DropDownButton.m

/*
     File: DropDownButton.m 
 Abstract: NSButton subclass for supporting drop down menus. 
  Version: 1.2 
  
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 */ 
 
#import "DropDownButton.h"
 
@implementation DropDownButton
 
// -------------------------------------------------------------------------------
//  awakeFromNib:
// -------------------------------------------------------------------------------
- (void)awakeFromNib
{
    if ([self menu] != nil)
    {
        [self setUsesMenu:YES];
    }
}
 
// -------------------------------------------------------------------------------
//  dealloc:
// -------------------------------------------------------------------------------
- (void)dealloc
{
    [popUpCell release];
    [super dealloc];
}
 
// -------------------------------------------------------------------------------
//  setUsesMenu:flag
// -------------------------------------------------------------------------------
- (void)setUsesMenu:(BOOL)flag
{
    if (popUpCell == nil && flag)
    {
        popUpCell = [[NSPopUpButtonCell alloc] initTextCell:@""];
        [popUpCell setPullsDown:YES];
        [popUpCell setPreferredEdge:NSMaxYEdge];
    }
    else if (popUpCell != nil && !flag)
    {
        [popUpCell release];
        popUpCell = nil;
    }
}
 
// -------------------------------------------------------------------------------
//  usesMenu:
// -------------------------------------------------------------------------------
- (BOOL)usesMenu
{
    return (popUpCell != nil);
}
 
// -------------------------------------------------------------------------------
//  runPopUp:theEvent
// -------------------------------------------------------------------------------
- (void)runPopUp:(NSEvent *)theEvent
{
    // create the menu the popup will use
    NSMenu *popUpMenu = [[self menu] copy];
    [popUpMenu insertItemWithTitle:@"" action:NULL keyEquivalent:@"" atIndex:0];    // blank item at top
    [popUpCell setMenu:popUpMenu];
    
    // and show it
    [popUpCell performClickWithFrame:[self bounds] inView:self];
    
    [popUpMenu release];
    
    [self setNeedsDisplay: YES];
}
 
// -------------------------------------------------------------------------------
//  mouseDown:theEvent
// -------------------------------------------------------------------------------
- (void)mouseDown:(NSEvent*)theEvent
{
    if ([self usesMenu])
    {
        [self runPopUp:theEvent];
    }
    else
    {
        [super mouseDown:theEvent];
    }
}
 
@end