Let's say I have a textfield where I tell the user to put in their name. The 'name' then gets populated into all the other appropriate fields. For example, say the 'other field' is where the person has to sign a document. Therefore, underneath that 'line' where the person would have to sign the document, the persons name will then be populated there.
How would I go about to fill out information in one part and it would then be populated in all the appropriate fields?
You could implement UITextFieldDelegate and your delegate will be called when the user enter something in your text field.
First set the delegate to self
txtField.delegate = self
Use this if you want to change the other fields when the user is done editiing your master field
func textFieldDidEndEditing(_ textField: UITextField, reason: UITextFieldDidEndEditingReason) {
// change other fields here
otherField.text = textField.text
}
Related
I have Swift object with about 20 Properties. In the app, there is a screen to get the user input and create the above swift object from the user entered value. Right now, if the user clicks the back button, all the user entered data will lose. So I want to alert the user to save the details if he/she has made any changes. How do we identify if the user has made any changes to the properties. Is it possible to use KVO in this case as we have too many properties?
What you need is a data model to hold the information in that particular screen, and then compare it with the original data when leaving the screen.
For the sake of simplicity, let's assume your screen has 2 text fields. One holds a name and another the age of a person.
struct Person: Equatable {
var name: String
var age: Int
}
When you first open this screen, the model will have the default values. Create a copy of this model and whenever the user makes any changes to the values on the screen, update the copy.
class YourViewController: UIViewController {
// Populate these 2 values when creating your view controller
var person: Person!
var personCopy: Person!
.
.
.
// You need to add this target to your text fields
#objc func textFieldDidChange(_ textField: UITextField) {
switch textField {
case personTextField:
personCopy.name = personTextField.text!
case ageTextField:
personCopy.age = Int(ageTextField.text!)!
default:
// Handle other text fields here or write separate cases for them
}
func dismissView() {
if person == personCopy {
// Dismiss your view
} else {
// Show alert
}
}
}
If the user presses the back button, all you need to do is compare these 2 models and check if they are the same. If they are the same, you can go back, if not, prompt an alert asking the user to save changes or discard.
I think KVO would be overkill here. Use KVO only for distant objects in your app.
Here you have the UITextFields in your viewController and you must have reference to the user object anyway.
Easier is: On the back button press you would check all text properties of your UITextField objects to the (existing) values of your user object. If one of them has changed then present the alert.
I am creating a conversion application. I have multiple text fields. What I intend to do is when I start entering Kg value its equivalent gram and pound value should be displayed in the gram and pound text fields. How can it be done using editingChanged function in iOS?
This question is very broad but I will try to give a short answer of how to track changed of text fields:
class YourViewController: UIViewController {
#IBOutlet weak var textField: UITextField!
#IBAction func textFieldDidChange(_ sender: UITextField) {
self.textField.text = doSomeCalculation(sender.text)
}
}
First, you need to set up a view controller (or a view or whatever suits your interface design) with a UITextField. Then you connect the UITextField with the variable textField and the desired action of the text field with the function textFieldDidChange. You can use the action Editing Changed but I prefer Value Changed (depends on what you want to achieve).
Any time the text field is changed the function textFieldDidChange is called and you can do your calculations and alter the text of textField.
Evening, in my app I have several UITextfield. Each one has to confirm to different limitations.
For example, I have a date Field, zipCode Field, SSN Field etc.
From the Apple Documentation I found:
Assign a delegate object to handle important tasks, such as:
Determining whether the user should be allowed to edit the text field’s contents.
Validating the text entered by the user.
Responding to taps in the keyboard’s return button.
Forwarding the user-entered text to other parts of your app.
Store a reference to the text field in one of your controller objects.
So I'm pretty sure I have to use delegates and func textFieldDidEndEditing(_:).
The only way that came to my mind is to use a switch statement inside the func textFieldDidEndEditing(_:) to confirm the delegate to the difference limitation.
Is there a better, safer and faster pattern to face this problem?
