TweetFollow Us on Twitter

Nov 97 - Getting Started

Volume Number: 13 (1997)
Issue Number: 11
Column Tag: Getting Started

VerySimpleText, Version 2

by Dave Mark , Copyright1997, All Rights Reserved

Three months ago, the August Getting Started column featured a program called VerySimpleText. We built this first version of VerySimpleText using ProjectBuilder and InterfaceBuilder. We started off by editing the nib file (the first version of VerySimpleText wrapped its entire user interface into a single nib file).

We added a Format submenu to the application's default menu, thus adding a series of powerful font, text, and page manipulation features to VerySimpleText. This was done by dragging a Format menu from the menu palette in the palette window.

We also added a scrollable text area (implemented by the NSScrollView class) to the default application window. We did this by dragging a scrollable text view from the DataViews portion of the palette window. We used the NSScrollView inspector to set the autosizing for this view so the scrollable text view grew and shrank along with its containing window. We used InterfaceBuilder's Test Interface feature to test out the window, making sure it looked and behaved as we wanted it to.

Next, we added an info panel (an about box) to VerySimpleText, along with a menu item to bring up the info panel. We edited an existing menu item (Info Panel...) to create our "About VerySimpleText..." item. We used the NSMenuItem inspector to enable the item (unchecking the disabled checkbox, actually). To create the panel itself, we used the Windows portion of the palette window and dragged out our new window, changing the name of the window instance in the nib window and the window's title in the inspector. We also used the palette window to drag some default text into the new info panel.

Once the about panel was built, we created an AboutPanelController class which brought up the about panel when the "About VerySimpleText..." item was selected. Working in the Classes tab within the nib window, we first subclassed NSObject, then created one outlet (abtWindow) and one action (show:). As a reminder, think of an outlet as a variable or object you want associated with your class. When InterfaceBuilder generates the source code for this class, outlets are declared in the header file as type id. An action is a method. In this case, the show: method will bring up the about panel.

Once we were done with our nib file, we told InterfaceBuilder to generate the source files for this project and to add them to the project.

Our next step was to link the "About VerySimpleText..." menu item to the AboutPanelController so when it was selected, the show: method would get called and the panel would appear. First, we instantiated our newly created AboutWindowController class. The instance appeared in the nib window's Instances tab. We then control-dragged from the "About VerySimpleText..." menu item (it's in the menu itself) to the AboutWindowController instance in the nib window. In the inspector window, we clicked the connect button to establish this link. Now, when the "About VerySimpleText..." item is selected, the AboutWindowController's show: method will be called.

Next, we control-dragged from the AboutWindowController instance to our AboutWindow instance. When the link appeared, we moved to the inspector window and clicked on the abtWindow outlet and clicked the Connect button to establish the link. This links the AboutWindowController's abtWindow variable to the AboutWindow. We added a line to the show: method to bring up the window:

- (void)show:(id)sender
{
	[abtWindow makeKeyAndOrderFront:self];
}

The Model, View, Controller Paradigm

Before we move on to this month's additions to VerySimpleText, I thought it might be useful to talk about the Model, View, Controller paradigm, described in Discovering OpenStep: A Developer Tutorial. The Model, View, Controller paradigm is also known as MVC. MVC originated with Smalltalk-80. It categorizes objects as either models, views, or controllers.

Models are objects that emulate some process or represent some knowledge-base. For example, an Employee object represents the knowledge or data associated with an employee. It is a model of an employee. A waterworks object might model the process of converting waste water to clean water and might include the data associated with that process. In general, a model object does not have a user interface. A model object may be distributable and persistent. A model class may be reusable and portable.

View objects are the user interface of your application. Anything displayed by your application is displayed in a view. For example, a window, editable, static, or scrolling text area, button, and scroll bar are all examples of view objects. View objects have no special knowledge of the data they display. In OpenStep, the Application Kit contains a complete set of view objects, all of them designed independent of any model objects. As is evidenced by the Application Kit, view objects are reusable.

Controller objects are the mediators between model objects and view objects. Typically, you'll have one controller object per window (or, possibly, a single controller for your entire application). Your controller object communicates between a model object and its representative view object. For example, an employeeController might use data from an employee object and use that data to create a visible representation of that employee within a view object. At the application level, a controller object would take care of tasks such as loading nib files and acting as a delegate for a window or application.

