trying to save jpeg to Documents directory of app - iphone

Question

So I have a function which gets an image from a URL which looks like this:
- (UIImage *) getImageFromURL:(NSString *)fileURL {
UIImage * result;
NSData * img_data = [NSData dataWithContentsOfURL:[NSURL URLWithString:fileURL]];
result = [UIImage imageWithData:img_data];
return result;
}
and then a function which saves the image from a UIImage Which looks like this:
-(void) saveImage:(UIImage *)image withFileName:(NSString *)imageName ofType:(NSString *)extension inDirectory:(NSString *)directoryPath {
if ([[extension lowercaseString] isEqualToString:#"png"]) {
[UIImagePNGRepresentation(image) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:#"%#.%#", imageName, #"png"]] options:NSAtomicWrite error:nil];
} else if ([[extension lowercaseString] isEqualToString:#"jpg"] || [[extension lowercaseString] isEqualToString:#"jpeg"]) {
[UIImageJPEGRepresentation(image, 1.0) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:#"%#.%#", imageName, #"jpg"]] options:NSAtomicWrite error:nil];
NSLog(#"Image named %# wrote to %#", imageName, directoryPath);
} else {
NSLog(#"Image Save Failed\nExtension: (%#) is not recognized, use (PNG/JPG)", extension);
}
}
The issue I am facing is that when I run a UIImage through the saveImage function I dont think it is saving the image. This is because when I check for a UIImage imageNamed:#"Documents/filenamesavedas.jpeg" it returns (null). The image does however download correctly.
Here is my Documents Directory path function:
- (NSString *)getDocumentsDirectoryPath {
NSString * documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSLog(documentsDirectoryPath);
return documentsDirectoryPath;
}
Here is where I am downloading and trying to save the image:
dispatch_async(jsonQueue, ^{
// check to see if data authenticate runs successfully.
NSString *documentsDirectoryPath = [util getDocumentsDirectoryPath];
UIImage *imageToSave = [util getImageFromURL:[properties objectForKey:#"current_group_logoURL"]];
[util saveImage:imageToSave withFileName:[properties objectForKey:#"home_venue_logo"] ofType:#"jpeg" inDirectory:documentsDirectoryPath];
NSLog(#"Group Logo URL %#", [properties objectForKey:#"current_group_logoURL"]);
NSLog(#"Current Group Image %#", [properties objectForKey:#"home_venue_logo"]);
UIImage *testToSeeItHasDownloaded = imageToSave;
NSString *imageLocation = [documentsDirectoryPath stringByAppendingPathComponent:[properties objectForKey:#"home_venue_logo"]];
NSData *data = [NSData dataWithContentsOfFile:imageLocation];
UIImage *testToSeeImageHasSaved = [UIImage imageWithData:data];
NSLog(#"testToSeeImagehasDownloaded: %#", testToSeeItHasDownloaded);
NSLog(#"image location to save to: %#", imageLocation);
NSLog(#"testToSeeImagehasSaved: %#", testToSeeImageHasSaved );
});
The Console returns this:
2012-10-22 16:27:45.642 asdaf[46819:1d807] Group Logo URL http://somesite.com/50a0e42619424ba551a956511c098656.jpeg
2012-10-22 16:27:45.642 asdaf[46819:1d807] Current Group Image 50a0e42619424ba551a956511c098656.jpeg
2012-10-22 16:27:45.649 asdaf[46819:1d807] testToSeeImagehasDownloaded: <UIImage: 0xb09ed50>
2012-10-22 16:27:45.649 asdaf[46819:1d807] testToSeeImagehasSaved: (null)
testToSeeImagehasSaved should return null. But what am I doing wrong? Thanks.

Answer 1

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
//documentsDirectory is your documents directory path
//Now append your image name in this path
NSString *imagePath = [documentsDirectory stringByAppendingPathComponent:#"ImageName.jpeg"];
//convert your image in NSData
NSData *imageData = UIImagePNGRepresentation(image);
//Now write it at path
[imageData writeToFile:imagePath atomically:NO];
You can get this image in same way
NSData *data = [NSData dataWithContentsOfFile:imagePath];
UIImage *image = [UIImage imageWithData:data];
Edit:
-(void)saveImage:(UIImage *)image withFileName:(NSString *)imageName ofType:(NSString *)extension
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *imageName = [imageName stringByAppendingString:extension];
//Note extension should be like .png, .jpg, .jpeg dont forget dot (.).
NSString *imagePath = [documentsDirectory stringByAppendingPathComponent:imageName];
NSData *imageData = UIImagePNGRepresentation(image);
[imageData writeToFile:imagePath atomically:NO];
}
Well i dont now about your whole code but why you're passing an UIImage object when you have to save your image in documents directory. You can pass NSData as well in your method. You're doing more.
Your problem is you're saving .jpg image each time and at the time of retrieving you're trying to find .jpeg image on same path thats why you're getting null value. See this line in your saving method -
[UIImageJPEGRepresentation(image, 1.0) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:#"%#.%#", imageName, #"jpg"]] options:NSAtomicWrite error:nil];

Answer 2

this line doesn't look right to me:
UIImage *testToSeeImageHasSaved = [UIImage imageNamed: [#"Documents/" stringByAppendingString: [properties objectForKey:#"home_venue_logo"]]];
I think you have to do:
UIImage* image = [UIImage imageWithContentsOfFile:"YOUR_FILE_PATH"];
[UIImage imageNamed:"image_name"] is good only for images attached to your project

Answer 3

When you save it in the document folder, it does not exacly saves it in the "Document" directory but rather something like
path=/var/mobile/Applications/144B3628-5258-4939-8B80-006EC5BE45B2/Library/Caches/6_1.png
So to retreive your image you should use
NSString *uniquePath = [directory stringByAppendingPathComponent: filename];
image = [UIImage imageWithContentsOfFile: uniquePath];
where directory is the path you used to save it and filename the name of your jpeg.

Answer 4

[UIImage imageNamed:#"Documents/filenamesavedas.jpeg"]
Doesnt take paths it searches your bundle for the file with a specific name.
Locate the file using calls to NSFileManager and use the expected path and file name.