TweetFollow Us on Twitter

Drawers and Disclosure

Volume Number: 16 (2000)
Issue Number: 9
Column Tag: OS X

More or Less: Drawers and Disclosure Views for Cocoa

by Andrew C. Stone

In designing an intuitive interface for users, the great French architect Le Corbusier's adage still rings true: less is more. The less user interface you have visible, the more likely the user will be able to understand your program's feature set. But applications without depth and functionality are boring and leave the user feeling "if only the application could do X or Y". There are several ways to hide complexity and still have the features available for expert users. Along with the ubiquitous tabview, two major techniques are the drawer and the disclosure view.

Mac OS X introduces the concept of the drawer - a Daliesque subwindow which expands from under the parent window in a smooth opening animation, remaining attached to the window until no longer needed when it animates smoothly closed. An example of a good use of drawers is Mail.app's "Mailboxes". Drawers have certain limitations however - for instance, you cannot pull out a bottom-mounted drawer with a depth greater than the height of the window since this would violate the physical reality being emulated. Moreover, there were no drawers in Mac OS 9 or Mac OS X Server, so another technique, disclosure views must be used. The disclosure view, the little blue triangle that "shows more" by expanding the window to reveal more user interface, is one excellent technique. You can see this button in the standard Save Panel - which expands to show the file browser or collapses to present a very simple save interface. In this article, you will learn how to implement drawers and two types of disclosure views: one that expands the window to the right, and one that expands the window below.

<<ClosedDrawer.tiff This window presents a simplified interface for the user, with the drawer closed.>> <<ExpandedDrawer.tiff When the drawer is pulled out, additional options become available>>

Drawing Upon Drawers

The drawer is an instance of the NSDrawer object, a simple non-visual controller type object that acts as a coordinator. NSDrawer has a simple application programmer's interface (API) which allows you to specify the parent window, the content or container view which gets inserted into the drawer, the preferred edge from which the drawer expands, methods to programmatically open and close it, and a method to determine whether the drawer is open, closed, opening or closing. Moreover, there are optional delegate methods sent to the drawer's delegate and objects which register for drawer notifications before and after closing and opening and before resizing of the drawer. The full API is presented in /System/Library/Frameworks/AppKit.framework/Headers/NSDrawer.h.

InterfaceBuilder - the application to build graphical user interfaces via drag and drop of components - now has two ways to create drawers without writing a single line of code. From IB's Windows Palette, you can either drag out an NSDrawer object, and hook up the parent and content view yourself, or drag out a window with the drawer window already attached. The first method is excellent if you are modifying an existing interface, and the latter when you are designing from scratch.<<DrawersPalette.tiff: You can create completely functional drawers just by drag and drop from InterfaceBuilder>>.

I recommend that you create a new IB document and add a drawer/window combination to see how easy it is, and to learn a trick of the trade: the invisible box grouping technique. All visible objects in Cocoa are NSView subclasses, and they form a hierarchy that is rooted in the window's content view, the root enclosing view which contains everything in the window except the window controls and shadows. Because you cannot use IB to connect to this content view directly, you'll need to explicitly create a view which contains all of the user interface items that belong in the drawer. Select all the items and choose Layout -> Group in Box. Bring up the Inspector, and choose the Attributes pop-up menu item. Click on "No Title" and the no border icon - now you have an invisible containing view. If you click on the smaller drawer window created when you added the drawer/window combination, you see just such an invisible NSBox. Be sure to add your drawer components inside of this box by double-clicking it before dragging on new user interface elements.

Interface Builder allows you to specify the preferred edge from which the drawer should expand with the NSDrawer Inspector's Attributes sub-panel. For full control of the drawer's appearance and position, you may have to actually write a few lines of code, because some functionality is not yet fully exposed in Interface Builder. As of DP4, you need to set the drawer's delegate and size constraints programmatically. You can control the maximum and minimum size of the drawer, as well as the leading and trailing offsets. On a side mounted window, the leading offset is the height difference between the top of the drawer, and the top of the parent window's content view. Likewise, the trailing offset is the difference between the bottom of the drawer and the bottom of the parent window. All of the size constraints are mostly hints because there may be conflicting parameters.

