Swift tip

Optional

출처 : 옵셔널 (Optional)

//: Playground - noun: a place where people can play

import UIKit

var email: String?
print(email) // nil

nickname = "bluexmas"
print(nickname) // Optional("bluexmas")

var str = "Hello, playground"

var name:Optional<string> = "name"
var name2:String? = "name2"

var name4:ImplicitlyUnwrappedOptional<string> = "name4";
var name3:String! = "name3"

print() name2 값이 nil 아니면 name2값 출력, name2의 값이 nil 및 경우 ?? 뒤에 있는 값 출력

if name != nil {
    print(name!)
}

if val n = name {
    print(n)
}

if let n = name {
    print(n)
}

var text1:String = "abc"
Int(test1)  // nil


var test:String = "123"
print(Int(test)! + 10)

nil 전달 함수

	var lampOn:Bool? = false
	
	func lampOnOffRemove(isOn : Bool?) {
		if let onOff = isOn {
			self.lampOn = onOff
			self.lampImageView.image = UIImage(named : onOff ? "lamp-on.png" : "lamp-off.png")
		} else {
			self.lampOn = nil
			self.lampImageView.image = UIImage(named : "lamp-remove.png")
		}
	}

	@IBAction func lampOffClicked(_ sender: AnyObject) {
		if lampOn! { // <-- 컴파일시 느낌표(!) 있어야 컴파일이 되고, 값이 nil 인 경우 런타임시 오류 발생
			//
		} else {
			//
		}
	}

WebView HTML 문자열 로딩

	@IBAction func HTMLClicked(_ sender: AnyObject) {
		let htmlString = "
HTML String 
 
String 변수를 이용한 웹페이지
 
애플 홈페이지로 이동
"
		webView.loadHTMLString(htmlString, baseURL: nil)
	}

WebView HTML 파일 로딩

	func loadPageWithUrlString(urlString : String) {
		if let url = URL(string : urlString) {
			webView.loadRequest(URLRequest(url: url))
		}
	}
		
	@IBAction func fileClicked(_ sender: AnyObject) {
		if let path = Bundle.main.path(forResource: "Sample", ofType : "html") {
			loadPageWithUrlString(urlString: path)
		}
	}

WebView Delegate

class ViewController: UIViewController, UIWebViewDelegate {

	@IBOutlet weak var webView: UIWebView!
	@IBOutlet weak var loadingIndicator: UIActivityIndicatorView!
	
	override func viewDidLoad() {
		super.viewDidLoad()
		// Do any additional setup after loading the view, typically from a nib.
		self.webView.delegate = self
	}
	
	public func webView(_ webView: UIWebView, shouldStartLoadWith request: URLRequest, navigationType: UIWebViewNavigationType) -> Bool
	{
		guard let urlString = request.url?.absoluteString else {
			return true;
		}
		
		print(request.url?.absoluteString ?? "")
		
		if urlString.contains("daum.net") {
			return false;
		}
		
		return true;
	}
	
	public func webViewDidStartLoad(_ webView: UIWebView)
	{
		loadingIndicator.startAnimating()
	}
	
	public func webViewDidFinishLoad(_ webView: UIWebView)
	{
		loadingIndicator.stopAnimating()
	}
	
	public func webView(_ webView: UIWebView, didFailLoadWithError error: Error)
	{
		print(error.localizedDescription)
		loadingIndicator.stopAnimating()
	}

포커스 이동

		// 텍스트필드 컨트롤에 포커서를 줘서 키패드가 자동으로 올라오도록 함
		self.urlTextField.becomeFirstResponder()

Objective-C main 함수

출처 : The App Life Cycle

//
//  main.m
//  study2
//
//  Created by Mac on 2017. 5. 27..
//  Copyright © 2017년 Mac. All rights reserved.
//

#import <uikit uikit.h="">
#import "AppDelegate.h"

int main(int argc, char * argv[]) {
	@autoreleasepool {
	    return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
	}
}

UIImageView 확대

	@IBAction func OnBtnScaleClick(_ sender: UIButton) {
		imgLamp.frame.size.width *= 1.2
		imgLamp.frame.size.height *= 1.2
	}

형변환

	@IBAction func typeCast(_ sender: AnyObject) {
		if let tmpButton = sender as? UIButton {
			tmpButton.setTitle("확대2", for: .normal)
		}
	}

loadImage 함수 구현

	func loadImage(fileName : String, fileType : String) -> UIImage? {
		if let path = Bundle.main.path(forResource: fileName, ofType: fileType) {
			return UIImage(contentsOfFile : path)
		} else {
			return nil;
		}
	}

	@IBAction func OnRadio1Change(_ sender: UISwitch) {
		imgLamp.image = loadImage( fileName : sender.isOn ? "lamp_on.png" : "lamp_off.png", fileType : "png" )
	}

