Run Time runtime

1. Methods for replacing private classes at Object-c run time

Runtime full interpretation

2. Add a method to an object at run time

C method form definition of the added method

void Hellolog (id self, SEL _cmd)

{

NSLog (@ "Hellolog");

}

Oc method form definition is added method

-(void) Hellolog

{

NSLog (@ "Hellolog");

}

Classes that require new methods

Class Newclass = [NSObject class];

C Method Form

Class_addmethod (Newclass, @selector (Hellolog), (IMP) hellolog, "[email protected]:");

Oc Method Form

Class_addmethod (Newclass, @selector (Hellolog), (IMP) hellolog, "[email protected]:");

Call New method

id instance = [[NSObject alloc] init];

[Instance Performselector: @selector (Hellolog) Withobject:nil];

The OBJECTIVE-C runtime defines several important types.

• Class: Defining the Objective-c Class
• Ivar: Defines an instance variable of an object, including the type and name.
• Protocol: Define formal agreements.
• objc_property_t: Defines a property. This name may be called to prevent conflicts with user types in Objective-c 1.0, when there are no attributes.
• Method: Defines an object method or class method. This type provides the name of the method (that is, the * * selector), the number and type of parameters, and the return value (which together is called the * * Signature of the method), and a function pointer to the code (that is, the method's implementation * *).
• SEL: Defines the selector. The selector is a unique identifier for the method name.

• IMP: Defines the method implementation. This is just a pointer to a function that takes an object, a selector, and a variable-length argument list (varargs), returning an object

Run Time runtime