You can set unique tag to your every text field and can compare in textFieldDidEndEditing or you can take IBOutlet of every textField and can compare it in textFieldDidEndEditing like,
func textFieldDidEndEditing(textField: UITextField) {
// By tag
if textField.tag == 100 {
}
// OR
//by outlet
if textField == self.myTextField {
}
}
You are right, you will have to check the textfield, either you can check tags assigned for different text fields using switch statement like you said,
or you can compare textfields itself,
if textfield1,textfield2 are outlets to two text fields, you can compare as following,
func textFieldDidEndEditing(textField: UITextField)
{
if textField == textfield1
{
}
else if textField == textfield2
{
}
}
you can create enum for validation
enum Type {
case zipcode
case number
}
then you can create a method for validation like this :
func isValidate(text: String, type: Type) -> Bool {
switch type {
case .zipcode:
...
}
}
this method can be in Util class. this is best practice. because your logic is encapsulate from out .
If you need more control over the text which is committed to the text field or if you want to provide feedback while the text field is being edited, you should implement a different delegate instead:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
// Build and check the new text value. Accept or reject the change.
}
In the delegate, you can build the new text value. Validate it, apply constraints, decide on which feedback the user should receive ("Your password must be at least eight characters long", "This is not a valid IBAN"), accept or reject the change (i.e. return false).
Keep in mind, that the delegate is not called if you assign the text property manually. Moreover, this delegate is called when text is pasted into or deleted from the text field, which can make matters much more complicated depending on what you do.
I want to know if there is a way to know the value of textfield before the value is changed to the new value.
For example:
If the text field had a value "a" and the user entered "b", so the editing changed event is fired. When I try to fetch the value of the text field in the debugger it will display "ab". Is there a way that I can get "a" before "b" was written?
Here is a piece of code where I am trying to fetch the value:
#IBAction func commentEditingChanged(sender: AnyObject) {
if(!((sender as? UITextField)!.text!.isEmpty)){
counter++
}
else
{
counter--
}
}
In this case I want to know if the text was empty before the user entered text because I don't want the counter increments every time the user enters a character. I want to increment once the user entered any text.
And please don't propose to use delegate function textField:shouldChangeCharactersInRange:replacementString because my question is about this IBAction method.
If there is no way to do that using this IBAction Method, is there is any other IBAction method that can achieve what i want?
I have two UITextfield the user enters his name into the first and email into the second. I would like to know how to change the UIKeyboards return key depending if the name text field has an entry or not.
For instance if nametextfield is empty then I would like the UIkeyboard return key to be Next
else if the nametextfield has an entry in it then when the user selects the email text field I would like the return key to be submit.
Is this possible? if so how would I go about accomplishing it? any help would be appreciated.
You can have return key customized to prefixed values that you can see in UIReturnKeyType enum for each UITextField.
textFieldName.returnKeyType = UIReturnKeyNext;
textFieldEmail.returnKeyType = UIReturnKeyDefault;
Not sure if this is what you're looking for though.
You have a chance to set up keyboard characteristics in the UITextFieldDelegate Protocol method textFieldShouldBeginEditing: which is called before the text field becomes the first responder (indeed to decide if it may become the first responder). If you don't already have a delegate for the text field(s) in question you would have to assign one and implement at least that method. Presumably the same object handling the text field could hold the delegate methods. The following implementation sets the return key to "Search".
- (BOOL) textFieldShouldBeginEditing:(UITextField *)textField {
NSLog(#"textFieldShouldBeginEditing");
textField.returnKeyType = UIReturnKeySearch;
return YES;
}
You'd have to look at the contents of your text fields to decide what value to use.
Make use of the textField.returnKeyType property.
you can check out all the available options here http://developer.apple.com/library/ios/documentation/uikit/reference/UITextInputTraits_Protocol/Reference/UITextInputTraits.html#//apple_ref/doc/c_ref/UIReturnKeyType
textfield.returnKeyType = UIReturnKeySearch;