iosDev

Try to learn and practice developing iOS app with Swift.

Note

A GitBook version of the notes below has been created, check here: Swift Newbie.

If you want to contribute, please contact me (hi@chengkang.me).

部分项目截图、涉及内容的介绍：《Intro to Projects》。例如：

###ios tutorial

• the new boston
• Devslopes Video Lessons
• A Beginner’s Guide to NSDate in Swift
• Swift A Day

videos better watch again:

• Intro to statck view

###websites to check

• blackmoondev
• Get clear idea of MVC: Model View Controller (MVC)
• Extensions are fun: Extensions
• How does clipsToBounds work?: StackOverflow: How does clipsToBounds work?
• Parse JSON with NSJSONSerialization: How to parse JSON using NSJSONSerialization
• Error handling in Swift 2: try, catch, do and throw: Error handling in Swift 2: try, catch, do and throw

Transform

• introduction-to-3d-drawing-in-core-animation
• CATransform3D 特效详解

print(img.frame.height)
var tf = CATransform3DIdentity
tf.m34 = 1/(-500)
tf = CATransform3DRotate(tf, -45.0 * CGFloat(M_PI) / 180.0, 1.0, 0.0, 0.0)
self.img.layer.transform = tf
print(img.frame.height)

###informative links

• enable-disable-auto-layout-constraints
• dynamic-height-issue-for-uitableview-cells-swift/36185105#36185105
• iOS Fundamentals: Frames, Bounds, and CGGeometry
• about UILabel

Articles

Articles written by myself during my journey to iOS development.

• UISearchBar（一）修改背景层和输入框层的背景颜色和边框颜色
• AutoLayout：UITableViewCell 自适应高度的一个例子
• AutoLayout：constraint priority 约束优先级（九宫格续，一个更优方案）
• 【译】iOS 基础：Frames、Bounds 和 CGGeometry
• 仿微博 iOS 客户端 TabBar 中间按钮
• 自定义 UITabBar 总结（一个模拟 instagram TabBar 的例子）
• 实现 instagram 底部弹出菜单的一个例子（模拟 instagram 系列）
• Swift 实现多个 TableView 的侧滑与切换（模拟 instagram 系列）
• AutoLayout 中需要注意的点
• 模拟凤凰新闻 | 更复杂的标签动画 - Swift 实现多个 TableView 的侧滑与切换
• 【译】UICollectionView 轻松重排
• UICollectionView 总结

To Do

• Custom gif RefreshControl
• addTextFieldWithConfigurationHandler
• deinit

Nice Frameworks

• ObjectMapper
• Alamofire
• ShareSDK

Notes

If the layout isn't what you expect, check if you've added the constraints!!!

Use 'Equal Widths' to set the width of any StackView inside ScrollView, otherwise the width will go wrong.

###1.change present view

1 set storyboard_id

2 for example:

let tv = self.storyboard?.instantiateViewControllerWithIdentifier("TapViewController") as! TapViewController
self.presentViewController(tv, animated: true, completion: nil)

###2.differences between the content modes

###3.how to load and play a audio

How to play sounds using AVAudioPlayer

drag the audio file to the app directory and just press enter

import UIKit
import AVFoundation

class ViewController: UIViewController{
    
    var btnSound: AVAudioPlayer!
    override func viewDidLoad() {
        super.viewDidLoad()
        let path = NSBundle.mainBundle().pathForResource("btn", ofType: "wav")
        let soundUrl = NSURL(fileURLWithPath: path!)
        
        do {
            try btnSound = AVAudioPlayer(contentsOfURL: soundUrl)
            btnSound.prepareToPlay()
        } catch {
            
        }
    }
    ...

###4.animationImages

    @IBOutlet weak var monsterImg: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        var imgArray = [UIImage]()
        //init your image array, for example
        for var x = 1; x <= 4; x++ {
            let img = UIImage(named: "idle\(x).png")
            imgArray.append(img!)
        }
        
        monsterImg.animationImages = imgArray
        monsterImg.animationDuration = 0.8
        monsterImg.animationRepeatCount = 0
        monsterImg.startAnimating()
        
        //animationImages
        //An array of UIImage objects to use for an animation.
        
        //animationDuration
        //The amount of time it takes to go through one cycle of the images.
        //The time duration is measured in seconds. The default value of this property is equal to the number of images multiplied by 1/30th of a second. Thus, if you had 30 images, the value would be 1 second.
        
        //animationRepeatCount
        //Specifies the number of times to repeat the animation.
        //The default value is 0, which specifies to repeat the animation indefinitely.
    }

###5.a dragable image class

import Foundation
import UIKit

class DragImg: UIImageView {
    
    var originalPosition: CGPoint!
    
