I have added refreshcontrol to my table view , while pulling down , it should call a local method with dictionary as parameter. But i searched a lot but couldnt send a dictionary as a parameter in addTarget of uirefreshcontrol. Please help me calling a local method with dictionary as a parameter.
What i have tried is using objc and also without selector but it didnt work.
let defaultParam = ["buyer_id":UserDefaults.standard.string(forKey: "UserName")!,"transaction_type":""]
refreshControl.addTarget(self, action: "loadStatement:", for: .valueChanged)
}
func loadStatement(parameter : Dictionary<String, Any>) {
}
It would be very helpful if i can call this local method with parameter i wish to send.
The dictionary that you want to pass doesn't contain anything specific to the refreshControl.
You can create the defaultParams dictionary in the loadStatement() method itself instead of trying to pass it in the refreshControl event, i.e.
func loadStatement() {
var defaultParam = [String:Any]()
defaultParam["buyer_id"] = UserDefaults.standard.string(forKey: "UserName")
defaultParam["transaction_type"] = ""
//rest of the code here...
}
Or if there are some dependants, you can use instance properties instead.
Edit:
Try using default parameter values to get that working,
override func viewDidLoad() {
super.viewDidLoad()
refreshControl.addTarget(self, action: #selector(loadStatement(parameter:)), for: .valueChanged)
}
func method1() {
var params = [String:Any]()
//....
loadStatement(parameter: params) //called with custom params here....
}
#objc func loadStatement(parameter: [String:Any] = ["buyer_id":UserDefaults.standard.string(forKey: "UserName")!,"transaction_type":""]) {
print(parameter)
//rest of the code here...
}
I have found myself another kind of solution. Simply another method is written with no parameter and that is called. That empty method should call with the required parameter. And its fine now. Thanks for your concern.
refreshControl.addTarget(self, action: #selector(loadDatas), for: .valueChanged)
#objc func loadDatas(){
loadStatement(parameter: ["buyer_id":UserDefaults.standard.string(forKey: "UserName")!,"transaction_type":""])
}
Related
I'm programmatically adding a UITapGestureRecognizer to one of my views:
let gesture = UITapGestureRecognizer(target: self, action: #selector(self.handleTap(modelObj:myModelObj)))
self.imageView.addGestureRecognizer(gesture)
func handleTap(modelObj: Model) {
// Doing stuff with model object here
}
The first problem I encountered was "Argument of '#selector' does not refer to an '#Objc' method, property, or initializer.
Cool, so I added #objc to the handleTap signature:
#objc func handleTap(modelObj: Model) {
// Doing stuff with model object here
}
Now I'm getting the error "Method cannot be marked #objc because the type of the parameter cannot be represented in Objective-C.
It's just an image of the map of a building, with some pin images indicating the location of points of interest. When the user taps one of these pins I'd like to know which point of interest they tapped, and I have a model object which describes these points of interest. I use this model object to give the pin image it's coordinates on the map so I thought it would have been easy for me to just send the object to the gesture handler.
It looks like you're misunderstanding a couple of things.
When using target/action, the function signature has to have a certain form…
func doSomething()
or
func doSomething(sender: Any)
or
func doSomething(sender: Any, forEvent event: UIEvent)
where…
The sender parameter is the control object sending the action message.
In your case, the sender is the UITapGestureRecognizer
Also, #selector() should contain the func signature, and does NOT include passed parameters. So for…
func handleTap(sender: UIGestureRecognizer) {
}
you should have…
let gesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(sender:)))
Assuming the func and the gesture are within a view controller, of which modelObj is a property / ivar, there's no need to pass it with the gesture recogniser, you can just refer to it in handleTap
Step 1: create the custom object of the sender.
step 2: add properties you want to change in that a custom object of the sender
step 3: typecast the sender in receiving function to a custom object and access those properties
For eg:
on click of the button if you want to send the string or any custom object then
step 1: create
class CustomButton : UIButton {
var name : String = ""
var customObject : Any? = nil
var customObject2 : Any? = nil
convenience init(name: String, object: Any) {
self.init()
self.name = name
self.customObject = object
}
}
step 2-a: set the custom class in the storyboard as well
step 2-b: Create IBOutlet of that button with a custom class as follows
#IBOutlet weak var btnFullRemote: CustomButton!
step 3: add properties you want to change in that a custom object of the sender
btnFullRemote.name = "Nik"
btnFullRemote.customObject = customObject
btnFullRemote.customObject2 = customObject2
btnFullRemote.addTarget(self, action: #selector(self.btnFullRemote(_:)), for: .touchUpInside)
step 4: typecast the sender in receiving function to a custom object and access those properties
#objc public func btnFullRemote(_ sender: Any) {
var name : String = (sender as! CustomButton).name as? String
var customObject : customObject = (sender as! CustomButton).customObject as? customObject
var customObject2 : customObject2 = (sender as! CustomButton).customObject2 as? customObject2
}
Swift 5.0 iOS 13
I concur a great answer by Ninad. Here is my 2 cents, the same and yet different technique; a minimal version.
