# Useful Swift Things

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    <img src="https://github.com/jphong1111/Useful_Swift/blob/main/Images/swift.jpeg">
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    <img src="https://img.shields.io/badge/-OneDayOneCommit-critical?style=plastic&logo=swift" />
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## Content
- [Coding convention](#Coding-convention)
    - [Swift Lint](#Swift-lint)
- [Design Pattern](#Design-Pattern)
    - [Delegate](#Delegate)
    - [Singleton](#Singleton)
    - [Observer](#Observer-Pattern)
- [Code Structuring](#Code-Structuring)
    - [MVC](#MVC)
    - [MVVM](#MVVM)
    - [VIPER](#VIPER)
- [UIDesign](#UIDesign)
- [Helper](#Helper)
    - [Email, Message, Call](#email-message-call)
    - [Network Layer](#Network-Layer)
    - [Image Picker](#Image-Picker)
    - [File Manager](#File-Manager)
    - [Video Downloader](#Video-Downloader)
    - [Image Downloader](#Image-Downloader)
    - [Location Manager](#Location-Manager)
- [API](#API)	
- [JSON](#JSON)
- [User Default](#User-Default)
    - [How to find documentDirectory](#How-to-find-documentDirectory)
- [Core Data](#Core-Data)
- [Third Party Library](#Third-Party-Library)
- [GCD](#GCD)
    - [DispatchQueue](#DispatchQueue)
    - [DispatchGroup](#DispatchGroup)
    - [DispatchWorkItem](#DispatchWorkItem)
    - [Thread Sanitizer](#Thread-Sanitizer)
- [Testing](#Testing)
    - [Code Coverage](#Code-Coverage)
    - [Unit Test](#Unit-Test)
    - [UI Test](#UI-Test)
- [IAP](#IAP)
- [APNS](#APNS)
- [FRP](#FRP)
- [Useful Stuff](#Useful-Stuff)
    - [Show Preview in UIKit(Build UI with Code Base)](#show-preview-in-uikitbuild-ui-with-code-base-----)
    - [Write README.md](#write-readmemd)
    - [Roadmap for iOS Developer](#Roadmap-for-iOS-Developer)


## Coding convention
set of guidelines for a specific programming language that recommend programming style

### Swift Style Guide

- [Swift Style Guide](https://github.com/linkedin/swift-style-guide)

### Swift Lint
The way of force you to adapt coding convention 
>otherwise project build will **FAILED**
- [Swift Lint](https://github.com/realm/SwiftLint) apply for all project:+1:
```swift
if which swiftlint >/dev/null; then
  swiftlint
else
  echo "error: SwiftLint not installed, download from https://github.com/realm/SwiftLint"
  exit 1
  fi
```
put .yml file into root folder and apply following code in Build Phases

**You can modify(delete) SwiftLint Option with opening .yml file**

> Shift + Command + . will show the hidden file

<img src="https://github.com/jphong1111/Useful_Swift/blob/main/Images/swiftLintChange.png">

## Design Pattern
Design pattern is

Check [this](https://refactoring.guru/design-patterns/swift) website for design pattern in Swift

### Delegate Pattern

```swift
weak var delegate: SomeProtocol?
```

### Singleton Pattern


```swift
class SingletonPattern {
    static let manager = SingletonPattern()
    
    private init() {}
}
```

### Observer Pattern

The observer pattern lets one object observe changes on another object. Apple added language-level support for this pattern in Swift 5.1 with the addition of Publisher in the Combine framework.

<img src = "https://github.com/jphong1111/Useful_Swift/blob/main/Images/observer.png" />

## Code Structuring

### MVC

<img src="https://github.com/jphong1111/Useful_Swift/blob/main/Images/MVCModel.png">

### MVVM

##### MVC vs MVVM

<img src="https://github.com/jphong1111/Useful_Swift/blob/main/Images/MVVMvsMVC.png">

M -> Model – Which holds the application data

V –> View – It displays the data that is stored in model. These are visual elements through which a user interacts. These are subclasses of UIView

VM –> View Model – Transform model information/data and it interacts with controller or view to display those informations.

