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

calibre 3.8.0 - 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
Carbon Copy Cloner 5.0.2 - Easy-to-use b...
Carbon Copy Cloner backups are better than ordinary backups. Suppose the unthinkable happens while you're under deadline to finish a project: your Mac is unresponsive and all you hear is an ominous,... Read more
Evernote 6.12.3 - Create searchable note...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
Default Folder X 5.1.6 - Enhances Open a...
Default Folder X attaches a toolbar to the right side of the Open and Save dialogs in any OS X-native application. The toolbar gives you fast access to various folders and commands. You just click on... Read more
Geekbench 4.1.2 - Measure processor and...
Geekbench provides a comprehensive set of benchmarks engineered to quickly and accurately measure processor and memory performance. Designed to make benchmarks easy to run and easy to understand,... Read more
GraphicConverter 10.5 - $39.95
GraphicConverter is an all-purpose image-editing program that can import 200 different graphic-based formats, edit the image, and export it to any of 80 available file formats. The high-end editing... Read more
Dropbox 35.4.20 - Cloud backup and synch...
Dropbox is an application that creates a special Finder folder that automatically syncs online and between your computers. It allows you to both backup files and keep them up-to-date between systems... Read more
XMind 8 Update 4 - Popular mind mapping...
XMind is the most popular mind mapping tool. Millions of people use XMind to clarify thinking, manage complex information, run brainstorming and get work organized. It couldn't be easier to get... Read more
Safari Technology Preview 11.1 - The new...
Safari Technology Preview contains the most recent additions and improvements to WebKit and the latest advances in Safari web technologies. And once installed, you will receive notifications of... Read more
Chromium 61.0.3163.91 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 61.0.3163.91: Release notes were unavailable... Read more

Stormbound: Kingdom Wars guide - how to...
Stormbound: Kingdom Wars is an excellent new RTS turned card battler out now on iOS and Android. Lovers of strategy will get a lot of enjoyment out of Stormbound's chess-like mechanics, and it's cardbased units are perfect for anyone who loves the... | Read more »
The best AR apps and games on iOS right...
iOS 11 has officially launched, and with it comes Apple's ARKit, a helpful framework that makes it easier than ever for developers to create mobile AR experiences. To celebrate the occassion, we're featuring some of the best AR apps and games on... | Read more »
Phoenix Wright: Ace Attorney - Spirit of...
Phoenix Wright: Ace Attorney - Spirit of Justice 1.00.00 Device: iOS Universal Category: Games Price: $.99, Version: 1.00.00 (iTunes) Description: ************************************************※IMPORTANT※・Please read the “When... | Read more »
Kpressor (Utilities)
Kpressor 1.0.0 Device: iOS Universal Category: Utilities Price: $4.99, Version: 1.0.0 (iTunes) Description: The ultimate ZIP compression application for iPhone and iPad. - Full integration of iOS 11 with support for multitasking.-... | Read more »
Find out how you can save £35 and win a...
Nothing raises excitement like a good competition, and we’re thrilled to announce our latest contest. We’ll be sending one lucky reader and a friend to the Summoners War World Arena Championship at Le Comedia in Paris on October 7th. It’s the... | Read more »
Another Lost Phone: Laura's Story...
Another Lost Phone: Laura's Story 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Another Lost Phone is a game about exploring the social life of a young woman whose phone you have just... | Read more »
The Witness (Games)
The Witness 1.0 Device: iOS Universal Category: Games Price: $9.99, Version: 1.0 (iTunes) Description: You wake up, alone, on a strange island full of puzzles that will challenge and surprise you. You don't remember who you are, and... | Read more »
Egg, Inc. guide - how to build your gold...
Egg, Inc.'s been around for some time now, but don't you believe for one second that this quirky clicker game has gone out of style. The game keeps popping up on Reddit and other community forums thanks to the outlandish gameplay (plus, the... | Read more »
The best deals on the App Store this wee...
Good news, everyone! Your favorite day of the week has arrived at last -- it's discount roundup day! This fine Wednesday evening we're gathering up the hottest deals on the App Store. We've got action platformers, we've got puzzle games, we've got... | Read more »
Morphite (Games)
Morphite 1.08 Device: iOS Universal Category: Games Price: $7.99, Version: 1.08 (iTunes) Description: | Read more »

