Overview

The protocol from which the PXEventDispatcher is derived. You should implement this protocol when your class requires event dispatching functionallity but cannot extend the PXEventDispatcher class.

The implementing class should simply create a private PXEventDispatcher object and pass along all method invocations to it.

Example: We want to create a subclass of SomeOtherClass and we want it to have event dispatching capabilities. The easy thing to do would be to have our class extend PXEventDispatcher. But since it already extends from SomeOtherClass we need a different solution. The solution is to implement the PXEventDispatcher protocol, since one class can implement any number of protocols but only inherit from a single class. Here’s what our class would need to do to support the PXEventDispatcher protocol:

Header:

#import "SomeOtherClass.h"
#import "PXEventDispatcher.h"

@interface MyEventDispatchingClass : SomeOtherClass <PXEventDispatcher>
{
@private
    PXEventDispatcher *eventDispatcher;
}

@end 

Implementation:

#import "MyEventDispatchingClass.h"

@implementation MyEventDispatchingClass

- (id) init
{
    self = [super init];

    if (self)
    {
        eventDispatcher = [[PXEventDispatcher alloc] initWithTarget:self];
    }

    return self;
}

- (void) dealloc
{
    [eventDispatcher release];
    eventDispatcher = nil;

    [super dealloc];
}

// Implementation of protocol methods. They just pass the parameters to the
// internal PXEventDispatcher object.

- (BOOL) addEventListenerOfType:(NSString *)type
                       listener:(PXEventListener *)listener
                     useCapture:(BOOL)useCapture
                       priority:(int)priority
{
    return [eventDispatcher addEventListenerOfType:type listener:listener useCapture:useCapture priority:priority];
}

- (BOOL) removeEventListenerOfType:(NSString *)type
                          listener:(PXEventListener *)listener
                        useCapture:(BOOL)useCapture
{
    return [eventDispatcher removeEventListenerOfType:type listener:listener useCapture:useCapture];
}

- (BOOL) dispatchEvent:(PXEvent *)event
{
return [eventDispatcher dispatchEvent:event];
}

- (BOOL) hasEventListenerOfType:(NSString *)type
{
    return [eventDispatcher hasEventListenerOfType:type];
}
- (BOOL) willTriggerEventOfType:(NSString *)type
{
    return [eventDispatcher willTriggerEventOfType:type];
}

@end