Delegates

Delegates allow you to provide methods that get called by a class without actually having to subclass the class. Classes which allow delegates feature a set of delegation methods. For example, the NSWindow class features a delegation method called windowWillClose. In this month's sample program, we're going to create a class called Document which will act as an NSWindow delegate. When the NSWindow object gets ready to close, it first calls the delegate's windowWillClose method (assuming the delegate provides such a method). When we define the Document class, we'll provide a windowWillClose method so you can see how this works. You might want to take a look at the NSApplication and NSWindow classes. Their delegation methods are listed at the end of their respective files.

Loading A Nib File

As you've already seen, every application comes with at least one nib file. The nib file is similar to a Macintosh resource file, though it has much more of an object orientation. In fact, one of the primary things stored in a nib file is a set of archived objects. The information in the nib file includes information about each object (like object size and location). It also reflects the position of each object in the overall object hierarchy as well as details about connections between objects in the hierarchy (connections such as the ones we created in the August version of VerySimpleText).

An important part of the object hierarchy is the File's Owner object. Figure 1 shows VerySimpleText's main nib file with the icon representing the File's Owner object in the upper left corner of the Instances tab. The File's Owner sits at the top of each nib file's archived object hierarchy and comes into play when you want to load a nib file other than the main nib file (which is loaded for you automatically).

Figure 1. VerySimpleText's main nib file, showing the File's Owner object.

This line of code:

[NSBundle loadNibNamed:@"NEXTSTEP_Document" owner:self]

loads a nib file named "NEXTSTEP_Document.nib" and sets the File's Owner of the loaded nib file to point to the specified File's Owner. For example, in this month's sample program, we'll define a Document class and we'll tell InterfaceBuilder that the Document class will act as the File's Owner in "NEXTSTEP_Document.nib". Before the nib file can be loaded, we instantiate a Document object. In the Document's init method, we'll call the method loadNibNamed, passing in the nib file name "NEXTSTEP_Document.nib", as well as the object reference self, which refers to the Document object. This second parameter is used as the newly opened nib file's owner.

And Now, Addint to Verysimpletext

Hopefully, the quick review above brought you back up to speed on the overall structure of the August version of VerySimpleText and gave you enough background to follow this month's changes. This month, we're going to add the ability to handle multiple documents to VerySimpleText. We'll tie this functionality to the Document menu's New item. You'll want to start off with a copy of the August version of VerySimpleText. Be sure to keep a copy of the original around just in case. I named my original folder VerySimpleText.01 and named the copy VerySimpleText.02. Once you've made your copy, open the ProjectBuilder project in the duplicate.

  • Find the file PB.project in the duplicate directory and double-click it to launch ProjectBuilder.
  • Next, we're going to create a new nib file.
  • Click the ProjectBuilder Interfaces item, then double-click the NEXTSTEP_VerySimpleText.01.nib file.
  • The selected nib file will be opened in InterfaceBuilder. Now to create the new file:
  • In InterfaceBuilder, select Document/New Module/New Empty.

A new, untitled nib window will appear (See Figure 2). If you click on the Instances tab, you'll see two instances. One is the File's Owner. If you click on the File's Owner icon, the inspector window (attributes popup) will list a set of classes and the NSObject class will be selected. We'll revisit this a bit later in the column.

Figure 2. The new, untitled nib file.

  • Click on the Classes tab in the new nib window.
  • Select NSObject.
  • Select Classes/Subclass.
  • Rename the new subclass from MyNSObject to Document.
  • Save the new nib file.

You'll name your new nib file as NEXTSTEP_Document.nib (you can leave off the .nib if you like). Be sure to save the new nib file in the same directory as the main nib file, NEXTSTEP_VerySimpleText.01.nib (Figure 3).

Figure 3. Saving the new nib file.

  • When asked, say yes to insert the file in the project.

You will now be in ProjectBuilder.

  • Go back to InterfaceBuilder.
  • Be sure the Document line in the nib file's Classes tab is hilited.
  • Click on the outlet icon (the left of the two icons).
  • Be sure that the Outlets line is highlighted.
  • Select Classes/Add Outlet.
  • Change the outlet name myOutlet to window.
  • Click on the outlet icon to get out of outlet mode.
  • Select Classes/Create Files.
  • When asked whether we want to create a Document.h and .m file, click Yes.
  • When asked to insert files in project, click Yes.
  • We'll be back in Project Builder.

