Handling touches within UIScrollview - ios

Question

I have a view that contains a UIScrollView. The UIScrollView contains an UIImageView (only one for now but there will be more latter). I want to be able to drag the UIImageView out of the UIScrollView and into the superview.
I have reviewed every similar question and example I can find online and still cant get my head around how this works.
At first I couldn't get touches to register all whithin the scrollview. After a lot of searching I have found a way to get touchesbegan to register as follows:
First I created a new view based project and in the auto-created "ViewController.h"
I created an IBOutlet named slider.
Then in the auto-created "ViewController.m" I created the UIScrollview.
In IB I added a UIScrollView to the storyboard then connected it to the "slider" IBOutlet.
Next I added class file to the projects. This new class is a subclass os UIImageView. I named this class "DragableImage" In the
Then in IB I dropped an image into the UIScrollview clicked on it and changed the class to "DragableImage"
In the DragableImage.m I voided touches began and simply told it to become hidden if clicked.
This works and the touch registers and makes the image disappear but how do I now add the new image to the main view and have it follow my finger?
This is what I have in the way of code:
ViewController.h
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController {
IBOutlet UIScrollView *slider;
}
#end
ViewController.m
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad
{
[slider setScrollEnabled:YES];
[slider setContentSize:CGSizeMake(306, 1560)];
[slider setShowsVerticalScrollIndicator:NO];
slider.canCancelContentTouches = NO;
slider.delaysContentTouches = NO;
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation)interfaceOrientation
{
return YES;
}
#end
DragableImage.h
#import <UIKit/UIKit.h>
#interface DragableImage : UIImageView
#end
DragableImage.m
#implementation DragableImage
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
self.hidden = YES;
}
#end
How to make this work?

Answer 1

There is one obvious problem that can arise here. Namely, how to tell the difference between dragging to scroll and dragging an image. The way I would handle this is to setup a tap and hold gesture recognizer (http://developer.apple.com/library/ios/#documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/GestureRecognizers/GestureRecognizers.html).
Once you detect a hold you could set it up so that further touches/gestures get routed to you drag and drop code. You can find a nice tutorial for that here:
http://www.ancientprogramming.com/2012/04/05/drag-and-drop-between-multiple-uiviews-in-ios/