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

TotalFinder 1.12.2 - Adds tabs, hotkeys,...
TotalFinder is a universally acclaimed navigational companion for your Mac. Enhance your Mac's Finder with features so smart and convenient, you won't believe you ever lived without them. Features... Read more
Duet 2.3.0.3 - Use your iPad as an exter...
Duet is the first app that allows you to use your iDevice as an extra display for your Mac using the Lightning or 30-pin cable. Note: This app requires a $9.99 iOS companion app. Version 2.3.0.3:... Read more
FileMaker Pro Advanced 18.0.3 - Powerful...
FileMaker Pro Advanced is the tool you use to create a custom app. You also use FileMaker Pro Advanced to access your app on a computer. Start by importing data from a spreadsheet or using a built-in... Read more
OsiriX Lite 10.0.6 - 3D medical image pr...
OsiriX Lite is an image processing software dedicated to DICOM images (".dcm" / ".DCM" extension) produced by medical equipment (MRI, CT, PET, PET-CT, ...) and confocal microscopy (LSM and BioRAD-PIC... Read more
Ableton Live 10.1.5 - 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
Burn 2.7.8 - Easily burn data, audio, vi...
Burn... There are a lot of ways to approach burning discs. Burn keeps it simple, but still offers a lot of advanced options. Create data discs with advanced data settings like, file permissions, the... Read more
Malwarebytes 4.0.30.3073 - Adware remova...
Malwarebytes (was AdwareMedic) helps you get your Mac experience back. Malwarebytes scans for and removes code that degrades system performance or attacks your system. Making your Mac once again your... Read more
Acorn 6.5.3 - Bitmap image editor.
Acorn is a new image editor built with one goal in mind - simplicity. Fast, easy, and fluid, Acorn provides the options you'll need without any overhead. Acorn feels right, and won't drain your bank... Read more
Fantastical 2.5.13 - Create calendar eve...
Fantastical is the Mac calendar you'll actually enjoy using. Creating an event with Fantastical is quick, easy, and fun: Open Fantastical with a single click or keystroke Type in your event... Read more
A Better Finder Rename 11.05 - File, pho...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more

Latest Forum Discussions

See All

Eternal Warfare is a new idle clicker fo...
Idle games are a popular genre on mobile, they might not be to everyone's taste but they're made with such regularity and receive a lot of downloads, so it's hard to argue it's not big business. Eternal Warfare is set to join the sea of idle games... | Read more »
New heroes and balance updates set to ar...
It feels like Hearthstone: Battlegrounds only launched yesterday, and already the auto batter addition to Blizzard's megahit card game is set to receive new heroes and balance updates. [Read more] | Read more »
Pre-register for Hello Kitty AR: Kawaii...
Hello Kitty — the cute cat that launched a multi-billion-pound franchise — has been brought to life… sort of. Sanrio has teamed up with the Bublar Group to create a new mobile game that uses AR tech to turn the real world into Hello Kitty’s... | Read more »
Gorgeous and tranquil puzzler Spring Fal...
One-man indie studio SPARSE//GameDev has now launched its tranquil puzzler, Spring Falls. It's described as "a peaceful puzzle game about water, erosion, and watching things grow". [Read more] | Read more »
Black Desert Mobile gets an official rel...
Pearl Abyss has just announced that its highly-anticipated MMO, Black Desert Mobile, will launch globally for iOS and Android on December 11th. [Read more] | Read more »
Another Eden receives new a episode, cha...
Another Eden, WFS' popular RPG, has received another update that brings new story content to the game alongside a few new heroes to discover. [Read more] | Read more »
Overdox guide - Tips and tricks for begi...
Overdox is a clever battle royale that changes things up by adding MOBA mechanics and melee combat to the mix. This new hybrid game can be quite a bit to take in at first, so we’ve put together a list of tips to help you get a leg up on the... | Read more »
Roterra Extreme - Great Escape is a pers...
Roterra Extreme – Great Escape has been described by developers Dig-It Games as a mini-sequel to their acclaimed title Roterra: Flip the Fairytale. It continues that game's tradition of messing with which way is up, tasking you with solving... | Read more »
Hearthstone: Battlegrounds open beta lau...
Remember earlier this year when auto battlers were the latest hotness? We had Auto Chess, DOTA Underlords, Chess Rush, and more all gunning for our attention. They all had their own reasons to play, but, at least from where I'm standing, most... | Read more »
The House of Da Vinci 2 gets a new gamep...
The House of Da Vinci launched all the way back in 2017. Now, developer Blue Brain Games is gearing up to deliver a second dose of The Room-inspired puzzling. Some fresh details have now emerged, alongside the game's first official trailer. [Read... | Read more »