Go back to InterfaceBuilder.

  • Back in the nib window, click on the Instances tab.
  • Click on File's Owner.

In the inspector window, the class NSObject will be selected.

  • Scroll up to Document and select it.

Document will now be highlighted when you click on File's Owner.

  • Bring the original nib file to the front.
  • In the Instances tab, select the MyWindow icon.
  • Select Edit/Cut.
  • When you are asked Do you really want to delete the window?", click Delete.
  • Bring the new nib file to the front.
  • Select Edit/Paste.

The MyWindow icon should appear in the new nib window and the window itself should reappear.

  • Hold down the control key and drag from File's Owner icon to MyWindow icon.
  • When you let go, go to the inspector window and click Connect.

You've just connect MyWindow to the File Owner's outlet (in this case, the Document classes' window variable).

  • In the NEXTSTEP_Document.nib window, control drag from MyWindow to File's Owner.
  • Select the word delegate in the left-hand column.
  • Click the Connect button.

You've just made Document MyWindow's delegate.

  • Select Document/Save.

We are now done with this nib window.

  • Bring the old nib file to the front.
  • Click on the nextstep menu to bring it to the front.
  • Select Tools/Palettes/Palettes.
  • Select the leftmost palette (Menus).
  • Drag a Document menu into the nextstep menu, just below Info

The new Document menu will appear, just to the right of the nextstep menu.

  • In the Document menu, click on New.
  • In the inspector window, select attributes from the popup menu.
  • Click the Disabled checkbox so it is unchecked.
  • In the Document menu, click on Close.
  • In the inspector window, click the Disabled checkbox so it is unchecked.
  • Click on the old nib window and select the Classes tab.
  • Click on NSObject.
  • Select Classes/Subclass.
  • Rename subclass to AppDelegate.
  • Click on action icon (on right).
  • Click on Actions line, select Classes/Add Action.
  • Rename new Action to new:.
  • Click off the Actions icon.
  • Click Classes/CreateFiles.
  • Create the files (answer yes to create files and add to project).

We are now back in ProjectBuilder.

  • Go back to InterfaceBuilder.
  • In the old nib file's classes tab, select AppDelegate line.
  • Select Classes/Instantiate.
  • In the instances tab, control-drag from File's Owner to AppDelegate.
  • In the inspector window, be sure delegate is selected, then click Connect.

We have just marked AppDelegate as the NSApplication delegate. We won't implement any of the NSApplication delegate methods in our AppDelegate code, but we could. Take a look at NSApplication and take a few of the delegation methods for a spin.

  • Go to the nextstep menu and control-drag from New to AppDelegate in the old nib window.
  • In the inspector window, select new from the actions list, then click Connect.

We've just connected the new menu item to the AppDelegate's new: method.

  • Select Document/Save.

OK. That's it for the nib files. Now all we need to do is add a bit of code and we are on our way.

  • Go to ProjectBuilder.
  • Under Classes, select Document.m.

Here's what the code looks like now:

#import "Document.h"

@implementation Document

@end
  • Edit the code so it looks like this:
#import "Document.h"

@implementation Document

- init
{
	//Find the nib and load it in.  This instance will be the
	//File's Owner object, so we pass ourself as owner
	if (![NSBundle loadNibNamed:
					@"NEXTSTEP_Document" owner:self])
	{
		//for whatever reason, we failed.  Clean up and go
		NSLog(@"Failed to load Document.nib");
		[self release];
		return nil;
	}
	return self;
}

//Since the Document is the Windows's delegate,
//it will get the following
//method called whenever the window closes.  
- (void)windowWillClose:(NSNotification *)aNotification
{
	//We remove ourself as the delegate as
	//we are going to release ourselves
	[window setDelegate:nil];
	//Let garbage collection do the actual deletion
	[self autorelease];
}

@end
  • Under Classes, select AppDelegate.m.

Here's what the code looks like now:

#import "AppDelegate.h"

@implementation AppDelegate

- (void)new:(id)sender
{
}

@end

Edit the code so it looks like this:

#import "AppDelegate.h"

@implementation AppDelegate

- (void)new:(id)sender
{
}

@end

Change it to look like this:

#import "AppDelegate.h"
#import "Document.h"

@implementation AppDelegate

- (void)new:(id)sender
{
	//Just instantiate a Document. It will know what to do.
	[[Document alloc] init];
}

@end
  • Click on the hammer icon to bring up the project build window.
  • Click on the hammer again to build the project.
  • When prompted with the Save Modified Files dialog, click Save and build.
  • Assuming the build succeeds, click on the monitor icon to bring up the launch window.
  • Click on the monitor icon in the launch window to run the application.

