Forward references for iOS development categories

Categories (category) in addition to extending the class, the ability to forward references is also strong. For some private methods (no method declared within the. h file) If we want to use it, some use performselector to perform a dynamic call, so that the private method can be called completely, but it is not always a good way to avoid the compiler's syntax checking. Using categories to make forward references can solve this problem.

Define an item class

@interface zjitem:nsobject-(void) info; @end

. m file

@implementation zjitem-(void) info{    NSLog (@ "This is in the interface section");} -(void) myprivate{    NSLog (@ "own method");} @end

We make the call in the main function. First forward referencing without using analogies

You can see the error message.

Error disappears after adding a forward reference

Forward references for iOS development categories