UIButton in UITableViewCell crashes when clicked - iphone

Question

This should be simple, but I can't figure out what's wrong. I'm creating a tableview and I want a button that I can click to switch between checked and unchecked:
UITableViewCell *cell;
cell = [tableView dequeueReusableCellWithIdentifier:DiaperCellIdentifier];
if (cell == nil)
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:DiaperCellIdentifier] autorelease];
wetButton = [[UIButton buttonWithType:UIButtonTypeCustom] retain];
image = [UIImage imageNamed:#"unchecked_large.png"];
CGRect frame = CGRectMake(150.0, 5.0, image.size.width, image.size.height);
wetButton.frame = frame;
[wetButton setBackgroundImage:image forState:UIControlStateNormal];
[wetButton addTarget:self action:#selector(wetClicked:) forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:wetButton];
Now when I click this button, I get a stack trace....[NSCFString scale]: unrecognized selector sent to instance.... thanks for any help.
- (void) wetClicked:(id)sender{
if (isWet) {
isWet = NO;
[wetButton setBackgroundImage:#"unchecked_large.png" forState:UIControlStateNormal];
} else {
isWet = YES;
[wetButton setBackgroundImage:#"checked_large.png" forState:UIControlStateNormal];
}
}
and here's the trace:
2011-03-09 10:19:57.124 InfantCare[64064:207] -[NSCFString scale]: unrecognized selector sent to instance 0x33be0
2011-03-09 10:19:57.240 InfantCare[64064:207] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSCFString scale]: unrecognized selector sent to instance 0x33be0'
* Call stack at first throw:
(
0 CoreFoundation 0x00f2dbe9 __exceptionPreprocess + 185
1 libobjc.A.dylib 0x010825c2 objc_exception_throw + 47
2 CoreFoundation 0x00f2f6fb -[NSObject(NSObject) doesNotRecognizeSelector:] + 187
3 CoreFoundation 0x00e9f366 ___forwarding___ + 966
4 CoreFoundation 0x00e9ef22 _CF_forwarding_prep_0 + 50
5 UIKit 0x003d1e7b -[UIImageView setImage:] + 250
6 UIKit 0x004ea353 -[UIButton layoutSubviews] + 273
7 QuartzCore 0x01d58451 -[CALayer layoutSublayers] + 181
8 QuartzCore 0x01d5817c CALayerLayoutIfNeeded + 220
9 QuartzCore 0x01d5137c _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 310
10 QuartzCore 0x01d510d0 _ZN2CA11Transaction6commitEv + 292
11 QuartzCore 0x01d817d5 _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 99
12 CoreFoundation 0x00f0efbb __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 27
13 CoreFoundation 0x00ea40e7 __CFRunLoopDoObservers + 295
14 CoreFoundation 0x00e6cbd7 __CFRunLoopRun + 1575
15 CoreFoundation 0x00e6c240 CFRunLoopRunSpecific + 208
16 CoreFoundation 0x00e6c161 CFRunLoopRunInMode + 97
17 GraphicsServices 0x017cf268 GSEventRunModal + 217
18 GraphicsServices 0x017cf32d GSEventRun + 115
19 UIKit 0x0031642e UIApplicationMain + 1160
20 InfantCare 0x00002228 main + 102
21 InfantCare 0x000021b9 start + 53
)
terminate called after throwing an instance of 'NSException'
Program received signal: “SIGABRT”.

Answer 1

I think you need to use an UIImage instance as a parameter when you call the function setBackgroundImage:
[wetButton setBackgroundImage:#"unchecked_large.png" forState:UIControlStateNormal];
use instead:
[wetButton setBackgroundImage:[UIImage imageNamed:#"unchecked_large.png"] forState:UIControlStateNormal];

Answer 2

The code you have posted is fine. The problem is most likely in your wetClicked: method, you are calling the scale method on an NSString.
Now that you've posted wetClicked: and the trace, I see the problem: You're passing a string instead of an image to setBackgroundImage:forState:. Try this instead:
- (void) wetClicked:(id)sender{
if (isWet) {
isWet = NO;
[wetButton setBackgroundImage:[UIImage imageNamed:#"unchecked_large.png"] forState:UIControlStateNormal];
} else {
isWet = YES;
[wetButton setBackgroundImage:[UIImage imageNamed:#"checked_large.png"] forState:UIControlStateNormal];
}
}