Now that the drawer is configured, all that is required is to provide the user a means of opening and closing it. You need to have a button on the main window or a menu item which will expand the drawer when closed, and close it when open, simultaneously adjusting the text and/or icon on the button to synchronize with the drawer's state. Because the drawer can be in the act of opening or closing, you might want your button to do something only if it is actually closed or open, and just ignore clicks if the drawer is still animating between the open and closed state.

// given an instance variable "drawer" for the NSDrawer  and the sender is the button:

- (void)openOrCloseDrawer:(id)sender {
     if ([drawer state] == NSDrawerClosedState) {
	// tell the drawer to begin the opening animation:
		[drawer open:sender];
	// remember, not everyone speaks English! Code internationally:
		[sender setTitle:NSLocalizedStringFromTable(@"Less Options",@"CoolApp",
		@"title of drawer open and close button when the drawer is open")];
		[sender setImage:[NSImage imageNamed:@"OpenDrawer"];
    } else if ([drawer state] == NSDrawerOpenState) {
		[drawer close:sender];
		[sender setTitle:NSLocalizedStringFromTable(@"More Options",@"CoolApp",
		@"title of drawer open and close button when the drawer is closed")];
		[sender setImage:[NSImage imageNamed:@"CloseDrawer"];
    }
    // if it's in an opening or closing state, we'll ignore the click
}

As for initializing the drawer, you might want to do some of the following in the method that gets called by any object in an IB nib file after all the outlets are initialized, awakeFromNib:

- (void)awakeFromNib
{
  [drawer setLeadingOffset:10.];
  [drawer setTrailingOffset:40.];
  [drawer setContentSize:[rightBox frame].size];
  [drawer close:self];
  [drawer setDelegate:self];
  ...

Secret Disclosures

When a drawer is inappropriate because of size, backwards compatibility, or design issues, the classic disclosure view comes in handy. When disclosing additional user interface elements, the programmer is responsible for resizing the window and making sure everything fits correctly. All of this can be done easily using the technique of the invisible box as the top level container of the items in the standard window, and another invisible box as the top level container of the additional items which are presented when the window is expanded. The two most typical configurations are windows which expand to the right, and windows which expand below. We'll look at the expand to the right case first since it is simpler, because it does not involve moving the origin of the window. The underlying window display mechanism in the AppKit will automatically handle the cases where expanding the window would place part of the window off screen.

To understand the automatic resizing behavior of views (autosizing), it is helpful to look at InterfaceBuilder's Autosizing interface element of the Size Inspector. Each of the 6 possible stretch behaviors are represented graphically with rods and springs. A rod means "leave this dimension static" and a spring means "let this dimension fluctuate with the changing size of the window". <<StretchTheObject.tiff In this case, the object stretches and shrinks to fit into its containing view>> <<LeaveObjectRelativeToLowerRight.tiff Here, the object will remain in relative position to the lower right of its containing view.>>

Of course, you can set these all programmatically using NSView's -setAutosizing:(int)mask method by or'ing together the vertical and horizontal stretching behaviors: NSViewNotSizable, NSViewMinXMargin, NSViewWidthSizable, NSViewMaxXMargin, NSViewMinYMargin, NSViewHeightSizable andNSViewMaxYMargin.

Usually, you want the main items in the window to be resized when the user resizes the window - for example, a scrollable text view. In order that the disclosure view maintains the correct size whether it's showing or not, we'll approach the problem by always leaving the extra box in the window. When the extra box is hidden, the window will clip the box, when it's revealed, the window will be resized to contain it. This solves two problems: one, the extra items will be correctly freed when the window is released regardless of whether the extra items are showing, and two, the extra items will be correctly resized when the window is resized, even if they are not currently exposed.

In the following example, we have subclassed NSWindowController and placed the logic of resizing in the subclass controller. In InterfaceBuilder, the autosizing of the elements has been established, and we honor these settings by noting them at the beginning, and resetting them after resizing the window.

The button is set to be a two state "toggle" button, and we assign the images inside InterfaceBuilder in the Icon and Alternate Icon fields. By changing the state of the button, the icon automatically changes. This works with text as well by assigning an alternate title to the button, however, a down facing triangle image when the window is collapsed but can be expanded downward and an upward facing triangle image when it is expanded but can be collapsed works well.

// given: the controls to be displayed when the window expands are all inside
// an invisible NSBox named rightBox. The main controls are all inside a box named
// leftBox. The two boxes are laid out side by side in the window to fill the window's 
// contentView. Inside the left box, near the upper right is the two-state button whose
// target is the window controller with the action moreOrLessToTheRightAction:.

