how to call a mothod defined in another class - objective-c

Question

Hi
I have a class named as root:
In root.h :-
#import "UIKit/UIKit.h"
#import "AVFoundation/AVFoundation.h"
#import "AudioToolbox/AudioToolbox.h"
#interface root : UIView {
}
+(void)somefunction:(BOOL) sf;
#end
in root.m the definition of somefunction is as follows
-(void)somefunction:(BOOL) sf {
//AVAudioPlayer *myExampleSound; //this variable can be named differently
if ( issoundon==TRUE) {
NSString *path =[[NSBundle mainBundle] pathForResource:"bg" ofType:#"wav"];
SystemSoundID soundID;
AudioServicesCreateSystemSoundID(
(CFURLRef) [NSURL fileURLWithPath:path], &soundID);
AudioServicesPlaySystemSound(soundID);
}
else{
NSString *path =[[NSBundle mainBundle] pathForResource:nil ofType:#"wav"];
SystemSoundID soundID;
AudioServicesCreateSystemSoundID(
(CFURLRef) [NSURL fileURLWithPath:path], &soundID);
AudioServicesPlaySystemSound(soundID);
}
now i have imported root.h in another class and i am calling the "somefunction" as follows
bool abc=true;
[root somefunction:true];
but at this point my app terminates(crashes).
basically i am trying to set background music to my app (as the game starts) and in the middle of the game i allow user to switch of the sound.(it is crashing even i am calling the function in delegate of the view.)
please tell me what is happening wrong coz my code is compiling properly(with a few warning though).

Answer 1

Sure, your code compiles successfully. But you know what? There is a typo in your code which is causing your program to crash. Never assume your code has no typos just because it compiles successfully.
In your root.m file you have this:
-(void)somefunction:(BOOL) sf {
It should be a +, not a -, like in your header file:
+(void)somefunction:(BOOL) sf {
There might be a discrepancy between the C type bool and the Objective-C type BOOL too, but I'm not too sure about that:
bool abc=true; // Shouldn't this be BOOL abc = YES, and
[root somefunction:true]; // shouldn't you be passing abc here?

Answer 2

Your code is incomplete, and without context it's really hard to say what the bug might be. However:
You haven't defined issoundon anywhere
where have you constructed your root object? in interface builder?
why is it a subclass of UIView?
is AudioServicesPlaySystemSound synchronous?
But mainly, I think your problem is here:
why would you expect to be able to play a file called (nil).wav?
I suggest you provide a crash dump and error log to assist people in answering this question.
See this SO question: playing background audio on iphone

Answer 3

"but at this point my app terminates(crashes)"
We need to know more about that to help you with this.
In the Xcode console, it should be putting out messages that would narrow in on what the problem is. A stack trace would be helpful too.
My total guess is that your local instance of root is undefined and so you're calling an unrecognized selector on that object. But without more help from the console, that's a complete guess.