Closures are self-contained blocks of functionality that can be passed around and used in your code. Closures in Swift are similar to blocks in C and Objective-C and to lambdas in other programming languages.
Syntax with Function
[code language=”obj-c”]
func yourFunctionName(parameter:Type, … , withCompletionHandler:(result:Type) -> Void)
[/code]
For more closure syntax : goshdarnclosuresyntax.com
Example
Function Definition:
[code language=”obj-c”]
func closureReturn(isTest:Bool, withCompletionHandler:(result:String) -> Void) {
if(isTest){
withCompletionHandler(result: "Yes")
}
else{
withCompletionHandler(result: "No")
}
}
[/code]
Calling Function:
[code language=”obj-c”]
closureReturn(true) { (result) -> Void in
print(result)
}
[/code]
Output should be respective to value true/false.
In next post I will write a tutorial on a wrapper class for Alamofire with use of SwiftyJSON by using closures.
Swift Constant Test
In Objective-C we are using a header file to create constant variables like as
[code lang=”obj-c”]
// Objective-C
#define APP_ALERT_TITLE "Objective-C Constant"
[/code]
Swift has new syntax to define the constant (#define)
[code lang=”obj-c”]
// Swift
let APP_ALERT_TITLE = "Swift Constants"
[/code]
Lets try
Create a swift file with the constants
[code lang=”obj-c”]
import Foundation
class Constants {
// MARK: List of Constants
static let APP_ALERT_TITLE = "Swift Constants"
static let SAMPLE_MESSAGE = "The alert is working !!"
}
[/code] Note : Here the MARK statement is also changed.
[code lang=”obj-c”]
// Objective-C
#pragma mark –
#pragma mark List of Constants
[/code]
[code lang=”obj-c”]
// Swift
// MARK: List of Constants
[/code]
This article is updated with Swift 4 – Xcode 9 – iOS 11
Why to use a library everytime? Slider Menu (Drawer) Let’s create our own Slide Menu (Drawer) in Swift 4. 1. Create New Project in Xcode 9 with Swift Language
2. Design the Menu in UIViewController Menu UIViewController
Declaration of Variables and Protocols (Delegate) :
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protocol SlideMenuDelegate {
func slideMenuItemSelectedAtIndex(_ index : Int32)
}
class MenuViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
/**
* Array to display menu options
*/
@IBOutlet var tblMenuOptions : UITableView!
/**
* Transparent button to hide menu
*/
@IBOutlet var btnCloseMenuOverlay : UIButton!
/**
* Array containing menu options
*/
var arrayMenuOptions = [Dictionary<String,String>]()
/**
* Menu button which was tapped to display the menu
*/
var btnMenu : UIButton!
/**
* Delegate of the MenuVC
*/
vardelegate:SlideMenuDelegate?
}
Following method is for updating the Items in the Menu :
3. Now we will create a Base UIViewController to use anywhere in the project which control the delegate of menu.
First we will create this 3 lines Drawer Icon via Code
To open a view controller by identifier :
Set the Restoration Identifier and Storyboard Identifier. If current view is open then we will not open it once again for that we have to check via Restoration Identifier.
4. Now We will assign this drawer to any of the UIViewController
We have to use only one method to add drawer (slide menu) self.addSlideMenuButton()
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importUIKit
classHomeVC: BaseViewController{
overridefuncviewDidLoad(){
super.viewDidLoad()
addSlideMenuButton()
}
}
Source Code is available at the Github AKSwiftSlideMenu GitHub AKSwiftSlideMenu Releases
You can download for versions of Swift 2, Swift 3 or Swift 4. From Releases Tab at GitHub AKSwiftSlideMenu.
I have uploaded a video for easy way to integrate AKSwiftSlideMenu in your project :
By giving you a simple example that we can not change the corner radius from the design view. We have to change it run time. If you want to make possible it with design time then you can use the @IBDesignable and @IBInspectable.
So, We are taking an example as IBButtonExtender for this the functionality
Border Color
Border Width
Corner Radius
Create an Custom Class for UIButton with @IBDesignable
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@IBDesignable
classButtonExtender: UIButton{
}
Create an @IBInspectable for Inspect the element. the Border Color property will be added to the list in the right panel when you create button with this class.
Presenting the ButtonExtender for Border Color, Border Width and Corner Radius function with the @IBDesignable and @IBInspectable in the Swift Language.
By making some corner radius and colors, You will get neat and clean output. Output
Github
Find IBButtonExtender on github 🙂
Check other articles on Swift Language.
All suggestions are acceptable. Put it in the comments!
Happy Coding 🙂
What is Realm?
Realm is a mobile database
Realm is a replacement for SQLite & Core Data.
It can save you thousands of lines of code & weeks of work,
and lets you craft amazing new user experiences.
