[学习]Carbon 加载 NIB...

浅浅的花香味﹌ 2022-07-16 19:09 118阅读 0赞

## Nib File Design Guidelines ##

When creating your Carbon nib files, keep the following guidelines in mind:

*  Store only launch-related resources in your application’s main nib file. The main nib file should contain the application menu bar and any resources that are needed at launch time only. Other resources should be stored separately.
 *  Store frequently used user-interface components (such as document windows) in their own separate nib files. This nib file should contain only the resources needed immediately by that component.
 *  Store infrequently used user-interface components (such as alert panels) in separate nib files. Avoid storing infrequently used components in nib files with frequently used components. When a nib file is loaded, the data for the entire file is loaded into memory and objects are instantiated from that data as needed. Thus, if an object is not used it is still occupying space in memory.

## Loading Objects from Nib Files ##

There are three main ways to load objects. You can:

*  Load a menu bar and main window from your application’s main nib file.
 *  Load objects from an auxiliary nib file in the main bundle.
 *  Load objects from nib files in other bundles.

In this section, you’ll find steps and code examples for each technique.

### Unarchiving Objects from the Main Nib File ###

When your application starts up, you need to call Interface Builder Services functions to open the main nib file and [unarchiving][] the interface objects that should be open after startup. The main nib file should contain only those items that are essential when your application starts up. In most cases, the main nib file should contain only the menu bar and perhaps a main window.

The steps below outline how to open a main nib file and unarchive the objects in it. [Listing A-1][] shows how to implement the steps for a nib file that contains a menu bar and a main window. If your application needs only one of these objects at startup, you can easily modify the sample code.

1.  Call the function `CreateNibReference` to create a reference to the main nib file.
2.  Unarchive the menu bar from the main nib file by calling the function `SetMenuBarFromNib` . This function also sets the menu bar so users can use the menu bar when your application has started up.
3.  If your application has a main window, call the function `CreateWindowFromNib` to unarchive the main window.
4.  After you have unarchived the objects from the main nib file, dispose of the nib reference by calling the function `DisposeNibReference` .
5.  The function `CreateWindowFromNib` unarchives the window so that it is hidden. If you want the window to be visible, you must call the Window Manager function `ShowWindow` .

<table> 
 <tbody> 
  <tr> 
   <td> <pre>   <br>
 代码：<br>
 // Create a nib reference to a nib file.</pre> </td> 
  </tr> 
  <tr> 
   <td> <pre>    err = CreateNibReference (CFSTR ("main"), &amp;nibRef);</pre> </td> 
  </tr> 
  <tr> 
   <td> <pre>    // Call the macro require_noerr to make sure no errors occurred</pre> </td> 
  </tr> 
  <tr> 
   <td> <pre>    require_noerr (err, CantGetNibRef);</pre> </td> 
  </tr> 
  <tr> 
   <td> <pre> </pre> </td> 
  </tr> 
  <tr> 
   <td> <pre>    // Unarchive the menu bar and make it ready to use.</pre> </td> 
  </tr> 
  <tr> 
   <td> <pre>    err = SetMenuBarFromNib (nibRef, CFSTR("MainMenu"));</pre> </td> 
  </tr> 
  <tr> 
   <td> <pre>    require_noerr (err, CantSetMenuBar);</pre> </td> 
  </tr> 
  <tr> 
   <td> <pre> </pre> </td> 
  </tr> 
  <tr> 
   <td> <pre>    // Unarchive the main window.</pre> </td> 
  </tr> 
  <tr> 
   <td> <pre>    err = CreateWindowFromNib (nibRef, CFSTR("MainWindow"), &amp;window);</pre> </td> 
  </tr> 
  <tr> 
   <td> <pre>    require_noerr (err, CantCreateWindow);</pre> </td> 
  </tr> 
 </tbody> 
</table>

详细信息和代码请参见：

http://developer.apple.com/library/mac/\#documentation/Cocoa/Conceptual/LoadingResources/CarbonNibs/CarbonNibs.html

[unarchiving]: http://developer.apple.com/library/mac/documentation/General/Conceptual/DevPedia-CocoaCore/Archiving.html#//apple_ref/doc/uid/TP40008195-CH1
[Listing A-1]: http://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/LoadingResources/CarbonNibs/CarbonNibs.html#//apple_ref/doc/uid/10000051i-CH5-SW2