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ios-labs-s14:basics-methods

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=====Methods==== “Method”, “message”, and “function” all (sort of) refer to the same thing in Objective-C. A method is a section of code that we can call from elsewhere in our code. Components to methods: -Declaration -Definition -Invocation ====Declaration==== **Declaration**- the act of informing other objects about a function's name, return type, and parameters. Declarations for public methods are included in the header files of Objective-C objects. Declarations for private methods are included in the Definition and do not need additional code. These methods can only be called within a class. Declarations take the form: *- (RETURNTYPE) METHODNAME:(ARGUMENTTYPE*)ARGUEMENTNAME METHODNAME2:(ARGUMENTTYPE*)ARGUEMENTNAME2; A dash at the start indicates a **instance method**. Can only be called on an instantiated object. When creating a method, always use a dash unless you have some overriding reason. A plus sign at the start indicates a **class method**. Can only be called on the class itself, commonly used as custom initialization method. ====Definition==== **Definition**- writing the code that executes/is contained within the method. Known as the method body. Methods are defined in **implementation** files, or //.m// files. The form is the same as the declaration, except with curly braces instead of a semicolon which contain the method body. *- (RETURNTYPE) METHODNAME:(ARGUMENTTYPE*)ARGUEMENTNAME METHODNAME2:(ARGUMENTTYPE*)ARGUEMENTNAME2 {CODE} ====Invocation=== **Invocation**- the act of running the code contained within a method. Also known as calling the method or sending a message. Consists of two parts -Target- the target object or class that owns the method; where the method will be invoked -Name- the name of the method to be invoked Invoking a method takes the form: [TARGET NAME]; and can be nested infinitely deep: [TARGET NAME] NAME2] NAME3]; where NAME2 and NAME3 are methods called on the objects returned by methods NAME and NAME2, respectively.

ios-labs-s14/basics-methods.1392658074.txt.gz · Last modified: 2014/02/17 11:27 by mbarboi