iOS

Install specific iOS beta on simulator

Apple release the new iOS SDK every day, as the developer, we want to test our apps on those new SDK before they are officially released. For example, we want to have the iOS 17 beta on the MacOS Ventura 13.3 (22E252). Here are the steps: First need to

iOS

How to do a deep cleaning for pod

If you are like me, the project is still using the pod to manage the libraries and frameworks. We need to clean the projects from time to time. The following command can help us to clean all the cached pods. In the root directory: pod deintegrate pod cache clean --all

Swift

Nested class in Swift

A nested class in Swift is a class that is defined within another class. Some key features: * Nested class have access to local variables or constants of the outer class unless these variables or constants are marked as static. * Nested class can be marked as private, fileprivate, or internal. Here

RxSwift

2 hours to master RxSwift - Part 2

In this article we will dig a bit more depth in some core concepts on 2 hours to master RxSwift - Part 1. Section 1: Observable Like mentioned in the last article, an Observable in RxSwift will emit events (values and errors) over time, and notifies its observers, and nearly

RxSwift

2 hours to master RxSwift - Part 3

Introduction In the previous post: 2 hours to master RxSwift - Part 1 (needone.app) and 2 hours to master RxSwift - Part 2 (needone.app), we get to know the the core concept behind the RxSwift and how RxSwift works. In this tutorial, we are going to combine what

Swift Featured

2 hours to master RxSwift - Part 1

a simple introudction on rxswift, including what is rxswift, how to use it and a quick example (with swift code) on demo that.

Kotlin

Singleton in Kotlin

In the Kotlin programming language, a singleton is a design pattern that allows you to create only one instance of a class. This is useful when you want to make sure that there is only one instance of a particular class, for example, if you want to create a global

Kotlin

Use keystore to store your sensitive in Kotlin

The keystore is a secure storage location in Android that is used to store encryption keys, digital certificates, and other sensitive information. The keystore is encrypted with a hardware-based key, which makes it much more difficult for an attacker to access the stored data. To use the keystore in Kotlin,

Swift

Generic type vs. Any in Swift

Generic type In Swift, a generic type is a placeholder for a specific type that is specified when the generic type is used. A generic type allows you to write flexible and reusable code that can work with any type, while still taking advantage of type safety. For example, you

iOS

indirect enum in Swift

An indirect enum in Swift is an enum that can be used to define a recursive data structure. This means that one or more of its cases can refer to an instance of the same enum type. Here is an example of an indirect enum in Swift: indirect enum TreeNode&

Swift

UITraitCollection

UITraitCollection is a class in the UIKit framework that defines a set of interface traits that specify the environment in which your app is running. These traits include the device’s display scale, user interface style, and size class. You can use the information contained in a UITraitCollection object to

Swift

UIKit vs. SwiftUI - A general discussion

UIKit and SwiftUI are two different frameworks for building user interfaces on Apple platforms. UIKit UIKit is the older of the two frameworks, and has been around since the early days of iOS development. It is a mature and powerful framework that provides a wide range of tools and APIs

Kotlin

Certificate pinning and Public key pinning in Kotlin

With the last article (Certificate pinning and Public key pinning), we know the concept of Certificate pinning and Public key pinning, and how to implement them in iOS. This article will demonstrate how to implement them in Kotlin. Implement certificate pinning Certificate pinning is a security technique that involves associating

Encryption and decryption

Certificate pinning and Public key pinning

Certificate pinning and public key pinning are both techniques that are used to enhance the security of a network connection by ensuring that the client trusts only a specific certificate or public key. Certificate pinning Certificate pinning is a security technique that is used to ensure that an app is

Android

Download image from URL in Kotlin

In Android, we can get the image from synchronously and asynchronously, but it is more common to see in the later. Download image synchronously To download an image from a URL in Kotlin, you can use the URL class and the readBytes function from the kotlin.io library. The URL

Swift

Sort custom objects by property in Swift

Many of us have met the situation that we have an array/list of custom objects, and we want them can be sorted in a specific order. For example, we are have a group of people, and we want to sort the whole array by the person's age.

Android

RunBlocking in Kotlin Coroutine

In previous post, we have gone through most of the key concepts and methods in Coroutine: Kotlin Coroutines Table Content 1, Introduction to Coroutine in Kotlin 2, Non-blocking in Kotlin Coroutines 3, Start and Suspend a Coroutine in Kotlin However, we haven't talked about runBlocking yet, which is

Swift

Format currency in Swift

Recently I have done quite an amount of work on formatting currency in Swift project, here are some tricks on how to format number in Swift: Format currency with auto  currency symbol By using the NumberFormatter class, we can convert numbers into string(s), and vice versa. More conveniently, we

Android

Lazy in Kotlin

In the Kotlin programming language, the term "lazy" typically refers to a type of property or variable that is only initialized when it is first accessed, rather than when the containing object is created. This can be useful for optimizing the performance of an application, by delaying the

iOS

Get the current week in Swift

To get the current week in Swift 5, you can use the Calendar and DateComponents classes to calculate the week number for the current date. Here's an example of how you might do this: let calendar = Calendar.current let currentDate = Date() let currentWeek = calendar.component(.weekOfYear, from: currentDate)

iOS

SceneDelegate

In iOS, the SceneDelegate is a class that is responsible for managing the scenes in your app. A scene is a discrete unit of your app's user interface, such as a window or tab. The SceneDelegate class provides methods that are called at various points in the lifecycle

Swift

Data Racing in Swift

A data race in Swift occurs when two or more threads access the same memory location simultaneously and at least one of them is writing to it, without proper synchronization. This can lead to unexpected behavior or crashes in your program. In Swift, there are two common scenarios on data

Android

Encode URL in Kotlin

In Kotlin, you can use the URLEncoder class to encode a URL string so that it can be safely transmitted over the internet. The URLEncoder class is part of the Java standard library, and it provides a method called encode that can be used to encode a URL string. Here&

SwiftUI

@AppStorage vs. @UserDefault in SwiftUI

Both the @AppStorage and @UserDefault property wrappers in SwiftUI allow you to store and retrieve data using UserDefaults. However, there are a few key differences between the two: @AppStorage In SwiftUI, you can use the @AppStorage property wrapper to store and retrieve data using UserDefaults. The @AppStorage property wrapper binds

Other

HTTP Encoding

HTTP encoding, also known as percent-encoding or URL encoding, is a way of encoding special characters in URLs and other HTTP data, such as headers and body content. HTTP encoding uses a special encoding scheme, called percent-encoding, to represent the special characters as a combination of the % character and two