C –> Controller class – It will be there but the responsibility of view business logic has been removed and give to view model


### VIPER

## UIDesign

### HIG(Human Interface Guidelines)
- [Apple UI Kit](https://developer.apple.com/documentation/uikit)
- [iOS Design Guide](https://ivomynttinen.com/blog/ios-design-guidelines)

### iOS icon 

- [icon8](https://icons8.com/) You can download icons imge for your **APP**
- [appicon](https://appicon.co/) generate the app icon size

### UIdesign inspiration

- [dribble](https://dribbble.com/)
- [pinterest](https://pinterest.com/)
- [behance](https://www.behance.net/)
- [pttrns](https://pttrns.com/)
- [awwwards](https://www.awwwards.com/)
- [flickr](http://www.flickr.com/)
- [mobbin](https://mobbin.design/)

## Helper

All files are resuable files and protocol oriented. **Just Copy and Paste inside your project and use it!!** 👍
 
## Email, Message, Call

You can check the file in the follow link

- [Email, Message, Call](https://github.com/jphong1111/Useful_Swift/blob/main/Helper/ConversationManager.swift) 

### Usage
import MesaageUI first

```swift
import MessageUI
```

Then use it
> Don't forget to extend the mail, message delegate to your ViewController!

```swift
    lazy var conversation = ConversationManager(presentingController: self, mailDelegate: self, messageDelegate: self, viewController: self)
    
    @IBAction private func sendEmail(_ sender: UIButton) {
        conversation.sendEmail(feedback: MailFeedback(recipients: ["abcd@google.com"], subject: "FeedBack", body: "Write feedback here"))
    }
    @IBAction private func sendMessage(_ sender: UIButton) {
        conversation.sendMessage(feedback: MessageFeedBack(recipients: ["1111111111"], body: "Type here"))
    }
    @IBAction private func startCall(_ sender: UIButton) {
        conversation.makeCall(number: "1111111111")
    }
```

Good To GO 👏👏👏
> See Example [here](https://github.com/jphong1111/ImageMessageHandler_DemoApp)

## Network Layer

- [Network Layer](https://github.com/jphong1111/Useful_Swift/tree/main/Helper/Network%20Layer) 

### Usage

First, set the base URL in **EndPointType file**
> Don't forget to put your API key in it!

```swift
var baseURL: URL {
        guard let url = URL(string: "https://api.openweathermap.org/data/2.5/") else {
            fatalError("baseURL could not be configured.")
        }
        return url
    }
```

then make a instance of router.swift file in your code

```swift
private let router = Router<YourAPI>()
```

for **YourAPI part**, simply create a new **enum** with cases about specific api URL
> It will make your router more dynamic!
> Don't forget extension to EndPointType!

```swift
enum YourAPI {
    case first(country: String)
    case second(time: Int)
    case third(name: String)
}

extension YourAPI: EndPointType {
    var path: String {
        switch self {
        case .first(let country):
            return "\(country).json"
        case .second(let time):
            return "\(time).json"
        case .third(let name):
            return "\(name).json"
        }
    }
}
```

then, use it like this

```swift
router.request(.first(country: London)) { [weak self] (results: Result<CountryWeather, AppError>) in
            guard let self = self else { return }
            switch results {
            case .success(let data):
                // insert your modifications!
                
            case .failure(let error):
                // insert your modifications!
                print(error)
            }
        }
```

> **CountryWeather should be a model with Decodable**

If you want to see how can I use Network Layer in Project, check [this](https://github.com/jphong1111/Unsplash_Clone/tree/main/Unsplah_Clone/ReusableComponent/NetworkLayer)

This reusable network layer files for referenced from [here](https://medium.com/flawless-app-stories/writing-network-layer-in-swift-protocol-oriented-approach-4fa40ef1f908)

> Also [Alamofire](https://github.com/Alamofire/Alamofire) will be a great option for Network Layer!

