NSMenuItem 自定义视图上方的间隙

Question

我在NSMenuItem 上使用setView: 方法来设置自定义视图。在这个自定义视图中，有一个图像占据了整个视图。带有此自定义视图的NSMenuItem 是菜单中的第一个，但问题是它与菜单顶部不齐，您可以在此处看到一个很大的差距：

为什么会发生这种情况，我该如何阻止它？

---

编辑

我现在正在使用此代码，但我在InstallControlEventHandler 线上收到了EXC_BAD_ACCESS。

-(void)applicationDidFinishLaunching:(NSNotification *)aNotification {
    HIViewRef contentView;
    MenuRef menuRef = [statusMenu carbonMenuRef];

    HIMenuGetContentView(menuRef, kThemeMenuTypePullDown, &contentView);

    EventTypeSpec hsEventSpec[1] = {
        { kEventClassMenu, kEventMenuCreateFrameView }
    };

    InstallControlEventHandler(contentView,
                           NewEventHandlerUPP((EventHandlerProcPtr)hsMenuCreationEventHandler),
                           GetEventTypeCount(hsEventSpec),
                           hsEventSpec,
                           NULL,
                           NULL); // Get EXC_BAD_ACCESS here.
}

static OSStatus hsMenuContentEventHandler( EventHandlerCallRef caller, EventRef event, void* refcon )
{
    OSStatus  err;

    check( GetEventClass( event ) == kEventClassControl );
    check( GetEventKind( event ) == kEventControlGetFrameMetrics );

    err = CallNextEventHandler( caller, event );
    if ( err == noErr )
    {
        HIViewFrameMetrics  metrics;

        verify_noerr( GetEventParameter( event, kEventParamControlFrameMetrics, typeControlFrameMetrics, NULL,
                                        sizeof( metrics ), NULL, &metrics ) );

        metrics.top = 0;

        verify_noerr( SetEventParameter( event, kEventParamControlFrameMetrics, typeControlFrameMetrics,
                                        sizeof( metrics ), &metrics ) );
    }

    return err;
}

static OSStatus hsMenuCreationEventHandler( EventHandlerCallRef caller, EventRef event, void* refcon )
{
    OSStatus  err = eventNotHandledErr;

    if ( GetEventKind( event ) == kEventMenuCreateFrameView)
    {
        err = CallNextEventHandler( caller, event );
        if ( err == noErr )
        {
            static const EventTypeSpec  kContentEvents[] =
            {
                { kEventClassControl, kEventControlGetFrameMetrics }
            };

            HIViewRef          frame;
            HIViewRef          content;

            verify_noerr( GetEventParameter( event, kEventParamMenuFrameView, typeControlRef, NULL,
                                            sizeof( frame ), NULL, &frame ) );
            verify_noerr( HIViewFindByID( frame, kHIViewWindowContentID, &content ) );
            InstallControlEventHandler( content, hsMenuContentEventHandler, GetEventTypeCount( kContentEvents ),
                                       kContentEvents, 0, NULL );
        }
    }

    return err;
}

还要注意metrics.top = 0 行，这是应该消除顶部间隙的行。但是我不能让它工作那么远。有谁知道我为什么会在那里收到EXC_BAD_ACCESS。我已经创建并分配了statusMenu，所以它应该可以工作吗？

Answer 1

您的帖子被标记为“Objective-C”和“Cocoa”，尽管您的示例代码是 C 和 Carbon。我假设您更喜欢 Cocoa 解决方案？

在 Cocoa 中实际上非常简单。唯一的窍门是学习如何画线外。 :-)

@interface FullMenuItemView : NSView
@end

@implementation FullMenuItemView
- (void) drawRect:(NSRect)dirtyRect
{
    NSRect fullBounds = [self bounds];
    fullBounds.size.height += 4;
    [[NSBezierPath bezierPathWithRect:fullBounds] setClip];

    // Then do your drawing, for example...
    [[NSColor blueColor] set];
    NSRectFill( fullBounds );
}
@end

像这样使用它：

CGFloat menuItemHeight = 32;

NSRect viewRect = NSMakeRect(0, 0, /* width autoresizes */ 1, menuItemHeight);
NSView *menuItemView = [[[FullMenuItemView alloc] initWithFrame:viewRect] autorelease];
menuItemView.autoresizingMask = NSViewWidthSizable;

yourMenuItem.view = menuItemView;