Note:  December-2018

1. Set image opacity in programmatically

-- imageView.alpha = 0.5 // 50% opacity
-- imageView.alpha = 0 // 0% opacity - completely transparent
-- imageView.alpha = 1 // 100% opacity - completely opaque

2. Time Stamp / Date Format 

Use GMT format in a format date

-- yyyy-MM-dd'T'HH:mm:ssZ  =  2018-11-23T04:02:11+0700
--yyyy-MM-dd'T'HH:mm:ss.SSSXXXXX = 2018-11-22T15:39:59.568+07:00

3. Asynchronous use time after

DispatchQueue.main.asyncAfter(deadline: .now() + 1) {

        }

4. Play video in UIImageView 
 use imageView as player video :

* imageView.layer.insertSublayer(avPlayerLayer, at: 0)


import AVFoundation
import AVKit
import UIKit

class AutoplayViewController: UIViewController {
    @IBOutlet weak var imageview: UIImageView!
    @IBOutlet weak var viewView: UIView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Video
        let url = URL(string: "https://Video_20181203_102048_.mp4")!
        let avPlayer = AVPlayer(playerItem: AVPlayerItem(url: url))
        let avPlayerLayer = AVPlayerLayer(player: avPlayer)
        avPlayerLayer.frame = viewView.bounds
        imageview.layer.insertSublayer(avPlayerLayer, at: 0)
        avPlayer.play()
    }
}

Or can use this library -> https://github.com/ashish0309/AutoVideoPlayer/tree/master/videoplayer
 for autoplay video


5.  Difference viewWillAppear & viewDidAppear

 Whenever You push a view controller, It will call viewDidLoad then viewWillAppear and lastviewDidAppear. But if you are coming back to viewController only viewWillAppear and viewDidAppear will call.




6.  Process scroll view if the condition did end.

--  here is one of the option available which is fairly simple

import UIKit

class ContentOffsetViewController: UIViewController, UIScrollViewDelegate {
    @IBOutlet weak var scrollViewR: UIScrollView!
    @IBOutlet weak var labelScroll: UILabel!
    var imageArray = [UIImage]()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        scrollViewR.frame = view.frame
        scrollViewR.delegate = self
        labelScroll.text = "Naruto"
    }
    
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        let pageWidth: CGFloat = scrollViewR.frame.width
        let currentPage: CGFloat = floor((scrollViewR.contentOffset.x - pageWidth / 2) / pageWidth) + 1
        
        // Change the text accordingly
        if Int(currentPage) == 0 {
            labelScroll.text = "Boruto"
        } else {
            labelScroll.text = "Other character"
        }
    }
}


7. Stashing (Git)
Stashing your work to demonstrate, you’ll go into your project and start working on a couple of files and possibly stage one of the changes. If you run git status, you can see your dirty stat. use in your terminal.

$ git stash  //saves it on a stack of unfinished changes that you can reapply at any time

$ git stash apply // call your data on a stack


8. How to use "didSet" & "willSet"

 With willSet and didSet, you can take action when the value is modified without needing another field. For instance

var person: Person? {
        didSet{

            print("Called after setting the new value")
            if let name = person?.name {
                print("New name is \(name) and old name is \(String(describing: oldValue?.name))")
            }
        }
9. Use thumbnail if format video.webp (use library Nuke)

-- This  example how use thumbnail video if you use library image Nuke, can use like code below
-- link: https://github.com/kean/Nuke

// in view did load
if let url = URL(string: "yourVideoUrl.webp") {
         self.setImageUrl(with: url, self.postImageView)  
  }

// in function
  func setImageUrl(with url: URL, _ imageView: UIImageView) {
        DispatchQueue.main.async {
            let request = self.makeRequest(with: url)
            var options = ImageLoadingOptions(transition: .fadeIn(duration: 0.25))
            options.pipeline = self.pipeline
            Nuke.loadImage(with: request, options: options, into: imageView)
        }
    }

Thanks for :

