每天在固定时间运行任务(Run a task at fixed time everyday)

 我想每天在固定的时间运行一个功能（拨打api电话），比如每天上午10点和晚上10点。 什么是swift中的cronjob等价物？ 
 
 我尝试将Timer实现为： 
 
var dateComponents = DateComponents()

dateComponents.timeZone = TimeZone(abbreviation: "NPT") 
dateComponents.hour = 10
dateComponents.minute = 00

let userCalendar = Calendar.current
let myTime = userCalendar.date(from: dateComponents)

let timer = Timer(fireAt: myTime!, interval: 0, target: self, selector: #selector(updateTimer), userInfo: nil, repeats: false)
RunLoop.main.add(timer, forMode: RunLoopMode.commonModes)
 
 选择器功能： 
 
@objc func updateTimer() {
    print("Hello")
}
 
 选择器函数不是在指定的时间运行，而是在每次运行应用程序时执行，而不是在指定的时间执行。 我怎么解决这个问题？ 
 
 编辑：我也需要这个也可以从后台运行。 我将在我的应用中使用位置服务。 

I would like to run a function (make an api call) at fixed time everyday, say 10 am and 10 pm daily. What would be the cronjob equivalent in swift?
 
I tried implementing Timer as:
 
var dateComponents = DateComponents()

dateComponents.timeZone = TimeZone(abbreviation: "NPT") 
dateComponents.hour = 10
dateComponents.minute = 00

let userCalendar = Calendar.current
let myTime = userCalendar.date(from: dateComponents)

let timer = Timer(fireAt: myTime!, interval: 0, target: self, selector: #selector(updateTimer), userInfo: nil, repeats: false)
RunLoop.main.add(timer, forMode: RunLoopMode.commonModes)
 
The selector function:
 
@objc func updateTimer() {
    print("Hello")
}
 
Instead of being run at the specified time, the selector function gets executed everytime I run the app and not at the specified time. How can I solve this?
 
Edit: I’ll be needing this to be run from the background as well. I’ll be using location service in my app.