Create a custom class, throw a enum to keep/make the code as maintainable as possible.
enum Vs: String {
case pulse = "pulse"
case precision = "precision"
}
class customTap: UITapGestureRecognizer {
var cutomTag: String?
}
Use it, making sure you set the custom variable into the bargin. Using a simple label here, note the last line, important labels are not normally interactive.
let precisionTap = customTap(target: self, action: #selector(VC.actionB(sender:)))
precisionTap.customTag = Vs.precision.rawValue
precisionLabel.addGestureRecognizer(precisionTap)
precisionLabel.isUserInteractionEnabled = true
And setup the action using it, note I wanted to use the pure enum, but it isn't supported by Objective C, so we go with a basic type, String in this case.
#objc func actionB(sender: Any) {
// important to cast your sender to your cuatom class so you can extract your special setting.
let tag = customTag as? customTap
switch tag?.sender {
case Vs.pulse.rawValue:
// code
case Vs.precision.rawValue:
// code
default:
break
}
}
And there you have it.
cell.btn.tag = indexPath.row //setting tag
cell.btn.addTarget(self, action: #selector(showAlert(_ :)), for: .touchUpInside)
#objc func showAlert(_ sender: UIButton){
print("sender.tag is : \(sender.tag)")// getting tag's value
}
Just create a custom class of UITapGestureRecognizer =>
import UIKit
class OtherUserProfileTapGestureRecognizer: UITapGestureRecognizer {
let userModel: OtherUserModel
init(target: AnyObject, action: Selector, userModel: OtherUserModel) {
self.userModel = userModel
super.init(target: target, action: action)
}
}
And then create UIImageView extension =>
import UIKit
extension UIImageView {
func gotoOtherUserProfile(otherUserModel: OtherUserModel) {
isUserInteractionEnabled = true
let gestureRecognizer = OtherUserProfileTapGestureRecognizer(target: self, action: #selector(self.didTapOtherUserImage(_:)), otherUserModel: otherUserModel)
addGestureRecognizer(gestureRecognizer)
}
#objc internal func didTapOtherUserImage(_ recognizer: OtherUserProfileTapGestureRecognizer) {
Router.shared.gotoOtherUserProfile(otherUserModel: recognizer.otherUserModel)
}
}
Now use it like =>
self.userImageView.gotoOtherUserProfile(otherUserModel: OtherUserModel)
You can use an UIAction instead:
self.imageView.addAction(UIAction(identifier: UIAction.Identifier("imageClick")) { [weak self] action in
self?.handleTap(modelObj)
}, for: .touchUpInside)
that may be a terrible practice but I simply add whatever I want to restore to
button.restorationIdentifier = urlString
and
#objc func openRelatedFact(_ sender: Any) {
if let button = sender as? UIButton, let stringURL = factButton.restorationIdentifier, let url = URL(string: stringURL) {
if UIApplication.shared.canOpenURL(url) {
UIApplication.shared.open(url, options: [:])
}
}
}
I am currently learning swift 5.2 and I found a problem when I try to use #selector and #objc function.
I created a #objc function and I call it in the #selector, but the function has a strikethrough in the autofill. Just like some other functions that is deprecated. It doesn't really affect anything, the app work just fine. But I really want to know why the strikethrough appears.
Someone says that is because the function recommend a return value. And I tried to return something, like a Bool, in the #objc function. And the strikethrough is gone, but it still affect nothing, no matter what the function returns.
This really confused me. Is there any one who can tell me why? Thanks!
Here is my minimal reproducible example:
let refreshControl_A = UIRefreshControl()
let refreshControl_B = UIRefreshControl()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
refreshControl_A.addTarget(self, action: #selector(refresh_A(sender:)), for: .valueChanged)
refreshControl_B.addTarget(self, action: #selector(refresh_B(sender:)), for: .valueChanged)
}
#objc func refresh_A(sender: UIRefreshControl) {
print("Have strikethrough!")
}
#objc func refresh_B(sender: UIRefreshControl) -> Bool {
print("No strikethrough!")
return true
}
The refresh_A function has the strikethrough in the autofill.
