store (x, y) positions in some output file using Xcode for iPhone?

Question

Hello, I want to program an application on iPhone and I want to know if the idea of this application is doable. So in the Application I want to have an image that appears to the users (this is easy. When the user touches the image, the application records the (x,y) position of where the user touches exactly in the image and stores it in a file (.pdf, .txt or what ever) I need these (x,y) positions to be stored in some kind of file but I don't know if this is doable in iPone or iPad

Thank you

Answer 1

sure. Each app gets its own place to save things to. You would write out a file just like any other program. Some locations are meant to be temporary, some are meant to be backed up when synced with iTunes.

You could also use Core Data to persist these x,y locations.

Answer 2

Yes this is perfectly doable. You would have to:

Create a custom view. Override the touchesBegan:withEvent: method with code like this:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    CGPoint locationOfTouch = [touch locationInView:self];
    // You can now use locationOfTouch.x and locationOfTouch.y as the user's coordinates
}

Save the CGPoint. You can create a NSDictionary of it like this:

NSDictionary *coordinates = (NSDictionary *) CGPointCreateDictionaryRepresentation(locationOfTouch);

Then write it to a file:

[coordinates writeToFile:filePath atomically:YES];

That's all.