NSFileManager: removing item

问题

The problem is removing an item that´s been written using writeToFile: method, I cannot seem to remove it. I tried NSFileManager but I guess these are two different types of storage.

- (BOOL) removeObject: (NSString *)objectToRemove inCategory:(StorageType)category
{
    BOOL result = NO;
    NSError *removeError;
    NSString *storageFolder = [self getCategoryFor:category];

    if (objectToRemove) {
        NSFileManager *fileManager = [[NSFileManager alloc]init];

        // Find folder
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
        NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:storageFolder];
        NSString *dataPathFormated = [dataPath stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

        if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath]) {
            NSLog(@"Removing file error: folder was not found");
        }

        NSURL *destinationURL = [[NSURL alloc]initWithString:[NSString stringWithFormat:@"%@/%@",dataPathFormated,objectToRemove]];
        //NSString *destinationString = [NSString stringWithFormat:@"%@/%@",dataPath,objectToRemove];

        if ([fileManager fileExistsAtPath:[destinationURL path]]) {
            NSLog(@"destination URL for file to remove: %@", destinationURL);
            // Remove object
            result = [fileManager removeItemAtURL:destinationURL error:&removeError];
            NSLog(@"ERROR REMOVING OBJECT: %@",removeError);
        } else {
            NSLog(@"Object to remove was not found at given path");
        }
    }
    return result;
}

I add the objects using the writeToFile method of NSData, I guess this must be the problem, since it uses plist to store while NSData something else, if it is - how do I remove this item written with writeToFile ?:

[object writeToFile:destinationString atomically:YES];

Error message removing file

ERROR REMOVING OBJECT: Error Domain=NSCocoaErrorDomain Code=4 "The operation couldn’t be completed. (Cocoa error 4.)" UserInfo=0xd4c4d40 {NSURL=/Users/bruker/Library/Application%20Support/iPhone%20Simulator/6.1/Applications/14480FD3-9B0F-4143-BFA4-728774E7C952/Documents/FavoritesFolder/2innernaturemusic}

回答1:

If your file is present at that path you can try this:

    [[NSFileManager defaultManager] removeItemAtPath:[destinationURL path] error:&error];

Hope this helps.

回答2:

And the "for some reason": your "URL" is just a path, it's not a valid filesystem URL. For that, you would need to prepend file:// before the actual path, or even better, use [NSURL fileURLWithPath:].

回答3:

In this place

result = [fileManager removeItemAtURL:destinationURL error:&removeError];
NSLog(@"ERROR REMOVING OBJECT: %@",removeError);

you log and do not check the result value. Is it really NO? You should check return value first, and then if it is NO, check the removeError.

And also I prefer to write

NSError * removeError = nil;

when declarate it. May be removeError object contains some old information.

来源：https://stackoverflow.com/questions/17568890/nsfilemanager-removing-item

标签

ios

objective-c

persistence

nsfilemanager

writetofile