AVAudioPlayer isPlaying crashing app

Question

I'm using an AVAudioPlayer to manage some sounds but the isPlaying method seems to be crashing.

done when I initiate the page:

self.soundClass = [AVAudioPlayer alloc];

how I play the sound:

-(void)playSound:(NSString *)fileName:(NSString *)fileExt {

    if ( [self.soundClass isPlaying] ){
        [self.soundClass pause];
    }
    else if (newSoundFile == currentSoundFile) {
        [self.soundClass play];
    }
    else {
        NSLog(@"PlaySound with two variable passed function");
        [[NSBundle mainBundle] pathForResource: fileName ofType:fileExt]], &systemSoundID);

        [self.soundClass initWithContentsOfURL:[NSURL fileURLWithPath: [[NSBundle mainBundle] pathForResource: fileName ofType:fileExt]] error:nil];

        [self.soundClass prepareToPlay];
        [self.soundClass play];
    }

    self.currentSoundFile = fileName;

}

My soundClass is pretty empty right now:

soundclass.h

#import <UIKit/UIKit.h>
#import <AudioToolbox/AudioToolbox.h>
#import<AVFoundation/AVFoundation.h>


@interface SoundClass : AVAudioPlayer <AVAudioPlayerDelegate> {

}

@end

SoundClass.m

#import "SoundClass.h"

@implementation SoundClass 
-(void)dealloc {


    [super dealloc];
}

@end

Do you see anything here I might be doing wrong? It crashes right at if ( isPlaying )

Answer 1

You point to space that is allocated for an instance of AVAudioPlayer in the first line you list, but you don't actually initialize an instance. In Cocoa, "alloc" is 99.9% of the time followed by some form of -init (like -initWithContentsOfURL:error: in the case of AVAudioPlayer).

Also, "soundClass" is an odd name for an instance variable. You should read up on the difference between a class (the blueprint of an object) and an instance of a class (an actual object built from the blueprint). Solid knowledge of this concept is critical to your understanding of Cocoa (and all object-oriented) programming.