But the refresh_B function doesn't have the strikethrough in the autofill.
The only difference between these two functions is the return type, one is Viod, and the other is Bool. Both functions work fine.
So I am trying to base in a objc function as a parameter however I get the an error Use of unresolved identifier 'handler'
typealias Handler = (_ sender: UIControl) -> Void
class Custom {
var item = UIControl()
init(hander: Handler) {
item.addTarget(item.self, action: #selector(handler(_ :)), for: .touchUpInside)
}
}
var temp = Custom(hander: myFunc)
#objc func myFunc(_ sender: UIControl) {
print("hi")
}
The expected value is that if temp is pressed, then I should see hi in the console. Thank you so much for your help!
P.S.I tried to look at other questions for help, however they did not help at all. I have tried everything.
Use parameter type as Selector and your problem solved. Try following code
class Custom {
var item = UIControl()
init(handler: Selector) {
item.addTarget(item.self, action: handler, for: .touchUpInside)
}
}
var temp = Custom(handler: #selector(myFunc(_:)))
#objc func myFunc(_ sender: UIControl) {
print("hi")
}
I'm programmatically adding a UITapGestureRecognizer to one of my views:
let gesture = UITapGestureRecognizer(target: self, action: #selector(self.handleTap(modelObj:myModelObj)))
self.imageView.addGestureRecognizer(gesture)
func handleTap(modelObj: Model) {
// Doing stuff with model object here
}
The first problem I encountered was "Argument of '#selector' does not refer to an '#Objc' method, property, or initializer.
Cool, so I added #objc to the handleTap signature:
#objc func handleTap(modelObj: Model) {
// Doing stuff with model object here
}
Now I'm getting the error "Method cannot be marked #objc because the type of the parameter cannot be represented in Objective-C.
It's just an image of the map of a building, with some pin images indicating the location of points of interest. When the user taps one of these pins I'd like to know which point of interest they tapped, and I have a model object which describes these points of interest. I use this model object to give the pin image it's coordinates on the map so I thought it would have been easy for me to just send the object to the gesture handler.
It looks like you're misunderstanding a couple of things.
When using target/action, the function signature has to have a certain form…
func doSomething()
or
func doSomething(sender: Any)
or
func doSomething(sender: Any, forEvent event: UIEvent)
where…
The sender parameter is the control object sending the action message.
In your case, the sender is the UITapGestureRecognizer
Also, #selector() should contain the func signature, and does NOT include passed parameters. So for…
func handleTap(sender: UIGestureRecognizer) {
}
you should have…
let gesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(sender:)))
Assuming the func and the gesture are within a view controller, of which modelObj is a property / ivar, there's no need to pass it with the gesture recogniser, you can just refer to it in handleTap
Step 1: create the custom object of the sender.
step 2: add properties you want to change in that a custom object of the sender
step 3: typecast the sender in receiving function to a custom object and access those properties
For eg:
on click of the button if you want to send the string or any custom object then
step 1: create
class CustomButton : UIButton {
var name : String = ""
var customObject : Any? = nil
var customObject2 : Any? = nil
convenience init(name: String, object: Any) {
self.init()
self.name = name
self.customObject = object
}
}
step 2-a: set the custom class in the storyboard as well
step 2-b: Create IBOutlet of that button with a custom class as follows
#IBOutlet weak var btnFullRemote: CustomButton!
step 3: add properties you want to change in that a custom object of the sender
btnFullRemote.name = "Nik"
btnFullRemote.customObject = customObject
btnFullRemote.customObject2 = customObject2
btnFullRemote.addTarget(self, action: #selector(self.btnFullRemote(_:)), for: .touchUpInside)
step 4: typecast the sender in receiving function to a custom object and access those properties
#objc public func btnFullRemote(_ sender: Any) {
var name : String = (sender as! CustomButton).name as? String
var customObject : customObject = (sender as! CustomButton).customObject as? customObject
var customObject2 : customObject2 = (sender as! CustomButton).customObject2 as? customObject2
}
Swift 5.0 iOS 13
I concur a great answer by Ninad. Here is my 2 cents, the same and yet different technique; a minimal version.
Create a custom class, throw a enum to keep/make the code as maintainable as possible.
enum Vs: String {
case pulse = "pulse"
case precision = "precision"
}
class customTap: UITapGestureRecognizer {
var cutomTag: String?