TextField Delegate

	public func textFieldShouldReturn(_ textField: UITextField) -> Bool // called when 'return' key pressed. return NO to ignore.
	{
		loadPageWithUrlString(urlString: urlTextField.text ?? "")
		
		// 포커스 해지
		view.endEditing(true)
		
		return true;
	}

배열추가, String format, 이미지 변경

	var flowerArray = [String]()

	override func viewDidLoad() {
		super.viewDidLoad()
		// Do any additional setup after loading the view, typically from a nib.
		
		for i in 1...6 {
			flowerArray.append( String(format : "%02d.png", i))
		}
	}

	@IBAction func onBtnNextClick(_ sender: UIButton) {
		if sender.currentTitle == "이전" {
			current_img_index -= 1
		} else {
			current_img_index += 1
		}
		
		if current_img_index >= flowerArray.count {
			current_img_index = 0
		}
		
		if current_img_index < 0 {
			current_img_index = flowerArray.count - 1
		}
		
		imgLamp.image = UIImage(named : flowerArray[current_img_index])
	}

Timer

		// 1초에 한번씩 호출
		Timer.scheduledTimer(withTimeInterval: 1, repeats: true, block: {
			(timer) -> Void in
//			NSLog("%G", #function)
			
			let dateFormatter = DateFormatter()
			dateFormatter.dateFormat = "yyyy M d HH:mm:ss"
			
			
			self.lblCurrentTime.text = "현재시간 : " + dateFormatter.string(from : Date())
		})

UIAlertController

	override func viewDidAppear(_ animated: Bool) {
		/*
		let messageBox = UIAlertView(title : "알림", message : "메시지", delegate : nil, cancelButtonTitle : "OK")
		messageBox.show()
		*/

		let messageBox = UIAlertController(title: "알림", message: "메시지", preferredStyle: .alert)
		messageBox.addAction(UIAlertAction(title : "OK", style : .default, handler : {
			(action) -> Void in
			print("OK 선택")
			
		}))
		
		messageBox.addTextField(configurationHandler: {
			(textfield) in
			textfield.backgroundColor = UIColor.yellow
		})
		
		present(messageBox, animated : true, completion : nil)
	}

picker

import UIKit

class ViewController: UIViewController,  UIPickerViewDataSource, UIPickerViewDelegate {
	
	@IBOutlet weak var imagePickerView: UIPickerView!
	@IBOutlet weak var selectedItemLable: UILabel!
	@IBOutlet weak var selectedImageView: UIImageView!
	
	var mArray = [String]()

	override func viewDidLoad() {
		super.viewDidLoad()
		// Do any additional setup after loading the view, typically from a nib.
		
		
		imagePickerView.dataSource = self
		imagePickerView.delegate = self
		
		for i in 1...6 {
			mArray.append(String(format: "%02d", i))
		}
	}

	override func didReceiveMemoryWarning() {
		super.didReceiveMemoryWarning()
		// Dispose of any resources that can be recreated.
	}
	
	
	// picker 열의 개수
	public func numberOfComponents(in pickerView: UIPickerView) -> Int {
		return 1
	}
	
	// picker 행의 개수
	public func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
		
		return mArray.count;
	}
	
	/*
	func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
		
		return mArray[row]
	}*/
	
	// picker 행의 높이 설정
	public func pickerView(_ pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat
	{
		return 100;
	}
	
	// picker 행을 이미지로 표시
	public func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView
	{
		let imageView = UIImageView(frame:CGRect(x:0, y:0, width:100, height:100));
		imageView.image = UIImage(named : mArray[row])
		return imageView
	}
	
	// 선택이벤트
	public func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
		selectedItemLable.text = "선택 = " + mArray[row]
		selectedImageView.image = UIImage(named : mArray[row])
	}
}

이미지 비동기 로딩

       if let urlString = movieArray[indexPath.row].thumbnailUrl,
            let url = URL(string : urlString)
        {
            do {
                /*
                // 동기방식
                let imageData = try Data(contentsOf: url)
                cell.thumbnailImageView.image = UIImage(data : imageData)
                */
            } catch {
                
            }
            
            // 비동기방식
            let task = URLSession.shared.dataTask(with: url) {
                (data, response, error) -> Void in
                
                if let imageData = data {
                    DispatchQueue.main.async {
                        cell.thumbnailImageView.image = UIImage(data : imageData)
                    }
                }
            }
                
            task.resume()
        }

동영상 플레이

   func playVideo(url : URL) {
        let playerVC = AVPlayerViewController()
        let player = AVPlayer(url: url)
        playerVC.player = player
        
        present(playerVC, animated: true, completion: {
            playerVC.player?.play()
        })
    }