- (void)moreOrLessToTheRightAction:(id)sender
{
   NSWindow *win = [self window];
   NSRect winFrame = [win frame];
   NSRect rightFrame = [rightBox frame];

// get the original settings for reestablishing later:
   int leftMask = [leftBox autoresizingMask];
   int rightMask = [rightBox autoresizingMask];
   
// toggle the state
   int stateToSet = 1 - [sender tag];

// set the boxes to not automatically resize when the window resizes:
   [leftBox setAutoresizingMask:NSViewNotSizable];
   [rightBox setAutoresizingMask:NSViewNotSizable];

   // if the button's state is 1, then stateToSet == 0, let's collapse:
   if (stateToSet == 0) {
	    // reduce the desired size by the width of the right box:
        winFrame.size.width -= NSWidth(rightFrame);
   } else {
	   // increase the desired width by the width of the right box:
       winFrame.size.width += NSWidth(rightFrame);
    }

   // change the state of the button
   [sender setState:stateToSet];
   [sender setTag:stateToSet];

   // resize the window and display:
   [win setFrame:winFrame display:YES];

   // reset the boxes to their original autosize masks:
   [leftBox setAutoresizingMask:leftMask];
   [rightBox setAutoresizingMask:rightMask];
}

Adding a disclosure view which expands the window below is slightly more tricky because we'll have to move the origin of the window as we increase or decrease the height of the window so that the window keeps the title bar in the same location. Moreover, since origins begin at the bottom and move to positive Y upwards, we'll have to move the origins of the boxes as well.

- (IBAction)moreOrLessDownAction:(id)sender {
   NSWindow *win = [self window];
   NSRect winFrame = [win frame];

// we'll need to know the size of both boxes in this case:
   NSRect topFrame = [topBox frame];
   NSRect bottomFrame = [bottomBox frame];

// get the original settings for reestablishing later:
   int topMask = [topBox autoresizingMask];
   int bottomMask = [bottomBox autoresizingMask];
   
// toggle the state
   int stateToSet = 1 - [sender tag];

// set the boxes to not automatically resize when the window resizes:
   [topBox setAutoresizingMask:NSViewNotSizable];
   [bottomBox setAutoresizingMask:NSViewNotSizable];

   // if the button's state is 1, then stateToSet == 0, collapse it:
   if (stateToSet == 0) {
       // adjust the desired height and origin of the window:
        winFrame.size.height -= NSHeight(bottomFrame);
        winFrame.origin.y += NSHeight(bottomFrame);
	    // adjust the origin of the bottom box well below the window:
        bottomFrame.origin.y = -NSHeight(bottomFrame);
		// begin the top box at the bottom of the window
        topFrame.origin.y = 0.0;
   } else {
	   // stack the boxes one on top of the other:
       bottomFrame.origin.y = 0.0;
       topFrame.origin.y = NSHeight(bottomFrame);

       // adjust the desired height and origin of the window:
       winFrame.size.height += NSHeight(bottomFrame);
       winFrame.origin.y -= NSHeight(bottomFrame);
   }

   // adjust locations of the boxes:
   [topBox setFrame:topFrame];
   [bottomBox setFrame:bottomFrame];

   // change the state of the button to reflect new arrangement:
   [sender setState:stateToSet];
   [sender setTag:stateToSet];

  // resize the window and display:
   [win setFrame:winFrame display:YES];

   // reset the boxes to their original autosize masks:
   [topBox setAutoresizingMask:topMask];
   [bottomBox setAutoresizingMask:bottomMask];
}

Conclusion

With drawers and disclosure views, you have the tools and techniques to present simple and elegant interfaces, with more features available at the click of a button. InterfaceBuilder can provide almost all of the support necessary to fully implement drawers, and with just a few lines of code, your applications can take advantage of the powerful new features of Cocoa.