## Image Picker

- [Image Picker](https://github.com/jphong1111/Useful_Swift/blob/main/Helper/ImagePickerHandler/ImagePicker.swift) 

### Usage

Copy and Paste in your project and then declare Image Picker object inside your project 

```swift
lazy var imagePicker = ImagePicker(presentationController: self, delegate: self)
```

Then, extend ImagePickerDelegate to your viewController

```swift
extension ViewController: ImagePickerDelegate {
    func didSelect(image: UIImage?) {
        self.yourImageView.image = image
        self.dismiss(animated: true, completion: nil)
    }
}
```

Good To GO 👏👏👏
> See Example [here](https://github.com/jphong1111/ImageMessageHandler_DemoApp)


## File Manager

- [File Manager](https://github.com/jphong1111/Useful_Swift/blob/main/Helper/FileManageHelper.swift) 

### Usage

Copy and Paste in your project 

```swift
let readData = FileManageHelper.manager.readFile(filename: fileNameTextField.text ?? "", type: extensionTextField.text ?? "")
resultTextField.text = readData
```
> File Manager are wrote with singleton pattern, therefore no need to declare in side your code!

Good To GO 👏👏👏

## Video Downloader

- [Video Downloader](https://github.com/jphong1111/Useful_Swift/blob/main/Helper/VideoManager.swift) 

## Usage

Make an object of VideoManager inside your code

```swift
let videoManager = VideoManager()
```

use downloadVideoLinkAndCreateAsset function to start download with entering URL

```swift
self.videoManager.downloadVideoLinkAndCreateAsset(text)
```
Good To GO 👏👏👏

## Image Downloader

There is no file for Image Downloader.

To download images into device, only thing is this

```swift
if let data = try? Data(contentsOf: urls),
   let image = UIImage(data: data) {
   UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
}
```
Just **change urls into your image URL**

> UIImageWriteToSavedPhotosAlbum will take care it to download to device.

> For more info go [here](https://www.hackingwithswift.com/example-code/media/uiimagewritetosavedphotosalbum-how-to-write-to-the-ios-photo-album)

Good To GO 👏👏👏

## Location Manager

- [Location Manager](https://github.com/jphong1111/Useful_Swift/tree/main/Helper/LocationHandler/LocationManager.swift)

## API

API(Application Programming Interface) is an interface that defines interactions between multiple software applications or mixed hardware-software intermediaries. It defines the kinds of calls or requests that can be made, how to make them, the data formats that should be used, the conventions to follow, etc.

## JSON
JSON is a language-independent data format
> Which is relative with **KEY - VALUE** pair
```json
{
    "main": [
        {
            "title": "example1",
            "body": "body1"
        },
        {
            "title": "example2",
            "body: "body2"
        }
    ]
}
```
### JSON parser extension for Chrome
This extension makes JSON more structable
[JSON parser pro](https://chrome.google.com/webstore/detail/json-viewer-pro/eifflpmocdbdmepbjaopkkhbfmdgijcc) **FREE** :+1:

### JSON Decoding

To use JSON Decoding in swift, you have to define the model to be Codable or Decodable

```swift
public typealias Codable = Decodable & Encodable
```

> Decodable can only decode the json data. Can't encoded json file!!

```swift
struct User: Codable {
    var first_name: String
    var last_name: String
    var country: String
}
```

To use JSONDecoding, declare JSONDecoder and use decode() function

```swift
 do {
    let data = try JSONDecoder().decode(T.self, from: unwrappedData)
    completionOnMain(.success(data))
} catch {
    print(error)
    completionOnMain(.failure(.parseError))
}
 ```
 
T.self -> Model(Struct) of the data that you want to decode
 > data will decoded to form of T

unwrappedData -> Input actual data from file or server
> This should be a Data Type!!
 
