OS X 中的 TrackPopupMenu 等效项

Question

Windows has this nifty little API to create & display a popup menu on the desktop even from a background hidden application. Is there something similar in Mac?

I've a background process started by launcher (in user context) and would like to display a popup menu, with a few options for user to select, when it receives a command from the network. Possible?

The background process itself is a plain C++ command line program.

Answer 1

You can try to use popUpMenuPositioningItem:atLocation:inView: .

The documentation says:

If view is nil, the location is interpreted in the screen coordinate system. This allows you to pop up a menu disconnected from any window.

So, for example:

[myMenu popUpMenuPositioningItem:nil atLocation:[NSEvent mouseLocation] inView:nil];

Answer 2

For the record here's the code that I wrote that displays the menu on the desktop (I'm not a Mac programmer, so there could be errors or my implementation need not be the most optimal):

// Dummy View class used to receive Menu Events
@interface DummyView : NSView
{
    NSMenuItem* nsMenuItem;
}
- (void) OnMenuSelection:(id)sender;
- (NSMenuItem*)MenuItem;
@end

@implementation DummyView
- (NSMenuItem*)MenuItem
{
    return nsMenuItem;
}

- (void)OnMenuSelection:(id)sender
{
    nsMenuItem = sender;
}
@end

static void HandleRButtonDown()
{
@autoreleasepool {
    NSRect    graphicsRect;  // contains an origin, width, height
    graphicsRect = NSMakeRect(200, 200, 50, 100);


    [NSApplication sharedApplication];
        // Style flags:
    NSUInteger windowStyle = NSWindowStyleMaskTitled | NSWindowStyleMaskClosable | NSWindowStyleMaskResizable;

    // Window bounds (x, y, width, height).
    NSRect windowRect = NSMakeRect(0, 0, 0, 0);
    NSWindow * window = [[NSWindow alloc] initWithContentRect:windowRect
                                          styleMask:windowStyle
                                          backing:NSBackingStoreBuffered
                                          defer:NO];

    // Window controller:
    NSWindowController * windowController = [[NSWindowController alloc] initWithWindow:window];

    DummyView *nsView = [[DummyView alloc] initWithFrame:graphicsRect];
    [window setContentView:nsView];

    // Create Menu and Dummy View
    NSMenu *nsMenu = [[NSMenu alloc] initWithTitle:@"Contextual Menu"];
    [nsMenu setAutoenablesItems:NO];

    NSMenuItem* item1 = [nsMenu addItemWithTitle:@"Menu Item #1" action:@selector(OnMenuSelection:) keyEquivalent:@""];

    [item1 setTag:100];
    [item1 setTarget:nsView];
    [item1 setEnabled:YES];

    NSMenuItem *item2 = [nsMenu addItemWithTitle:@"Menu Item #2" action:@selector(OnMenuSelection:) keyEquivalent:@""];

    [item2 setTag:200];
    [item2 setTarget:nsView];
    [item2 setEnabled:YES];

    [nsMenu popUpMenuPositioningItem:item1 atLocation:[NSEvent mouseLocation] inView:nsView];

    printf("Selected item: %d\n", (int)[[nsView MenuItem] tag]);
}

}

Call HandleRButtonDown() from main and you should get a popup menu on the screen.

Hope this helps someone.