Access int variable from other class - objective-c

Question

I have two windows, my main window "window" and "help window" all inside my App Delegate. In my main window its view is subclassed and I want to draw a rect inside it. My help window has a rect also but it has an NSTracker on it. What I want to do is draw my rect in my window subclass with the x and y coordinates equal to my NSTracker position. The problem I am having is it crashes when I try to bring in the coordinates, any ideas of what I could be doing wrong? thanks
//My subclass of window is called CutoutView. This is all in draw rect
AppDelegate *controller = [[[NSApp delegate] window] contentView];
xValue = controller.mouseLoc.x;
yValue = controller.mouseLoc.y;
NSRectFillUsingOperation(NSMakeRect(xValue,yValue, 600, 400), NSCompositeClear);
[self update];
- (void)update
{
NSLog(#"test");
[self setNeedsDisplay:YES];
}
//My AppDelegate with the tracker helpView is a reference to the view of my second window "Help Window"
-(void)updateTrackingAreas
{
if(trackingArea != nil) {
[self.helpView removeTrackingArea:trackingArea];
[trackingArea release];
}
opts = (NSTrackingActiveAlways | NSTrackingMouseEnteredAndExited | NSTrackingMouseMoved);
trackingArea = [ [NSTrackingArea alloc] initWithRect:[self.helpView bounds]
options:opts
owner:self
userInfo:nil];
[self.helpView addTrackingArea:trackingArea];
}
-(void)mouseMoved:(NSEvent *)theEvent
{
mouseLoc = [NSEvent mouseLocation];
NSLog(#"mouseMoved: %f %f", mouseLoc.x, mouseLoc.y);
}
in my CutoutView am i getting the AppController wrong because it is in a different window "helpWindow"? or does it have to do with my int values?

Answer 1

There are many things wrong with your code and it's obvious that you are fundamentally misunderstanding some basic concepts.
Firstly, you state that this code is in your drawRect: method;
AppDelegate *controller = [[[NSApp delegate] window] contentView];
xValue = controller.mouseLoc.x;
yValue = controller.mouseLoc.y;
NSRectFillUsingOperation(NSMakeRect(xValue,yValue, 600, 400), NSCompositeClear);
[self update];
There are several immediate flaws apparent. Firstly, why are you declaring controller to be of type AppController* when the method you are calling (-contentView) returns an NSView?
Your AppController is not a view (at least it should not be!), so you should be declaring the object as such:
NSView* mainView = [[[NSApp delegate] window] contentView];
If you are indeed using a view as a controller then this is completely wrong. See below for my note about MVC.
You don't specify where the mouseLoc property is coming from. We need to see where this is declared, because that will affect whether or not there are problems with it.
Your drawing code calls [self update], which simply tells the view to redraw itself. This will result in an infinite loop because every time the view draws it is forced to redraw. You should never call setNeedsDisplay: from inside drawRect:.
Even after making these changes, this code is very badly structured and the design is broken.
As it stands, your code violates the Model-View-Controller pattern. A views should not have knowledge of other views. You need to restructure things so that your views display properties of your controller without needing knowledge of other views. That means that you must store the mouse location in your controller (or a model object) and use some method for the view to access that information, preferably a datasource protocol or similar. In my answer to this other question I give an example of how to do that.
You need to read the Cocoa Drawing Guide. You also need to learn more core Cocoa concepts as it is clear you are misunderstanding how Cocoa is supposed to work.