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我有一個大綱視圖和一個按鈕。我想要按鈕刪除大綱視圖中的選定行。我將大綱視圖的選擇索引路徑綁定到樹控制器，將按鈕連接到樹控制器的remove:選擇器，並將按鈕綁定到樹控制器的canRemove:屬性。但是，一旦我完成了所有這些工作（我期望能夠工作），它就完全打破了大綱視圖，當我說休息時，我的意思是它不再有效，它不顯示我添加的任何數據。從輪廓視圖中刪除一行
現在瞭解更多信息，這裏是陣列控制器和樹控制器連接的一些圖片。
NSArrayController的連接
alt text http://snapplr.com/snap/b5a1
NSTreeController連接（如你沒有選擇索引路徑綁定看到）
alt text http://snapplr.com/snap/qv62
最後一點，大綱視圖具有一個允許它拖拽的數據源，我認爲與它無關，因此下面是數據源中的代碼。
執行文件。
#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
沒有D是針對稱爲完成的不同按鈕。 – