I am trying to build a zodiac sign app for class. I am using a UIDatePicker and an UIImageView to display the image once the user picks a date (date range, say if the date of birth is between a certain date). The zodiac will be revealed in text and also the image appears. So far I have my user interface and all the images ready, but I am not sure how to go with the main code for it to function properly.
var zodiac = ["Aqurius", "Pisces", ...]
override func viewDidLoad() {
zodiacSign.text = zodiac[0]
}
Add an #IBAction by ctrl-dragging from your UIDatePicker in Interface Builder to your view controller.
#IBAction func datePickerChanged(sender: AnyObject) {
let date = datePicker.date
// configure your labels and images according to date
}
Related
I am having this strange issue in UIDatePicker mode .countdownTimer
When I add constraints of up/down/left/right to the datePicker view, the callback is not registered for the first time. However, if I add only Alignment constraints, the callback works everytime. Maybe its a bug. Any idea why isn't it working?
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var datePicker: UIDatePicker!
override func viewDidLoad() {
super.viewDidLoad()
datePicker.datePickerMode = .countDownTimer
datePicker.addTarget(self, action: #selector(datePickerValueChanged(_:)), for: .valueChanged)
}
#objc func datePickerValueChanged(_ sender: UIDatePicker){
print("Selected value \(sender.countDownDuration)")
}
}
OK, it's a long-known bug in iOS, since iOS 7 or so.
You can work-around in your case if you put the following somewhere into viewDidLoad:
DispatchQueue.main.async {
self.datePicker.countDownDuration = self.datePicker.countDownDuration
}
Seems nasty, and is nasty.
The workaround of setting the countDownDuration didn't work for me. Instead the only way I managed to solve this is to replace the UIDatePicker with a UIPickerView and populate it myself with 4 components: hours, "hour(s)" label, mins, "min(s)" label.
The hours are 0-23
The hours label is a single row component, which
gets reloaded when the hours are changed so that it switches to
"hour" when it's 1 hour
The mins are 0-59
The mins label is the same
as the hours label
I was able to fix this issue in SwiftUI (using a "UIDatePicker" created with "UIViewRepresentable") by appending an "onAppear" to the picker and inside the closure updating the state variable used for tracking the duration to any value that is not the default value. This forces a programmatic update on the first render which then allows the picker to work correctly on the first spin.
I have 2 text fields in my storyboard. One for username, the other one to pick a date. However, I am trying to validate the if the user has a specific amount of characters in the username:
func addTargetToTextField() {
registerUserNameText.addTarget(self, action: #selector(textFieldDidChange), for: UIControl.Event.editingChanged)
}
and
#objc func textFieldDidChange() {
let isText = registerUserNameText.text?.count ?? 0 > 3
if isText { ... etc
I am trying to copy that methods on my date picker text field, but it is not working. Im not a Swift expert, but I think it is because the user picks a date and not writing something in the textfield.
How can I check if a date in the textfield was picked?
I changed the addTarget method of my DatePicker and not the TextField using .valueChanged and it is working now.
Let's say that I have a UIDatePicker and the mode is set to .date.
I want the following behaviour:
For example, March has 30 days. If I scroll below the 30th day, I want the month to be automatically incremented to April and so on.
Is there a property that does just that? I couldn't find one.
Thanks.
I don't think there's any way to do what you want with a normal UIDatePicker. You could attach an action to the valueChanged event, but that doesn't get called until the date picker stops moving.
You could probably create a custom date picker using a standard UIPickerView. You could use the data source methods to figure out when the "wheels" are turned, call selectedRow(inComponent:) to figure out which values are selected for each wheel, and then call selectRow(_:inComponent:animated) to switch the month if the user scrolls the day past the end of the month.
How to advance other fields in datePicker automatically?
The best way to do this is using the Target-Action design pattern. Basically, when a user chooses a new date (action), the view (a target) does something.
Here's some code that changes the day value to 1 if it's set to 0:
override func viewDidLoad() {
...
let datePicker = UIDatePicker()
datePicker.datePickerMode = .date
datePicker.addTarget(self, action: #selector(doStuff(sender:)), for: UIControlEvents.valueChanged)
view.addSubview(datePicker)
...
}
#IBAction func doStuff(sender: UIDatePicker) {
let calendar = Calendar.current
let components = calendar.dateComponents([.day], from: sender.date)
if components.day == 0 {
// Using Calendar.current automatically takes care of Time Zones for us.
if let date = calendar.date(byAdding: .day, value: 1, to: sender.date) {
sender.setDate(date, animated: true)
}
}
}
Note: This example is in Swift 4.
