问题描述
我有一个日期选择器。我想将显示的日期更改为使用手势控制之前或之后的日期。即,当一个人向左滑动时,日期会推迟一天,如果一个人向右滑动,则日期会推迟一天。我不知道如何实现这一点,因为我已经尝试了下面的方法,但我收到一条错误消息,指出“无法转换‘UITextField 类型的值?’到预期的参数类型“日期”。如果有人可以帮助我或为我指明正确的方向,我将不胜感激!谢谢
视图控制器:
@IBOutlet weak var userDate: UITextField!
private var datePicker: UIDatePicker?
override func viewDidLoad() {
super.viewDidLoad()
datePicker = UIDatePicker()
datePicker?.datePickerMode = .date
datePicker?.addTarget(self,action: #selector(Test.dateChanged(datePicker:)),for: .valueChanged)
userDate.inputView = datePicker
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "EEEE,MMM d,yyyy"
let todayDate = dateFormatter.string(from: Date.init())
self.userDate.text = todayDate
let swipeLeft = UISwipeGestureRecognizer(target: self,action: #selector(self.handleGesture(gesture:)))
swipeLeft.direction = .left
self.view.addGestureRecognizer(swipeLeft)
let swipeRight = UISwipeGestureRecognizer(target: self,action: #selector(self.handleGesture(gesture:)))
swipeRight.direction = .right
self.view.addGestureRecognizer(swipeRight)
}
@objc func handleGesture(gesture: UISwipeGestureRecognizer) -> Void {
if gesture.direction == UISwipeGestureRecognizer.Direction.right {
print("Swipe Right")
view.backgroundColor = .black
// WHERE I WOULD LIKE TO CHANGE THE DATE ONE DAY AFTER
}
else if gesture.direction == UISwipeGestureRecognizer.Direction.left {
print("Swipe Left")
view.backgroundColor = .yellow
// WHERE I WOULD LIKE TO CHANGE THE DATE ONE DAY BEFORE
}
}
Calendar.current.date(byAdding: .day,value: 1,to: userDate)!
解决方法
函数 date(byAdding:value:to:options:)
期望将日期类型作为参数传递。您正在传递 UITextField 而不是日期类型。
我想你想做的是
Calendar.current.date(byAdding: .day,value: 1,to: datePicker.date)!
,
您正在尝试设置一个文本字段,该方法在此处需要一个日期:
Calendar.current.date(byAdding: .day,to: userDate)!
从您的问题来看,您似乎想从 textField 中显示的当前日期中添加或减去一天。尝试以下代码来做到这一点。这从 userDate.text 获取日期,并根据将 userDate.text 设置为新值的滑动方向添加或减去一天。
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var userDate: UITextField!
private var datePicker: UIDatePicker?
private let dateFormatter = DateFormatter()
override func viewDidLoad() {
super.viewDidLoad()
datePicker = UIDatePicker()
datePicker?.datePickerMode = .date
// datePicker?.addTarget(self,action: #selector(Test.dateChanged(datePicker:)),for: .valueChanged)
userDate.inputView = datePicker
dateFormatter.dateFormat = "EEEE,MMM d,yyyy"
let todayDate = dateFormatter.string(from: Date.init())
self.userDate.text = todayDate
let swipeLeft = UISwipeGestureRecognizer(target: self,action: #selector(self.handleGesture(gesture:)))
swipeLeft.direction = .left
self.view.addGestureRecognizer(swipeLeft)
let swipeRight = UISwipeGestureRecognizer(target: self,action: #selector(self.handleGesture(gesture:)))
swipeRight.direction = .right
self.view.addGestureRecognizer(swipeRight)
}
@objc func handleGesture(gesture: UISwipeGestureRecognizer) -> Void {
if gesture.direction == UISwipeGestureRecognizer.Direction.right {
print("Swipe Right")
// WHERE I WOULD LIKE TO CHANGE THE DATE ONE DAY AFTER
let date = dateFormatter.date (from: userDate.text ?? dateFormatter.string(from: Date()))!
let plusDay = Calendar.current.date(byAdding: .day,to: date)!
userDate.text = dateFormatter.string(from: plusDay)
}
else if gesture.direction == UISwipeGestureRecognizer.Direction.left {
print("Swipe Left")
// WHERE I WOULD LIKE TO CHANGE THE DATE ONE DAY BEFORE
let date = dateFormatter.date (from: userDate.text ?? dateFormatter.string(from: Date()))!
let minusDay = Calendar.current.date(byAdding: .day,value: -1,to: date)!
userDate.text = dateFormatter.string(from: minusDay)
}
}
}