    //why override this?
    override init(frame: CGRect) {
        super.init(frame: frame)
    }
    
    //what's this?
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
    
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        originalPosition = self.center
    }
    
    override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
        if let touch = touches.first {
            let position = touch.locationInView(self.superview)
            self.center = CGPointMake(position.x, position.y)
        }
    }
    
    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
        self.center = originalPosition
    }
}

###6.NSTimer

var timer: NSTimer!
timer = NSTimer.scheduledTimerWithTimeInterval(TIME_INCREMENT, target:self, selector: "FUNCTION", userInfo: nil, repeats: BOOL)

###7.NSNotificationCenter

//somewhere
NSNotificationCenter.defaultCenter().postNotification(NSNotification(name: "NOTIFICATION_NAME", object: nil))

//somewhere else
NSNotificationCenter.defaultCenter().addObserver(self, selector: "FUNCTION", name: "NOTIFICATION_NAME", object: nil)

###8.must add these init when create a subclass of UIImageView

    override init(frame: CGRect) {
        super.init(frame: frame)
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

An article about 'init': Swift init patterns

###9.Segue pass message to the next segue

//somewhere
  performSegueWithIdentifier("IDENTIFIER", sender: A_SENDER)
  
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyOBject?) {
  if segue.identifier == "IDENTIFIER" {
    if let whatVC = segue.destinationViewController as ? SomeViewController {
      if let theString = sender as? String {
        whatVC.someStr = theString
      }
    }
  }
}

###10.Extensions

extension Double {
  var currency: String {
    return "$\(self)"
  }
}

###11.To load page with http protocol edit the info.plist

NSAppTransportSecurity Dictionary
NSAllowsArbitraryLoads Boolean YES

###11.hide keyboard

Add the following to your viewDidLoad():

let tap = UITapGestureRecognizer(target: self, action: "dismissKeyboard")
tap.cancelsTouchesInView = false
view.addGestureRecognizer(tap)

and then add the following method declaration:

func dismissKeyboard()
{
    view.endEditing(true)
}

###12.UITableViewCell automatic resizing

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return UITableViewAutomaticDimension
}

func tableView(tableView: UITableView, estimatedHeightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return UITableViewAutomaticDimension
}

参考：Automatically resizing UITableViewCells with Dynamic Type and NSAttributedString

###13.change view size

view.frame.CGRectMake(0 , 0, self.view.frame.width, self.view.frame.height * 0.7) 

###14.set UICollectionViewCell spacing & line spacing

let layout = collectionView.collectionViewLayout as! UICollectionViewFlowLayout
layout.minimumInteritemSpacing = 1
layout.minimumLineSpacing = 1

collectionView.collectionViewLayout = layout

###15.UITableViewCell Animation

override willDisplayCell

override func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell,
    forRowAtIndexPath indexPath: NSIndexPath) {
    //Animation Code
}

###16.self.view.endEditing(true)

###17.draw image with render color

drawImage(UIImage(named: "image")!, size: CGSizeMake(30, 30), renderColor: UIColor(red: 149.0/255, green: 149.0/255, blue: 149.0/255, alpha: 1))

###18.replace sub-string

let text = (stringName as NSString).stringByReplacingOccurrencesOfString("whatever", withString: "")

###19.The file “” couldn’t be opened because you don’t have permission t

clean and re-build

###20.check if text is Int

if Int(strToCheck) == nil {
  print("Not Int")
} else {
  print("Is Int")
}

###21.localizedStringWithFormat

String.localizedStringWithFormat(NSLocalizedString("Blahblahblah %d.", comment: "Some Comment"), intVar)

###22.an alertView example, pop up at the screen center

import UIKit

class ExampleAlertView: UIView {
    
    
    @IBOutlet weak var wechatPayButton: UIButton!
    @IBOutlet weak var alipayButton: UIButton!
    
    @IBOutlet weak var amountTextField: UITextField!
    
    @IBOutlet weak var infoLabel: UILabel!
    
    private var shadowBtn: UIButton!
    
    let ApplicationDelegate = (UIApplication.sharedApplication().delegate as! AppDelegate)
    private var showView: UIView {
        return ApplicationDelegate.window!
    }
    
    private var confirmClosure: (() -> ())?
    private var cancelClosure: (() -> ())?
    