Price Scanner via MacPrices.net

Snag a 13-inch 2.3GHz MacBook Pro for $100 of...
B&H Photo has 2017 13″ 2.3GHz MacBook Pros in stock today and on sale for $100 off MSRP, each including free shipping plus NY & NJ sales tax only: – 13-inch 2.3GHz/128GB Space Gray MacBook... Read more
Verizon offers new iPhone 8 for $100-$300 off...
Verizon is offering the new iPhone 8 for up to $300 off MSRP with an eligible trade-in: • $300 off: iPhone 6S/6S Plus/7/7 Plus, Google Pixel XL, LG G6, Moto Z2 Force, Samsung Galaxy S7/S7 edge/S8/S8... Read more
Apple Refurbished 2017 13-inch MacBook Pros a...
Apple has Certified Refurbished 2017 13″ Touch Bar MacBook Pros in stock today and available for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is... Read more
OWC USB-C Travel Dock with 5 Ports Connectivi...
OWC have announced the new OWC USB-C Travel Dock, the latest addition to their line of connectivity solutions. The USB-C Travel Dock lets you connect its integrated USB-C cable to a Mac or PC laptop... Read more
Pelican Products, Inc. Unveils Cases For All...
Pelican Products, Inc. has announced the launch of its full line of cases including Voyager, Adventurer, Protector, Ambassador, Interceptor (for the Apple iPhone 8 and 8 Plus backwards compatible... Read more
$100 off new 2017 13-inch MacBook Airs
B&H Photo has 2017 13″ MacBook Airs on sale today for $100 off MSRP including free shipping. B&H charges NY & NJ sales tax only: – 13″ 1.8GHz/128GB MacBook Air (MQD32LL/A): $899, $100 off... Read more
Apple restocks Certified Refurbished 13-inch...
Apple has Certified Refurbished 2015 13″ MacBook Airs available starting at $719 and 2016 models available starting at $809. An Apple one-year warranty is included with each MacBook, and shipping is... Read more
Is iPhone X Really The Future Of The Smartpho...
Should iPhone X even be called a telephone? It does of course support telephony and texting, but its main feature set is oriented to other things. It is also debatable whether it makes any rational... Read more
OtterBox Announces Full Case Lineup for iPhon...
Apple revolutionized the smartphone industry 10 years ago with the original iPhone, and OtterBox has set the standard of protection from the very beginning by protecting every generation of iPhone.... Read more
LifeProof Introduces What’s NEXT Cases for iP...
LifeProof built its reputation on sleek, ultra-protective iPhone cases. From 360-degree coverage to the first screenless waterproof case, the protection pioneer has always pushed the limits.... Read more

Jobs Board

Development Operations and Site Reliability E...
Development Operations and Site Reliability Engineer, Apple Payment Gateway Job Number: 57572631 Santa Clara Valley, California, United States Posted: Jul. 27, 2017 Read more
Full time *Apple* Hardware Tech needed - ma...
…high level of attention to detail Ethics, integrity and trust Be a geek & Previous Apple experience a must. Previous Apple Retail or other Apple Specialist Read more
Development Operations and Site Reliability E...
Development Operations and Site Reliability Engineer, Apple Payment Gateway Job Number: 57572631 Santa Clara Valley, California, United States Posted: Jul. 27, 2017 Read more
*Apple* Store - Technical Specialist - Apple...
…customers purchase our products, you're the one who helps them get more out of their new Apple technology. Your day in the Apple Store is filled with a range of Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.