Found 199 Articles for IOS

What does "Fatal error: Unexpectedly found nil while unwrapping an Optional value" mean?

Nitin Aggarwal
Updated on 02-Jan-2023 14:29:11
This error is very frequent as you can see many times while writing code. Don't worry, you will understand this error in detail in this article. Before jumping to the cause of this error, let's understand what is optional in Swift. Optional Initially, when we receive a value from another source, such as the backend server, it might contain a valid value or nothing at all. In that case, you use optionals that represent a variable with two possible situations: either a value or no value at all. var possibleNumber = "450" var convertedNumber = Int(possibleNumber) In the above ... Read More

Swift: print() vs println() vs NSLog()

Nitin Aggarwal
Updated on 02-Jan-2023 14:30:46
In this article, you will learn about logging methods in the Swift language. You will also learn what the differences between them are. Debugging is the most common practice while writing code for an iOS application. It enables you to debug logic, code, errors, etc. Swift provides in-built libraries to print logs on the console. We have some options to print logs on the console like print(), println(), and NSLog(). Let's try to understand each of them. print() In Swift, print() is a function that prints a message to standard output (e.g., the console). It takes one or more arguments, ... Read More

Loading/Downloading an image from a URL in Swift

Nitin Aggarwal
Updated on 02-Jan-2023 14:25:57
In this article, you will learn how you can download an image from a URL in the Swift language. In the iOS application, image downloading from the image URL is the most common task. Apple provides us with a native library to download any data from any URL. There are many third-party libraries available on GitHub to download the images. But in this tutorial, we are not going to use any third-party library. We will use the URLSession class provided by Apple itself. What is the URLSession Class? URLSession is a class in the Foundation framework that provides an API ... Read More

How to find the index of a list item in Swift?

Nitin Aggarwal
Updated on 02-Jan-2023 13:40:14
Swift gives you some methods to perform on the collection type to get the index of a particular object. To find the index of an item in an array in Swift, you can use the firstIndex(of:) method of the Array type. This method returns the index of the first element in the array that is equal to the given element or nil if no such element is found. How to print the Index of List items? Let's look at an example. Algorithm Step 1 − Define an input array. Step 2 − Call the firstIndex() method on the input array. ... Read More

How to add constraints programmatically using Swift

Nitin Aggarwal
Updated on 02-Jan-2023 12:57:00
The goal of this article is to explain how you can add constraints programmatically in the Swift language. To programmatically add constraints in Swift, you can use the NSLayoutConstraint class to define the constraints you want to add. Concepts That Will Be Used To Add Constraints Are The Following The translatesAutoresizingMaskIntoConstraints is a property of UIView in the UIKit framework. It is a boolean value that determines whether the view's autoresizingMask properties are translated into Auto Layout constraints. When translatesAutoresizingMaskIntoConstraints is set to NO, the autoresizingMask is ignored and the view is resized accrding to any constraints that have been ... Read More

How does one generate a random number in Apple's Swift language?

Nitin Aggarwal
Updated on 02-Jan-2023 12:51:25
This article will explain to you how to generate random numbers in the Swift language. There are some common situations when you need to generate random values in your iOS apps such as Simulating dice rolls. Shuffling playing cards. Create a unique ID for a user. The random value from collection type. In Swift 4.2, there are new, simple and secure ways to generate random values. Before that, there was a random function written in the C language. Today, you'll learn about the random() function that takes a range of values and as an output, it returns a ... Read More

How do I get a reference to the app delegate in Swift?

Nitin Aggarwal
Updated on 02-Jan-2023 12:39:40
You should know what an AppDelegate is in Swift before jumping to how to get a reference to it. AppDelegate In an iOS application, the app delegate is the entry point for the application. Throughout the application, this object has been created once by iOS and is accessible in shared mode. It's responsible for handling key events and tasks related to your app's lifecycle, such as responding to system notifications and managing the app's window and view hierarchy. Where it is Defined? The app delegate class is typically defined in the AppDelegate.swift file of your Xcode project. It should conform ... Read More

Mention the tools required to develop iOS applications

Nitin Aggarwal
Updated on 09-Dec-2022 12:28:27
In this tutorial, we are going to study about different types of tools required to develop iOS applications. As we already know, there are approximately 1 billion iPhone users. Thus, Apple always provides a hassle−free environment for developers who want to build applications for iPhone, iPad, MacBook, and Apple Watch. Apple has built a strong ecosystem for developers so they can focus on writing code and building apps. Today, we will see what tools we need to develop applications on the Apple platform. Xcode This is an editor or IDE to write code for building apps. Apple released the ... Read More

What is plist in iOS?

Nitin Aggarwal
Updated on 09-Dec-2022 12:17:04
In this tutorial, we will talk about how we can use the plist in the application to store information. Let’s first understand what is plist. What is plist? The plist file is also called the property list and is used by operating systems (e.g. iOS) and users. The information is stored in a key-value format similar to a dictionary. A plist file can contain different types of values like strings, arrays, dictionaries, booleans, dates, data, and numbers, such as integers. Most of these types correspond to native Swift types, such as Array and Bool. You can also store nested arrays ... Read More

How can iOS Causes Breakdown in Great Devices?

Sharon Christine
Updated on 24-Jan-2020 08:11:48
Every iPhone user has an unusual habit of displaying their Apple logo so that onlookers can check it out. If someone owns an iPhone and wants to take pride in it, it’s okay for few minutes, but dude- why the show-off? The entire world knows of iPhone, which is more than the Apple logo displayed. No, I am not jealous that I don’t own an iPhone, it just doesn’t give me the phony vibe. A few days ago I happened to check out this gold iPhone 5. I didn’t check it’s features or drawbacks, I just saw the phone and ... Read More
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