Observing the changes to Object Swift 4
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?
ios swift
edited Nov 26 '18 at 9:49
Rakesha Shastri
7,55121635
asked Nov 26 '18 at 9:25
RP89RP89
2839
add a comment |
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?
ios swift
edited Nov 26 '18 at 9:49
Rakesha Shastri
7,55121635
asked Nov 26 '18 at 9:25
RP89RP89
2839
Easiest way would probably to subclassNSObjectyour model layer. It'll give you KVO for standard types
– SirCJ
Nov 26 '18 at 9:33
add a comment |
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?
ios swift
edited Nov 26 '18 at 9:49
Rakesha Shastri
7,55121635
asked Nov 26 '18 at 9:25
RP89RP89
2839
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?
ios swift
ios swift
edited Nov 26 '18 at 9:49
Rakesha Shastri
7,55121635
asked Nov 26 '18 at 9:25
RP89RP89
2839
edited Nov 26 '18 at 9:49
Rakesha Shastri
7,55121635
asked Nov 26 '18 at 9:25
RP89RP89
2839
edited Nov 26 '18 at 9:49
Rakesha Shastri
7,55121635
edited Nov 26 '18 at 9:49
Rakesha Shastri
7,55121635
edited Nov 26 '18 at 9:49
Rakesha Shastri
7,55121635
7,55121635
asked Nov 26 '18 at 9:25
RP89RP89
2839
asked Nov 26 '18 at 9:25
RP89RP89
2839
asked Nov 26 '18 at 9:25
RP89RP89
2839
2839
Easiest way would probably to subclassNSObjectyour model layer. It'll give you KVO for standard types
– SirCJ
Nov 26 '18 at 9:33
add a comment |
Easiest way would probably to subclassNSObjectyour model layer. It'll give you KVO for standard types
– SirCJ
Nov 26 '18 at 9:33
Easiest way would probably to subclass
NSObject your model layer. It'll give you KVO for standard types– SirCJ
Nov 26 '18 at 9:33
Easiest way would probably to subclass
NSObject your model layer. It'll give you KVO for standard types– SirCJ
Nov 26 '18 at 9:33
add a comment |
2 Answers
2
active
oldest
votes
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.
answered Nov 26 '18 at 9:46
Rakesha ShastriRakesha Shastri
7,55121635
For this we have to write == function comparing each property of the object right?
– RP89
Nov 26 '18 at 12:31
@RP89 Try it! :) ( Hint: The default one is already implemented by default for structs ;) )
– Rakesha Shastri
Nov 26 '18 at 13:40
1
Thank you for helping in resolving this.
– RP89
Nov 26 '18 at 14:28
add a comment |
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.
answered Nov 26 '18 at 9:44
Super GeroySuper Geroy
616
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
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.
answered Nov 26 '18 at 9:46
Rakesha ShastriRakesha Shastri
7,55121635
For this we have to write == function comparing each property of the object right?
– RP89
Nov 26 '18 at 12:31
@RP89 Try it! :) ( Hint: The default one is already implemented by default for structs ;) )
– Rakesha Shastri
Nov 26 '18 at 13:40
1
Thank you for helping in resolving this.
– RP89
Nov 26 '18 at 14:28
add a comment |
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.
answered Nov 26 '18 at 9:46
Rakesha ShastriRakesha Shastri
7,55121635
For this we have to write == function comparing each property of the object right?
– RP89
Nov 26 '18 at 12:31
@RP89 Try it! :) ( Hint: The default one is already implemented by default for structs ;) )
– Rakesha Shastri
Nov 26 '18 at 13:40
1
Thank you for helping in resolving this.
– RP89
Nov 26 '18 at 14:28
add a comment |
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.
answered Nov 26 '18 at 9:46
Rakesha ShastriRakesha Shastri
7,55121635
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.
answered Nov 26 '18 at 9:46
Rakesha ShastriRakesha Shastri
7,55121635
answered Nov 26 '18 at 9:46
Rakesha ShastriRakesha Shastri
7,55121635
answered Nov 26 '18 at 9:46
Rakesha ShastriRakesha Shastri
7,55121635
answered Nov 26 '18 at 9:46
Rakesha ShastriRakesha Shastri
7,55121635
7,55121635
For this we have to write == function comparing each property of the object right?
– RP89
Nov 26 '18 at 12:31
@RP89 Try it! :) ( Hint: The default one is already implemented by default for structs ;) )
– Rakesha Shastri
Nov 26 '18 at 13:40
1
Thank you for helping in resolving this.
– RP89
Nov 26 '18 at 14:28
add a comment |
For this we have to write == function comparing each property of the object right?
– RP89
Nov 26 '18 at 12:31
@RP89 Try it! :) ( Hint: The default one is already implemented by default for structs ;) )
– Rakesha Shastri
Nov 26 '18 at 13:40
1
Thank you for helping in resolving this.
– RP89
Nov 26 '18 at 14:28
For this we have to write == function comparing each property of the object right?
– RP89
Nov 26 '18 at 12:31
For this we have to write == function comparing each property of the object right?
– RP89
Nov 26 '18 at 12:31
@RP89 Try it! :) ( Hint: The default one is already implemented by default for structs ;) )
– Rakesha Shastri
Nov 26 '18 at 13:40
@RP89 Try it! :) ( Hint: The default one is already implemented by default for structs ;) )
– Rakesha Shastri
Nov 26 '18 at 13:40
1
1
Thank you for helping in resolving this.
– RP89
Nov 26 '18 at 14:28
Thank you for helping in resolving this.
– RP89
Nov 26 '18 at 14:28
add a comment |
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.
answered Nov 26 '18 at 9:44
Super GeroySuper Geroy
616
add a comment |
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.
answered Nov 26 '18 at 9:44
Super GeroySuper Geroy
616
add a comment |
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.
answered Nov 26 '18 at 9:44
Super GeroySuper Geroy
616
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.
answered Nov 26 '18 at 9:44
Super GeroySuper Geroy
616
answered Nov 26 '18 at 9:44
Super GeroySuper Geroy
616
answered Nov 26 '18 at 9:44
Super GeroySuper Geroy
616
answered Nov 26 '18 at 9:44
Super GeroySuper Geroy
616
616
add a comment |
add a comment |
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Easiest way would probably to subclass
NSObjectyour model layer. It'll give you KVO for standard types– SirCJ
Nov 26 '18 at 9:33