ios - Swift 4:检查周、月、2 个月等自使用日历首次启动以来是否已过去
问题描述
我正在尝试包含计时器,以便在应用程序的初始启动日期后一周、一个月、2 个月等出现一个按钮。
我使用过Date.addingTimeInterval(请参阅下面的代码),但它似乎在较长的时间段(周/月)内没有那么有效。Swift 文档建议使用日历,但我不知道该怎么做。
override func viewDidLoad() {
super.viewDidLoad()
if installedDate == nil {
installedDate = Date()
let timer = Calendar.current
Button1.isHidden = true
Button2.isHidden = true
Button3.isHidden = true
}
else {
print("Not first run")
print(installedDate!)
let Button1Date = Date().addingTimeInterval(604800) //for after 1 week
let Button2Date = Date().addingTimeInterval(2592000) //for after 1 month
let Button3Date = Date().addingTimeInterval(5184000) //for after 2 months
if installedDate == Button1Date {
Button1.isHidden = false
}
if installedDate == Button2Date {
Button2.isHidden = false
}
if installedDate == Button3Date {
Button.isHidden = false
}
}
}
var installedDate: Date? {
get {
return UserDefaults.standard.object(forKey: "installedDateKey") as? Date
}
set {
UserDefaults.standard.set(newValue, forKey: "installedDateKey")
}
}
将发布日期与我需要的预期日期进行比较的更有效方法是什么?
解决方案
根据我对您问题的了解,如果他们使用该应用程序的时间超过一定时间,您希望显示一个按钮。如果是这种情况,我已经编写了一些对您有帮助的代码:
let timeSinceInstalled = -(installedDate ?? Date()).timeIntervalSinceNow
Button1.isHidden = timeSinceInstalled < 604800
Button2.isHidden = timeSinceInstalled < 2592000
Button3.isHidden = timeSinceInstalled < 5184000
您实际上可以替换viewDidLoad()
函数内部的大部分代码,甚至是您检查 if 的部分installedDate == nil
。这是您更新的代码:
override func viewDidLoad() {
super.viewDidLoad()
let timeSinceInstalled = -(installedDate ?? Date()).timeIntervalSinceNow
Button1.isHidden = timeSinceInstalled < 604800
Button2.isHidden = timeSinceInstalled < 2592000
Button3.isHidden = timeSinceInstalled < 5184000
}
var installedDate: Date? {
get {
return UserDefaults.standard.object(forKey: "installedDateKey") as? Date
}
set {
UserDefaults.standard.set(newValue, forKey: "installedDateKey")
}
}
如果您想在按钮不可点击时将标题设置为“您没有可用的”,则代码如下:
override func viewDidLoad() {
super.viewDidLoad()
let timeSinceInstalled = -(installedDate ?? Date()).timeIntervalSinceNow
setTitle(Button1, timeSinceInstalled < 604800)
setTitle(Button2, timeSinceInstalled < 2592000)
setTitle(Button3, timeSinceInstalled < 5184000)
}
func setTitle(_ button: UIButton, _ statement: Bool) {
button.setTitle(statement ? "You have none available" : "Click me", for: .normal)
button.isEnabled = !statement
}
var installedDate: Date? {
get {
return UserDefaults.standard.object(forKey: "installedDateKey") as? Date
}
set {
UserDefaults.standard.set(newValue, forKey: "installedDateKey")
}
}