从轮廓视图中删除一行

Question

我有一个大纲视图和一个按钮。我想要按钮删除大纲视图中的选定行。我将大纲视图的选择索引路径绑定到树控制器，将按钮连接到树控制器的remove:选择器，并将按钮绑定到树控制器的canRemove:属性。但是，一旦我完成了所有这些工作（我期望能够工作），它就完全打破了大纲视图，当我说休息时，我的意思是它不再有效，它不显示我添加的任何数据。

现在了解更多信息，这里是阵列控制器和树控制器连接的一些图片。

NSArrayController的连接

alt text http://snapplr.com/snap/b5a1

NSTreeController连接（如你没有选择索引路径绑定看到）

alt text http://snapplr.com/snap/qv62

最后一点，大纲视图具有一个允许它拖拽的数据源，我认为与它无关，因此下面是数据源中的代码。

执行文件。

#import "DragController.h" 


@implementation DragController 
- (void)awakeFromNib { 

    dragType = [NSArray arrayWithObjects: @"factorialDragType", nil]; 

    [ dragType retain ]; 

    [ treeTable registerForDraggedTypes:dragType ]; 
    NSSortDescriptor* sortDesc = [[NSSortDescriptor alloc] initWithKey:@"position" ascending:YES]; 
    [groupTreeControl setSortDescriptors:[NSArray arrayWithObject: sortDesc]]; 
    [ sortDesc release ]; 
} 


//------------------------------------ 
#pragma mark NSOutlineView datasource methods -- see NSOutlineViewDataSource 
//--------------------------------------------------------------------------- 
- (BOOL) outlineView : (NSOutlineView *) outlineView 
      writeItems : (NSArray*) items 
     toPasteboard : (NSPasteboard*) pboard { 

    [ pboard declareTypes:dragType owner:self ];   
    // items is an array of _NSArrayControllerTreeNode see http://theocacao.com/document.page/130 for more info 
    draggedNode = [ items objectAtIndex:0 ]; 

    return YES; 
} 




- (BOOL)outlineView:(NSOutlineView *)outlineView acceptDrop:(id <NSDraggingInfo>)info item:(id)item childIndex:(int)index { 

    _NSArrayControllerTreeNode* parentNode = item; 
    _NSArrayControllerTreeNode* siblingNode; 
    _NSControllerTreeProxy* proxy = [ groupTreeControl arrangedObjects ]; 

    NSManagedObject* draggedGroup = [ draggedNode observedObject ]; 

    BOOL draggingDown = NO; 
    BOOL isRootLevelDrag = NO; 

    // ---------------------- 
    // Setup comparison paths 
    // ------------------------- 
    NSIndexPath* draggedPath = [ draggedNode indexPath ]; 
    NSIndexPath* siblingPath = [ NSIndexPath indexPathWithIndex: index ]; 
    if (parentNode == NULL) {  
     isRootLevelDrag = YES; 
    } else { 
     // A non-root drag - the index value is relative to this parent's children 
     siblingPath = [ [ parentNode indexPath ] indexPathByAddingIndex: index ]; 
    } 

    // ---------------------- 
    // Compare paths - modify sibling path for down drags, exit for redundant drags 
    // -----------------------------------------------------------------------------  
    switch ([ draggedPath compare:siblingPath]) { 
     case NSOrderedAscending: // reset path for down dragging 
      if (isRootLevelDrag) { 
       siblingPath = [ NSIndexPath indexPathWithIndex: index - 1];        
      } else { 
       siblingPath = [ [ parentNode indexPath ] indexPathByAddingIndex: index - 1 ]; 
      } 
      draggingDown = YES; 
      break; 

     case NSOrderedSame: 
      return NO; 
      break;    
    } 

    siblingNode = [ proxy nodeAtIndexPath:siblingPath ];  

    // NSLog(@"returning early"); 
    // return NO; // TODO robustify 


    // ------------------------------------------------------------ 
    // SPECIAL CASE: Dragging to the bottom 
    // ------------------------------------------------------------ 
    // - K        - K       - C        - C 
    // - - U        - - C  OR  - U        - F 
    // - - C  ====>  - - F     - F        - K 
    // - - F    - U    - K        - U 
    // ------------------------------------------------------------ 
    if (isRootLevelDrag && siblingNode == NULL) {   
     draggingDown = YES; 
     siblingPath = [ NSIndexPath indexPathWithIndex: [ proxy count ] - 1 ];   
     siblingNode = [ proxy nodeAtIndexPath:siblingPath ] ; 
    } 

    // ------------------------------------------------------------ 
    // Give the dragged item a position relative to it's new sibling 
    // ------------------------------------------------------------ 
    NSManagedObject* sibling = [ siblingNode observedObject ]; 
    NSNumber* bystanderPosition = [ sibling valueForKey:@"position"]; 
    int newPos = (draggingDown ? [ bystanderPosition intValue ] + 1 : [ bystanderPosition intValue ] - 1); 
    [draggedGroup setValue:[ NSNumber numberWithInt:newPos ] forKey:@"position"]; 

