How to Create Professional iOS Applications from Scratch

How to Create Professional iOS Applications from Scratchby James Tredwell

These days, different iOS applications are used by the tech-savvy people. So, there is a great demand for such applications. To be frank, creating and developing iOS applications is a fun and rewarding task. But, if you are new to the iOS development, then you must have questions about where to start. With the help of Mac, you can easily create iOS apps for iPad, iPhone, and iPod touch. So, in this article, we will discuss all the tools, knowledge and skills for creating applications for iOS! Let’s get started.

Required knowledge

To program different web projects and for iOS, in particular, one must know Mathematics and logic at first. Although, Modern technologies have saved the programmer from the need to thoroughly know the architecture of the computer,  a good command over the basic mechanisms, such as number systems, their conversion, the speed of subroutines or the efficiency of algorithms, etc, helps you a lot. At a higher level, iOS-developers must know the operating system macOS, iOS, the “apple” programming language. Always keep in mind that the Knowledge of Delphi, C ++, C # or VB.NET will not help you at all the times. Apple has its own ecosystem with its own languages: Objective-C and Swift. So, you must learn both.

Tools for Development

The XCode programming environment is the main developer tool for macOS and iOS. It includes tools for creating applications for Mac, iPhone, iPad, Apple TV, Apple Watch and all Apple platforms. XCode contains an interface builder and a code editor that supports all modern tools for working with code. Furthermore, you can test the application without leaving XCode if it is developed for an external device and run the emulator easily. You can easily develop applications for macOS Sierra, iOS 10, watchOS 3 and tvOS 10 on Xcode 8.

Objective-C language

In simple words, Objective-C is a compiled object-oriented programming language which is used to write applications for “apple” systems. It is a superset, inheriting from the latter syntax, data types. In C ++, Objective-C objects with four paradigms- abstraction, encapsulation, inheritance, polymorphism. The C ++ language is strongly typed, whereas Objective-C is weakly typed or has a dynamic data type system.

  1. Develop an iOS Application

Determine the same of the iOS Application and add a button, pressing which visitors can get the message: “Hello, World”. Start XCode in the window select Create a new project, or in the main menu File -> New -> Project. The next window will prompt you to select the target platform and application type.

      2. Choose the Application Type

There are different types of applications. Choose one of them as per your specific needs:

Types of Applications Brief Explanation
The Single View Application It includes the View Controller component, which allows you to customize the application view using the Interface Builder.
Master-Detail Application It is a good app here a collection of objects is displayed in a table view. Detailed information about this object is displayed when you choose one of them.
With Page-Based Applications Applications with the screen.
Tabbed application It allows you to create applications where each screen can be switched at any time. Each screen has its own button to activate it, which displays a title. For instance- iTunes.
Sticker Pack Application It is a new kind of application that appeared in iOS 10 and Xcode 8. It is a set of simple or animated images used in the new iMessage. It doesn’t require encoding.
iMessage Application It is a new kind of application that appeared in iOS 10 and Xcode 8. It allows you to create add-ons for iMessage. By using the iMessage API, you can create your own analog of this application, including playing audio, video, using stickers and more.

      3. Create Your First Project

First Project

Let’s select the Single View Application and Click Next and enter the name of the project on the next page of the wizard. In the Language drop-down list, leave the default language – Objective-C. Next, in the Devices drop-down list, leave the selection Universal. Here it is determined for which device (iPhone or iPad) an application is created. Universal means both, so define your priorities right. Uncheck the Include Unit Tests and Include UI Tests checkboxes. Next, Choose the folder to save the project and click the Create button. A window is opened with a list of all the parameters applied to the project. You can change the parameters previously set in the wizard: orientation, target device, etc, in the opened window.

First of all, you need to create an application interface. To do this, with a single click, select Main. Storyboard in the list on the left. The entire interface will be occupied by Interface Builder the right side of the list. The device layout will be displayed in the center. The Components panel remains in the lower right corner of the window. A list of properties is shown in above the component panel.

Select the Label component and set its Text property in the layout: leave the choice of Plain in the drop-down list, in the line below enter the necessary inscription. If the text does not fit into the borders of the label, change them by dragging the markers on the edges of the component. To centralize it horizontally, go to the Size Inspector page by clicking on the Show the Size Inspector button and select Center Horizontally in Container from the Arrange drop-down list. Now select the Button component and change its Text property to the desired label.

      4. Create a Link Between Graphic Elements and the Code

In Visual Studio, the object in the code is created automatically at the moment when you put the visual component on the form. This does not happen in XCode. Just Open the contents of the ViewController.h header file in a separate window by double-clicking on it. In this file, there is an extension declaration of class UIViewController.

It is marked with the keyword @interface. move the mouse cursor over the component – the text label, press the Ctrl key and the left mouse button. Move the cursor to the window with the code (file ViewController.h), the cursor will draw a blue line. Release the mouse and the key inside the ViewController interface description. Then, The Outlet window will appear immediately:

This is an object property that references another object, so enter the name of the Outlet object or it will refer to the visual component. Next, the type of the object is selected, it is selected correctly: UILabel. After that, the following line will be added to the code:

 

@property (weak, nonatomic) IBOutlet UILabel *lab;

Now create the Outlet for the button using the following code:

@property (weak, nonatomic) IBOutlet UIButton *but;

As a result, have two pointers to the visual components: lab and but – respectively, the inscription and the button. Now, using pointers, you can manipulate the components in the code.

Then you need to create an event handler for the button click event. To do this, open the ViewController.m implementation file in a separate window. Exactly, in the same way, as you dragged the line into the header file to create the outlet, from the button drag the line to the implementation file and release it to the closing command bracket – @end. A window will appear for creating an event, similar to the window for creating an outlet. You see the difference: in the header file, a reference to the object is created, in the implementation file there is a method.

Fill in the Name field, its value represents the name of the method property. Let it be onClick. Leave the Type field as the default id. In the Event drop-down list, the Touch Up Inside event is selected by default, which occurs when the pointer (mouse, finger …) is released above the button, that is, the final stage of pressing the button. That’s what we need it. In the Arguments list, leave the default value: Sender is the object that sent this signal, in this case, it will always be a button. Click the Connect button. As a result, the following code will be added:

– (IBAction)onClick:(id)sender {

}

Between the parentheses, write the code that executes when the button is pressed:

_lab.hidden = !_lab.hidden;

Swift Language

In 2014, Apple introduced a new programming language – Swift. It quickly became the most discussed and most dynamically developing language in the world. This is a reliable, safe, intuitive language for developing applications for the operating systems macOS, iOS, tvOS and watchOS for the entire fleet of devices from Apple. Swift is an effective programming language.

It’s easier to learn than its predecessor, Objective-C, at the same time Swift has borrowed the most successful ideas from it. At the same time, the developers have made the languages compatible. During the development of Swift, the goal was to create the most convenient system programming language – fast, safe and expressive. The algorithm in Swift works 2.6 times faster than the same algorithm on Objective-C, and 8.4 times faster than in Python. Using Swift makes the programming process more flexible and convenient.

Uploading your iOS app on the App Stores

Every app developer can create and sell apps for free. For this, you need to register as a developer and buy a license to sell your applications. This is the fee for the provided service. So, register on different app stores, upload your apps and start selling them as far as possible.

Final Words

The demand for different iOS applications is increasing with each passing day. By following the above-mentioned ways, you can easily iOS apps yourself from scratch and start selling them to the interested customers.

This article is contributed by James Row, passionate blogger and professional software developer at Awebstar Technologies Pte Ltd.