Category: Swift / SwiftUI

override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        return "section-\(section)"
    }

エミュレーターに反映される時とされない時があるな。。

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "MemoTableViewCell", for: indexPath)

        // Configure the cell...
        cell.textLabel?.text = self.memos[indexPath.section][indexPath.row]

        return cell
    }

import UIKit

class MemoTableViewController: UITableViewController {
    
    var memos = ["blue", "red", "pink"]
    override func viewDidLoad() {
        super.viewDidLoad()

        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
        // self.navigationItem.rightBarButtonItem = self.editButtonItem
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of rows
        return self.memos.count
    }

    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "MemoTableViewCell", for: indexPath)

        // Configure the cell...
        cell.textLabel?.text = self.memos[indexPath.row]

        return cell
    }
    

    /*
    // Override to support conditional editing of the table view.
    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        // Return false if you do not want the specified item to be editable.
        return true
    }
    */

    /*
    // Override to support editing the table view.
    override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {
            // Delete the row from the data source
            tableView.deleteRows(at: [indexPath], with: .fade)
        } else if editingStyle == .insert {
            // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
        }    
    }
    */

    /*
    // Override to support rearranging the table view.
    override func tableView(_ tableView: UITableView, moveRowAt fromIndexPath: IndexPath, to: IndexPath) {

    }
    */

    /*
    // Override to support conditional rearranging of the table view.
    override func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool {
        // Return false if you do not want the item to be re-orderable.
        return true
    }
    */

    /*
    // 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.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}

なるほど

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var timerLabel: UILabel!
    var startTime: TimeInterval? = nil
    var timer = Timer()
    var elapsedTime: Double = 0.0
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }
    
    setButtonEnabled(start: true, stop: flase, reset: false){
    
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    func setButtonEnabled(start: Bool, stop: Bool, reset: Bool){
        self.startButton.isEnabled = start
        self.stopButton.isEnabled = stop
        self.resetButton.isEnabled = reset
    }
    
    
    
    @objc func update(){
//        print(Date.timeIntervalSinceReferenceDate)
        if let startTime = self.startTime {
            let t: Double = Date.timeIntervalSinceReferenceDate - startTime + self.elapsedTime
            print(t)
            let min = Int(t / 60)
            let sec = Int(t) % 60
            let msec = Int((t - Double(sec)) * 100.0)
            self.timerLabel.text = String(format: "%02d:%02d:%02d", min, sec, msec)
        }
    }
    
    @IBAction func startTimer(_ sender: Any) {
        self.startTime = Date.timeIntervalSinceReferenceDate
        self.timer = Timer.scheduledTimer(
            timeInterval: 0.01,
            target: self,
            selector: #selector(self.update),
            userInfo: nil,
            repeats: true)
    }
    
    @IBAction func stopTimer(_ sender: Any) {
        if let startTime = self.startTime {
            self.elapsedTime += Date.timeIntervalSinceReferenceDate - startTime
        }
        self.timer.invalidate()
    }

    @IBAction func resetTimer(_ sender: Any) {
        self.startTime = nil
        self.timerLabel.text = "00:00:00"
        self.elapsedTime = 0.0
    }
    
    
}

[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key resetTimer.’

はて？
いらない接続を解除すると消えるようだが、消えんぞ。

#selector(self.hoge)がエラーになる。
func update()を@objc func update()とするとエラーが解消してbuild出来る。

@objc func update(){
        print(Date.timeIntervalSinceReferenceDate)
    }
    @IBAction func startTimer(_ sender: Any) {
        Timer.scheduledTimer(
            timeInterval: 0.01,
            target: self,
            selector: #selector(self.update),
            userInfo: nil,
            repeats: true)
    }
    
    @IBAction func stopTimer(_ sender: Any) {
    }
    
    @IBAction func resetTimer(_ sender: Any) {
    }

override func shouldPerformSegue(withIdentifier identifier: String, sender: Any?) -> Bool {
        if identifier == "showResult" {
            guard self.nameText.text != "" else {
                let alertController = UIAlertController(title: "Error", message: "Please enter your name", preferredStye: alert)
                let defaultAction = UIAlertAction(title: "OK", style: .default, handler: nil)
                alertController.addAction(defaultAction)
                self.present(alertController, animated: true, completion: nil)
                return false
            }
            return true
        }
        return true
    }

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        guard let identifier = segue.identifier else {
            return
        }
        if identifier == "showResult"{
            let resultVC = segue.destination as! ResultViewController
            resultVC.myName = self.nameText.text!
        }
    }

iphone8のemulatorの立ちあがりが異常に遅いんだが。。。

あれ？

失敗してるーーーーーーーーーーーーーー
あ、いいのか

@IBAction func getOmikuji(sender: AnyObject) {
        // 0 - n
        // arc4random_uniform(n + 1)
        let random = arc4random_uniform(10)
        
        self.myLabel.text = String(random)
    }

おーおーお

@IBOutlet weak var myLabel: UILabel!
    
    @IBAction func getOmikuji(sender: AnyObject) {
        // 0 - n
        // arc4random_uniform(n + 1)
        let results = ["大吉", "中吉","吉", "大凶"]
        let random = arc4random_uniform(UInt32(results.count))
        
        self.myLabel.text = results[Int(random)]
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
//        myLabel.layer.borderColor = UIColor.orange.cgColor
//        myLabel.layer.borderWidth = 5
//        myLabel.layer.cornerRadius = 50
        myLabel.layer.masksToBounds = true
        myLabel.layer.cornerRadius = myLabel.bounds.width / 2
        
        
        // Do any additional setup after loading the view, typically from a nib.
    }

generic

// Generics

func getThree<T>(x: T){
    print(x)
    print(x)
    print(x)
}

getThree(x: 5)
getThree(x: "Hello")
getThree(x: 2.3)

guard

// func sayHi(_ msg: String?){
//     if let s = msg{
//         print(s)
//     } else {
//         print("value is not set!")
//     }
// }
// sayHi(nil)
// sayHi("hello")

func sayHi(_ msg: String?){
    guard let s = msg else{
        print("value not set!")
        return
    } 
    print(s)
}

sayHi(nil)
sayHi("hello")

例外処理

// 例外処理

enum LoginError: Error{
    case emptyName
    case shortName
}

class User {
    let name: String
    init(_ name: String){
        self.name = name
    }
    func login() throws{
        guard name != "" else {
            throw LoginError.emptyName
        }
        guard name.characters.count > 5 else {
            throw LoginError.shortName
        }
        print("login success")
    }
}
let tom = User("tom")

do {
    try tom.login()
} catch LoginError.emptyName {
    print("please enter your name")
} catch LoginError.shortName{
    print("too short")
}

optional

// class User {
//     var name: String = ""
// }

// let user: User
// user = User()
// user.name = "him"
// let s = user.name.uppercased()
// print(s)

class User {
    var name: String = ""
}

let user: User?
user = User()
user?.name = "him"
if let s = user?.name?.uppercased(){
    print(s)
}

// Implicity Unwrapped Optional

// var msg: String?
var msg: String!
msg = "hello"

// if msg != nil {
//     print(msg!)
// }

print(msg)