDownLabel)
view.bringSubview(toFront: countDownLabel)
timer = Timer.scheduledTimer(timeInterval: time, target: self, selector: #selector(updateCountDown), userInfo: nil, repeats: true)
}
func updateCountDown() {
if(countDown > 0) {
countDownLabel.text = String(countDown)
countDown = countDown - 1
} else {
removeCountDownLable()
}
}
private func removeCountDownLable() {
countDown = NUMBER_COUNT_DOWN
countDownLabel.text = ""
countDownLabel.removeFromSuperview()
timer?.invalidate()
timer = nil
}
Swift 4
Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(self.updateTime), userInfo: nil, repeats: true)
更新功能
@objc func updateTime(){
debugPrint("jalan")
}
Swift 4.1 和 Swift 5. updatetime 方法将在每一秒后调用,秒数将显示在 UIlabel 上。
var timer: Timer?
var totalTime = 60
private func startOtpTimer() {
self.totalTime = 60
self.timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateTimer), userInfo: nil, repeats: true)
}
@objc func updateTimer() {
print(self.totalTime)
self.lblTimer.text = self.timeFormatted(self.totalTime) // will show timer
if totalTime != 0 {
totalTime -= 1 // decrease counter timer
} else {
if let timer = self.timer {
timer.invalidate()
self.timer = nil
}
}
}
func timeFormatted(_ totalSeconds: Int) -> String {
let seconds: Int = totalSeconds % 60
let minutes: Int = (totalSeconds / 60) % 60
return String(format: "%02d:%02d", minutes, seconds)
}
XCode 10 与 Swift 4.2
import UIKit
class ViewController: UIViewController {
var timer = Timer()
var totalSecond = 10
override func viewDidLoad() {
super.viewDidLoad()
startTimer()
}
func startTimer() {
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(updateTime), userInfo: nil, repeats: true)
}
@objc func updateTime() {
print(timeFormatted(totalSecond))
if totalSecond != 0 {
totalSecond -= 1
} else {
endTimer()
}
}
func endTimer() {
timer.invalidate()
}
func timeFormatted(_ totalSeconds: Int) -> String {
let seconds: Int = totalSeconds % 60
return String(format: "0:%02d", seconds)
}
}
Swift4
@IBOutlet weak var actionButton: UIButton!
@IBOutlet weak var timeLabel: UILabel!
var timer:Timer?
var timeLeft = 60
override func viewDidLoad() {
super.viewDidLoad()
setupTimer()
}
func setupTimer() {
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(onTimerFires), userInfo: nil, repeats: true)
}
@objc func onTimerFires() {
timeLeft -= 1
timeLabel.text = "\(timeLeft) seconds left"
if timeLeft <= 0 {
actionButton.isEnabled = true
actionButton.setTitle("enabled", for: .normal)
timer?.invalidate()
timer = nil
}
}
@IBAction func btnClicked(_ sender: UIButton) {
print("API Fired")
}
Swift 5 闭包:
class ViewController: UIViewController {
var secondsRemaining = 30
@IBAction func startTimer(_ sender: UIButton) {
Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { (Timer) in
if self.secondsRemaining > 0 {
print ("\(self.secondsRemaining) seconds")
self.secondsRemaining -= 1
} else {
Timer.invalidate()
}
}
}
这是现在的 swift 5.0 和 newst
var secondsRemaining = 60
Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)
}
@objc func updateCounter(){
if secondsRemaining > 0 {
print("\(secondsRemaining) seconds.")
secondsRemaining -= 1
}
}
Swift 5 另一种方式。 抵抗与UI
的互动
我想展示一种解决方案,该解决方案可以防止用户在倒计时期间与其他 UI 元素进行交互。
我在评论中解释了每一行代码的含义。
var timeToSet = 0
var timer: Timer?
...
@IBAction func btnWasPressed(_ sender: UIButton) {
//Setting the countdown time
timeLeft = timeToSet
//Disabling any previous timers.
timer?.invalidate()
//Initialization of the Timer with interval every 1 second with the function call.
timer = Timer(timeInterval: 1.0, target: self, selector: #selector(countDown), userInfo: nil, repeats: true)
//Adding Timer to the current loop
RunLoop.current.add(timer!, forMode: .common)
}
...
@objc func countDown() {
if timeLeft > 0 {
print(timeLeft)
timeLeft -= 1
} else {
// Timer stopping
timer?.invalidate()
}
}
将此添加到代码的末尾...
并调用 startTimer 函数,参数是您要倒计时的位置...
