Question

Hullo all – I’ve got a NSView subclass that I move programmatically on mouseDown. Which works, but has an odd side effect:

1. I click the subview. The subview moves away [GOOD]
2. I wait a while. I do not move my mouse. Since the subview has moved it’s no longer under my cursor.
3. I click my mouse again.
   • I expect the underlying window to get the mouseDown event (since the subview is no longer under my cursor), however my subview somehow gets this event [ODD]
   • The mouseDown event clearly shows that the click was outside the bounds of my subclass [ODD]
   • The mouseDown event also clearly shows that the click count has incremented, even though I’ve waited several seconds between mouse clicks [ODD]

… there’s gotta be an explanation for what I’m seeing. Here’s my code – simply create a new Cocoa Application project called “OddMouse”, and copy the following into the OddMouseAppDelegate.h file:

#import <Cocoa/Cocoa.h>
@interface OddMouseAppDelegate : NSObject <NSApplicationDelegate> {
  NSWindow *window;
}
@property (assign) IBOutlet NSWindow *window;
@end

@interface OddView : NSView {
}
@end

… and the following into the OddMouseAppDelegate.m file:

#import "OddMouseAppDelegate.h"
@implementation OddMouseAppDelegate
@synthesize window;
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {

[[window contentView] addSubview:[[OddView alloc] init]];
}
@end

@implementation OddView
- (id)init {
  self = [super initWithFrame:NSMakeRect(100, 100, 100, 100)];
  return self;
}
- (void)drawRect:(NSRect)dirtyRect {
  NSBezierPath *bz = [NSBezierPath bezierPathWithRoundedRect:[self bounds] 
                                                 xRadius:9 yRadius:9];
  [[NSColor blueColor] set];
[bz fill];
}
- (void)mouseDown:(NSEvent *)event {
  NSPoint locationInMyself = [self convertPoint: [event locationInWindow] 
                                       fromView: nil];
  NSLog(@"MOUSE DOWN COORDS: x=%f y=%f, count=%i", 
          locationInMyself.x, locationInMyself.y, [event clickCount]);
  float newX = [self frame].origin.x+100;
  float newY = [self frame].origin.y+100;
  [self setFrame:NSMakeRect(newX, newY, 100, 100)];
}
@end

… then build, then run, then witness ! FWIW, here’s what I see in the console:

10-01-15 11:38:24 PM OddMouse[4583] MOUSE DOWN COORDS: x=48.000000 y=56.000000, count=1
10-01-15 11:38:37 PM OddMouse[4583] MOUSE DOWN COORDS: x=-52.000000 y=-44.000000, count=2
10-01-15 11:38:44 PM OddMouse[4583] MOUSE DOWN COORDS: x=-152.000000 y=-144.000000, count=3
10-01-15 11:38:52 PM OddMouse[4583] MOUSE DOWN COORDS: x=-252.000000 y=-244.000000, count=4
10-01-15 11:39:03 PM OddMouse[4583] MOUSE DOWN COORDS: x=-352.000000 y=-344.000000, count=5

Answer 1

Freaking heck – turns out this was something misbehaving with the double-click speed – changing the prefs did SFA, but a reboot resolved …