This article discusses the construction of a simple application for iOS, aiming to present to the reader the knowledge necessary to start in the development of applications for this platform.
Development for iOS with Xcode
This article discusses the construction of a simple application for iOS, aiming to present to the reader the knowledge necessary to start in the development of applications for this platform. Little by little the reader will become familiar with the use of Xcode (Apple’s development IDE), the use of storyboards in building applications, the standard MVC (Model-View-Controller) designs and some of the interface components user interface. Xcode is an integrated development environment that consists of a series of software makers. It is available free through the App Store for each Mojave and High Sierra user, two versions of the Mac operating system.
This environment is very useful for every Mac user who is not satisfied with standard applications. What’s interesting is that Xcode supports many programming languages; Ruby, Python, C, C ++, Java and many more. This is also open to third-party interference, as evidenced by the addition of Pascal, Perl, Fortran, and several others.
Universal binary files
Universal binary files accommodate various types of architecture. For information, universal binary files allow software to run on Intel and PowerPC platforms. The files bridge between different processors and they can be detected by the OS in the disk header. Universal binary files can run without speed reduction and to run them no additional memory is needed since all you need is a copy of the software. Its use is the final option for bridging between byte storage procedures owned by both PowerPC and Intel.
Debugging the applications
Xcode is also useful for debugging applications on iOS as long as it runs on the ARM architecture. Xcode stores documentation of most application developers associated with Apple and integrates them all into the Apple system.
An overview needed to develop iOS-related apps
It is hoped that with this reading, a novice developer will have an overview of the items needed to develop iOS applications and then be able to build their own applications autonomously. This explains why from day to day more and more applications are able to run with the same quality on iOS and Android. Some examples are iOS system recovery and various other data related software.
The development of applications for iOS (iPod, iPhone, and iPad) is based on a programming language called Objective-C, also known as ObjC. It is an object-oriented programming language that adds the Small talk messaging style to the C programming language. It was developed in the 1980s by StepStone and adopted and popularized by next for its Next Step operating system, from which OS X and iOS were born.
ObjC provides the syntax for the commands we use in our application, however, it does not support the user interface, network resources or the reading of files. This support comes from the Cocoa Touch library, developed by Apple and made up of several frameworks (collections of clustered classes).
The most used frameworks, which provide basic support for building iOS applications, are the Foundation Kit, which provides structured data, network resources, input and output capabilities, and string handling, among others; and UIKit, designed to assist in the development of GUIs (Graphical User Interfaces).
To facilitate the development of iOS applications, Apple provides developers with free Xcode, an IDE (Integrated Development Environment) quite powerful and easy to use. This action is proven to prevent error 4013 which is sometimes caused by some inappropriate application.
Xcode has several very useful tools, among the most important we can mention the compiler Apple LLVM, which in addition to compiling the code, provides a smart tool to complete the code; Interface Builder (IB), in which we work on the visual part of the application, building our screens; a tool for debugging; Organizer, which assists in the management of registered projects and devices for testing, in addition to presenting the auxiliary documentation; o Instruments; a tool for code performance analysis; and finally iOS Simulator, a simulator for iPhone and iPad on which we can check our applications.
Each developed application can and should be tested not only on the simulator but also on real devices. In addition, although the simulator has important features such as touch, gestures, and GPS, some features such as the accelerometer or compass, were not available, this way it is extremely necessary to test on real devices.
In order to test your applications on real devices, it is necessary for the developer to have an account with Apple, so they can register their devices, perform the tests and submit their applications to the Apple Store. The registration of a developer account is carried out directly on the Apple Developer website and costs $ 99 per year.
Finally, it’s important to understand that iOS applications follow the Model-View-Controller (MVC) standard. This pattern separates the model, a set of classes that manipulate data, views, user interfaces or screens, and allows a controller to manage the flow of information between the model and the screens.
This facilitates the construction of universal projects, which are projects for both iPhone / iPod and iPad. In this way, the developer can reuse all the model and controller code for both devices and only needs to do extra work in the views, one for iPad and one for iPhone.
It is very common, especially in simpler applications, not to implement classes for the model. These applications follow a logic that only needs a screen and a controller of this since there is no data to be stored.
From now on, after presenting the initial concepts, we can begin with the practice. The rest of this article introduces the step-by-step development of a simple application that aims to introduce the reader to the knowledge necessary to start building apps for this iOS.
Little by little the reader will become familiar with the use of Xcode, the use of storyboards in building applications and some of the most common user interface components.