例如(现在日期的未来 2 小时)-> startTimer(for: Date().addingTimeInterval(60*60*2))
Click here to view a screenshot of iPhone Simulator of how it'll look
extension ViewController
{
func startTimer(for theDate: String)
{
let todaysDate = Date()
let tripDate = Helper.getTripDate(forDate: theDate)
let diffComponents = Calendar.current.dateComponents([.hour, .minute], from: Date(), to: tripDate)
if let hours = diffComponents.hour
{
hoursLeft = hours
}
if let minutes = diffComponents.minute
{
minutesLeft = minutes
}
if tripDate > todaysDate
{
timer = Timer.scheduledTimer(timeInterval: 1.00, target: self, selector: #selector(onTimerFires), userInfo: nil, repeats: true)
}
else
{
timerLabel.text = "00:00:00"
}
}
@objc func onTimerFires()
{
secondsLeft -= 1
//timerLabel.text = "\(hoursLeft):\(minutesLeft):\(secondsLeft)"
timerLabel.text = String(format: "%02d:%02d:%02d", hoursLeft, minutesLeft, secondsLeft)
if secondsLeft <= 0 {
if minutesLeft != 0
{
secondsLeft = 59
minutesLeft -= 1
}
}
if minutesLeft <= 0 {
if hoursLeft != 0
{
minutesLeft = 59
hoursLeft -= 1
}
}
if(hoursLeft == 0 && minutesLeft == 0 && secondsLeft == 0)
{
timer.invalidate()
}
}
}
供新手在 Playground 中使用,在 Swift 5,Xcode 11:
Import UIKit
var secondsRemaining = 10
Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { (Timer) in
if secondsRemaining > 0 {
print ("\(secondsRemaining) seconds")
secondsRemaining -= 1
} else {
Timer.invalidate()
}
}
import UIKit
class ViewController: UIViewController {
let eggTimes = ["Soft": 300, "Medium": 420, "Hard": 720]
var secondsRemaining = 60
@IBAction func hardnessSelected(_ sender: UIButton) {
let hardness = sender.currentTitle!
secondsRemaining = eggTimes[hardness]!
Timer.scheduledTimer(timeInterval: 1.0, target: self, selector:
#selector(UIMenuController.update), userInfo: nil, repeats: true)
}
@objc func countDown() {
if secondsRemaining > 0 {
print("\(secondsRemaining) seconds.")
secondsRemaining -= 1
}
}
}
这是一个煮蛋计时器。
import UIKit
class ViewController: UIViewController {
let eggTimes = ["Soft": 0.1, "Medium": 2, "Hard": 3]
var eggTime = 0
var timer = Timer()
@IBOutlet weak var label: UILabel!
@IBAction func b(_ sender: UIButton) {
timer.invalidate()
let hardness = sender.currentTitle!
eggTime = Int(eggTimes[hardness]! * 60)
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(update), userInfo: nil, repeats: true)
}
@objc func update() {
if (eggTime > 0) {
print("\(eggTime) seconds")
eggTime -= 1
}
if (eggTime == 0){
label.text = ("done")
}
}
}
你真的不应该。 Grand Central Dispatch 更可靠。
如何使用 Swift 使用 NSTimer
进行倒计时?
问题 1:
@IBOutlet var countDownLabel: UILabel!
var count = 10
override func viewDidLoad() {
super.viewDidLoad()
var timer = Timer.scheduledTimer(timeInterval: 0.4, target: self, selector: #selector(UIMenuController.update), userInfo: nil, repeats: true)
}
func update() {
if(count > 0) {
countDownLabel.text = String(count--)
}
}
问题 2:
两者都可以。 SpriteKit 是用于场景、动作等的 SDK。Simple View Application 是项目模板。他们不应该冲突
计时器的变量
var timer = 60
以 1.0 为间隔的 NSTimer
var clock = NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, selector: "countdown", userInfo: nil, repeats: true)
在这里你可以减少定时器
func countdown() {
timer--
}
在 Swift 5.1 中,这将起作用:
var counter = 30
override func viewDidLoad() {
super.viewDidLoad()
Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)
}
@objc func updateCounter() {
//example functionality
if counter > 0 {
print("\(counter) seconds to the end of the world")
counter -= 1
}
}
制作倒计时应用 Xcode 8.1,Swift 3
import UIKit
import Foundation
class ViewController: UIViewController, UITextFieldDelegate {
var timerCount = 0
var timerRunning = false
@IBOutlet weak var timerLabel: UILabel! //ADD Label
@IBOutlet weak var textField: UITextField! //Add TextField /Enter any number to Countdown
override func viewDidLoad() {
super.viewDidLoad()
//Reset
timerLabel.text = ""
if timerCount == 0 {
timerRunning = false
}
}
//Figure out Count method
func Counting() {
if timerCount > 0 {
timerLabel.text = "\(timerCount)"
timerCount -= 1
} else {
timerLabel.text = "GO!"