- http://nsdateformatter.com/
- https://stackoverflow.com/questions/43768201/change-image-opacity-when-touched-swift-3-xcode
- https://stackoverflow.com/questions/37651259/viewdidappear-and-viewwillappear-is-being-called-multiple-times-on-one-viewdidlo/37651624
- https://stackoverflow.com/questions/46930402/change-label-text-while-image-in-uiscrollview-changes
- https://git-scm.com/book/en/v1/Git-Tools-Stashing
- https://medium.com/the-andela-way/property-observers-didset-and-willset-in-swift-4-c3730f26b1e9

Note:  November-2018

1. Selection color for selected in tableView and collectView

 -- " cell.selectionStyle = UITableViewCellSelectionStyle.none "

 --  that code can change color if you select table view too like

 -- "  cell.selectionStyle = UITableViewCellSelectionStyle.blue ", ".red / .gray " .etc


2. Or in .xib/.nib setting selection color for selected in tableView and collectView.

--   
--  Change selection from default to none.

--  


3. For Update Carthage fast use cache.

-- $ carthage update --cache-builds --platform iOS
-- or 
-- $ carthage update  --platform iOS --cache-builds


4. Use navigation barbutton
-- Error: button bar cannot change color

-- Don't
--

--Do
--

5.  Code "Swift" for Thumbnail video

  func createThumbnailOfVideoFromRemoteUrl(url: URL) -> UIImage? {
         let asset = AVAsset(url: url)
         let assetImgGenerate = AVAssetImageGenerator(asset: asset)
         assetImgGenerate.appliesPreferredTrackTransform = true
         let time = CMTimeMakeWithSeconds(1.0, 600)
         do {
             let img = try assetImgGenerate.copyCGImage(at: time, actualTime: nil)
             let thumbnail = UIImage(cgImage: img)
             return thumbnail
         } catch {
             print(error.localizedDescription)
             return nil
        }
     }

-- Note: for url from Api and local storage, if u want URL video from local storage, must get data from -- gallery  .photolibrary --> video after didfinish and check URL .

--  example :
--- local: file:///var/mobile/Media/DCIM/100APPLE/IMG_0028.MOV 
--- web / Api / cloud = https://img.google.com/video/Video_20181031_c2smyp.mp4


6. Count / limit character UITextView 

-- How to use, component is UITextView, UILabel and use shouldChangeTextIn
-- example: limit character < 300.

  public func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {

        let newText = (questionTextView.text as NSString).replacingCharacters(in: range, with: text)
        let numberOfChars = newText.count
        self.questionCountLabel.text = "\(300 - newText.count)" // questionCountLabel -> label show
        return numberOfChars < 300

    }

-- Note: for UITextField use shouldChangeCharactersIn 


7. Simple Video Player use  AVPlayerViewController

-- Remember to import AVKit, import AVFoundation, AVFoundation framework is needed even if you use AVPlayer

import UIKit
import AVKit
import AVFoundation

@IBAction func handleVideoPlayerr(_ sender: UIButton) {

      let  videoURL = "your_Url_Video"
     
        let player = AVPlayer(url: videoURL)
            let vc = AVPlayerViewController()
            vc.player = player
            
            present(vc, animated: true) {
                vc.player?.play()
            }    

8. Count / limit Character For UITextField

-- This for UITextField use shouldChangeCharactersIn 


func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let newLength = (textField.text?.utf16.count)! + string.utf16.count - range.length
        if newLength <= 16 {
            countLabel.text = "\(16 - newLength)"
            
            return true
        } else {
            return false
        }

    }
-- Full custom text field File



9.  Condition if UIScrollView in bottom ?

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    let  height = scrollView.frame.size.height
    let contentYoffset = scrollView.contentOffset.y
    let distanceFromBottom = scrollView.contentSize.height - contentYoffset
    if distanceFromBottom < height {
        print(" you reached end of the table")
    }
}

when my iPhone fell caused an error touch screen, if I touch in the screen random freezing not accurate,  and I try to fix it with several ways. finally, fix it use a setting in 3D touch disabled.

 Solution: Configure display settings and options.

• Go to Settings.
• Tap General.
• Tap Accessibility.
• Tap 3D Touch.
• Adjust the sensitivity settings.
• Reboot your iPhone.

