Drag UIImageView out of ScrollView - ios

Question

I have a RootViewController with a UIScrollViewController (boardScrollView).
This boardScrollView has a UIImageView as subview (boardImage) to create the board. I can zoom in and out and scroll on the boardImage within the boardScrollView. Works great!
Now I want to drag & drop other UIImageViews into the boardScrollImage within the boardScrollView and also OUT of the boardScrollView.
For these other UIImageViews (Tiles) I have created a subclass of the UIImageView class (TileViewClass).
I have the drag&drop working to drop the Tile INTO the boardScrollView/boardImage and also drag&drop INSIDE the boardScrollView/boardImage but I can not get the drag&drop to OUTSIDE the boardScrollView working..
I think this is because I can not access the views in the rootviewcontroller from the subclass.
Maybe it is even better to place the Tile back to the topview (window) in touchesBegan, and so the determination of the drop-position is always done from the same view.
But I don't know how this can be done...
I have tried [[UIApplication sharedApplication].keyWindow bringSubviewToFront:self.dragObject]; in the touchesBegan method, but this does not do the trick....
Maybe I am missing a removeFromSuperView somewhere?
Anyone any idea how I can get the drag&drop working?
RootViewController.h:
#interface RootViewController : UIViewController <UIScrollViewDelegate>
#property (nonatomic, strong) IBOutlet UIScrollView *boardScrollView;
#property (nonatomic, strong) UIImageView *dragObject;
#property (nonatomic, assign) CGPoint touchOffset;
#property (nonatomic, assign) CGPoint homePosition;
#property (nonatomic, strong) UIImageView *boardImage;
#end
RootViewController.m:
#implementation RootViewController
#synthesize boardScrollView;
#synthesize dragObject;
#synthesize touchOffset;
#synthesize homePosition;
#synthesize boardImage;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
UIImage *image = [UIImage imageNamed:#"greyblue_numbered_15x15_900x900.png"];
self.boardImage = [[UIImageView alloc] initWithImage:image];
self.boardImage.frame = (CGRect){.origin=CGPointMake(0.0f, 0.0f), .size=image.size};
[self.boardScrollView addSubview:self.boardImage];
self.boardImage.userInteractionEnabled = YES;
self.boardScrollView.contentSize = image.size;
self.boardScrollView.canCancelContentTouches = NO;
self.boardScrollView.userInteractionEnabled = YES;
self.boardScrollView.clipsToBounds = YES;
}
TileImageView.h:
#import <UIKit/UIKit.h>
#interface TileImageView : UIImageView
#property (nonatomic, strong) UIImageView *dragObject;
#property (nonatomic, assign) CGPoint touchOffset;
#end
TileImageView.m:
#import "TileImageView.h"
#implementation TileImageView
#synthesize dragObject;
#synthesize touchOffset;
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
self.exclusiveTouch = YES;
self.userInteractionEnabled = YES;
}
return self;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
if ([touches count] == 1) {
// one finger
CGPoint touchPoint = [[touches anyObject] locationInView:self.superview];
for (UIImageView *iView in self.superview.subviews) {
if ([iView isMemberOfClass:[TileImageView class]]) {
if (touchPoint.x > iView.frame.origin.x &&
touchPoint.x < iView.frame.origin.x + iView.frame.size.width &&
touchPoint.y > iView.frame.origin.y &&
touchPoint.y < iView.frame.origin.y + iView.frame.size.height)
{
self.dragObject = iView;
self.touchOffset = CGPointMake(touchPoint.x - iView.frame.origin.x,
touchPoint.y - iView.frame.origin.y);
[self.superview bringSubviewToFront:self];
}
}
}
}
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
CGPoint touchPoint = [[touches anyObject] locationInView:self.superview];
CGRect newDragObjectFrame = CGRectMake(touchPoint.x - touchOffset.x,
touchPoint.y - touchOffset.y,
self.dragObject.frame.size.width,
self.dragObject.frame.size.height);
self.dragObject.frame = newDragObjectFrame;
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
for (UIView *iView in self.superview.subviews) {
if ([iView isMemberOfClass:[UIScrollView class]])
{
CGPoint touchPointScreen = [[touches anyObject] locationInView:[UIApplication sharedApplication].keyWindow];
if (touchPointScreen.x > iView.frame.origin.x &&
touchPointScreen.x < iView.frame.origin.x + iView.frame.size.width &&
touchPointScreen.y > iView.frame.origin.y &&
touchPointScreen.y < iView.frame.origin.y + iView.frame.size.height)
{
for (UIView *iView2 in iView.subviews) {
[iView2 addSubview:self.dragObject];
CGPoint touchPointImage = [[touches anyObject] locationInView:iView2];
self.dragObject.frame = CGRectMake(touchPointImage.x - touchOffset.x,
touchPointImage.y - touchOffset.y,
self.dragObject.frame.size.width,
self.dragObject.frame.size.height);
}
}
self.dragObject = nil;
}
}

Answer 1

Basically you'r catching all touch events on the tileimageview and moving its origin CGPoint around.
If a touch event ended, your cycling though all subviews of your tileviews superview.
If any1 of this is a UIScrollview, you try to locate if the touchpoint matches its frame.
So basically you just checking the frame of your uiscrollview. Therefore your touchpoint cannot be outside it.
Solution: you have to check the view in which you want to drop the tileimageview! you can assume that its a sibling of your uiscrollview(what i assume).
Other way, which i would recommend: Create a View - dropgroundview, in which you catch the touches(=> implement touchesend)
there you can drop your views around and check for subclasses of e.g. dropviews.

Answer 2

Solution: I have delegated the touch methodes to the RootViewController. There, I have access to all subviews and most important: the highest view.
Here, I say:
[self.view bringSubviewToFront:self.tmpDragObject];
And then it works!