File Name NSString adds unnecessary %20 in space

问题

SOLVED (Thanks Regexident)

I have an app that passes the file path of a PDF to a custom -(id)init init method. It is added to the table and when it is selected, it calls the else statement for a non existent file:

- (void) gridView:(AQGridView *)gridView didSelectItemAtIndex:(NSUInteger)index {

NSLog (@"Selected theArgument=%d\n", index);

UIViewController *viewController = [[[UIViewController alloc]init]autorelease];
{
    //if file is built-in, read from the bundle
    if (index <= 3)
    {
        // first section is our build-in documents
        NSString *fileURLs = [_documentIconsURLs objectAtIndex:index];   
        NSLog(@"file url -%@", fileURLs);
        viewController = [[[xSheetMusicViewController alloc]initWithContentURL:fileURLs]autorelease];
    }
    //if file is external, read from URL
    else
    {
        // second section is the contents of the Documents folder
        NSString *fileURL = [_documentIconsURLs objectAtIndex:index];
        NSLog(@"file url -%@", fileURL);
        NSString *path;
        NSString *documentsDirectoryPath = [self applicationDocumentsDirectory];
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        path = [[paths objectAtIndex:0] stringByAppendingPathComponent:fileURL];


        if ([[NSFileManager defaultManager] fileExistsAtPath:documentsDirectoryPath])
        {
            viewController = [[[xSheetMusicViewController alloc]initWithDocumentURL:fileURL]autorelease];
        }
        else
        {
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Failure!"                                                            message:@"The Selected File Does Not Exist"
                                                           delegate:nil
                                                  cancelButtonTitle:@"OK"
                                                  otherButtonTitles: nil];
            [alert show];
            [alert release];        
            return;
        }
    }
[self.navigationController setNavigationBarHidden:YES animated:NO]; 
[UIView beginAnimations:@"animation" context:nil];
[UIView setAnimationDuration:1];
[UIView setAnimationTransition:UIViewAnimationTransitionCurlDown forView:self.navigationController.view cache:YES]; 
[self.navigationController pushViewController:viewController animated:NO];
[UIView commitAnimations];  
    }
}

So whenever I have a document with no space in it's name, it pushes and inits. But when the file name has a space in it, it says it does not exist. And when I remove the if-else method, it init's, but crashes because the file doesn't exist. I've tried to replace the %20 in the file path with a regular space, but the method continues to call the else part.

So, is the file path not standardized and readable, or is my else method wrong?

回答1:

As your path appears to be a percentage escaped path string I'd try this:

[fileURL stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]

And I'd rename fileURL to fileURLString to make clear that it's an NSString containing a URL path, not an actual NSURL (which your variable name would falsely imply).

But I'd check the code that populates _documentIconsURLs, as it's probabaly the origin of your problem.

来源：https://stackoverflow.com/questions/8107303/file-name-nsstring-adds-unnecessary-20-in-space