Question

这是我的代码：

import UIKit
import MessageUI
import UserNotifications

class TripDetailViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource, MFMessageComposeViewControllerDelegate {
    @IBOutlet weak var ScrollView: UIScrollView!
    @IBOutlet weak var tripImage: UIImageView!
    @IBOutlet weak var tripTitle: UILabel!
    @IBOutlet weak var datePickertxt: UITextField!
    @IBOutlet weak var numberOfPeopletxt: UITextField!
    @IBOutlet weak var meetingPoint: UILabel!
    @IBOutlet weak var maxNum: UILabel!
    @IBOutlet weak var tripTime: UILabel!
    @IBOutlet weak var spokenLanguage: UILabel!
    @IBOutlet weak var hostNumber: UILabel!
    @IBOutlet weak var tripLocation: UILabel!
    @IBOutlet weak var hostName: UILabel!
    @IBOutlet weak var tripDescription: UILabel!
    @IBOutlet weak var touristName: UITextField!

    let datePicker = UIDatePicker()
    var numbersOfPeoplePicker = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]
    let numberOfPeoplePicker = UIPickerView()
    var trip = Trip()

    @IBAction func bookButton(_ sender: Any)
    {
        let content = UNMutableNotificationContent()
        content.title = "DiscoverAround"
        content.subtitle = "Someone who booked up your trip!"
        content.body = touristName.text!; "Have booked your trip, and they are"; numberOfPeopletxt.text!; "people, in"; datePickertxt.text!;
        content.badge = 1
        let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 5, repeats: false)
        let request = UNNotificationRequest(identifier: "timerDone", content: content, trigger: trigger)
        UNUserNotificationCenter.current().add(request, withCompletionHandler: nil)
    }
}

我收到了这个错误：

“表达式解析为未使用的I值”

在这一行：

content.body = touristName.text!; "Have booked your trip, and they are"; numberOfPeopletxt.text!; "people, in"; datePickertxt.text!;

Answer 1

您没有正确格式化文本。如果你想连接字符串，你应该这样做：

content.body = "\(touristName.text!) Have booked your trip, and they are \(numberOfPeopletxt.text!) people, in \(datePickertxt.text!)"

如果您不确定该字段的值是否为零，则应先检查它或为其提供默认值：

if let tourist = touristName.text,
    let numberOfPeople = numberOfPeopletxt.text,
    let datePicker = datePickertxt.text {
    content.body = "\(tourist) Have booked your trip, and they are \(numberOfPeople) people, in \(datePicker)"
}

或

content.body = "\(touristName.text ?? "Nobody") Have booked your trip, and they are \(numberOfPeopletxt.text ?? "0") people, in \(datePickertxt.text ?? "nowhere")"

表达式解析为未使用的I值

1 个答案: