Mac OS X Leopard - ARCAism

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CHAPTER 25 MAC OS X DEVELOPMENT: THE TOOLS
Navigation
Though they’re easy to miss, there are several navigation aids along the top of any editor view
(shown in Figure 25-16). These make it easy to move between different areas of a file, or even
between files.
Figure 25-16. Navigation controls on the top of Xcode’s editor
On the left side there are back and forward buttons, a history menu, which lets you jump
between recently edited files, and a function menu. The function menu lists any function,
method, or class declarations, as well as defines, typedefs, and pragmas. Selecting an item from
the function menu jumps to that item on the page.
You can add navigation aids to your page, which will then show up in the function menu.
Perhaps the most common is the mark pragma:
#pragma mark This is some text.
This will cause any text after mark to show up in the navigation menu, like so:
This is some text.
As with anything else, you can jump to the mark by selecting it. If you group your methods
by functionality, marks are a great way to add subheadings to set off the sections. You can also
use the mark pragma to add separators to the menu.
#pragma mark -
You can add comments to the function menu by beginning them with certain special prefixes.
These prefixes and some examples of their use are listed in Table 25-1.
Table 25-1. Xcode’s Special Comment Prefixes
Prefix Example Result
//???: //???: Is this really necessary? ???: Is this really necessary?
//!!!: //!!!: This crashes every 3rd time !!!: This crashes every 3rd time
//TODO: //TODO: Implement the edge case TODO: Implement the edge case
//FIXME: //FIXME: The image no longer shows FIXME: The image no longer shows
The editor’s upper right has several small buttons. These reveal menus for jumping to bookmarks,
breakpoints, includes, and other files that define the current class, including superclasses,
subclasses, and categories. There is also a button to jump between the current class’s header and
implementation files.
TIP You can jump between a class’s header and implementation files by typing
Option+Cmd+up arrow.
In the upper-right corner, there is a small lock icon. Clicking this icon will lock (or unlock)
the current file, preventing accidental edits. Below the lock is a button that will horizontally split
the editor into two independent views of the same file. Halves can be further split, and the split
can be adjusted by dragging the divider. When an editor is split, a button will appear for rejoining
the two halves.