Quickies search for 'nsarraycontroller'

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Found 5 items:

• Binding an NSPopupButton (General->General) [permalink]
  To bind an NSPopupButton:
  • Have an NSArray somewhere that you want to supply the popup
  • Make an NSArrayController in the nib file (say call it "greeble"), and binds its Value to some keypath (such as your AppDelegate.greebleArray ivar)
  • Bind the popup's Content to the array controller's arranged objects (greeble.arrangedObjects). These are the objects that are behind the popup.
  • Bind the popup's Content Values to a key path that includes a displayable string. Assuming the objets in the greebleArray array have a title property, you'd bind it to greeble.arrangedObjects.title
  • Bind the popup's Selected Object to something, such as an ivar of the type of object that's in the greebleArray. If said ivar is called selectedGreeble, you'd bind to AppDelegate's selectedGreeble.

• Hooking up a search box to your array controller (Bindings->General) [permalink]
  Tiger supposedly does this for us. If you're having to support Panther as well, here's a way to have a search box filter the contents managed by an NSArrayController.

  In the header file

  #import <Cocoa/Cocoa.h>
  
  @interface BWSearchArrayController : NSArrayController
  {
      NSString *searchString;
  }
  
  - (IBAction) search: (id) sender;
  
  @end // BWSearchArrayController

  and then in the implementation:

  // returns an array containing the content of the objects arranged
  // with the user's critera entered into the search box thingie
  
  - (NSArray *) arrangeObjects: (NSArray *) objects
  {
      // result of the filtering
      NSArray *returnObjects = objects;
  
      // if there is a search string, use it to compare with the
      // search field string
  
      if (searchString != nil) {
  
          // where to store the filtered
          NSMutableArray *filteredObjects;
          filteredObjects = [NSMutableArray arrayWithCapacity: [objects count]];
  
          // walk the enumerator
          NSEnumerator *enumerator = [objects objectEnumerator];
  
          id item; // actully BWFileEntries
          while (item = [enumerator nextObject]) {
  
              // get the filename from the entry
              NSString *filename;
              filename = [item valueForKeyPath: @"fileName"];
  
              // see if the file name matches the search string
              NSRange range;
              range = [filename rangeOfString: searchString
                                options: NSCaseInsensitiveSearch];
  
              // found the search string in the file name, add it to
              // the result set
              if (range.location != NSNotFound) {
                  [filteredObjects addObject: item];
              }
          }
  
          returnObjects = filteredObjects;
      }
  
      // have the superclass arrange them too, to pick up NSTableView sorting
      return ([super arrangeObjects:returnObjects]);
  
  } // arrangeObjects

  and then to set the search string:

  - (void) setSearchString: (NSString *) string
  {
      [searchString release];
  
      if ([string length] == 0) {
          searchString = nil;
      } else {
          searchString = [string copy];
      }
  
  } // setSearchString
  
  
  - (void) search: (id) sender
  {
      [self setSearchString: [sender stringValue]];
      [self rearrangeObjects];
  
  } // search
  

• KVO Array controller gotcha (Bindings->General) [permalink]
  If you're doing KVO and don't override observeValueForKeyPath:ofObject:change:context:, (or you do override it but don't handle your callbacks) you'll generally get an exception. This trains you to do it right and never call super for the callbacks you're handling, or you'll get an exception.

  Except if you've added KVO to a subclass of NSArrayController (and possibly all controller types), and don't call super's observeValueForKeyPath:ofObject:change:context:, bindings won't work at all, with no warning/notice/nothing. (Courtesy of Duncan Wilcox)

• Monitoring one array from two controllers (Bindings->General) [permalink]
  If you're wanting to use two NSArrayControllers to monitor one NSMutableArray, you'll need to use each of the controller's contentArray binding. Just using the content outlet (or setContent: call), you'll only get arrangedObjects updates from one controller. (thanks to Duncan Wilcox for this one)

• NSSearchField filtering for an NSArrayController (Bindings->General) [permalink]
  In Tigger, NSSearchField can now automagically filter an array via IB magic.

  In Interface Builder, drag over the NSSearchField, and bind the predicate like this:

  • Bind To: your array controller
  • Controller Key: filterPredicate
  • Predicate Format: what contains[c] $value (assuming the attribute you're filtering is called what)
  If you're wanting to be able to filter on multiple attributes, make additional predicate bindings. Doing the CoreData option-drag of an entity into IB is really handy - take a peek at how it configures the search field for filtering multiple columns.

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