Guideline: Developing Apps for iOS

Here we’ve collected all the main approaches to Apple app creation. If you are looking for simple and clear explanation for all possible solutions for developing apps for iOS, have a look and send us your questions, we are ready to share our knowledge, collected within years in mobile development.

Classical Approach to iOS Creation

Objective-C is the main programming language when developing apps for iOS and Mac OS X. You can also develop iOS apps using other languages ​​and technologies such as C ++, MacRuby, PyObjC, Pure C, MonoTouch, but this is mainly for additional functions and secondary purposes.

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Web-based Solution

Another way to develop an app that can be run on the iOS platform is to design a non-native web-based program that looks like a native mobile iOS app, but in fact it is a website that you access through a Web navigator. Although there are many frameworks and platforms for developing web-based apps, they are mainly described by technologies such as HTML, CSS, JavaScript and others.

Do I Really Need to Learn Goal-C?

If you are completely satisfied with the functionality of the web-based app, even if you are familiar with the Cocoa Framework without mastering Objective-C, you do not actually read this guide, but a tutorial on developing HTML-based apps. Please find On the other hand, if you want to develop high quality native apps for the iOS mobile operating system, use the Objective-C guide to help this venture.

Objective-C Programming Language

Objective-C is a generic object-oriented coding language that is basically an extension of the C language. Smalltalk style messaging, runtime reflection, multiple inheritance, and other functions are added to the C language. It has a very syntax different from other languages. People who are familiar with languages ​​such as Java and Ruby, at first glance. The fact that Objective-C is a superset of C gives you the opportunity to go back to C every time you code an iOS app. For example, you can easily find C basic data types and calls to native functions in iOS and Mac apps, along with the code written in Objective-C.

Objective C class, purpose and method

If you are not familiar with iOS apps that need to update their memory, the developers prepare a simple tutorial on classes, objects and methods and explain how they are used in Objective-C. I will do it. A class is a plan that defines a set of objectives and behaviors for the object that will be developed. Classes usually correspond to some real-world concepts, such as plants.

How to run the call method in iOS

If you still do not know what's going on, let's take a closer look at the method call. [Plant alloc] means calling the method + alloc class for the Plant class. There is always one more sign before the class method. It is used to return the generic type of object identification. The use of -init means that you can call the instance method to initialize the memory and access the use of the new object. The instance method indicator is a minus sign that precedes it. You can not use Objective-C objects without performing these two actions.

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Instances and behavior in iOS development

It is very likely that the classes of plants identify not only specific variables such as color, height, species, but also behavior, such as flowering, reproduction and photosynthesis. An object that belongs to a class is an instance of that class. Each instance has its own variables. As an example, you can develop 200 instances in the Plant class and define different variables for each one. A method is the behavior of an instance within a class or class. Therefore, it is called class method and instance method.

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Difference between pile and pile

When handling variables of a specific size in the compilation stage, the variables are stored in the stack. The stack provides storage for local data that can be accessed without a pointer. For example, the stack contains all primitive data types (boolean, long, byte, char, short, int, etc.). Objective-C objects are not limited in size, they should be stored in a heap that can dynamically allocate memory and use pointers, as it grows as much as necessary. The pointer is a memory address, and if you need to access what is stored in memory, you need to dereference the pointer.

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How to create an instance

To create a new instance, you need to assign the memory block of that class to help. Heap is a memory that stores all Objective-C objects and fulfills the dynamic assignment function. All Objective-C objects are pointers to the heap and are indicated by asterisks. Here is an example of how to create an instance of the Plant class.

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Read Objective-C for iOS development

Well, you understand what it means. Do you know what the brackets represent? As they contain method calls, we are ready to use more with Objective-C. On the left you can see that after creating a new plant variant * called ourPlant, we have defined two method calls to the right to return them to ourPlant.

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Memory management

When working with objects, remember to notify the execution time when the object is complete and released when you allocate a certain amount of memory. Objective-C uses a reference counting system to track where each object is being used, since several elements of an iOS app can use one object at a time. When you create an object, the object has only one reference. When you use an object to complete a specific part of an iOS app, a release message is sent to the object, which results in the number of references decreasing by one. If there are no references left in the object, the memory is released.

  • Memory management

    When working with objects, remember to notify the execution time when the object is complete and released when you allocate a certain amount of memory. Objective-C uses a reference counting system to track where each object is being used, since several elements of an iOS app can use one object at a time. When you create an object, the object has only one reference. When you use an object to complete a specific part of an iOS app, a release message is sent to the object, which results in the number of references decreasing by one. If there are no references left in the object, the memory is released.

  • Ensure the stability of the iOS app

    If you forget to free up memory on the object when the object is no longer in use, the program may use too many resources, causing the iOS app to crash and decrease performance. For Mac apps, it not only locks, it also slows down the overall system speed and increases memory. I have definitely left the Safari browser for a couple of days or I have experienced a game running in the background. This happens because the iOS app uses a lot of memory exponentially and leaves few resources to run other programs quickly. Memory is one of the most important resources for iOS app developers, so use them wisely. Apple's memory management guide is a wonderful resource to help you gain a deeper understanding of the management of Cocoa memory.

  • Data attribute

    Despite having a behavior, the object can also store data. For example, what kind of data attributes can a smartphone object have?

    • Model name
    • Maker
    • Color
    • OS

    Here we have to examine these attributes. The first is the name of the model. It can be represented by a combination of numbers. The data type of this attribute is numeric. There are several ways to represent numerically objective C:

    • As an instance of the NSNumber class
    • Primitive int
    • Data type NSInteger used in Foundation
  • The number of iOS apps written in Objective-C

    As you can see, there are at least three options. I explain the meaning here. The first option is the NSNumber class defined in the Foundation framework. The variable type int is a primitive data type C that contains a numeric value with the largest value. The third method is the NSInteger basic data type that comes from the underlying framework and its size is adapted to the needs of the iOS program at that time. The Foundation is one of the frameworks of Apple to develop iOS apps.

  • More information

    Because the object is not an object, you do not need to allocate memory for NSInteger or int. In other words, the size is already defined. However, since it is developed on the stack instead of the stack, we need a pointer to access the content. Elements such as NSInteger, CGRect, CGSize, CGPoint, etc. they are not objects in the Foundation data type reference, so you do not need a pointer in the form of an asterisk.

  • Useful class methods

    Let's go back to the first case of storing the model number 1900738 as an NSNumber object. After creation, it becomes the following.

    NSNumber * model = [NSNumber number WithInt: 1900738].

    But, if that is an instance of the NSNumber class, why is there nothing? Is not it Whi + alloc? It is not necessary to configure the memory and has a practical method of class to do automatically, so it is returned in this object.

Developing apps for iOS with professionals

Thanks to an incredible creativity of our designers and proficiency of our coders, we are developing high quality iOS apps with advanced functionality and an excellent user experience that will stand out from the crowd. The developers have been dedicated to our technology and have offered hundreds of successful iOS B2C programs, specialized business systems, MVP startup, beautiful websites from various industries. The base of our culture is the open communication with the clients, the transparency of the process and a solid collaboration in team. Contact us to discuss your ideas -glad to see you at the London headquarters.