EXC_BAD_ACCESS when closing modal window ([NSWindow _restoreLevelAfterRunningModal]: message sent to deallocated instance) - objective-c

Question

In my main ViewController I have the following code:
- (IBAction)listFunctions:(id)sender //button clicked
{
FunctionListController *functionListController = [[FunctionListController alloc] initWithWindowNibName:#"FunctionList"];
NSWindow *functionListWindow = [functionListController window];
[NSApp runModalForWindow: functionListWindow];
NSLog(#"done");
}
FunctionListController is the File's Owner of FunctionList.nib and a subclass of NSWindowController and implements the protocol NSWindowDelegate.
Here is the implementation of FunctionListController:
#implementation FunctionListController
- (id)initWithWindow:(NSWindow *)window
{
self = [super initWithWindow:window];
if(self)
{
// Initialization code here.
}
return self;
}
- (void)windowDidLoad
{
[super windowDidLoad];
// Implement this method to handle any initialization after your window controller's window has been loaded from its nib file.
self.window.delegate = self;
}
- (void)windowWillClose:(NSNotification *)notification
{
[NSApp stopModal];
}
#end
When the modal window is closed, the NSLog(#"done"); runs and displays, however after listFunctions is done, I get a EXC_BAD_ACCESS error.
With NSZombiesEnabled I get the error [NSWindow _restoreLevelAfterRunningModal]: message sent to deallocated instance.
Edit:
I am using ARC.

Answer 1

Try [functionListWindow setReleasedWhenClosed:NO] and hold a strong reference to your window until closing.

Answer 2

In your listFunctions method, you first create a FunctionListController object:
- (IBAction)listFunctions:(id)sender //button clicked
{
FunctionListController *functionListController = [[FunctionListController alloc] initWithWindowNibName:#"FunctionList"];
which is referenced through a local variable; it will be released at the end of the scope (the method itself);
you then get a reference to the functionListController window and run it as a modal:
NSWindow *functionListWindow = [functionListController window];
[NSApp runModalForWindow: functionListWindow];
This object will be retained by the NSApp.
However, the method exits (runModalForWindow will not block your thread) and functionListController is deallocated:
NSLog(#"done");
}
so you get a dangling reference and a modal window owned by an object which is not longer there. Hence, then crash.
Simply, make functionListController a strong property of your class and it will work.
Your new listFunctions would look like:
- (IBAction)listFunctions:(id)sender //button clicked
{
self.functionListController = [[FunctionListController alloc] initWithWindowNibName:#"FunctionList"];
...

Answer 3

Your functionListWindow is a local variable in your listFunctions: method. When that method finishes executing, you will lose any strong reference you have to that object, so nothing will own it and it will be deallocated. When your modal window actually closes, it tries to send the appropriate message to its delegate, however this no longer exists.
Have you tried making functionListWindow an instance variable on your main view controller?