Events not working in NSView in transparent NSWindow

Question

I've been using this code...

static const CGFloat kSwipeGestureLeft  =  1.0;
static const CGFloat kSwipeGestureRight = -1.0;
static const CGFloat kSwipeGestureUp    =  1.0;
static const CGFloat kSwipeGestureDown  = -1.0;

- (void)swipeWithEvent:(NSEvent *)event {

    if ([event deltaX] == kSwipeGestureLeft) {

        NSLog(@"LEFT SWIPE!");
    } 
    else if ([event deltaX] == kSwipeGestureRight) {

        NSLog(@"RIGHT SWIPE!");
    } 
    else if ([event deltaY] == kSwipeGestureUp) {

        NSLog(@"UP SWIPE!");
    } 
    else if ([event deltaY] == kSwipeGestureDown) {

        NSLog(@"DOWN SWIPE!");
    } 
    else {
        [super swipeWithEvent:event];
    }
}

in an NSView which was sent to back in Interface Builder , inside a window that I made partially transparent through code . However , it **only seems to work when inside an opaque window, not a transparent window.

Why? How can I fix this? If I can't do this is there anyway I can, like taking a snap of the entire screen then setting that (slightly darkened) as the background of the window?

I tried subclassing NSWindow** and putting this in, but it still didn't work.

The code I'm using isn't actually making the window transparent, just change it's background colour to transparent:

    //Set up the window

[window setLevel:kCGNormalWindowLevel];
[window setOpaque:NO];
[window setStyleMask:0];
[window setBackgroundColor:[NSColor colorWithCalibratedWhite:0.0 alpha:0.3]];
[window setAlphaValue:0];


    //Resize the window to fill the screen

[window
 setFrame:[window frameRectForContentRect:[[window screen] frame]]
 display:YES
 animate:YES];

    //Fade the window in

[window makeKeyAndOrderFront:self];
[[window animator] setAlphaValue:1.0]; 

Answer 1

Make sure your window is in fact the key window. That is, don't assume makeKeyAndOrderFront succeeded in making your window the key window. See the -[NSWindow canBecomeKeyWindow] method for details (you may have to override it for your custom window to return YES). I've run into this problem in the past for windows that don't have a title bar, not sure if you are encountering the same (or a similar) problem.

Answer 2

Do not set alpha to 0, set it to some low value like 0.01 instead. Events are ignored for completely transparent views.

Answer 3

Are you using UIGestureRecognizer? It seems to be the simplest method to use as of now :)