When the application runs, select Document/New to create new windows.

Till Next Month...

Between delegates, File's Owner, and nib file loading, you've learned a lot this month. Be sure to spend some time looking at NSWindow and NSApplication to get a feel for the power of delegation. This will give you something to chew on until we have releases of Rhapsody and Rhapsody developer tools.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

OmniGraffle 6.3 - Create diagrams, flow...
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
PDFKey Pro 4.3.2 - Edit and print passwo...
PDFKey Pro can unlock PDF documents protected for printing and copying when you've forgotten your password. It can now also protect your PDF files with a password to prevent unauthorized access and/... Read more
Ableton Live 9.2.2 - Record music using...
Ableton Live lets you create and record music on your Mac. Use digital instruments, pre-recorded sounds, and sampled loops to arrange, produce, and perform your music like never before. Ableton Live... Read more
Macs Fan Control 1.3.1.0 - Monitor and c...
Macs Fan Control allows you to monitor and control almost any aspect of your computer's fans, with support for controlling fan speed, temperature sensors pane, menu-bar icon, and autostart with... Read more
NetShade 6.3.1 - Browse privately using...
NetShade is an anonymous proxy and VPN app+service for Mac. Unblock your Internet through NetShade's high-speed proxy and VPN servers spanning seven countries. NetShade masks your IP address as you... Read more
Dragon Dictate 4.0.7 - Premium voice-rec...
With Dragon Dictate speech recognition software, you can use your voice to create and edit text or interact with your favorite Mac applications. Far more than just speech-to-text, Dragon Dictate lets... Read more
Persecond 1.0.2 - Timelapse video made e...
Persecond is the easy, fun way to create a beautiful timelapse video. Import an image sequence from any camera, trim the length of your video, adjust the speed and playback direction, and you’re done... Read more
GIMP 2.8.14p2 - Powerful, free image edi...
GIMP is a multi-platform photo manipulation tool. GIMP is an acronym for GNU Image Manipulation Program. The GIMP is suitable for a variety of image manipulation tasks, including photo retouching,... Read more
Sandvox 2.10.2 - Easily build eye-catchi...
Sandvox is for Mac users who want to create a professional looking website quickly and easily. With Sandvox, you don't need to be a Web genius to build a stylish, feature-rich, standards-compliant... Read more
LibreOffice 5.0.1.2 - Free, open-source...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more

ReBoard: Revolutionary Keyboard (Utilit...
ReBoard: Revolutionary Keyboard 1.0 Device: iOS Universal Category: Utilities Price: $1.99, Version: 1.0 (iTunes) Description: Do everything within the keyboard without switching apps! If you are in WhatsApp, how do you schedule a... | Read more »
Tiny Empire (Games)
Tiny Empire 1.1.3 Device: iOS Universal Category: Games Price: $2.99, Version: 1.1.3 (iTunes) Description: Launch cannonballs and blow tiny orcs into thousands of pieces in this intuitive fantasy-themed puzzle shooter! Embark on an... | Read more »
Astropad Mini (Productivity)
Astropad Mini 1.0 Device: iOS iPhone Category: Productivity Price: $4.99, Version: 1.0 (iTunes) Description: *** 50% off introductory price! ​*** Get the high-end experience of a Wacom tablet at a fraction of the price with Astropad... | Read more »
Emo Chorus (Music)
Emo Chorus 1.0.0 Device: iOS Universal Category: Music Price: $1.99, Version: 1.0.0 (iTunes) Description: Realistic Choir simulator ranging from simple Chorus emulation to full ensemble Choir with 128 members. ### introductory offer... | Read more »
Forest Spirit (Games)
Forest Spirit 1.0.5 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.5 (iTunes) Description: | Read more »
Ski Safari 2 (Games)
Ski Safari 2 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: The world's most fantastical, fun, family-friendly skiing game is back and better than ever! Play as Sven's sister Evana, share... | Read more »
Lara Croft GO (Games)
Lara Croft GO 1.0.47768 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.47768 (iTunes) Description: Lara Croft GO is a turn based puzzle-adventure set in a long-forgotten world. Explore the ruins of an ancient... | Read more »
Whispering Willows (Games)
Whispering Willows 1.23 Device: iOS Universal Category: Games Price: $4.99, Version: 1.23 (iTunes) Description: **LAUNCH SALE 50% OFF** - Whispering Willows is on sale for 50% off ($4.99) until September 9th. | Read more »
Calvino Noir (Games)
Calvino Noir 1.1 Device: iOS iPhone Category: Games Price: $3.99, Version: 1.1 (iTunes) Description: The film noir stealth game. Calvino Noir is the exploratory, sneaking adventure through the 1930s European criminal underworld.... | Read more »
Angel Sword (Games)
Angel Sword 1.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.0 (iTunes) Description: Prepare to adventure in the most epic full scale multiplayer 3D RPG for mobile! Experience amazing detailed graphics in full HD.... | Read more »