Price Scanner via MacPrices.net

B&H offers $100 discounts on 4-Core and 6...
B&H Photo has new 4-Core and 6-Core Mac minis in stock and on sale today for $100 off Apple’s MSRP. Prices start at $699. Overnight shipping is free to many addresses in the US: – 3.6GHz Quad-... Read more
Save $200 today on a 2019 13″ MacBook Air wit...
Apple has a full line of Certified Refurbished 2019 13″ MacBook Airs available starting at only $929 and up to $200 off the cost of new Airs. Each MacBook features a new outer case, comes with a... Read more
New Verizon Pre-Black Friday 2019 deal: Buy o...
Buy one new Apple iPhone 11 model or 2018 iPhone XS model at Verizon and get a second one for free. One new line of service required. Offer is valid from November 21, 2019 to November 27, 2019. Here... Read more
AirPods with Wireless Charging Case on sale t...
Abt Electronics has 2019 AirPods with the Wireless Charging Case on sale today for $163 shipped. Their price is $36 off Apple’s MSRP, and it’s currently the cheapest price for these AirPods from any... Read more
Apple continues to offer 2017 13″ Dual-Core n...
Apple has Certified Refurbished 2017 13″ 2.3GHz Dual-Core non-Touch Bar MacBook Pros still available starting at $1019. An standard Apple one-year warranty is included with each model, outer cases... Read more
Save up to $120 on the new 16″ MacBook Pro at...
Apple’s resellers are starting to receive stock of new 16″ MacBook Pros, and the first set of sales & deals are now available: (1) Amazon 16″ MacBook Pros start on sale for $100-$116 off Apple’s... Read more
Apple Watch Series 3 models on sale at Amazon...
Amazon has Apple Watch Series 3 GPS models on sale for $30 off MSRP, starting at only $169. There prices are the lowest we’ve ever seen for these models from any Apple reseller. Choose Amazon as the... Read more
The ‘Mac Potpourri’ Mailbag: Edition #1- Info...
COMMENTARY: 11.20.19- Welcome to the inaugural edition of the “Mac Potpourri” Mailbag where we take a look at correspondence received from readers of this column from all over the world who write in... Read more
13″ 2.4GHz MacBook Pros available for up to $...
Apple has a full line of Certified Refurbished 2019 13″ 2.4GHz 4-Core Touch Bar MacBook Pros available starting at $1529 and up to $300 off MSRP. Apple’s one-year warranty is included, shipping is... Read more
New at T-Mobile: Switch to T-Mobile, and get...
T-Mobile is offering a free 64GB iPhone 8 for new customers who switch to T-Mobile and open a new line of service. Eligible trade-in required, and discount applied over a 24 month period. The fine... Read more

Jobs Board

Best Buy *Apple* Computing Master - Best Bu...
**747303BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Store NUmber or Department:** 001413-Cypress-Store **Job Description:** **What Read more
*Apple* Mobility Pro - Best Buy (United Stat...
**743221BR** **Job Title:** Apple Mobility Pro **Job Category:** Store Associates **Store NUmber or Department:** 000230-Greenwood-Store **Job Description:** At Best Read more
*Apple* Mobility Pro - Best Buy (United Stat...
**747338BR** **Job Title:** Apple Mobility Pro **Job Category:** Store Associates **Store NUmber or Department:** 000254-Superstition Springs-Store **Job Read more
Best Buy *Apple* Computing Master - Best Bu...
**745516BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Store NUmber or Department:** 001101-Manhattan-Store **Job Read more
Best Buy *Apple* Computing Master - Best Bu...
**746655BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Store NUmber or Department:** 002518-Atlantic Center-Store **Job Description:** Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.