Question

Like many people I’m interested on Objective – C and Cocoa programming. I know conceptually what a delegate it is but I don’t understand how to use them or when to use them. Here is some example code:

#import "AppControler.h"


@implementation AppControler

-(id)init
{
    [super init];
    NSLog(@"init");

    speechSynth = [[NSSpeechSynthesizer alloc] initWithVoice:nil];
    //
    [speechSynth setDelegate:self];
    voiceList = [[speechSynth availableVoices] retain];

    return self;
}

I’m setting the AppControler to be the delegate of the speechSynthasizer. Which means that the speechSynthasizer is telling hte AppControler what to do.
But I don’t understand this line:
[speechSynth setDelegate:self];

Answer 1

self is the current object, so [speechSynth setDelegate:self] sets the delegate of the speechSynth object to the current object, i.e. your AppControler (sic) instance.

Edit: In addition to the code shown, your AppControler should implement the NSSpeechSynthesizerDelegate protocol for the messages you wish to delegate to it.