Spawn and Drag UIImage

[jcc]

I am spawning and dragging a UIImageView however, when it comes time to set the image in it's new position the app crashes.

Am I missing something?

Draggable.h:

#import <Foundation/Foundation.h>
@interface Draggable : UIImageView {
    CGPoint startLocation;
}
@end

Draggable.m:

#import "Draggable.h"
@implementation Draggable

- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
    // Retrieve the touch point
    CGPoint pt = [[touches anyObject] locationInView:self];
    startLocation = pt;
    [[self superview] bringSubviewToFront:self];
}
- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
    // Move relative to the original touch point
    CGPoint pt = [[touches anyObject] locationInView:self];
    CGRect frame = [self frame];
    frame.origin.x += pt.x - startLocation.x;
    frame.origin.y += pt.y - startLocation.y;
    [self setFrame:frame];
}
@end

Call it:

	UIImage *tmpImage = [[UIImage imageNamed:@"myImage.png"] retain];
	UIImageView *imageViewX = [[UIImageView alloc] initWithImage:tmpImage];
	
	CGRect cellRectangle;
	cellRectangle = CGRectMake(0,0,tmpImage.size.width ,tmpImage.size.height );
	UIImageView *dragger = [[Draggable alloc] initWithFrame:cellRectangle];
	[dragger setImage:tmpImage];
	[dragger setUserInteractionEnabled:YES];
	
	[self.view addSubview:dragger];
	[self.view bringSubviewToFront:dragger];
	[imageViewX release];
	[tmpImage release];

[harrytheshark]

It might be useful to post the contents of the console when the app crashes, but I imagine it has something to do with this line:

UIImageView *dragger = [[Draggable alloc] initWithFrame:cellRectangle];

I think it should be

Draggable *dragger = [[Draggable alloc] initWithFrame:cellRectangle];

And make sure you release it when you're done, addSubview: will retain it for you.

[jcc]

Thanks for your help. I tried making the changes you suggested but nothing has changed. The console shows the following . . . although, I don't know what it means.

2010-08-18 19:18:30.989 Book-iPad[7021:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSCFArray insertObject:atIndex:]: attempt to insert nil'
2010-08-18 19:18:30.990 myApp[7021:207] Stack: (
46651472,
47809324,
46389003,
46388842,
1006603,
447296,
447060,
10272,
4007787,
3399144,
3290691,
3322328,
55292284,
45930652,
45926568,
55285917,
55286114,
3314546,
8802,
8674
)
terminate called after throwing an instance of 'NSException'

[harrytheshark]

It looks like "dragger" is returning nil. You can check by doing this:

if (dragger == nil) {
    NSLog(@"Yup");
}

[jcc]

Originally Posted by harrytheshark

It looks like "dragger" is returning nil. You can check by doing this:

if (dragger == nil) {
    NSLog(@"Yup");
}

Thanks for the help. Unfortunately, the console doesn't return "Yup", so I don't think the dragger is returning nil. Any other ideas?

[harrytheshark]

Puzzling, are you using an array at any point?