No, there is no property that does this that I am aware of.
I have a UIViewController with several UITextFields. When tap one text field, it should present the barcode scanning view controller. Once the scanning is completed, my barcode scanning viewcontroller is disappearing (used "dismissViewcontroller") and the scanned value should entered into the text field I tapped. This is working fine. I have set the delegate for each text field like this.
[field addTarget:metrixUIViewControllerIn action:#selector(executeScriptOnTextFieldChange:) forControlEvents:UIControlEventEditingChanged];
The problem is this :
Lets say I have set an alert to display inside this executeScriptOnTextFieldChange method. Once I tapped on the 1st text field, then the barcode scanner comes. Once I scanned barcode scanner closes and set the value for the first text field and fire the alert.Thats ok. But then if scanned by tapping the 2nd textfield and the string will set to that textfield and fire the alert related to 2nd textfield also fire the alert related to first textfield as well. I want to stop happening this. Is there any way to disable the delegate for one textfield? This happens because I am refreshing the view in the viewDidAppear. But I have to do that as well. Please help me.
UIControlEventEditingChanged for a textField can fire at many different events that are not even directly related to that textField, but related inderectly.
For instance, when your ViewController is presenting the barcodeScanner it may trigger a "resignFirstResponder" event on the textField. Also when the 2nd textField is tapped, cause the 2nd becomes first responder and the 1st suffers a "resignFirstResponder".
I suggest trying to use a UITapGestureRecognizer in your textField instead. Example:
Swift 4
#IBOutlet weak var textField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
self.textField.tag = 1
self.textField.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(fireTextField(_:))))
}
#objc func fireTextField(_ sender: UIGestureRecognizer){
let view = sender.view
guard view != nil else{
//Do nothing
return
}
let condition = view!.tag == 1
if condition{
//or do whatever other stuff you need
self.textField.becomeFirstResponder()
}else{
//Whatever for other textFields
}
}
This way, you could use the "tag" attribute to determine which textField is firing and so adjust "condition". You could also filter the flow with a switch using the "tag".
Not sure if any of this will really help as I would need more info about the flow you need to accomplish. Hope it does help!
There is similar question on Stack Overflow, but the problem there was different then mine, so I feel free to open this one.
I have iOS view controller with a UIDatePicker defined in storyboard.
I have defined(connected) IBOutlet in view controller code like this:
#IBOutlet weak var endTimeDatePicker: UIDatePicker!
At one point I set initial date like this:
endTimeDatePicker.date = state!.endTime;
or like this:
endTimeDatePicker.setDate(state!.endTime, animated: true);
and it shows correct date indicating that date picker is connected correctly.
But then, if I pick another date and try to get selected date with endTimeDatePicker.date it always returns the same - today's date, no matter what I pick.
Storyboard properties for date picker are:
Mode - Date and Time
Interval - 1 minute
Date - Current Date (but it's the same with custom, only returning defined custom date every time)
Is there something that I've missed to do?
I don't have for sure two different datePickers (like in potential duplicate Stack Overflow questions)
EDIT: looks like it only happens when Date Picker has set initial value from code.
EDIT: code that sets Date Picker:
private func reloadData (state : State?)
{
if (state != nil)
{
endTimeDatePicker.setDate(state!.endTime, animated: true);
backgroundImage.image = UIImage(named: state!.type.imageName)!;
}
else
{
let endDate = NSDate(timeIntervalSinceNow: 1800);
endTimeDatePicker.setDate(endDate, animated: true);
backgroundImage.image = UIImage(named: StateType.Active.imageName);
}
}
Code that tries to read selected date:
#IBAction func doneTapped(sender: AnyObject) {
let row: Int = self.stateTypePicker.selectedRowInComponent(0);
state = State (id: -1, type: stateTypes[row], startTime: NSDate(), endTime: self.endTimeDatePicker.date);
service.addState(state!) {
(responseDict) in
}
}
func reloadData is called in callback for http request. Could be thread lock problem maybe?
Your issue is related to the callback method reloadData from the NSURLSession. In here, you are updating the UIDatePicker in a background thread, but all UI updates have to be done on the main thread.
This is the reason why you are seeing todays date, when you are reading the date property of the UIDatePicker.