Drag out new UIImageView objects from a stationary UIImageView or button - objective-c

Question

I'm a beginner at iOS development and I'm working on a side project for my school. What I would like to do is have a small image where the user can drag out more images from. Essentially I have an app where I'm generating squares and I need to have a set square where the user can touch the square and drag out new squares onto a board. I have achieved this to a certain point but it's not the desired behavior yet. Currently the user has to touch the button and then release before they can interact with the new square to drag it off of the button. What i would like is to have the touch event somehow passed over to the new UIImageView object that is created so it is seamless dragging out a new square. Below is my current code.
//UIViewController
#import <UIKit/UIKit.h>
#import "Tile.h"
#interface MenuViewController : UIViewController
{
Tile *tileObject;
}
#end
#import "MenuViewController.h"
#implementation MenuViewController
- (IBAction)createTile:(UIButton *)sender {
CGFloat tileX = sender.center.x;
CGFloat tileY = sender.center.y;
tileObject = [[Tile alloc]initWithX:tileX andY:tileY];
[self.view addSubview:tileObject];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return YES;
}
#end
//Custom Tile Class
#import <UIKit/UIKit.h>
#interface Tile : UIImageView
{
CGPoint startLocation;
}
- (id)init; //Default Initialization
- (id)initWithX:(CGFloat)x andY:(CGFloat)y; //Initialization with coordinate points from single screen tap
#end
#import "Tile.h"
#implementation Tile
//Default initialization
-(id) init
{
self = [self initWithX:0 andY:0];
return self;
}
//Initialization with coordinate points from single screen tap
- (id)initWithX:(CGFloat)centerX andY:(CGFloat)centerY
{
//Creates a UIImageView object from an image file
UIImage *image = [UIImage imageNamed:#"redblock.png"];
self = [super initWithImage:image];
//Used to center the image under the single screen tap
centerX -= (image.size.height/2);
centerY -= (image.size.height/2);
//Sets the position of the image
self.frame = CGRectMake(centerX, centerY, image.size.width, image.size.height);
self.userInteractionEnabled = YES; //required for interacting with UIImageViews
return self;
}
/* Methods from Stack Overflow
http://stackoverflow.com/questions/1991899/uiimage-detecting-touch-and-dragging
Referenced from http://www.iphoneexamples.com/
*/
- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
// Retrieve the touch point
CGPoint point = [[touches anyObject] locationInView:self];
startLocation = point;
[[self superview] bringSubviewToFront:self];
}
- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
// Move relative to the original touch point
CGPoint point = [[touches anyObject] locationInView:self];
CGRect frame = [self frame];
frame.origin.x += point.x - startLocation.x;
frame.origin.y += point.y - startLocation.y;
[self setFrame:frame];
}
/*
end of methods from Stack Overflow
*/
#end

Answer 1

If the initial touch down point can be an image view with the image you want to drag as its image, then you can do it like this:
In your menuViewController class, put this in the viewDidLoad (and delete the button and its method):
- (void)viewDidLoad
{
[super viewDidLoad];
tileObject = [[Tile alloc]initWithX:160 andY:200];
[self.view addSubview:tileObject];
}
Then in your Tile class, in the touchesBegan:withEvent: method you create a new tile, and carry out the drag as you did before:
- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
Tile *newTile = [[Tile alloc]initWithX:160 andY:200];
[self.superview addSubview:newTile];
// Retrieve the touch point
CGPoint point = [[touches anyObject] locationInView:self];
startLocation = point;
[[self superview] bringSubviewToFront:self];
}

Answer 2

Instead of using a button with touchDown event, you need to:
1) Detect touchesBegan and create your tile
2) Detect touchesMoved and move your tile