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iOS How do I save an image to the camera roll?

V

ViviUO

macrumors 6502
Original poster
Jul 4, 2009
307
22
First, I am a little new to iOS programming.

After searching through the SDK documentation, I was unable to find a solution to saving an image to the camera roll.

For instance, lets say I wanted to make an app that displayed a "picture of the day" from a website inside of a UIWebView. I am going to use an IBOutlet connected to a button, which will then save the image to the phone.

This is probably very easy to implement, but I am absolutely stumped. Thanks in advance.
 
Okay, I think I found it:

Code: 
void UIImageWriteToSavedPhotosAlbum (
   UIImage *image,
   id completionTarget,
   SEL completionSelector,
   void *contextInfo
);

So my next question is, does it HAVE to be a UIImage, or can I substitute it for an NSURL?
 
It has to be an image: it is up to you to download the contents of the URL and turn them into an image. If the URL is pointing at a jpg/png this is very easy.
 
robbieduncan said:
It has to be an image: it is up to you to download the contents of the URL and turn them into an image. If the URL is pointing at a jpg/png this is very easy.
Click to expand...

What would be the easiest way to go about implementing this?
 
I'd start with the URL Loading System Guide concentrate specifically on NSURLConnection and asynchronous loading. Once you have the data you can easily create a UIImage using the obvious method (look at the UIImage documentation for a convenience constructor that takes a NSData parameter).
 
robbieduncan said:
I'd start with the URL Loading System Guide concentrate specifically on NSURLConnection and asynchronous loading. Once you have the data you can easily create a UIImage using the obvious method (look at the UIImage documentation for a convenience constructor that takes a NSData parameter).
Click to expand...

Great, I will give it a look. So far I have come up with this:

Code: 
NSURL * imageURL = [NSURL URLWithString:@"http:image.jpg"];
NSData * imageData = [NSData dataWithContentsOfURL:imageURL];
UIImage * image = [UIImage imageWithData:imageData];

This looks like it would work without any problems, i'll report back if I run into any issues.
 
It will work (in theory: I've not checked the code in detail) but will block the thread whilst it downloads the data. Which is why I suggested looking at the async methods to download data. Try what you have (especially on slower network connections like Edge). It might be OK for you, if not you know you need to go async to make it better.
 
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