}
Use it, making sure you set the custom variable into the bargin. Using a simple label here, note the last line, important labels are not normally interactive.
let precisionTap = customTap(target: self, action: #selector(VC.actionB(sender:)))
precisionTap.customTag = Vs.precision.rawValue
precisionLabel.addGestureRecognizer(precisionTap)
precisionLabel.isUserInteractionEnabled = true
And setup the action using it, note I wanted to use the pure enum, but it isn't supported by Objective C, so we go with a basic type, String in this case.
#objc func actionB(sender: Any) {
// important to cast your sender to your cuatom class so you can extract your special setting.
let tag = customTag as? customTap
switch tag?.sender {
case Vs.pulse.rawValue:
// code
case Vs.precision.rawValue:
// code
default:
break
}
}
And there you have it.
cell.btn.tag = indexPath.row //setting tag
cell.btn.addTarget(self, action: #selector(showAlert(_ :)), for: .touchUpInside)
#objc func showAlert(_ sender: UIButton){
print("sender.tag is : \(sender.tag)")// getting tag's value
}
Just create a custom class of UITapGestureRecognizer =>
import UIKit
class OtherUserProfileTapGestureRecognizer: UITapGestureRecognizer {
let userModel: OtherUserModel
init(target: AnyObject, action: Selector, userModel: OtherUserModel) {
self.userModel = userModel
super.init(target: target, action: action)
}
}
And then create UIImageView extension =>
import UIKit
extension UIImageView {
func gotoOtherUserProfile(otherUserModel: OtherUserModel) {
isUserInteractionEnabled = true
let gestureRecognizer = OtherUserProfileTapGestureRecognizer(target: self, action: #selector(self.didTapOtherUserImage(_:)), otherUserModel: otherUserModel)
addGestureRecognizer(gestureRecognizer)
}
#objc internal func didTapOtherUserImage(_ recognizer: OtherUserProfileTapGestureRecognizer) {
Router.shared.gotoOtherUserProfile(otherUserModel: recognizer.otherUserModel)
}
}
Now use it like =>
self.userImageView.gotoOtherUserProfile(otherUserModel: OtherUserModel)
You can use an UIAction instead:
self.imageView.addAction(UIAction(identifier: UIAction.Identifier("imageClick")) { [weak self] action in
self?.handleTap(modelObj)
}, for: .touchUpInside)
that may be a terrible practice but I simply add whatever I want to restore to
button.restorationIdentifier = urlString
and
#objc func openRelatedFact(_ sender: Any) {
if let button = sender as? UIButton, let stringURL = factButton.restorationIdentifier, let url = URL(string: stringURL) {
if UIApplication.shared.canOpenURL(url) {
UIApplication.shared.open(url, options: [:])
}
}
}
I'm trying to create a dynamic menu where I send the text and the action of a button from one controller to the next controller and then I want to generate the button that runs the action, but I'm having trouble with the syntax.
So as an example in the first controller i have:
let vc = storyboard.instantiateViewController(withIdentifier:
"CompetitiveKPIChart") as! CompetitiveKPIChartViewController
vc.Menu = [["Menu1":ClickBack()],["Menu2":ClickBack()],["Menu3":ClickBack()]]
func ClickBack() {
self.dismiss(animated: true, completion: {});
}
and in the second controller:
var Menu : [Dictionary<String,()>] = []
override func viewDidLoad() {
let gesture2 = UITapGestureRecognizer(target: self,action: Menu["Menu1"])
btnBack.addGestureRecognizer(gesture2)
}
How can I call the ClickBack() from the first controller in the second controller GestureRecognizer?
The syntax of your Menu declaration is wrong - it should be () -> () for a void function, not ().
This works in Playground, your syntax does not...
var menu : [Dictionary<String,() -> ()>] = [] // Don't use capitals for variables...
func aFunc() {
print("Hello aFunc")
}
menu = [["aFunc": aFunc]]
menu.first!["aFunc"]!() // Prints "Hello aFunc"
However, I think there is a second problem with your code. Your line
UITapGestureRecognizer(target: self,action: Menu["Menu1"])
cannot compile, as Menu is an array, not a dictionary. I think you probably meant
var menu : Dictionary<String,() -> ()> = [:]
in which case your set-up code should say
vc.menu = ["Menu1":ClickBack, "Menu2":ClickBack, "Menu3":ClickBack]
However, there is a final, and probably insurmountable problem, which is that your code
override func viewDidLoad() {
let gesture2 = UITapGestureRecognizer(target: self, action: menu["Menu1"])
btnBack.addGestureRecognizer(gesture2)
}
will still give an error, since action: needs to be a Selector, which is an #objc message identifier, not a Swift function.
I'm afraid I can't see a good way to make this (rather clever) idea work. Time to refactor?