XCode grimoire

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swift API


Application Programming Interface

Apple Developer Documentation

developer.apple.com

 

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re indent the code

select the code->editor->structure->re-indent

:hmm: in swift functions can have inner functions
to see a functions scope choose a {} or move <> around the curly brackets

 

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link many buttons to one action


drag click from the circle left to the code to the extra button
while in assistant view (main->adjust editor options->assistant)

import UIKit
import AVFoundation

class ViewController: UIViewController {
    
    var player: AVAudioPlayer!
    var tempSender: UIButton? = nil // save last used btn
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func keyPressed(_ sender: UIButton) {
        if tempSender != nil {tempSender!.layer.opacity*=2} // revert opacity changes
        tempSender=sender // save last clicked btn
        sender.layer.opacity = sender.layer.opacity / 2 // decrease opacity of clicked btn
        playSound(noteToPlay: sender.currentTitle!)
    }
    
    func playSound(noteToPlay: String) {
        let url = Bundle.main.url(forResource: noteToPlay, withExtension: "wav")
        player = try! AVAudioPlayer(contentsOf: url!)
        player.play()
                
    }
}

each button results in a different sender.currentTitle!
which is used to play a different sound on this app example

 

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timer

import UIKit

class ViewController: UIViewController {
    let times: [String: Int] = ["soft":300, "medium":420,"hard":720]
    var secondsRamaining = 60
    var timer = Timer() // declare the timer
    @IBAction func hardnessSelected(_ sender: UIButton) {
        secondsRamaining = times[sender.currentTitle!.lowercased()]!
        timer.invalidate() // kill the timer
       
        // engage the timerevery 1 second in this case
        timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(fireTimer), userInfo: nil, repeats: true)
    }
    @objc func fireTimer() {
        // this func will run every 1 second (assuming the timer has been engaged)
        if secondsRamaining > 0 {
            secondsRamaining-=1
            print("\(secondsRamaining) remaining")
        }
    }
}

The ultimate guide to Timer

How to schedule timers, repeat timers, and more

www.hackingwithswift.com

 

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defraculating a progress bar




set the height to > 1 to make it fatter
than set the color and BG color with the tint property :


:hmm: to see what a var type is select it and click option key

 

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defraculating a label



set lines to 0 to have it add lines instead of trumping long strings

and auto shrink to a minimum font size (15 in this example)
the bigger the string the smaller the font will be

 

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adding a swift file

these files are where to store classes and structures

file->new file (cmd + n)->swift file
or right click the 1st dir in the project->new file

 

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setting view background color

sender.backgroundColor = UIColor.green
rest to clear :
sender.backgroundColor = UIColor.clear

 

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MVC packaging

R_click swift file->new group from selection->name the folder (model view or controler)


set custom function parameter name :

func greeter(msg message: String){

    print(message)

}

greeter(msg: "hey")



set custom func with no parameter name :



func greeter(_ message: String){

    print(message)

}

greeter("hey")

 

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add a 2nd activity

object library (the +), search view controller





adding views programmatically

(view controller in this example (2nd activity))

controller dir->Rclick->new file->(ios tab) swift file

import UIKit

class SecondViewController: UIViewController {
    // this is a 2nd activity
    var data:Float = 0.0
    override func viewDidLoad() {
        super.viewDidLoad()
        // func fires up when called by other activity
        let label = UILabel() // create a label
        label.text = String(format: "%.1f", data)
        label.frame = CGRect(x: 0, y: 0, width: 100, height: 50)
        //view.backgroundColor = UIColor.green
        view.backgroundColor = .green
        view.addSubview(label) // add label on this view controller
    }
}

to summon the above view controller 2nd activity :

let secondVC = SecondViewController()
secondVC.data = BMI // example passing data to 2nd activity
self.present(secondVC, animated: true, completion: nil) // summon 2nd activity view controller

 

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Cocoa Touch Class

// these are used to build extra activities not programmatically

file->new file->Cocoa Touch Class



and place the class in the controller directory

select an activity from the story board :



from the identity inspector set the selected activity class name
to that of the cocoa class you've created

go to assistant view and set the new activity active :

 

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segue
// these are links between story boards (activities) and they enable
//switching between them

create a segue by control drag from one segue to another :




choose present modally

name the segue :



the cocoa class code :

import UIKit

class ResultViewController: UIViewController {
    var BMIResult :Float? = nil
    @IBOutlet weak var lblBMI: UILabel!
    
    @IBOutlet weak var lblAdvice: UILabel!
    override func viewDidLoad() {
        super.viewDidLoad()
        lblBMI.text = String(format: "%.1f", BMIResult!)
    }
    

    @IBAction func btnToMainActivity(_ sender: UIButton) {
        self.dismiss(animated: true, completion: nil) // kill activity
        // and thus go back to the summoning (prev) activity
    }
    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using segue.destination.
        // Pass the selected object to the new view controller.
    }
    */

}

main activity that summons the above cocoa class via the segue :

import UIKit

class ViewController: UIViewController {
    var BMIResult :Float? = nil
    @IBOutlet weak var lblHeight: UILabel!
    @IBOutlet weak var lblWeight: UILabel!
    @IBOutlet weak var sliderHeight: UISlider!
    @IBOutlet weak var sliderWeight: UISlider!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    @IBAction func heightSlideEvent(_ sender: UISlider) {
        let temp = String(format: "%.2f", sender.value)
        lblHeight.text = "\(temp)m"
    }
    @IBAction func weightSliderEvent(_ sender: UISlider) {
        let temp : Int = Int(sender.value)
        lblWeight.text = "\(temp)kg"
    }
    
    @IBAction func btnCalculate(_ sender: UIButton) {
        let height = sliderHeight.value
        let weight = sliderWeight.value
        BMIResult = weight / pow(height,2)
        self.performSegue(withIdentifier: "goToResult", sender: self)
        
    }
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // this method runs right befor the segued activity is summoned
        // refer to specific segue :
        if segue.identifier == "goToResult"{
            let destinationViewController = segue.destination as! ResultViewController // downcast to summoned activity view controller
            destinationViewController.BMIResult = self.BMIResult // pass
            //value from self to a value in the summoned activity
        }
    }
}

 

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pancake view

while the app is running you can see a 3d model of the layered activities

click :


drag the mouse to get the 3d pancake view :