NYC Tech Engineer NYC Tech Engineer - 1 year ago 43
Objective-C Question

How do I download an image from a URL and save it to my computer?

How would I download an image from a URL, and have that saved to the computer using Objective-C? This is what I got so far:

NSString *documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

UIImage *imageFromURL = [self getImageFromURL:@"https://www.google.com/images/srpr/logo11w.png"];

[self saveImage:imageFromURL withFileName:@"Google Logo" ofType:@"png" inDirectory:documentsDirectoryPath];

UIImage *imageFromWeb = [self loadImage:@"Google Logo" ofType:@"png" inDirectory:documentsDirectoryPath];


Xcode complains about UIIMage, trying to replace with NSImage. It also complains about an undeclared identifier 'self'.

I need to make an HTTP call to perform this as well. Explain this to me like I'm 5.

Answer Source

Here is the code to Save the image into document Directory.

-(void)saveImagesInLocalDirectory
{
        NSString * documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
            NSString *imgName = @"image.png";
            NSString *imgURL = @"www.xxx.com/image/image.png";
            NSFileManager *fileManager = [NSFileManager defaultManager];
            NSString *writablePath = [documentsDirectoryPath stringByAppendingPathComponent:imgName];

            if(![fileManager fileExistsAtPath:writablePath]){
                // file doesn't exist
                NSLog(@"file doesn't exist");
                if (imgName) {
                    //save Image From URL
                    [self getImageFromURLAndSaveItToLocalData:imgName fileURL:imgURL inDirectory:documentsDirectoryPath];
                }
            }
            else{
                // file exist
                NSLog(@"file exist");
            }
}

-(void) getImageFromURLAndSaveItToLocalData:(NSString *)imageName fileURL:(NSString *)fileURL inDirectory:(NSString *)directoryPath {
    NSData * data = [NSData dataWithContentsOfURL:[NSURL URLWithString:fileURL]];

    NSError *error = nil;
    [data writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@", imageName]] options:NSAtomicWrite error:&error];

    if (error) {
        NSLog(@"Error Writing File : %@",error);
    }else{
        NSLog(@"Image %@ Saved SuccessFully",imageName);
    }
}

And this is the one method code..

-(void)saveImagesInLocalDirectory
{
        NSString * documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
            NSString *imgName = @"image.png";
            NSString *imgURL = @"www.xxx.com/image/image.png";
            NSFileManager *fileManager = [NSFileManager defaultManager];
            NSString *writablePath = [documentsDirectoryPath stringByAppendingPathComponent:imgName];

            if(![fileManager fileExistsAtPath:writablePath]){
                // file doesn't exist
                NSLog(@"file doesn't exist");
                    //save Image From URL
                    NSData * data = [NSData dataWithContentsOfURL:[NSURL URLWithString: imgURL]];

                    NSError *error = nil;
                    [data writeToFile:[documentsDirectoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@", imgName]] options:NSAtomicWrite error:&error];

                   if (error) {
                          NSLog(@"Error Writing File : %@",error);
                   }else{
                          NSLog(@"Image %@ Saved SuccessFully",imgName);
                   }
            }
            else{
                // file exist
                NSLog(@"file exist");
            }
}