}
}
//ADD Action Button
@IBAction func startButton(sender: UIButton) {
//Figure out timer
if timerRunning == false {
_ = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(ViewController.Counting), userInfo: nil, repeats: true)
timerRunning = true
}
//unwrap textField and Display result
if let countebleNumber = Int(textField.text!) {
timerCount = countebleNumber
textField.text = "" //Clean Up TextField
} else {
timerCount = 3 //Defoult Number to Countdown if TextField is nil
textField.text = "" //Clean Up TextField
}
}
//Dismiss keyboard
func keyboardDismiss() {
textField.resignFirstResponder()
}
//ADD Gesture Recignizer to Dismiss keyboard then view tapped
@IBAction func viewTapped(_ sender: AnyObject) {
keyboardDismiss()
}
//Dismiss keyboard using Return Key (Done) Button
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
keyboardDismiss()
return true
}
}
Swift 3
private let NUMBER_COUNT_DOWN = 3
var countDownLabel = UILabel()
var countDown = NUMBER_COUNT_DOWN
var timer:Timer?
private func countDown(time: Double)
{
countDownLabel.frame = CGRect(x: 0, y: 0, width: 300, height: 300)
countDownLabel.font = UIFont.systemFont(ofSize: 300)
countDownLabel.textColor = .black
countDownLabel.center = CGPoint(x: self.view.frame.width / 2, y: self.view.frame.height / 2)
countDownLabel.textAlignment = .center
self.view.addSubview(countDownLabel)
view.bringSubview(toFront: countDownLabel)
timer = Timer.scheduledTimer(timeInterval: time, target: self, selector: #selector(updateCountDown), userInfo: nil, repeats: true)
}
func updateCountDown() {
if(countDown > 0) {
countDownLabel.text = String(countDown)
countDown = countDown - 1
} else {
removeCountDownLable()
}
}
private func removeCountDownLable() {
countDown = NUMBER_COUNT_DOWN
countDownLabel.text = ""
countDownLabel.removeFromSuperview()
timer?.invalidate()
timer = nil
}
Swift 4
Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(self.updateTime), userInfo: nil, repeats: true)
更新功能
@objc func updateTime(){
debugPrint("jalan")
}
Swift 4.1 和 Swift 5. updatetime 方法将在每一秒后调用,秒数将显示在 UIlabel 上。
var timer: Timer?
var totalTime = 60
private func startOtpTimer() {
self.totalTime = 60
self.timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateTimer), userInfo: nil, repeats: true)
}
@objc func updateTimer() {
print(self.totalTime)
self.lblTimer.text = self.timeFormatted(self.totalTime) // will show timer
if totalTime != 0 {
totalTime -= 1 // decrease counter timer
} else {
if let timer = self.timer {
timer.invalidate()
self.timer = nil
}
}
}
func timeFormatted(_ totalSeconds: Int) -> String {
let seconds: Int = totalSeconds % 60
let minutes: Int = (totalSeconds / 60) % 60
return String(format: "%02d:%02d", minutes, seconds)
}
XCode 10 与 Swift 4.2
import UIKit
class ViewController: UIViewController {
var timer = Timer()
var totalSecond = 10
override func viewDidLoad() {
super.viewDidLoad()
startTimer()
}
func startTimer() {
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(updateTime), userInfo: nil, repeats: true)
}
@objc func updateTime() {
print(timeFormatted(totalSecond))
if totalSecond != 0 {
totalSecond -= 1
} else {
endTimer()
}
}
func endTimer() {
timer.invalidate()
}
func timeFormatted(_ totalSeconds: Int) -> String {
let seconds: Int = totalSeconds % 60
return String(format: "0:%02d", seconds)
}
}
Swift4
@IBOutlet weak var actionButton: UIButton!
@IBOutlet weak var timeLabel: UILabel!
var timer:Timer?
var timeLeft = 60
override func viewDidLoad() {
super.viewDidLoad()
setupTimer()
}
func setupTimer() {
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(onTimerFires), userInfo: nil, repeats: true)
}
@objc func onTimerFires() {
timeLeft -= 1
timeLabel.text = "\(timeLeft) seconds left"
if timeLeft <= 0 {
actionButton.isEnabled = true
actionButton.setTitle("enabled", for: .normal)
timer?.invalidate()
timer = nil
}
}
@IBAction func btnClicked(_ sender: UIButton) {
print("API Fired")
}
Swift 5 闭包:
class ViewController: UIViewController {
var secondsRemaining = 30
@IBAction func startTimer(_ sender: UIButton) {
Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { (Timer) in
if self.secondsRemaining > 0 {
print ("\(self.secondsRemaining) seconds")
self.secondsRemaining -= 1
} else {
Timer.invalidate()
}
}
}
这是现在的 swift 5.0 和 newst
var secondsRemaining = 60
Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)
}
@objc func updateCounter(){
if secondsRemaining > 0 {
print("\(secondsRemaining) seconds.")
