Question

Lately something weird has been happening to my projects in xcode: I’ve been trying to learn a lot of new stuff, and doing so by testing things out in different simple cocoa apps (written by me, from scratch). sometimes I will get a code that doesn’t have any error messages, but when i run it, i will stop at some break-point. I then conclude that I have probably done something wrong, and restores the code back to the form it was before the error, but from then on out it is impossible to get the code to run. even if i restore the code to a state that i am 100 % sure that has worked before, it just stops at the same break-point. in order to fix this problem, i have to copy my code from the class this has happened to, delete the class, make a new one with the exact same name, paste the exact same code back in the class, and voila, it works again. what on earth is happening? my newest problem code goes like this:

-(IBAction)openFile:(id)sender {

    NSOpenPanel *openPanel = [[NSOpenPanel alloc] init];
    NSURL *fileURL;

    [openPanel setCanChooseFiles:YES];
    [openPanel setCanChooseDirectories:NO];
    [openPanel setAllowsMultipleSelection:NO];
    [openPanel setAllowedFileTypes:[NSArray arrayWithObject:@"txt"]];

    if ( [openPanel runModal] == NSOKButton ) {
        fileURL = [openPanel URL];
    }
    [openPanel release];
}

I know this code has worked before. It is currently my only method, and it activates when i press open in the menu. If I delete everything inside the method, so that pressing open should do nothing it stops at a break-point inside the method anyway. I have had exactly the same kind of problem before with openGL codes, and with a method that used c syntax to do file reading. Does anybody know what kind of horrible mistake I’m making over and over again?

Answer 1

A Breakpoint is something you yourself set explicitly to tell Xcode to pause the program at this exact line. Superficially it might look like the program crashed, but in reality it’s just waiting for you to tell it to go on.

This page looks like it has a nice explanation of the breakpoint interface in Xcode. (This is from a framework called Cocos2D, but ignore that. You should stick to ordinary Cocoa until you know what you’re doing.)