In my mind, I ask How to create a gradient in background viewControler, and finally I found the answer check this.





you can see full in https://www.youtube.com/watch?v=3gUNg3Jhjwo
I learn from sean alen,  thanks for tutorial.


how to use:

import UIKit

class GradientViewController: UIViewController {
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.setGradientBackground(colorOne: UIColor.blue), colorTwo: UIColor.white)
    }
    
    
}

In Use " info[UIImagePickerControllerOriginalImage] as? UIImage " => ".camera"

Specifies the original, uncropped image selected by the user.
The value for this key is a UIImage object

Use:

@IBAction func bAction(_ sender: Any) {
        picker.delegate = self
        picker.sourceType = .camera
        picker.allowsEditing = false
        picker.isEditing = true
        present(picker, animated: true, completion: nil)
        
    }

  func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String: Any]) {
        if let image = info[UIImagePickerControllerOriginalImage] as? UIImage {
           self.imageview.image = image
           
        }
      
     dismiss(animated: true, completion: nil)
    }

In Use  " info[UIImagePickerControllerEditedImage] as? UIImage " => ".photoLibrary"

Specifies the edit image, cropped image selected by the user, this work select in if you
get image from library

Use :  

@IBAction func bAction(_ sender: Any) {
        picker.delegate = self
        picker.sourceType = .photoLibrary
        picker.allowsEditing = true
        picker.isEditing = true
        present(picker, animated: true, completion: nil)
        
    }

  func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String: Any]) {
        if let image = info[UIImagePickerControllerEditedImage] as? UIImage {
           self.imageview.image = image
           
        }
      
     dismiss(animated: true, completion: nil)
    }

If you have a problem in the code convert video and rename the video , look this error and solution.
-  Error Domain=AVFoundation Error Domain Code=-11823 "Cannot Save"
-  Can not rename file video
-  Can not rename change extension
-  post url video after change extansion

you can implement this code below in your project

if you are looking for a way to fix a bug like "string regex delete use character swift 4", maybe this code can help you.



source: https://stackoverflow.com/questions/37484357/delete-characters-in-range-of-string https://stackoverflow.com/questions/46145418/replacing-a-string-with-a-capture-group-in-swift-3

for check (.regularExpression) https://developer.apple.com/documentation/foundation/nsregularexpression

This time I tried to make UILabel part of a bold text,  using func so that many other UILabels can be used.





import UIKit

class MentionHalfBoldViewController: UIViewController {
    @IBOutlet weak var labelBold: UILabel!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        labelBold.attributedText = attributedTextWith(withString: String(format: "Name : %@", "Jonny"), boldString: "Name", font: labelBold.font)
    }
    
    func attributedTextWith(withString string: String, boldString: String, font: UIFont) -> NSAttributedString {
        let attributedString = NSMutableAttributedString(string: string,
                                                         attributes: [NSAttributedStringKey.font: font])
        let boldFontAttribute: [NSAttributedStringKey: Any] = [NSAttributedStringKey.font: UIFont.boldSystemFont(ofSize: font.pointSize)]
        let range = (string as NSString).range(of: boldString)
        attributedString.addAttributes(boldFontAttribute, range: range)
        return attributedString
    }
}

link GitHub https://github.com/andresilvagomez/Localize

You can use Cocoapod or Carthage, for install cek link github Localize, this time I try localize use xib file. let's start.

1. Create new file ".xib" and ".swift" file
2. Intall library Localize
3.  In xib file use label and button,  in view you can give 4 label and 1 button like image below.



