Question

I’m trying to convert a NSURL to a NSString to use elsewhere in my program.

Here’s my code:

- (IBAction)openExistingDocument:(id)sender {
NSOpenPanel* panel = [NSOpenPanel openPanel];
[panel setCanChooseDirectories:NO];
[panel setAllowsMultipleSelection:NO];
[panel setMessage:@"Please select a File or Folder containing your character's .png layers"];

[panel beginWithCompletionHandler:^(NSInteger result){
    if (result == NSFileHandlingPanelOKButton) {

        NSURL*  theDoc = [[panel URLs] objectAtIndex:0];
        NSString* unformattedURL = [NSString stringWithContentsOfURL:theDoc encoding:NSASCIIStringEncoding error:NULL];
        NSString * formattedURL = [unformattedURL stringByReplacingOccurrencesOfString:@"file:/" withString:@""];
        NSLog(@"the url says:%@", theDoc);
        NSLog(@"the unformatted string says: %@", unformattedURL);
        NSLog(@"the formatted string says: %@", formattedURL);
    }

}];
}

When I run the program, here’s what my command line outputs:

2012-01-29 18:43:19.205 Cocos2dCharacterRigger[516:407] the url says:file://localhost/Users/*****/Desktop/mockupsite.jpg
2012-01-29 18:43:19.213 Cocos2dCharacterRigger[516:407] the unformatted string says: ÿØÿá.]Exif
2012-01-29 18:43:19.219 Cocos2dCharacterRigger[516:407] the formatted string says: ÿØÿá.]Exif

Can someone point out what I’m doing incorrectly?

Answer 1

You are loading the contents of the file at the URL into the string. You are loading the file as an ASCII string (which that file almost certainly is not — it’s an image) and you are ignoring any errors.

To get the actual path for the url, you send the url the -path message. So, to get a string with the path:

NSString* filePath = [theDoc path];
NSLog(@"the url: %@", theDoc);
NSLog(@"the path: %@", filePath);

This should print the following (based on your logs above):

the url: file://localhost/Users/*****/Desktop/mockupsite.jpg
the file: /Users/*****/Desktop/mockupsite.jpg