secondsRemaining -= 1
}
}
Swift 5 另一种方式。 抵抗与UI
的互动我想展示一种解决方案,该解决方案可以防止用户在倒计时期间与其他 UI 元素进行交互。 我在评论中解释了每一行代码的含义。
var timeToSet = 0
var timer: Timer?
...
@IBAction func btnWasPressed(_ sender: UIButton) {
//Setting the countdown time
timeLeft = timeToSet
//Disabling any previous timers.
timer?.invalidate()
//Initialization of the Timer with interval every 1 second with the function call.
timer = Timer(timeInterval: 1.0, target: self, selector: #selector(countDown), userInfo: nil, repeats: true)
//Adding Timer to the current loop
RunLoop.current.add(timer!, forMode: .common)
}
...
@objc func countDown() {
if timeLeft > 0 {
print(timeLeft)
timeLeft -= 1
} else {
// Timer stopping
timer?.invalidate()
}
}
将此添加到代码的末尾...
并调用 startTimer 函数,参数是您要倒计时的位置...
例如(现在日期的未来 2 小时)-> startTimer(for: Date().addingTimeInterval(60*60*2))
Click here to view a screenshot of iPhone Simulator of how it'll look
extension ViewController
{
func startTimer(for theDate: String)
{
let todaysDate = Date()
let tripDate = Helper.getTripDate(forDate: theDate)
let diffComponents = Calendar.current.dateComponents([.hour, .minute], from: Date(), to: tripDate)
if let hours = diffComponents.hour
{
hoursLeft = hours
}
if let minutes = diffComponents.minute
{
minutesLeft = minutes
}
if tripDate > todaysDate
{
timer = Timer.scheduledTimer(timeInterval: 1.00, target: self, selector: #selector(onTimerFires), userInfo: nil, repeats: true)
}
else
{
timerLabel.text = "00:00:00"
}
}
@objc func onTimerFires()
{
secondsLeft -= 1
//timerLabel.text = "\(hoursLeft):\(minutesLeft):\(secondsLeft)"
timerLabel.text = String(format: "%02d:%02d:%02d", hoursLeft, minutesLeft, secondsLeft)
if secondsLeft <= 0 {
if minutesLeft != 0
{
secondsLeft = 59
minutesLeft -= 1
}
}
if minutesLeft <= 0 {
if hoursLeft != 0
{
minutesLeft = 59
hoursLeft -= 1
}
}
if(hoursLeft == 0 && minutesLeft == 0 && secondsLeft == 0)
{
timer.invalidate()
}
}
}
供新手在 Playground 中使用,在 Swift 5,Xcode 11:
Import UIKit
var secondsRemaining = 10
Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { (Timer) in
if secondsRemaining > 0 {
print ("\(secondsRemaining) seconds")
secondsRemaining -= 1
} else {
Timer.invalidate()
}
}
import UIKit
class ViewController: UIViewController {
let eggTimes = ["Soft": 300, "Medium": 420, "Hard": 720]
var secondsRemaining = 60
@IBAction func hardnessSelected(_ sender: UIButton) {
let hardness = sender.currentTitle!
secondsRemaining = eggTimes[hardness]!
Timer.scheduledTimer(timeInterval: 1.0, target: self, selector:
#selector(UIMenuController.update), userInfo: nil, repeats: true)
}
@objc func countDown() {
if secondsRemaining > 0 {
print("\(secondsRemaining) seconds.")
secondsRemaining -= 1
}
}
}
这是一个煮蛋计时器。
import UIKit
class ViewController: UIViewController {
let eggTimes = ["Soft": 0.1, "Medium": 2, "Hard": 3]
var eggTime = 0
var timer = Timer()
@IBOutlet weak var label: UILabel!
@IBAction func b(_ sender: UIButton) {
timer.invalidate()
let hardness = sender.currentTitle!
eggTime = Int(eggTimes[hardness]! * 60)
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(update), userInfo: nil, repeats: true)
}
@objc func update() {
if (eggTime > 0) {
print("\(eggTime) seconds")
eggTime -= 1
}
if (eggTime == 0){
label.text = ("done")
}
}
}
你真的不应该。 Grand Central Dispatch 更可靠。