I'm developing first app using Swift.
in one of my Class I need to store closure in an Array. Like an event manager :
typealias eventCallback = (eventName:String, data:[MasterModel]?) -> Void;
class MHttpLoader: NSObject
{
var eventRegister : [String: [eventCallback]];
class var instance : MHttpLoader
{
struct Static {
static let instance : MHttpLoader = MHttpLoader(baseURL:NSURL(string:"http://192.168.0.11:3000"));
}
return Static.instance;
}
class func registerEvent(eventName:String, callback:eventCallback)
{
if var tab = MHttpLoader.instance.eventRegister[eventName]
{
tab.append(callback);
}
else
{
MHttpLoader.instance.eventRegister[eventName] = [callback];
}
}
func fireEvent(eventName: String, data:[MasterModel]?)
{
if let tab = self.eventRegister[eventName]
{
for callback in tab
{
callback(eventName:eventName, data:data);
}
}
}
}
All this code work pretty well, the problem is when i want to remove a closure from my array.
For exemple :
class func removeEvent(eventName:String, callback:eventCallback)
{
if var tab :Array = MHttpLoader.instance.eventRegister[eventName]
{
if let index = find(tab, callback) as? Int
{
tab.removeAtIndex(index);
}
}
}
I have the error which says that my closure is not conform to protocol "Equatable"
I also tried :
class func removeEvent(eventName:String, callback:eventCallback)
{
if var tab :Array = MHttpLoader.instance.eventRegister[eventName]
{
tab = tab.filter({ (currentElement) -> Bool in
return currentElement != callback;
});
}
}
But I have the error : Cannot invoke '!=' with an argument list of type '((eventCallback), eventCallback)'
Here is my question how can i find the index of closure in array or simply compare closure?
Thank you
Related
I'm trying to pass data between viewControllers, but something seems wrong.
The first viewController I want to set the "Bool" to the protocol function to be able to recover in the other screen. What am I doing wrong, I always used protocols but at this time I got in trouble.
That's how I'm doing that:
//
// ComboBoxNode.swift
//
import Foundation
import SWXMLHash
protocol ComboBoxNodeDelegate {
func getCustomOption(data:Bool)
}
class ComboBoxNode: FormControlNode, IFormControlDataSource {
var listType: String?
var dataSource: String?
var dataSourceValue: String?
var dataSourceText: String?
var hasCustomOption:Bool?
var customOptionText: String?
var ctrlDataSourceType: String?
var parameters = [ParameterNode]()
var staticList: FormControlStaticListNode?
var delegate:ComboBoxNodeDelegate?
override init(indexer: XMLIndexer) {
super.init(indexer: indexer)
guard let element = indexer.element else {
preconditionFailure("Error")
}
let isCustomOption = element.bool(by: .hasCustomOption) ?? hasCustomOption
if isCustomOption == true {
self.delegate?.getCustomOption(data: hasCustomOption!)
}
self.readFormControlDataSource(indexer: indexer)
}
override func accept<T, E: IViewVisitor>(visitor: E) -> T where E.T == T {
return visitor.visit(node: self)
}
}
That's how I'm trying to recover on next screen:
// FormPickerViewDelegate.swift
import Foundation
import ViewLib
import RxSwift
class FormPickerViewDelegate: NSObject {
var items = Variable([(value: AnyHashable, text: String)]()) {
didSet {
PickerNodeDelegate = self
self.setDefaultValues()
}
}
private var controlViewModel: FormControlViewModel
private var customText:Bool?
private var PickerNodeDelegate:ComboBoxNodeDelegate?
init(controlViewModel: FormControlViewModel) {
self.controlViewModel = controlViewModel
}
func getItemByValue(_ value: Any) -> (AnyHashable, String)? {
if value is AnyHashable {
let found = items.value.filter {$0.value == value as! AnyHashable}
if found.count >= 1 {
return found[0]
}
}
return nil
}
}
extension FormPickerViewDelegate:ComboBoxNodeDelegate {
func getCustomOption(data: Bool) {
customText = data
}
}
Instead of setting PickerNodeDelegate = self in didSet {} closure
var items = Variable([(value: AnyHashable, text: String)]()) {
didSet {
PickerNodeDelegate = self
self.setDefaultValues()
}
}
Assign it in your init() function instead
init(controlViewModel: FormControlViewModel) {
self.controlViewModel = controlViewModel
PickerNodeDelegate = self
}
Note, your should declare your delegate to be weak also, since it's a delegate, your protocol should conform to be a class type in order to be weakified.
protocol ComboBoxNodeDelegate: class
...
weak var delegate: ComboBoxNodeDelegate?
Here is an example, hope it helps!
protocol ComboBoxNodeDelegate {
func getCustomOption(data:Bool) -> String
}
class ViewOne:ComboBoxNodeDelegate {
var foo:Bool = false
var bar:String = "it works!"
