helloB helloB - 10 days ago 6
iOS Question

Error: The file...doesn't exist when calling writeToFile on imageData

I am trying to write data to a file with the following code in a completion block for

NSURLSessionDownloadTask
:

void (^completionBlock)(NSURLResponse *response, NSURL *filePath, NSError *error) = ^void (NSURLResponse *response, NSURL *filePath, NSError *error) {
dispatch_async(dispatch_get_main_queue(), ^{
if (!error){
NSData *imageData = [NSData dataWithContentsOfURL:filePath];
if(imageData) NSLog(@"image is not null");

if(pic == 1) self.imageView.image = [UIImage imageWithData:imageData];
else if(pic==2) self.imageView2.image = [UIImage imageWithData:imageData];

NSArray *paths = [[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask];
NSURL *documentsDirectoryURL = [paths lastObject];
NSURL *saveLocation;
if(pic == 1) saveLocation = [documentsDirectoryURL URLByAppendingPathComponent:self.pictureName1];
else if (pic == 2) saveLocation = [documentsDirectoryURL URLByAppendingPathComponent:self.pictureName2];
else saveLocation = [documentsDirectoryURL URLByAppendingPathComponent:self.pictureName3];

NSLog(@"for # %d writing to file %@", pic, saveLocation);

NSError *error = nil;
[imageData writeToFile:[saveLocation absoluteString] options:NSAtomicWrite error: &error];
if(error){
NSLog(@"FAILED\n\n\n %@ \n\n\n", [error description]);
}
}


I am able to display the downloaded images in
UIImageViews
and my null check on
imageData
likewise confirms it's not null. However, when I try to write the data to a file, My
NSLog
prints out the following error indicating that the write failed:

(log statements)
# 3 writing to file file:///var/mobile/Containers/Data/Application/3743A163-7EE1-4A5A-BF81-7D1344D6DA45/Documents/pic3.png
Error Domain=NSCocoaErrorDomain Code=4 "The file “pic1.jpg” doesn’t exist."
UserInfo={NSFilePath=file:///var/mobile/Containers/Data/Application/3743A163-7EE1-
4A5A-BF81-7D1344D6DA45/Documents/pic1.jpg, NSUnderlyingError=0x16d67200 {Error
Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}


I haven't been able to find another question on SO indicating this error message for this file, and I'm finding the error message quite counterintuitive. Where is my error?

Answer

Instead of [saveLocation absoluteString], use [saveLocation path]. Basically the former gives you "file:///path/filename" while the latter gives you "/path/filename", which is the correct format.

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