如何使用选定的UIPickerView值作为通知的时间间隔？

Question

我正在尝试从UIPickerView中的选定行中获取一个值，并根据选定的行设置重复通知的时间间隔。也就是说，用户在UIPickerView中选择“每2分钟一次”，并每120.0秒收到一次通知。

第二个"didSelectRow“方法似乎没有将值存储在变量interval中，到目前为止还没有找到解决方案。

到目前为止，这是我的代码：

import UIKit
import  UserNotifications
import UserNotificationsUI

class ViewController: UIViewcontroller, UIPickerViewDataSource, UIPickerViewDelegate {
    // The following lines define the parameters for Picker View
    @IBOutlet weak var myLabel: UILabel!
    @IBOutlet weak var myPicker: UIPickerView!

    let pickerData = ["Every minute", "Every 2 minutes", "Every 3 minutes", "Every 4 minutes", "Every 5 minutes", "Every 6 minutes", "Every 7 minutes", "Every 8 minutes", "Every 9 minutes", "Every 10 minutes"]

    override func viewDidLoad() {
        super.viewDidLoad()
        myPicker.delegate = self
        myPicker.dataSource = self
    }

    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
            return pickerData.count
    }

    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return pickerData[row]
    }

    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        myLabel.text = pickerData[row]
    }

    var interval: TimeInterval = 60.0 // Assume that row 0 is selected by default

    // The following method might be the tricky part I guess.

    func pickerView(pickerView: UIPickerView!, didSelectRow row: Int, inComponent component: Int) {
interval = Double(row+1) * 60.0
    }


    let requestIdentifier = "SampleRequest" //identifier is to cancel the notification request

    @IBAction  func triggerNotification(){
        print("notification will be triggered in five seconds..Hold on tight")
        let content = UNMutableNotificationContent()
        content.title = "Placeholder"
        content.subtitle = "Placeholder"
        content.body = "Placeholder"
        content.sound = UNNotificationSound.default()

        let trigger = UNTimeIntervalNotificationTrigger.init(timeInterval:self.interval, repeats: true)
        let request = UNNotificationRequest(identifier:requestIdentifier, content: content, trigger: trigger)

        UNUserNotificationCenter.current().delegate = self
        UNUserNotificationCenter.current().add(request){(error) in
            if (error != nil){
                print(error?.localizedDescription ?? "User instance is nil")
            }
        }
    }

    @IBAction func stopNotification(_ sender: AnyObject) {

        print("Removed all pending notifications")
        let center = UNUserNotificationCenter.current()
        center.removePendingNotificationRequests(withIdentifiers: [requestIdentifier])
    }
}

有人能帮我吗？

Answer 1

似乎我已经通过以下步骤解决了这个问题。因为我注意到一切都在正常运行，直到我试图在interval中存储我所需的值--这个方法就是做不到，但是之前的方法会正确地分配row。

而不是这个

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int,          inComponent component: Int) {
    myLabel.text = pickerData[row]
}

var interval: TimeInterval = 60.0 // Assume that row 0 is selected by default

func pickerView(pickerView: UIPickerView!, didSelectRow row: Int, inComponent component: Int) {
interval = Double(row+1) * 60.0
}

我将行interval = Double(row+1) * 60.0包含在具有myLabel.text = pickerData[row]的函数中，如下所示：

var interval: TimeInterval = 60.0 // Assume that row 0 is selected by default
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int,          inComponent component: Int) {
    myLabel.text = pickerData[row]
    interval = Double(row+1) * 60.0
}

这在interval中工作并存储正确的值，例如，当您选择行“每2分钟”时，它存储120.0。

Answer 2

创建一个分钟数组，并在分钟数组下面声明interval变量，如下所示

let pickerData = ["Every minute", "Every 2 minutes", "Every 3 minutes", "Every 4 minutes", "Every 5 minutes", "Every 6 minutes", "Every 7 minutes", "Every 8 minutes", "Every 9 minutes", "Every 10 minutes"]
let minutes[Int] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
var interval: Inte = 0

将pickerView didSelectRow函数更改为

func pickerView(pickerView: UIPickerView!, didSelectRow row: Int, inComponent component: Int) {
    interval = minutes[row]
}

现在，您的间隔为int，即从1到10，这取决于选择了哪一行。

@IBAction  func triggerNotification(){
    print("notification will be triggered in five seconds..Hold on tight")
    let content = UNMutableNotificationContent()
    content.title = "Placeholder"
    content.subtitle = "Placeholder"
    content.body = "Placeholder"
    content.sound = UNNotificationSound.default()

    let minute = TimeInterval(interval * 60)

    let trigger = UNTimeIntervalNotificationTrigger.init(timeInterval:(minute), repeats: true)
    let request = UNNotificationRequest(identifier:requestIdentifier, content: content, trigger: trigger)

    UNUserNotificationCenter.current().delegate = self
    UNUserNotificationCenter.current().add(request){(error) in
        if (error != nil){
            print(error?.localizedDescription ?? "User instance is nil")
        }
    }
}

我创建了一个新的分钟变量，它是一个TimeInterval，也是乘法间隔*60。如果间隔为2，则为2*60 = 120，依此类推。

Answer 3

您可以简单地将1添加到选定的行中，然后乘以60.0：

var interval: TimeInterval = 60.0 // Assume that row 0 is selected by default

func pickerView(pickerView: UIPickerView!, didSelectRow row: Int, inComponent component: Int) {
    interval = Double(row+1) * 60.0
}

@IBAction  func triggerNotification() {

    let content = UNMutableNotificationContent()
    content.title = "Placeholder"
    content.subtitle = "Placeholder"
    content.body = "Placeholder"
    content.sound = UNNotificationSound.default()

    let trigger = UNTimeIntervalNotificationTrigger.init(timeInterval:interval, repeats: true)
    let request = UNNotificationRequest(identifier:requestIdentifier, content: content, trigger: trigger)

    UNUserNotificationCenter.current().delegate = self
    UNUserNotificationCenter.current().add(request){(error) in
        if (error != nil){
            print(error?.localizedDescription ?? "User instance is nil")
        }
    }
}