/** Return: String */
func getCustomOption(data:Bool) -> String { //conform here to protocol
// do whatever you wanna do here ...example
self.foo = data // you can set
return bar // even return what you want
}
//initialize
func initalizeViewTwo() {
let v2 = ViewTwo()
v2.delegate = self //since `self` conforms to the ComboBoxNodeDelegate protcol you are allowed to set
}
}
class ViewTwo {
var delegate:ComboBoxNodeDelegate?
func getCustomOption_forV1() {
let view2_foo = delegate.getCustomOption(data:true)
print(view2_foo) // should print "it works!"
}
}
All parameters passed around in Swift are constants -- so you cannot change them.
If you want to change them in a function, you must declare your protocol to pass by reference with inout:
protocol ComboBoxNodeDelegate {
func getCustomOption(data: inout Bool)
}
Note: you cannot pass a constant (let) to this function. It must be a variable -- which I see you are doing!
I've followed the solution at Make a Swift dictionary where the key is "Type"? to create dictionaries that can use a class type as keys.
What I want to do is: I have one dictionary that should store class types with their class type (aka metatype) as keys, too:
class MyScenario {
static var metatype:Metatype<MyScenario> {
return Metatype(self)
}
}
var scenarioClasses:[Metatype<MyScenario>: MyScenario.Type] = [:]
Then I have methods to register and execute scenarios:
public func registerScenario(scenarioID:MyScenario.Type) {
if (scenarioClasses[scenarioID.metatype] == nil) {
scenarioClasses[scenarioID.metatype] = scenarioID
}
}
public func executeScenario(scenarioID:MyScenario.Type) {
if let scenarioClass = scenarioClasses[scenarioID.metatype] {
let scenario = scenarioClass()
}
}
... Problem is in the last line:
Constructing an object of class type 'MyScenario' with a metatype
value must use a 'required' initializer.
It looks like the compiler is confused at that point since I cannot use 'required' at that assignment. Does anyone have an idea how I would have to instantiate the scenarioClass in executeScenario()?
This must do the job.
import Foundation
struct Metatype<T> : Hashable
{
static func ==(lhs: Metatype, rhs: Metatype) -> Bool
{
return lhs.base == rhs.base
}
let base: T.Type
init(_ base: T.Type)
{
self.base = base
}
var hashValue: Int
{
return ObjectIdentifier(base).hashValue
}
}
public class MyScenario
{
var p: String
public required init()
{
self.p = "any"
}
static var metatype:Metatype<MyScenario>
{
return Metatype(self)
}
}
var scenarioClasses:[Metatype<MyScenario>: MyScenario.Type] = [:]
public func registerScenario(scenarioID:MyScenario.Type)
{
if (scenarioClasses[scenarioID.metatype] == nil)
{
scenarioClasses[scenarioID.metatype] = scenarioID
}
}
public func executeScenario(scenarioID:MyScenario.Type)
{
if let scenarioClass = scenarioClasses[scenarioID.metatype]
{
let scenario = scenarioClass.init()
print("\(scenario.p)")
}
}
// Register a new scenario
registerScenario(scenarioID: MyScenario.self)
// Execute
executeScenario(scenarioID: MyScenario.self)
// Should print "any"
I am trying to extend a UIKit class (which I can't edit normally) by creating a new function and a new Function-type variable, which is going to use ObjC Runtime to make it look&feel like a stored property.
extension UITextField {
private struct DynamicallyDefinedVars {
static var oneVar = "oneVar"
}
var oneVar: ((String?)->Bool)? {
get{
return objc_getAssociatedObject(self, &DynamicallyDefinedVars.oneVar) as? (String?)->Bool
}
set{
if let newValue: AnyObject = newValue {
objc_setAssociatedObject(self, &DynamicallyDefinedVars.oneVar, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
}
}
func callTheVarFunc() -> Bool {
if let oneVar = oneVar {
return oneVar("Foo")
}
return true
}
}
What I hope to achieve:
var foo: UITextField
foo.oneVar = { (bar: String?) -> Bool in
return true
}
if foo.callTheVarFunc {
doSomething
}
But I am getting the following error:
Cannot convert value of type '((String?) -> Bool)?' to specified type 'AnyObject?'
It would work fine if oneVar was typed something like String or an array of sorts, but I see the Function Types are not included in AnyObject, thus giving me issues when trying to objc_setAssociatedObject. Any thoughts on how I can get the desired behaviour (through extensions, without subclassing)? Each instance has to have a different oneVar value to be used with the callTheVarFunc function.