    
    @objc private func shadowBtnClick() {
        
        UIView.animateWithDuration(0.15, animations: {
            self.shadowBtn.alpha = 0
            self.alpha = 0
        }) { (success) in
            self.shadowBtn.removeFromSuperview()
            self.removeFromSuperview()
        }
    }

    class func exampleAlertView(initialMoney: String, canInput: Bool, confirmClosure:(()->()), cancelClosure: (() -> ())) -> DXPayAlertView {
        let alert = NSBundle.mainBundle().loadNibNamed("ExampleAlertView", owner: nil, options: nil).first as! ExampleAlertView
        alert.confirmClosure = confirmClosure
        alert.cancelClosure = cancelClosure
        
        return alert
    }
    
    override func awakeFromNib() {
        self.layer.cornerRadius = 10
        self.layer.masksToBounds = true
        self.shadowBtn = UIButton(frame: UIScreen.mainScreen().bounds)
        self.shadowBtn.addTarget(self, action: #selector(ExampleAlertView.shadowBtnClick), forControlEvents: .TouchUpInside)
        self.shadowBtn.backgroundColor = UIColor.blackColor()
        shadowBtn.alpha = 0.4
        UIApplication.sharedApplication().keyWindow?.addSubview(shadowBtn)
    }
    
    func show() {
        let size = UIScreen.mainScreen().bounds.size
        self.shadowBtn.center = CGPoint(x: size.width/2, y: size.height/2)
        self.center = self.shadowBtn.center
        self.shadowBtn.frame = self.showView.bounds
        self.shadowBtn.alpha = 0
        self.alpha = 0
        
        self.transform = CGAffineTransformMakeScale(1.2, 1.2)
        
        UIView.animateWithDuration(0.25) {
            
            self.shadowBtn.alpha = 0.4
            self.showView.addSubview(self.shadowBtn)
            
            UIView.animateWithDuration(0.25, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 0.1, options: .CurveEaseInOut, animations: {
                self.showView.addSubview(self)
                self.transform = CGAffineTransformMakeScale(1.0, 1.0)
                
                self.alpha = 1
                }, completion: { (_) in
                    self.transform = CGAffineTransformMakeScale(1.0, 1.0)
                    self.showView.addSubview(self)
                    self.alpha = 1
            })
        }
    }
    
    @IBAction func confirmBtnClick(sender: UIButton) {
        self.confirmClosure?()
        shadowBtnClick()
    }
    
    @IBAction func cancelBtnClick(sender: UIButton) {
        self.cancelClosure?()
        shadowBtnClick()
    }
}

23.deinit

deinit{
    print("WhicheverController deinit")
    // some code
}

24.deselectTableViewCell

tableView.deselectRowAtIndexPath(indexPath, animated: true)

25.get image from url

let url = NSURL(string: image.url)
let data = NSData(contentsOfURL: url!) //make sure your image in this url does exist, otherwise unwrap in a if let check
imageView.image = UIImage(data: data!)

//If you want to make the code run async, you can easily achieve this with GCD:

let url = NSURL(string: image.url)
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) {
    let data = NSData(contentsOfURL: url!) //make sure your image in this url does exist, otherwise unwrap in a if let check
    dispatch_async(dispatch_get_main_queue(), { 
        imageView.image = UIImage(data: data!)
    });
}

26.double tap gesture will cause tab switch slowing down, the reason is it needs a minimum amount of time to wait for possible taps.

27.format time label

func getStatusTime(dateStr: String) -> String {
    
    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
    let date = dateFormatter.dateFromString(dateStr)!
    
    //判断是否是同一年
    if isSameYear(date) {
        
        let calendar = NSCalendar.currentCalendar()
        
        if calendar.isDateInToday(date) {
            
            
            let time = abs(Int32(date.timeIntervalSinceNow))
            
            if time < 60 {
                
                return "刚刚"
            }else if time < 60 * 60 {
                
                return "\(time/60) 分钟前"
            }else{
                
                return "\(time / 60 / 60)小时前"
            }
            
        }else if calendar.isDateInYesterday(date) {
            
            dateFormatter.dateFormat = "HH:mm"
            return "昨天" + dateFormatter.stringFromDate(date)
            
        }else {
            
            dateFormatter.dateFormat = "MM-dd HH:mm"
            return dateFormatter.stringFromDate(date)
        }
        
    }else {
        
        dateFormatter.dateFormat = "yyyy-MM-dd HH:mm"
        return dateFormatter.stringFromDate(date)
    }
}

func isSameYear(date: NSDate) -> Bool{
    
    dateFormatter.dateFormat = "yyyy"
    
    return dateFormatter.stringFromDate(date) == dateFormatter.stringFromDate(NSDate())
    
}

28.how-to-add-ellipses-on-a-uitextview

You can do that by setting the properties of the textContainer like so:

textView.textContainer.maximumNumberOfLines = 2;
textView.textContainer.lineBreakMode = NSLineBreakByTruncatingTail;

29.imageWithRenderingMode

To make imageWithRenderingMode work, you need to seperate creating UIImage and setting renderingmode

// Correct way
let image = UIImage(named: "ImageName")!
self.someImgview.image = image.imageWithRenderingMode(.AlwaysTemplate)

