How do I declare private property in Objective-C?

As others have indicated, (currently) there is no way to truly declare a private property in Objetive-C. One of the things you can do to try and “protect” the properties somehow is to have a base class with the property declared as readonly and in your subclasses you can redeclare the same property as readwrite .

What are categories used for Objective-C?

Categories provide the ability to add functionality to an object without subclassing or changing the actual object. A handy tool, they are often used to add methods to existing classes, such as NSString or your own custom objects.

What is an unnamed category?

The anonymous category is an additional Objective C feature that provides an alternate way to declare private methods.

What are property attributes in Objective-C?

1a) The default attributes for a property are atomic , and strong (for an object pointer) or assign (for a primitive type), and readwrite . This assumes an all ARC project. So @property NSString *string; is the same as @property (atomic, strong, readwrite) NSString *string; .

Does Objective-C contain private methods?

Private methods in Objective-C are not as private as in other modern object-oriented programming languages. They are semi-private and have polymorphic behavior. That poses a certain risk: we can (accidentally) compromise the implementation of our extended class.

What is @synthesize Objective-C?

@synthesize tells the compiler to take care of the accessor methods creation i.e it will generate the methods based on property description. It will also generate an instance variable to be used which you can specify as above, as a convention it starts with _(underscore)+propertyName.

How do you declare a category in Objective-C?

Objective-C Language Categories Create a Category on XCode Open your XCode project, click on File -> New -> File and choose Objective-C file , click Next enter your category name say “CustomFont” choose file type as Category and Class as UIFont then Click “Next” followed by “Create.”

What is category in Swift?

In Objective C they were called categories, but in Swift they are called extensions. The purpose of both of them are to give additional functionality to existing classes without having to create subclasses.

Does Objective C have extensions?

Objective-C’s extensions are a special case of categories that let you define methods that must be declared in the main implementation block.

What is the difference between category and extension in Objective C?

Category and extension both are basically made to handle large code base, but category is a way to extend class API in multiple source files while extension is a way to add required methods outside the main interface file.

What is the difference between atomic and nonatomic properties?

Swift has no such specifier. In Objective-C the implementation of an atomic property allows properties to be safely read and written from different threads. For nonatomic properties, the underlying pointer of a read value could be released when a new value is being written at the same time.

How do you write Objective-C?

Objective-C uses the same phraseology as the C language. Like in C, each line of Objective-C code must end with a semicolon. Blocks of code are written within a set of curly brackets. All basic types are the same, such as int, float, double, long and more.