I've just seen this problem, in Swift closures cannot be casted to AnyObject so you can workaround this annoying thing creating a custom class:
extension UITextField {
class CustomClosure {
var closure: ((String?)->Bool)?
init(_ closure: ((String?)->Bool)?) {
self.closure = closure
}
}
private struct DynamicallyDefinedVars {
static var oneVar = "oneVar"
}
var oneVar: ((String?)->Bool)? {
get{
if let cl = objc_getAssociatedObject(self, &DynamicallyDefinedVars.oneVar) as? CustomClosure {
return cl.closure
}
return nil
}
set{
objc_setAssociatedObject(self, &DynamicallyDefinedVars.oneVar,CustomClosure(newValue), .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
}
func callTheVarFunc() -> Bool {
if let oneVar = oneVar {
return oneVar("Foo")
}
return true
}
}
I have a container class that has an underlying dictionary. I have implemented subscripts for this class to access member of the underlying dictionary. Now, I am trying to create a sequence on this class so that I could iterate over all the elements of the underlying dictionary by using 'for-in' loop on the class instance itself. I have been looking to find some examples for Sequences for Swift Dictionary but could not find anything that explains the stuff well. I have seen some custom sequence examples for Swift Array but none for the Swift Dictionary. I would really appreciate if anyone could explain how I can achieve that. Following is the code for the class (no sequence code yet as I am not sure where to begin)
import Foundation
class STCQuestionList : GeneratorType, SequenceType {
private var questionDict: [String : STCQuestion] = [ : ];
subscript(key : String?) -> STCQuestion? {
get {
if (key != nil) {
return self.questionDict[key!];
}
return nil;
}
set(newValue) {
if (key != nil) {
self.questionDict[key!] = newValue;
}
}
}
func generate() -> GeneratorType {
}
func next() -> (String, STCQuestion)? {
if (self.questionDict.isEmpty) {
return .None
}
}
}
If I'm understanding correctly, how about just forwarding on the generate?
func generate() -> DictionaryGenerator<String, STCQuestion> {
return questionDict.generate()
}
(You don't need to implement GeneratorType, just SequenceType should do. It's generate() itself that returns a GeneratorType, and that's what has to implement next(), which the existing generate() implementation in Dictionary already does for you.)
Full worked example based on your code:
// Playground - noun: a place where people can play
import Foundation
class STCQuestion {
let foo: String
init(_ foo: String) {
self.foo = foo
}
}
class STCQuestionList : SequenceType {
private var questionDict: [String : STCQuestion] = [ : ];
subscript(key : String?) -> STCQuestion? {
get {
if key != nil {
return self.questionDict[key!];
}
return nil;
}
set(newValue) {
if key != nil {
self.questionDict[key!] = newValue;
}
}
}
func generate() -> DictionaryGenerator<String, STCQuestion> {
return questionDict.generate()
}
}
var list = STCQuestionList()
list["test"] = STCQuestion("blah")
list["another"] = STCQuestion("wibble")
list["third"] = STCQuestion("doodah")
for (key, value) in list {
println("Key: \(key) Foo: \(value.foo)")
}
// Output:
// Key: test Foo: blah
// Key: another Foo: wibble
// Key: third Foo: doodah
(Note: I re-thought this -- original answer via the edited page...)
Swift has a generic GeneratorOf type that you can use to create a generator. You just provide a closure that returns the next value in the initializer:
class STCQuestionList : SequenceType {
private var questionDict: [String : STCQuestion] = [ : ];
subscript(key : String?) -> STCQuestion? {
get {
if (key != nil) {
return self.questionDict[key!];
}
return nil;
}
set(newValue) {
if (key != nil) {
self.questionDict[key!] = newValue;
}
}
}
/// Creates a generator for each (key, value)
func generate() -> GeneratorOf<(String, STCQuestion)> {
var index = 0
return GeneratorOf<(String, STCQuestion)> {
if index < self.questionDict.keys.array.count {
let key = self.questionDict.keys.array[index++]
return (key, self.questionDict[key]!)
} else {
return nil
}
}
}
}
If you don't care about the order, can't you just call the same methods of dictionary or make your class a subclass of a dictionary? For example:
func generate() -> GeneratorType {
return self.questionDict.generate()
}
func next() -> (String, STCQuestion)? {
return self.questionDict.next()
}
I want to create a Swift dictionary that holds String type as its keys and Closures as its values. Following is the code that I have but it gives me the error:
'#lvalue is not identical to '(String, () -> Void)'
class CommandResolver {
private var commandDict:[String : () -> Void]!
init() {
self.setUpCommandDict();
}
func setUpCommandDict() {
self.commandDict["OpenAssessment_1"] = {
println("I am inside closure");
}
}
}
I tried looking at other question on StackOverflow regarding closures in dictionaries but it does not give me any satisfactory answer. So I would really appreciate some help here.
Here is the way to go. I am not sure exactly why your implementation does not work though.
class CommandResolver {
typealias MyBlock = () -> Void
private var commandDict:[String : MyBlock] = [String:MyBlock]()
init() {
self.setUpCommandDict();
}
func setUpCommandDict() {
self.commandDict["OpenAssessment_1"] = {
print("I am inside closure");
}
}
}
If you initialize your dictionary in your init before calling your setup function, it should work:
class CommandResolver {
private var commandDict: [String: () -> Void]
init() {
commandDict = [:]
setUpCommandDict()
}
func setUpCommandDict() {
commandDict["OpenAssessment_1"] = {
println("I am inside closure")
}
}
}