// Wrong way
self.someImgview.image = UIImage(named: "ImageName")!.imageWithRenderingMode(.AlwaysTemplate)

30.get text view content height

To update UITextView height with it's content height, you need to update the correspond height constraint. Otherwise, it won't work.

extension UITextView {
    func heightThatFitsContent() -> CGFloat {
        let fixedWidth = self.frame.width
        let newSize = self.sizeThatFits(CGSize(width: fixedWidth, height: CGFloat(MAXFLOAT)))
        
        return newSize.height
    }
}

**textViewHeightConstraint.constant = textview.heightThatFitsContent()**

31.keyboard events, keyboard willShow

NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)

func keyboardWillShow(notification:NSNotification) {
    let userInfo:NSDictionary = notification.userInfo!
    let keyboardFrame:NSValue = userInfo.valueForKey(UIKeyboardFrameEndUserInfoKey) as! NSValue
    let keyboardRectangle = keyboardFrame.CGRectValue()
    let keyboardHeight = keyboardRectangle.height
}

32.get version number

func getVersion() -> String {
  let dict = NSBundle.mainBundle().infoDictionary
  return dict!["CFBundleShortVersionString"]! as! String
}

33.get build version

func getBuildVersion() -> String {
  let dict = NSBundle.mainBundle().infoDictionary
  return dict!["CFBundleVersion"]! as! String
}

34.alert with confirmAct, cancelAct, and textfield

func showCustomAlert(title: String, message: String, textfiledSetting: (textfield: UITextField)->()), cancelAct: ((alert: UIAlertController)->())?, confirmAct: ((alert: UIAlertController)->())?) {
  let alert = UIAlertController(title: title, message: message, preferredStyle: .Alert)
  let cancel = UIAlertAction(title: "Cancel", style: .Cancel) { (_) -> Void in
    cancelAct?(alert: alert)
  }
  let confirm = UIAlertAction(title: "Confirm", style: .Default) { (_) -> Void in
    confirmAct?(alert: alert)
  }
  alert.addTextFieldWithConfigurationHandler(textfieldSetting)
  alert.addAction(confirm)
  alert.addAction(cancel)
  ApplicationDelegate.window?.rootViewController?.presentViewController(alert, animated: true, complettion: nil)
}

35.UIFont' is not convertible to '(name: String, size: CGFloat) -> UIFont?'

UIFont(name: "Roboto-Regular", size: 15) ×
UIFont.init(name: "Roboto-Regular", size: 15) √

36.hex string to NSData Reference

extension String {

    /// Create `NSData` from hexadecimal string representation
    ///
    /// This takes a hexadecimal representation and creates a `NSData` object. Note, if the string has any spaces or non-hex characters (e.g. starts with '<' and with a '>'), those are ignored and only hex characters are processed.
    ///
    /// - returns: Data represented by this hexadecimal string.

    func dataFromHexadecimalString() -> NSData? {
        let data = NSMutableData(capacity: characters.count / 2)

        let regex = try! NSRegularExpression(pattern: "[0-9a-f]{1,2}", options: .CaseInsensitive)
        regex.enumerateMatchesInString(self, options: [], range: NSMakeRange(0, characters.count)) { match, flags, stop in
            let byteString = (self as NSString).substringWithRange(match!.range)
            var num = UInt8(byteString, radix: 16)
            data?.appendBytes(&num, length: 1)
        }

        return data
    }
}

37.Hex Color Convenience Function

// Hex Color Convenience Function
extension UIColor {
    convenience init(red: Int, green: Int, blue: Int) {
        assert(red >= 0 && red <= 255, "Invalid red component")
        assert(green >= 0 && green <= 255, "Invalid green component")
        assert(blue >= 0 && blue <= 255, "Invalid blue component")
        
        self.init(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: 1.0)
    }
    
    convenience init(netHex:Int) {
        self.init(red:(netHex >> 16) & 0xff, green:(netHex >> 8) & 0xff, blue:netHex & 0xff)
    }
}

38.add gesture recognizer after setting the frame

39.set center after setting the size

40.customize uipickerview

You can override pickerview:attributtedStringForTitle to change title color. However, you cannot change font with this method.

To customize font, use pickerview:viewForRow

41.if you see the error "Enum case 'someCase' not found in type 'someEnumType'", add ! to 'someEnumTypeVar'

// Error
switch someEnumTypeVar {
case .someCase:
    <#code#>
default:
    <#code#>
}

// Fixed
switch someEnumTypeVar! {
case .someCase:
    <#code#>
default:
    <#code#>
}

42.how does string substring work in swift 3

By the Way

1 Trapper should actually be Tapper. It's a typing mistake.