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Xcode

Xcode

Last updated: 1 week ago

Xcode is Apple's IDE, made for producing software on Mac for use on iOS, iPadOS, macOS, tvOS, and watchOS. Free to download and use, the IDE is chiefly used by developers to create iPhone and iPad apps, as well as programs for the Mac.

● IDE for macOS
● Used for macOS, iOS, iPadOS, watchOS, tvOS development
● Free to download and use
● Code editor offers suggestions and corrections
● Support for Swift and other languages
● Interface design tools


A long-standing tool for app production, Xcode is a well-known integrated development environment (IDE), enabling developers to write the code and compile apps that can be used on a variety of different devices and operating systems. As Apple's own IDE, it is primarily used for the development of apps within its own ecosystem, though it can be used for writing source code in a variety of languages for use in other projects. 

As an entire suite, Xcode can be used for designing the user interface, writing the code for apps, compiling the code, testing the code and app, and debugging. On completing an app to a quality where it can be accepted for distribution, Xcode is also used to submit the app to Apple's assorted App Store marketplaces. 

Xcode environment running on a MacBook Pro

Apple provides Xcode free to all macOS users, though in order to distribute apps via the different App Store versions, a subscription to the Apple Developer Program is required, at a cost of $99 per year. 

Xcode is based on Project Builder, an IDE originally created by NeXT for the NeXTSTEP OS. Launched in 2003 for Mac OS X 10.3 Panther, Xcode was given a new user interface to make it more useful for Mac software development. 

Since its introduction, Xcode has received a steady stream of updates over the years, adding support for newer operating systems and new features. Updates also saw the dropping of compatibility for legacy systems, such as PowerPC in Xcode 4.0, forcing developers to produce apps for Intel-based Macs. 

Xcode is currently on version 11.3, and is available to download from the Mac App Store

Writing Code in Xcode

The core of the Xcode suite is the IDE, which itself is also called Xcode. The application is used as the main interface for all other elements of the Xcode suite, and is used to display files that are being worked on, along with windows for other tools. 

Similar to other development environments, code is typed into a file that is displayed in a main window. As users type code, the IDE provides assistance in a variety of different ways, to help ensure users can produce clean and understandable code, as well as to minimize errors. 

These can include color-coding the source code to reflect different elements of the coding language's structure. Depending on the selected language used for development, the IDE can even offer suggestions of what the developer may want to enter into a location, such as variable names. 

The same system can also flag issues with how an element is coded, such as if expected symbols are missing or function names are typed in incorrectly. In flagging errors, there are also suggestions of what Xcode believes should be done to fix the problem.   

An example of how an app can appear in Xcode as it gets developed
An example of how an app can appear in Xcode as it gets developed

Multiple files can be opened in tabs and switched between at will, with the interface updating depending on the kind of file being accessed or the task at hand. It is also possible to switch between files in a side directory view, which shows all of the files and folders used for a development project. 

Xcode supports writing programs in Swift, AppleScript, C, C++, Objective-C, Objective-C++, Python, and Ruby, with third-party support also available for a number of other languages. 

To assist with the learning of using Xcode's features and app development, it is possible to set up a so-called Playground to experiment with code. In this case, it offers a variety of pre-made projects to educate the user and to provide education, rather than teaching how to code as with the iPad's Swift Playgrounds

SwiftUI

Apple strongly promotes Swift as its language of choice across all of its platforms, and as of Xcode 11, hints at the use of SwiftUI for development. 

A key element of this is that SwiftUI apps are native on all Apple-owned platforms. The core logic of a SwiftUI app for an iPhone can easily be transplanted across to a macOS app and vice versa, with platform-specific elements able to be accounted for in each version. 

This is most apparent in one feature where ticking a single checkbox can enable Xcode to convert an iPad app into a native Mac app, one that can be used with a keyboard and mouse rather than a touchscreen. The intent is to simplify the porting process of iPad apps for macOS, though developers have found the option does still require further refinement of the interface for iPad apps to be truly useful on macOS. 

As part of this, support for elements such as Dark Mode, localization, accessibility features, and dynamic type are also automatically applied to apps. 

SwiftUI uses a declarative syntax, where the developer states what the user interface should actually do, such as listing items in a text field then defining the formatting of each field. This also extends to animations and other areas, with SwiftUI handling most of the work to get the code running for many different built-in effects. 

Apple's example of SwiftUI's declarative syntax. Apple's example of SwiftUI's declarative syntax.

Further in terms of design, drag and drop elements can be applied in the design canvas and affect the code, while code changes are also applied to the live preview. Xcode recompiles the changes as part of the app automatically in these instances, so the app is always editable while it is running. 

Interface Design

A system is also included to assist with the creation of a user interface for an app, called Interface Builder. The tool is used to layout parts of the app itself, as well as the designing of menus, buttons, windows, and other elements. 

Xcode includes an extensive built-in library of objects and assets developers can use, as well as supporting assets developed elsewhere. 

To assist with producing apps for a wide variety of different screen sizes and orientations, an Auto Layout system can automatically line up elements of an interface. This enables the creation of responsive apps that visually appear similar across the Apple ecosystem, regardless of if the device is used in portrait or landscape orientation. 

Apple's example of designing an iOS app's interface in Xcode Apple's example of designing an iOS app's interface in Xcode

Interface Builder can be used to quickly prototype the interface, and to quickly connect it to just-written source code in a preview panel. The Storyboard can be employed for making designs of individual screens, as well as visualizing how users can navigate through the app's different screens. 

A storyboard's UI controls can be connected to code that regulates their behavior using the Assistant tool. In cases where no code has been written for an element, the Assistant can create a stub for an action, to be filled out later by the developer. 

Xcode Version Control

Projects are stored in Git repositories, a common way of containing an app during development. As well as remote and public Git repositories that can be accessed, Xcode is capable of creating local Git repositories for brand new projects. 

In cases where there are multiple people working on a project, version control is important as a means to keep track of changes in development. In Xcode's Version editor case, it is able to keep track of when changes were made and submitted to the repository, as well as who made the change. 

Rumors

Even an IDE gets rumors from time to time, and as we get closer to an ARM Mac rumors of an Xcode built for ARM computers continues to rise. There may be some version of Xcode released on iOS 14 and iPadOS this fall, capable of building apps for testing.

Such an app will be necessary going forward if an ARM Mac is coming this year. A transition period will exist for developers where software must be built for a computer that has not released, leaving only existing iPhones and iPads as their tools for development. If an Xcode for iOS does launch at WWDC, it will have huge implications for the platform going forward.

 

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