過濾樹控制器

我現在已經弄清楚如何過濾NSTreeController，做到這一點我有NSManagedObject子類，並添加了一些代碼到我的應用程序委託，我也綁定了我的NSSearchField到我的應用程序委託的filterPredicate但我想我需要以某種方式連接我的NSTreeController和NSSearchField以使其工作。下面我已經發布了所有我已經使用過的代碼，試着讓它工作。過濾樹控制器

NSManagedObject子類頭文件。

@interface Managed_Object_Sub_Class : NSManagedObject { 
    NSArray *filteredChildren; // this should fix the compiler error 
} 

- (NSArray *)filteredChildren; 


@end

NSManagedObject子類實現文件。

@implementation Managed_Object_Sub_Class 

static char *FilteredChildrenObservationContext; 

- (id)initWithEntity:(NSEntityDescription *)entity insertIntoManagedObjectContext:(NSManagedObjectContext *)context { 
    if (self = [super initWithEntity:entity insertIntoManagedObjectContext:context]) { 
     [[NSApp delegate] addObserver:self forKeyPath:@"filterPredicate" options:0 context:&FilteredChildrenObservationContext]; 
     [self addObserver:self forKeyPath:@"subGroup" options:0 context:&FilteredChildrenObservationContext]; 
    } 
    return self; 
} 

// use finalize with GC 
- (void)dealloc { 
    [[NSApp delegate] removeObserver:self forKeyPath:@"filterPredicate"]; 
    [self removeObserver:self forKeyPath:@"subGroup"]; 
    [super dealloc]; 
} 

- (NSArray *)filteredChildren { 
    if (filteredChildren == nil) { 
     NSPredicate *predicate = [[NSApp delegate] filterPredicate]; 
     if (predicate) 
      filteredChildren = [[[self valueForKey:@"subGroup"] filteredArrayUsingPredicate:predicate] copy]; 
     else 
      filteredChildren = [[self valueForKey:@"subGroup"] copy]; 
    } 
    return filteredChildren; 
} 

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { 
    if (context == &FilteredChildrenObservationContext) { 
     [self willChangeValueForKey:@"filteredChildren"]; 
     [filteredChildren release]; 
     filteredChildren = nil; 
     [self didChangeValueForKey:@"filteredChildren"]; 
    } else { 
     [super observeValueForKeyPath:keyPath ofObject:object change:change context:context]; 
    } 
} 

@end

代碼添加到應用程序委託頭文件

NSPredicate *filterPredicate;

代碼添加到應用程序委託實現文件

- (NSPredicate *)filterPredicate { 
    return filterPredicate; 
} 

- (void)setFilterPredicate:(NSPredicate *)newFilterPredicate { 
    if (filterPredicate != newFilterPredicate) { 
     [filterPredicate release]; 
     filterPredicate = [newFilterPredicate retain]; 
    } 
}

搜索字段綁定

alt text http://snapplr.com/snap/vs9q

這還沒有工作，所以這就是爲什麼我問什麼，我需要在這裏做的，使其工作，就像我說的，我想我需要連接NSSearchField和NSTreeController以某種方式結合在一起。

來源

2009-08-05 Joshua