### JSONSerialization


## User Default

The UserDefaults class provides a programmatic interface for interacting with the defaults system. Check [Apple Document](https://developer.apple.com/documentation/foundation/userdefaults) for more info

UserDefault has to have **key-value** pair

### How to find documentDirectory 

Put this line of code inside of your project
```swift
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        print(NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).last ?? "")
        return true
    }
```

simply move into that path and you can find the documentDirectory of your Application
> if Library is not shown up, just do **Shift + Command + .** to show hidden files in your folder

As you can see in the below, intArray will stored inside the device through UserDefaults(), so that if device is shut down, changed value wil be stored in device.

```swift
class ViewController: UIViewController {
    var intArray = [1,2,3,4,5]
    let defaults = UserDefaults()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        intArray = defaults.array(forKey: "IntArray") as! [Int]
    }
    
    @IBOutlet weak var textField: UILabel!
    @IBAction private func isClicked(_ sender: UIButton) {
        intArray.append(6)
        defaults.set(intArray, forKey: "IntArray")
        textField.text = "\(intArray)"
    }
}
```

## Core Data


### Various API Site
- [rapidAPI](https://www.rapidapi.com)

## Third Party Library
[This github](https://github.com/vsouza/awesome-ios) contains all the popular libraries in Swift:+1:

Recommand Useful Library
- [SDWebImage]
- [Hero]
- [Alamofire]
- [RxSwift]


## GCD
GCD(Grand Central Dispatch) is a low-level API for managing concurrent operations. It can help you improve your app’s responsiveness by deferring computationally expensive tasks to the background.

### DispatchQueue
An object that manages the execution of tasks serially or concurrently on your app's main thread or on a background thread.

#### main
We can say main is a serial queue

#### global()
We can say global is a concurrent queue

### DispatchGroup

### DispatchWorkItem

### Thread Sanitizer
Thread Sanitizer is a tool to identifies the potential thread-related corruption issues. And it is a good way to find the [Readers and Writers problem](https://en.wikipedia.org/wiki/Readers%E2%80%93writers_problem) in your application.

#### How to Use Address Sanitizer

Go to this Option and Click **EDIT SCHEME...** 👈

<img src="https://github.com/jphong1111/Useful_Swift/blob/main/Images/address_sanitizer.png">

And then go to **RUN** and check **THREAD SANITIZER** 👈

<img src="https://github.com/jphong1111/Useful_Swift/blob/main/Images/thread_sanitizer.png">

## Testing

Before start your Testing, add coverage will be a good option to show the result of test

### Code Coverage

First, check code coverage

<img src ="https://github.com/jphong1111/Useful_Swift/blob/main/Images/addCoverage1.png" />

Then, go to **EDIT SHEME**, check like this

<img src ="https://github.com/jphong1111/Useful_Swift/blob/main/Images/addCoverage2.png" />

### Unit Test

### UI Test

## IAP

IAP stands for **In App Purchase**

## APNS

APNS stands for **Apple Push Notification service**

## FRP

Functional Reactive Programming a.k.a [RxSwift](https://github.com/ReactiveX/RxSwift)

## Useful Stuff

### Show Preview in UIKit(Build UI with Code Base) 👍 👍 👍 👍 👍

Copy this code and Paste into your controller

```swift
#if canImport(SwiftUI) && DEBUG
import SwiftUI
struct SwiftLeeViewRepresentable: UIViewRepresentable {
    func makeUIView(context: Context) -> UIView {
        return UIStoryboard(name: "Main", bundle: Bundle.main).instantiateInitialViewController()!.view
    }
    
    func updateUIView(_ view: UIView, context: Context) {
        
    }
}

@available(iOS 13.0, *)
struct SwiftLeeViewController_Preview: PreviewProvider {
    static var previews: some View {
        SwiftLeeViewRepresentable()
    }
}
#endif
```

Enable canvas option like this

<img src="https://github.com/jphong1111/Useful_Swift/blob/main/Images/preview%20using%20canvas.png">

**You are GOOD TO GO**  👏👏👏

<img src="https://github.com/jphong1111/Useful_Swift/blob/main/Images/preivew_screenShot.png">

## Write README.md

[This](https://medium.com/@saumya.ranjan/how-to-write-a-readme-md-file-markdown-file-20cb7cbcd6f) will help you to write a README.md file more dynamically 👍

## Roadmap for iOS Developer

check this out [here](https://github.com/BohdanOrlov/iOS-Developer-Roadmap)

## Author

This README.md file is written by **Jungpyo Hong (Dennis)**