Question

In iPhone every UIContrrol has predefined delegate methods but how we will create our own custom delegate methods

Answer 1

In your class create an id object delegate. Create a getter and setter so other classes can set themselves as delegates.
In your class add this:

@interface MyClass (Private)
-(void)myDelegateMethod;
@end

Then in what ever function you want to call back to the class that is the delegate do something like this:

if ( [delegate respondsToSelector:@selector(myDelegateMethod)] ) {
[delegate myDelegateMethod];
}