Swift：尝试使用完成处理程序设置 ui 按钮标题

Question

我正在尝试使用来自 firebase 的数据来填充 UI 上的按钮。除了按钮标题没有更新外，一切都按预期工作。有关如何解决此问题的任何想法？

@IBAction func addNewTapped(_ sender: Any) {

    readOneDay2(lastMonday(trackerDate), completion: { message in
            let lastHourRead = message
            print(message)
            self.lastHour1.setTitle(lastHourRead, for: UIControl.State.application)

    })
}

func readOneDay2 (_ mydate: Date, completion: @escaping (_ message: String) -> Void){
    
    var db: DatabaseReference!
    db = Database.database().reference()
    var totalComb: Double = 0.0
    let userID = Auth.auth().currentUser?.uid
    db.child("TimesheetData").child(userID!).observeSingleEvent(of: .value, with: { (snapshot) in
        // Get user value
        let dict = snapshot.value as? NSDictionary
        
        for (key, value) in dict! {
            
            let myvalue = value as? [String: Any]
            let compDate: String = myvalue!["timeSheetDate"]! as! String
            if compDate == dateStringer(mydate) {
                let sHours: String = myvalue!["hours"]! as! String
                let sOverTime: String = myvalue!["overTime"]! as! String
                let sDoubleTime: String = myvalue!["doubleTime"]! as! String
                let dHours: Double = Double(sHours)!
                let dOverTime: Double = Double(sOverTime)!
                let dDoubleTime: Double = Double(sDoubleTime)!
                totalComb = totalComb + dHours + dOverTime + dDoubleTime
                print(key)
                
            }
        }
        print("First Sum " + String(totalComb))
        DispatchQueue.main.async {
            completion(String(totalComb))
        }
      }) { (error) in
        print(error.localizedDescription)
    }
    
    
} 

Answer 1

正如@Virender 所说，

将 UIControl.State.application 更改为 UIControl.State.normal

    DispatchQueue.main.async {
        self.lastHour1.setTitle(lastHourRead, for:.normal)
    }