Often you need a class to call back a method of its owner. In this example MainClass is the class that needs to be called back and SubClass is the class that will need to call back a method in the MainClass.
//MySubClassName Sub class name within the main class
//mySubClass1 Sub class object within the main class
//MethodNameToCallBack Main class method to be called back
//SubClassDelegate Delegate name
In MainClass.h
//Include the sub class header: #import "MySubClassName.h" //Add the delegate as an input to the class @interface MainClassViewController : UIViewController<SubClassDelegate> { MySubClassName *mySubClass1;
In MainClass.m
//When the create the sub class:
mySubClass1 = [[MySubClassName alloc] init];
[mySubClass1 setDelegate:self];
//The method that will be called back:
- (void)MethodNameToCallBack:(NSString *)s
{
NSLog(s);
}
//********** DEALLOC **********
- (void)dealloc
{
[mySubClass1 release];
In SubClass.h
#import <Foundation/Foundation.h>//Define the protocol for the delegate @protocol SubClassDelegate - (void)MethodNameToCallBack:(NSString *)s; @end @interface MySubClassName : NSObject {id <SubClassDelegate> delegate;} @property (nonatomic, assign) id <SubClassDelegate> delegate; @end
In SubClass.m
@implementation MySubClassName
//Synthesize the delegate property:
@synthesize delegate;
//When you want to callback the MainClass method:
[[self delegate] MethodNameToCallBack:@"Hello World"];