Andrew Stone <andrew@stone.com> is the chief executive haquer at Stone Design Corp <http://www.stone.com/> and divides his time between raising children, llamas & cane and writing applications for Mac OS X and playing with Darwin.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

OmniGraffle Pro 7.19.3 - Create diagrams...
OmniGraffle Pro helps you draw beautiful diagrams, family trees, flow charts, org charts, layouts, and (mathematically speaking) any other directed or non-directed graphs. We've had people use... Read more
OmniGraffle 7.19.3 - Create diagrams, fl...
OmniGraffle helps you draw beautiful diagrams, family trees, flow charts, org charts, layouts, and (mathematically speaking) any other directed or non-directed graphs. We've had people use Graffle to... Read more
Hopper Disassembler 5.3.3- - Binary disa...
Hopper Disassembler is a binary disassembler, decompiler, and debugger for 32- and 64-bit executables. It will let you disassemble any binary you want, and provide you all the information about its... Read more
calibre 5.35.0 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
Sound Studio 4.10.0 - Robust audio recor...
Sound Studio lets you easily record and professionally edit audio on your Mac. Easily rip vinyls and digitize cassette tapes, or record lectures and voice memos. Prepare for live shows with live... Read more
Sparkle Pro 4.0 - Visual website creator...
Sparkle Pro will change your mind if you thought building websites wasn't for you. Sparkle is the intuitive site builder that lets you create sites for your online portfolio, team or band pages, or... Read more
Dropbox 140.4.1951 - Cloud backup and sy...
Dropbox for Mac is a file hosting service that provides cloud storage, file synchronization, personal cloud, and client software. It is a modern workspace that allows you to get to all of your files... Read more
FotoMagico 6.0.5 - Powerful slideshow cr...
FotoMagico lets you create professional slideshows from your photos and music with just a few, simple mouse clicks. It sports a very clean and intuitive yet powerful user interface. High image... Read more
Remotix 6.4.2 - Access all your computer...
Remotix is a fast and powerful application to easily access multiple Macs (and PCs) from your own Mac. Features: Complete Apple Screen Sharing support - including Mac OS X login, clipboard... Read more
Microsoft Office 365, 2019 16.57 - Popul...
Microsoft Office 365. The essentials to get it all done. Unmistakably Office, designed for Mac Get started quickly with new, modern versions of Word, Excel, PowerPoint, Outlook and OneNote-... Read more

Latest Forum Discussions

See All

A House Full of Covid – The TouchArcade...
It’s been a rough week as both of our young children tested positive for Covid, and since recording this early on Friday my wife has tested positive now too. Thankfully the kids seemed to recover fairly quickly and are mostly back to normal, and I... | Read more »
TouchArcade Game of the Week: ‘Krispee S...
Krispee Street is a new hidden object game from Frosty Pop that is based on their popular and almost painfully sweet webcomic Krispee. This is one of the latest titles to be added to the Netflix Games catalog, which means you’ll need to log into... | Read more »
SwitchArcade Round-Up: ‘Escape Lala’, ‘B...
Hello gentle readers, and welcome to the SwitchArcade Round-Up for January 21st, 2022. In today’s article, we’ve got a lot of new releases. A lot. There were eight on the schedule when I went to bed last night. There were twenty-four when I woke up... | Read more »
Beta Testers Needed for Huge Version 2.0...
Ya’ll remember Dungeon Raid, right? The phenomenal matching RPG hybrid that launched on mobile more than a decade ago, but was more or less abandoned by its developer only to die a slow death on the App Store before the 32-bit Appocalypse finally... | Read more »
‘Ark Legends’ Gives Players a Chance to...
It’s Airpods and Amazon gift cards galore as Melting Games opens pre-registration for Ark Legends. The upcoming mobile RPG is giving away tons of in-game goodies such as gold, energy, iron core, hero summon chest and rare iron core to players who... | Read more »
‘Nickelodeon Extreme Tennis’ Out Now on...
Nickelodeon Extreme Tennis () from Old Skull Games and Nickelodeon is this week’s new Apple Arcade release. Nickelodeon Extreme Tennis features characters from old and new Nickelodeon shows including SpongeBob, TMNT, and many more. The tennis game... | Read more »
SwitchArcade Round-Up: ‘RPGolf Legends’,...
Hello gentle readers, and welcome to the SwitchArcade Round-Up for January 20th, 2022. In today’s article, we’ve got a massive amount of new releases to check out. We’ve got summaries of all of them, from heaven to hell. We also have the lists of... | Read more »
‘Zed Blade ACA NEOGEO’ Review – Well, It...
SNK’s NEOGEO platform played host to a great many classics, both famous and under-the-radar. The Metal Slug games. The King of Fighters series. Magician Lord. Shock Troopers. Sengoku 3. NEO Turf Masters. Fatal Fury. Samurai Shodown. Twinkle Star... | Read more »
‘Inua – A Story in Ice and Time’ is a Un...
One thing I know about ARTE from their output on mobile over the years is that they love collaborating with really interesting and unique studios to put out really interesting and unique gaming experiences. This is true yet again with the latest... | Read more »
Out Now: ‘Angry Birds Journey’, ‘RPG Dic...
Each and every day new mobile games are hitting the App Store, and so each week we put together a big old list of all the best new releases of the past seven days. Back in the day the App Store would showcase the same games for a week, and then... | Read more »