4.  Follow or copy this code. in full file

- LocalizeViewController.swift

import UIKit
import Localize

class MenuViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

     
    }
    @IBAction func bAction(_ sender: Any) {
        let alert = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
        alert.addAction(UIAlertAction(title: "English", style: .default, handler: { _ in
            Localize.update(language: "en")
        }))
        alert.addAction(UIAlertAction(title: "Indonesia", style: .default, handler: { _ in
            Localize.update(language: "id")
        }))
        alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
        present(alert, animated: true, completion: nil)
    }
}


- AppDelegate.swift

import UIKit
import Localize

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?


func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.

let localize = Localize.shared
// Set your localize provider.
localize.update(provider: .json)
// Set your file name
localize.update(fileName: "lang")
// Set your default languaje.
localize.update(defaultLanguage: "id")
// If you want change a user language, different to default in phone use thimethod.
localize.update(language: "en")
// If you want remove storaged languaje use
localize.resetLanguage()
// The used language
print(localize.currentLanguage)
// List of aviable languajes
print(localize.availableLanguages)

// Or you can use static methods for all
Localize.update(fileName: "lang")
Localize.update(defaultLanguage: "id")
Localize.update(language: "en-DE")
        
        window = UIWindow(frame: UIScreen.main.bounds)
        window?.makeKeyAndVisible()
        window?.rootViewController = UINavigationController(rootViewController: MenuViewController())

return true
}

func applicationWillResignActive(_ application: UIApplication) {}
func applicationDidEnterBackground(_ application: UIApplication) {}
func applicationWillEnterForeground(_ application: UIApplication) {}
func applicationDidBecomeActive(_ application: UIApplication) {}
func applicationWillTerminate(_ application: UIApplication) {}


}

Create new album use UIImagePickerController to take a photo by camera of iPhone, must setting info.plist









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My Favorite Quote:
One becomes a beginner after 1,000 days of training. One becomes a master after 10,000 days of practice

On this blog all are problems that I have encountered and how do I solve it, if you have some problem maybe we can help you, just send to email below, I'm happy to help you, and let's share knowledge.

you can request template app just send an email below

My app: https://apps.apple.com/id/app/scan-four/id1490755853
Email us: 21zerixpm@gmail.com

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I have problem "how to setting spotlight mac can't find all application in mac" that key word i search in google, in my mac can't find apps in spotlight search




First solution from apple follow this step

1. Choose Apple menu () > System Preferences, then click Spotlight.
2. Click the Privacy tab.
3. Drag the folder or disk that you want to index again to the list of locations that Spotlight is prevented from searching. Or click the Add (+) button and select the folder or disk to add.
   To add an item to the Privacy tab, you must have ownership permissions for that item. To learn about permissions, choose Help from the Finder menu bar, then search for “permissions.”
4. From the same list of locations, select the folder or disk that you just added. Then click the Remove (–) button to remove it from the list.
5. Quit System Preferences. Spotlight will reindex the contents of the folder or disk.

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1. download in github  https://github.com/nicklockwood/SwiftFormat, or can be download tag
https://github.com/nicklockwood/SwiftFormat/releases/tag/0.49.4

2. open -> SwiftFormat-master -> EditorExtension -> move file "SwiftFormat for Xcode" to aplication.





3. open SwiftFormat for Xcode.



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I have a problem if using UITabBarController, center button icon in hold touch an swipe icon make size small, If you have the same problem you can solve like this below



import UIKit

class TabbarViewController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()
        self.tabBar.backgroundImage = UIImage()
        self.tabBar.backgroundColor = #colorLiteral(red: 1.0, green: 1.0, blue: 1.0, alpha: 1.0)
        self.view.backgroundColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
   
        let leftVC = UIViewController()
        let centerVC = ForTestPart5VC()
        let rightVC = UIViewController()
       
        leftVC.tabBarItem = UITabBarItem(title: "Left", image: UIImage(named: "e1.png"), tag: 0)
        centerVC.tabBarItem = UITabBarItem(title: "Center", image: UIImage(named: "e2.png"), tag: 1)
        rightVC.tabBarItem = UITabBarItem(title: "Right", image: UIImage(named: "e3.png"), tag: 2)
       
        centerVC.tabBarItem.imageInsets = UIEdgeInsetsMake(7, 0, -6, 0) // Error in here
        viewControllers = [leftVC, centerVC, rightVC]
    }

}

Solution: In UIEdgeInsetsMake top and bottom must be same number setting.

centerVC.tabBarItem.imageInsets = UIEdgeInsetsMake(7, 0, -7, 0) // fix

This time I share code in swift 4 how to split your string into an index and use that in textField, try this code below maybe can help you.

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