Download the Realm framework for swift from https://realm.io/
[code language=”obj-c”]
import UIKit
import RealmSwift
class Person: Object {
dynamic var name = ""
dynamic var age = 0
}
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Initializing the object
let personObj1 = Person()
personObj1.name = "Ashish"
personObj1.age = 25
println("name of person : \(personObj1.name)")
// Writing it to realm
let realm = Realm()
realm.write {
realm.add(personObj1)
}
let personObj2 = Person()
personObj2.name = "Darshak"
personObj2.age = 27
realm.write {
realm.add(personObj2)
}
// Quering
let r = Realm().objects(Person).filter("age > 24")
println(r)
// Queries are chainable
let r2 = r.filter("name contains ‘Ashish’")
println(r2)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
[/code] Output :
[code language=”obj-c”]
name of person : Ashish
Results<Person> (
[0] Person {
name = Ashish;
age = 25;
},
[1] Person {
name = Darshak;
age = 27;
}
)
Results<Person> (
[0] Person {
name = Ashish;
age = 25;
}
)
[/code]
Happy Coding 🙂
Apple Watch represents a new chapter in the relationship people have with technology. Now you can deliver innovative new experiences to your customers on their wrist. And by adding WatchKit, you can take your apps even further by extending and enhancing their functionality on Apple Watch.
Lets learn how to work with WatchKit by an Counter Example. Counter Watch Create New Project in XCode with Swift Language New Project Add Apple Watch Target in your Application Add Target
Select Apple Watch Target Add Target Apple Watch
Select Options for Target Target Options Storyborad of watch
By adding target you will find the InterfaceController.swift and Interface.storyboard Storyboard And Swift Files Design watch with the controls
Design and reposition the controls with the properties of controls. Design Controls in Watch Now Time to do some code and connect the outlets Connect Outlets
Code:
[code language=”obj-c”]
// InterfaceController.swift
import WatchKit
import Foundation
class InterfaceController: WKInterfaceController {
@IBOutlet weak var lblCounter: WKInterfaceLabel!
var counter:Int = 0
override func awakeWithContext(context: AnyObject?) {
super.awakeWithContext(context)
// Configure interface objects here.
}
override func willActivate() {
// This method is called when watch view controller is about to be visible to user
super.willActivate()
}
override func didDeactivate() {
// This method is called when watch view controller is no longer visible
super.didDeactivate()
}
@IBAction func upButtonPressed() {
counter = counter + 1
lblCounter.setText("\(counter)")
}
@IBAction func downButtonPressed() {
counter = counter – 1
lblCounter.setText("\(counter)")
}
}
[/code]
Download project with this stuff AppleWatchCounterDemo.zip
Thanks!
Happy Coding 😀
It just simple.
Continue with the same example project.
Take data variables which you want to get in the parent view.
For example,
[code language=”obj-c”]
class ViewController2: UIViewController {
var data:String = "view 2 data"
….
}
[/code]
To get data from first view controller we have to get data from source view controller like follows :
[code language=”obj-c”]
@IBAction func unwindToVC(segue:UIStoryboardSegue) {
if(segue.sourceViewController .isKindOfClass(ViewController2))
{
var view2:ViewController2 = segue.sourceViewController as ViewController2
let alert = UIAlertView()
alert.title = "UnwindSegue Data"
alert.message = view2.data
alert.addButtonWithTitle("Ok")
alert.show()
}
if(segue.sourceViewController .isKindOfClass(ViewController3))
{
var view3:ViewController3 = segue.sourceViewController as ViewController3
let alert = UIAlertView()
alert.title = "UnwindSegue Data"
alert.message = view3.data
alert.addButtonWithTitle("Ok")
alert.show()
}
}
[/code]
Download project with this stuff UnwindSegueData.zip
Thanks!
Happy Coding 😀
An unwind segue (sometimes called exit segue) can be used to navigate back through push, modal or popover segues (as if you popped the navigation item from the navigation bar, closed the popover or dismissed the modally presented view controller). On top of that you can actually unwind through not only one but a series of push/modal/popover segues, e.g. “go back” multiple steps in your navigation hierarchy with a single unwind action.
To enable the Unwind Segue you need to add some code first.
[code language=”obj-c”]
@IBAction func unwindToVC(segue: UIStoryboardSegue) {
}
[/code]
You have to add this code in the view controller where you want to unwind (came back). Unwind To View
Suppose you want to came back from second or third view to first view then you have to add the code in first view. Then just connect any control(Which contains action) with the unwind segue. Unwind Segue
For check the particular view controller by unwind segue, use following code :
[code language=”obj-c”]
@IBAction func unwindToVC(segue:UIStoryboardSegue) {
if(segue.sourceViewController .isKindOfClass(ViewController2))
{
let alert = UIAlertView()
alert.title = "UnwindSegue"
alert.message = "Unwind from view 2"
alert.addButtonWithTitle("Ok")
alert.show()
}
if(segue.sourceViewController .isKindOfClass(ViewController3))
{
let alert = UIAlertView()
alert.title = "UnwindSegue"
alert.message = "Unwind from view 3"
alert.addButtonWithTitle("Ok")
alert.show()
}
}
[/code]
Download project with this stuff UnwindSegue.zip
In next tutorial you will find the topic Passing data with Unwind Segue in Swift Language – iOS 8
Thanks!
Happy Coding 😀