    // ---------------------------------------------------------------------------------------------- 
    // Set the new parent for the dragged item, resort the position attributes and refresh the tree 
    // ----------------------------------------------------------------------------------------------  
    [ draggedGroup setValue:[ parentNode observedObject ] forKey:@"parent" ]; 
    [ self resortGroups:[draggedGroup managedObjectContext] forParent:[ parentNode observedObject ] ];   
    [ groupTreeControl rearrangeObjects ]; 
    return YES;    
} 






- (NSArray*) getSubGroups:(NSManagedObjectContext*)objectContext forParent:(NSManagedObject*)parent { 
    NSFetchRequest *request = [[[NSFetchRequest alloc] init] autorelease]; 
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"projects" inManagedObjectContext:objectContext]; 

    [request setEntity:entity]; 
    NSSortDescriptor* aSortDesc = [[NSSortDescriptor alloc] initWithKey:@"position" ascending:YES]; 
    [request setSortDescriptors:[NSArray arrayWithObject: aSortDesc] ]; 
    [aSortDesc release]; 

    NSPredicate* validationPredicate = [NSPredicate predicateWithFormat:@"parent == %@", parent ]; 

    [ request setPredicate:validationPredicate ]; 

    NSError *error = nil; // TODO - check the error bozo 
    return [objectContext executeFetchRequest:request error:&error];  
} 




- (void) resortGroups:(NSManagedObjectContext*)objectContext forParent:(NSManagedObject*)parent { 

    NSArray *array = [ self getSubGroups:objectContext forParent:parent ]; 

    // Reset the indexes... 
    NSEnumerator *enumerator = [array objectEnumerator]; 
    NSManagedObject* anObject; 
    int index = 0; 
    while (anObject = [enumerator nextObject]) { 
     // Multiply index by 10 to make dragging code easier to implement ;) .... 
     [anObject setValue:[ NSNumber numberWithInt:(index * INTERVAL) ] forKey:@"position"];  
     index++; 
    } 


} 

- (NSDragOperation)outlineView:(NSOutlineView *)outlineView validateDrop:(id <NSDraggingInfo>)info proposedItem:(id)item proposedChildIndex:(int)index { 

    _NSArrayControllerTreeNode* newParent = item; 

    // drags to the root are always acceptable 
    if (newParent == NULL) { 
     return NSDragOperationGeneric; 
    } 

    // Verify that we are not dragging a parent to one of it's ancestors 
    // causes a parent loop where a group of nodes point to each other and disappear 
    // from the control 
    NSManagedObject* dragged = [ draggedNode observedObject ];  
    NSManagedObject* newP = [ newParent observedObject ]; 

    if ([ self category:dragged isSubCategoryOf:newP ]) { 
     return NO; 
    }  

    return NSDragOperationGeneric; 
} 

- (BOOL) category:(NSManagedObject*)cat isSubCategoryOf:(NSManagedObject*) possibleSub { 

    // Depends on your interpretation of subCategory .... 
    if (cat == possibleSub) { return YES; } 

    NSManagedObject* possSubParent = [possibleSub valueForKey:@"parent"]; 

    if (possSubParent == NULL) { return NO; } 

    while (possSubParent != NULL) {  
     if (possSubParent == cat) { return YES; } 

     // move up the tree 
     possSubParent = [possSubParent valueForKey:@"parent"];   
    } 

    return NO; 
} 




// This method gets called by the framework but the values from bindings are used instead 
- (id)outlineView:(NSOutlineView *)outlineView objectValueForTableColumn:(NSTableColumn *)tableColumn byItem:(id)item { 
    return NULL; 
} 

/* 
The following are implemented as stubs because they are required when 
implementing an NSOutlineViewDataSource. Because we use bindings on the 
table column these methods are never called. The NSLog statements have been 
included to prove that these methods are not called. 
*/ 
- (int)outlineView:(NSOutlineView *)outlineView numberOfChildrenOfItem:(id)item { 
    NSLog(@"numberOfChildrenOfItem"); 
    return 1; 
} 

- (BOOL)outlineView:(NSOutlineView *)outlineView isItemExpandable:(id)item { 
    NSLog(@"isItemExpandable"); 
    return NO; 
} 

- (id)outlineView:(NSOutlineView *)outlineView child:(int)index ofItem:(id)item { 
    NSLog(@"child of Item"); 
    return NULL; 
} 



@end 

Answer 1

我已经想通了，所以我会发布答案，以帮助所有可能有同样问题的人。要解决它只需执行此操作。

1. 绑定NSTreeController的managedObjectContext直接到AppDelegate中的managedObjectContext属性，删除整个NSArrayController的。 NSTreeController可以从managedObjectContext中添加/删除项目，但不能从NSArrayController的arrangeObjects中添加/删除项目，因为它是只读的。

2. 现在将添加按钮连接到树控制器的add:连接。

3. 最后将删除按钮连接到树控制器的remove:连接。

Answer 2

add:

• 内陷式按钮（d ...
• 内陷式按钮（N ...

是那些“新”和“删除”？

如果是这样，您将删除按钮连接到add:操作。改为连接到remove:。 （另外，您应该使用包含NSAddTemplate和NSRemoveTemplate图像的渐变按钮，而不是带有文字标签的凹陷按钮。请参阅系统偏好设置中的“帐户”窗格中有关此操作的示例，以及the HIG以获取有关隐藏按钮的说明应该用于。）