Price Scanner via MacPrices.net

Apple offering refurbished 2015 13-inch Retin...
The Apple Store is offering Apple Certified Refurbished 2015 13″ Retina MacBook Pros for up to $270 (15%) off the cost of new models. An Apple one-year warranty is included with each model, and... Read more
Apple refurbished 2015 MacBook Airs available...
The Apple Store has Apple Certified Refurbished 2015 11″ and 13″ MacBook Airs (the latest models), available for up to $180 off the cost of new models. An Apple one-year warranty is included with... Read more
21-inch iMacs on sale for up to $120 off MSRP
B&H Photo has 21″ iMacs on sale for up to $120 off MSRP including free shipping plus NY sales tax only: - 21″ 1.4GHz iMac: $999.99 $100 off - 21″ 2.7GHz iMac: $1199.99 $100 off - 21″ 2.9GHz iMac... Read more
5K iMacs on sale for up to $150 off MSRP, fre...
B&H Photo has the 27″ 3.3GHz 5K iMac on sale for $1899.99 including free shipping plus NY tax only. Their price is $100 off MSRP. They have the 27″ 3.5GHz 5K iMac on sale for $2149.99 $2199.99, $... Read more
1.4GHz Mac mini, refurbished, available for $...
The Apple Store has Apple Certified Refurbished 1.4GHz Mac minis available for $419. Apple’s one-year warranty is included, and shipping is free. Their price is $80 off MSRP, and it’s the lowest... Read more
iPad Air 2 on sale for up to $100 off MSRP
Best Buy has iPad Air 2s on sale for up to $100 off MSRP on their online store for a limited time. Choose free shipping or free local store pickup (if available). Sale prices available for online... Read more
MacBook Airs on sale for $100 off MSRP
Best Buy has MacBook Airs on sale for $100 off MSRP on their online store. Choose free shipping or free local store pickup (if available). Sale prices for online orders only, in-store prices may vary... Read more
Big Grips Lift Handle For iPad Air and iPad A...
KEM Ventures, Inc. which pioneered the extra-large, super-protective iPad case market with the introduction of Big Grips Frame and Stand in 2011, is launching Big Grips Lift featuring a new super-... Read more
Samsung Launches Galaxy Tab S2, Its Most Powe...
Samsung Electronics America, Inc. has announced the U.S. release of the Galaxy Tab S2, its thinnest, lightest, ultra-fast tablet. Blending form and function, elegant design and multitasking power,... Read more
Tablet Screen Sizes Expanding as iPad Pro App...
Larger screen sizes are gaining favor as the tablet transforms into a productivity device, with shipments growing 185 percent year-over-year in 2015. According to a new Strategy Analytics’ Tablet... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Desktop Analyst - KDS Staffing (Unit...
…field and consistent professional recruiting achievement. Job Description: Title: Apple Desktop AnalystPosition Type: Full-time PermanentLocation: White Plains, NYHot Read more
*Apple* Systems Engineer (Mclean, VA and NYC...
Title: Apple Systems Engineer (Mclean, VA and NYC) Location: United States-New York-New York-200 Park Ave (22005) Other Locations: United States-Virginia-Vienna-Towers Read more
*Apple* Systems Engineer (Mclean, VA and NYC...
…Assist in providing strategic direction and technical leadership within the Apple portfolio, including desktops, laptops, and printing environment. This person will Read more
*Apple* Subject Matter Expert - Experis (Uni...
We are seeking an Apple Subject Matter Expert to assist in developing the architecture, support and services for integration of Apple devices into the company's Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.