Price Scanner via MacPrices.net

Amazon lowers prices on select 13″ M1 MacBook...
Amazon has select Apple 13″ M1 MacBook Airs on sale for $150 off MSRP this weekend, starting at only $849. Their prices are the lowest available for new MacBook Airs today. Stock may come and go, so... Read more
Apple has 13″ M1 MacBook Airs back in stock s...
Apple has restocked a full line of 13″ M1 MacBook Airs, Certified Refurbished, starting at only $849 and up to $190 off original MSRP. These are the cheapest M1-powered MacBooks for sale today at... Read more
In stock and on sale! 16″ 10-Core M1 Pro MacB...
Amazon has new 16″ 10-Core/512GB M1 Pro MacBook Pros in stock today and on sale for $50 off MSRP including free shipping. Their prices are the lowest available for new M1 Pro 16″ MacBook Pro from any... Read more
Deal Alert!: 14″ M1 Pro with 10-Core CPU in s...
Amazon has the new 14″ M1 Pro MacBook Pro with a 10-Core CPU and 16-Core GPU in stock today and on sale for $2299.99 including free shipping. Their price is $200 off Apple’s standard MSRP, and it’s... Read more
Apple has 24-inch M1 iMacs (8-Core CPU/8-Core...
Apple has restocked a wide array of 24-inch M1 iMacs with 8-Core CPUs and 8-Core GPUs in their Certified Refurbished store. Models are available starting at only $1269 and range up to $260 off... Read more
Select 24″ M1 iMacs are on sale for $100 off...
Sales of Apple’s new 24″ M1 iMacs have been rare since its introduction, perhaps due to global supply issues. However, B&H is offering a $100 discount on select 24″ iMacs, and they’re in stock... Read more
M1 Mac minis are back in stock today at Apple...
Apple has M1-powered Mac minis available in their Certified Refurbished section starting at only $589 and up to $140 off MSRP. Each mini comes with Apple’s one-year warranty, and shipping is free: –... Read more
B&H has M1-powered Mac minis on sale for...
B&H Photo has Apple’s Mac minis with M1 Apple Silicon CPUs in stock today and on sale for $50-$100 off MSRP, starting at $649. Free 1-2 shipping is free to many US addresses. Their prices are... Read more
New Amazon sale: Apple’s 13″ M1 MacBook Airs...
Amazon has Apple 13″ M1 MacBook Airs on sale for $100 off MSRP, starting at only $899. Their prices are the lowest available for new MacBook Airs today. Stock may come and go, so check their site... Read more
Get an Apple Watch Series 7 for $50 off MSRP,...
Amazon has Apple Watch Series 7 models on sale for $50 off MSRP including free shipping. Their prices are the lowest available for Apple Watch Series 7 models today: – 41mm Apple Watch Series 7 GPS... Read more

Jobs Board

Registered Nurse (RN) Employee Health PSJH -...
…is calling for a Registered Nurse (RN) Employee Health PSJH to our location in Apple Valley, CA.** We are seeking a Registered Nurse (RN) Employee Health PSJH to be Read more
Systems Administrator - Pearson (United State...
…and troubleshoot Windows operating systems (workstation and server), laptop computers, Apple iPads, Chromebooks and printers** + **Administer and troubleshoot all Read more
IT Assistant Level 1- IT Desktop Support Anal...
…providing tier-1 or better IT help desk support in a large Windows and Apple environment * Experience using IT Service Desk Management Software * Knowledge of IT Read more
Human Resources Business Partner PSJH - Provi...
…**is calling a** **Human Resources Business Partner, PSJH** **to our location in Apple Valley, CA.** **Applicants that meet qualifications will receive a text with Read more
Manager Community Health Investment Programs...
…is calling a Manager Community Health Investment Programs PSJH to our location in Apple Valley, CA.** **Qualified candidates will be invited to do a self-paced video Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.