Khoa Pham
Khoa Pham

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My year in review 2020

Issue #715

I remember this time last year in December 2019, I spent almost every single bit of my free time on Puma because I want a Swift friendly version of fastlane that suits my need and leverages Swift 5 features.

Here’s my review of my …

How to use popover in SwiftUI

Issue #882

In SwiftUI, .popover shows as popover on Mac and iPad, but as .sheet on iPhone (compact size class)

We can use minWidth, minHeight to specify sizes on Mac and iPad. On iPhone, we can check and wrap it inside NavigationView. Setting …

How to select in List in SwiftUI

Issue #881

Specify optional value for List(selection:).

This keeps selection on macOS, but not on iPad. On iPad each row in the List needs to be NavigationLink, no need for .tag. The selection is not updated, need to manually update with onTapGesture …

How to use native SSL Pinning

Issue #880

From iOS 14, we can do Identity Pinning: How to configure server certificates for your app right from Info.plist

<key>NSAppTransportSecurity</key>
    <dict>
        <key>NSPinnedDomains</key> …

How to use NSPersistentCloudKitContainer

Issue #879

Setting Up Core Data with CloudKit

  • Enable iCloud
  • Enable CloudKit and Push Notifications
  • Enable Remote Notifications in the Background

Creating a Core Data Model for CloudKit

Initialize Your CloudKit Schema During Development

let …

How to allow multiple selection in List in SwiftUI

Issue #878

Note that

  • Explicit id is needed, although Book already conforms to Identifiable
  • selection needs a default value
class BookViewModel: ObservableObject {
    @Published var books: [Book] = []
    @Published var selectedBooks: Set<Book …

How to use ViewBuilder in SwiftUI

Issue #877

Over the course of making several SwiftUI apps, I’ve discovered quite a few hidden magic of SwiftUI that are quite fun.

Here are 6 interesting SwiftUI features in View Builder many don’t know are even possible 🤯

View protocol …

How to debounce TextField search in SwiftUI

Issue #876

Make a dedicate DebounceObject to debounce (or throttle). Then we can even observe with onChange on the debouncedText or just use it directly to sort

import Combine

public final class DebounceObject: ObservableObject {
    @Published var …

How to create document based macOS app

Issue #875

Read newDocument

This method calls openUntitledDocumentAndDisplay(_:).

Read openUntitledDocumentAndDisplay

The default implementation of this method calls defaultType to determine the type of new document to create, calls …

How to add dot indicator to tab bar item in iOS

Issue #874

From iOS 13, use UITabBarAppearance and UITabBarItemAppearance

let appearance = UITabBarAppearance()

let itemAppearance = UITabBarItemAppearance(style: .stacked)
itemAppearance.normal.badgeBackgroundColor = .clear
itemAppearance.normal. …

How to use Multipeer Connectivity

Issue #873

Use assistant

let assistant = MCAdvertiserAssistant(serviceType: "my-service, discoveryInfo: nil, session: mcSession)
assistant.start()

let browser = MCBrowserViewController(serviceType: "my-service", session: mcSession) …

How to generate Polygon wallet account in Swift

Issue #871

Use libraries

import web3
import web3keystore
import KeychainAccess

private final class KeyStorage: EthereumKeyStorageProtocol {
    enum Key: String { …

How to learn Polygon programming

Issue #870

Building

Sidechain

How to make simple Plist builder with resultBuilder in Swift

Issue #869

We can use PropertyListEncoder from Swift 4

let encoder = PropertyListEncoder()
encoder.outputFormat = .xml
let data = try encoder.encode(model)

Or we can manually do with resultBuilder style

Declare @resultBuilder for PlistBuilder that …

How to generate JWT token for App Store Connect API in Swift

Issue #868

Use JWTKit and code from AppStoreConnect library

import JWTKit

public struct Credential {
    let issuerId: String
    let privateKeyId: String
    let privateKey: String

    public init(
        issuerId: String,
        privateKeyId: …

How to send SPL token in Swift

Issue #867

Using https://github.com/ajamaica/Solana.Swift and the sendSPLToken method. Note that the from is the token account address and amount can have decimals

solana.action.sendSPLTokens(
    mintAddress: MINT_ADDRESS,
    from: …

How to calculate Solana transaction fee

Issue #866

A simple way is to use a fixed fee of 0.000005

For example from https://solscan.io/tx/5DkApvwTYuMqCiA94MhUVKJoLn8MGma9gAWXhreRJKqAs395P5CqEK3R84m3MWjcTKMem53XcLwYErGkaJAbQC2h?cluster=testnet

And call some exchange API, like Coingecko …

How to parse large JSON Dictionary in Swift

Issue #865

We can define some typealias and build extensions on JSONDictionary to easily extract values

typealias JSONDictionary = [String: Any]
typealias JSONArray = [JSONDictionary]

extension JSONDictionary {
    func dict(_ key: String) -> …

How to make simple async URLSession in Swift

Issue #864

Since async URLSession.shared.data is available in iOS 15+, we can build a custom one with withCheckedThrowingContinuation

import UIKit

enum HTTPMethod: String {
    case get = "GET"
    case post = "POST"
}

extension …

How to check SPL token balance on Solana

Issue #863

We will check USDC token balance on Solana testnet.

Firstly, we will use https://usdcfaucet.com/ to airdrop some USDC tokens into our wallet. Secondly, we check USDC token mint address on testnet cluster using Solana Explorer …

How to learn Solana programming

Issue #862

General

Khoa Pham

Hello, I’m Khoa

I’m a thinker and storyteller with a passion for exploring the intersection of creativity and technology

🧑‍💻 I love crafting high quality and useful apps
🔥 I love open source. My GitHub open source has 2.3k followers with packages that are integrated by 45k+ apps and over 3.4m+ downloads on CocoaPods.
✍️ I write here on my blog and on Medium, which has over 2.7k+ followers with tons of articles and 90k+ monthly views.
🖥 Follow me for sharings about Swift, SwiftUI, iOS and macOS development.
Hei