Building Cocoa Applications: A Step by Step Guide

Setting Up a Multi-View Panel

In this section, we’re going to change the Preferences panel into a multi-view panel, so that we can use it to change either the initial colors or the initial graph parameters (e.g., xmin, ymax). Figure 21-8 shows the pop-up menu and two NSViews that will show up in our new Preferences panel. The particular view that shows up depends on which tab (Colors or Initial) the user selects. In the final section of this chapter (and the book!), we’ll modify GraphView to read its initial graph conditions out of the defaults database.

Figure 21-8. The two views of the multi-view Preferences dialog

Tab Views

It’s quite easy to set up a tab view with Cocoa: just drag out the tab view and drop your GUI elements into place. Before we do this, however, we need to set up instance variables to hold the additional controls.

1. Insert the five outlet instance variables shown here in bold into PrefController.h:

   #import <Cocoa/Cocoa.h>
   
   @interface PrefController : NSObject
   {
       // Colors tab
       IBOutlet id axesColorWell;
       IBOutlet id graphColorWell;
       IBOutlet id labelColorWell;
       // Initial tab
                               IBOutlet id xminCell;
                               IBOutlet id xmaxCell;
                               IBOutlet id xstepCell;
                               IBOutlet id yminCell;
                               IBOutlet id ymaxCell;
   
       IBOutlet id window;
   }
   ...
   @end

2. Save PrefController.h.

3. Open Preferences.nib in IB.

4. Drag the PrefController.h icon from PB and drop it in the Preferences.nib window in IB.

The last step brought ...