iOS alloc popover控制器导致崩溃

Question

Hi I'm trying to make a popover happen on the click of a button, something I've done successfully before, but for some reason I can't make it happen. I'm using iOS 5 now.

So far I have

-(void)changetablebuttonPressed:(id)sender{
UIButton *button = (UIButton*)sender;

changetableView = [[ChangeTableViewController alloc] initWithNibName:@"ChangeTableViewController" bundle:nil];
changetablePopover = [[UIPopoverController alloc] initWithContentViewController:changetableView];
[changetablePopover presentPopoverFromRect:button.frame inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:TRUE];     
}

The code causes a SIGABRT error after trying to initWithContentViewController or even a straightforward init . I've checked that changetableView is not null and so I'm stumped!

The only custom code in the ChangeTableViewController is in viewDidLoad and is self.contentSizeForViewInPopover = CGSizeMake(320, 144);

Any guesses would be appreciated.

EDIT : The exception isn't being printed to the console (I don't think), here is the entire output, with Zombies enabled:

GNU gdb 6.3.50-20050815 (Apple version gdb-1708) (Mon Aug 15 16:03:10 UTC 2011)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "x86_64-apple-darwin".sharedlibrary apply-load-rules all
Attaching to process 7596.
Catchpoint 2 (throw)Pending breakpoint 1 - "objc_exception_throw" resolved

Catchpoint 2 (exception thrown).(gdb) bt
#0  0x03dc9a4f in __cxa_throw ()
#1  0x01745e15 in objc_exception_throw ()
#2  0x0155ca78 in +[NSException raise:format:arguments:] ()
#3  0x0155c9e9 in +[NSException raise:format:] ()
#4  0x001c7f0d in -[UIViewController _loadViewFromNibNamed:bundle:] ()
#5  0x001c83a9 in -[UIViewController loadView] ()
#6  0x001c85cb in -[UIViewController view] ()
#7  0x00596559 in -[UIPopoverController _transitionFromViewController:toViewController:animated:] ()
#8  0x00593b13 in -[UIPopoverController initWithContentViewController:] ()
#9  0x0000b7f7 in -[DetailViewController changetablebuttonPressed:] (self=0x6a510e0, _cmd=0x18af6, sender=0x6a696f0) at .../DetailViewController.m:385
#10 0x015b5ec9 in -[NSObject performSelector:withObject:withObject:] ()
#11 0x001055c2 in -[UIApplication sendAction:to:from:forEvent:] ()
#12 0x0010555a in -[UIApplication sendAction:toTarget:fromSender:forEvent:] ()
#13 0x001aab76 in -[UIControl sendAction:to:forEvent:] ()
#14 0x001ab03f in -[UIControl(Internal) _sendActionsForEvents:withEvent:] ()
#15 0x001aa2fe in -[UIControl touchesEnded:withEvent:] ()
#16 0x003c3a2a in _UIGestureRecognizerUpdate ()
#17 0x015889ce in __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ ()
#18 0x0151f670 in __CFRunLoopDoObservers ()
#19 0x014eb4f6 in __CFRunLoopRun ()
#20 0x014eadb4 in CFRunLoopRunSpecific ()
#21 0x014eaccb in CFRunLoopRunInMode ()
#22 0x0149d879 in GSEventRunModal ()
#23 0x0149d93e in GSEventRun ()
#24 0x00102a9b in UIApplicationMain ()
#25 0x00002b42 in main (argc=1, argv=0xbfffed78) at .../main.m:16
#26 0x00002ab5 in start ()
Current language:  auto; currently objective-c
(gdb) 

Answer 1

Check your nib for a rogue IBOutlet. It sometimes happens when you defined a view (in Interface Builder) as one class, then later change it to another class, but don't clean up the old connections. (I had originally stated it was simply from deleting the outlet in your .h, but realized that was the wrong scenario, and recalled the correct one).

You are looking for an outlet with the yellow triangle to the right, like:

It is happening during the loading of the view, which is when the nib loader is trying to pair up objects with their outlets.