我有一个大纲视图和一个按钮。我希望按钮删除大纲视图中的选定行。我已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（我希望工作）它完全打破了大纲视图，当我说休息时我的意思是它不再起作用，它没有显示我添加的任何数据。
现在获取更多信息，下面是一些阵列控制器和树控制器连接的图片。
NSArrayController连接
alt text http://snapplr.com/snap/b5a1
NSTreeController连接（如您所见，没有选择索引路径绑定）
alt text http://snapplr.com/snap/qv62
最后一点，大纲视图有一个允许它拖放的数据源，我认为这与它不起作用有关，所以下面是数据源中的代码。
实施档案。
#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
答案 0 :(得分：1)
我已经弄清楚了，所以我会发布答案，以帮助所有可能遇到同样问题的人。要修复它，只需执行此操作。
将NSTreeController的managedObjectContext直接绑定到AppDelegate的managedObjectContext属性，并删除整个NSArrayController。 NSTreeController可以添加/删除managedObjectContext中的项目，但不能添加/删除NSArrayController的arrangeObjects中的项目，因为它是只读的。
现在将添加按钮连接到树控制器的add:连接。
最后将删除按钮连接到树控制器的remove:连接。
答案 1 :(得分：0)
add:
- 凹进的按钮（D ......
- 凹进按钮（N ...
那些是“新”还是“删除”？
如果是，您将删除按钮与add:操作相关联。将其连接到remove:。
（另外，您应该使用带有NSAddTemplate和NSRemoveTemplate图像的渐变按钮，而不是带有语言标签的凹进按钮。有关此操作的示例，请参阅“系统偏好设置”中的“帐户”面板;有关详细信息，请参阅the HIG凹进的按钮应该用于。）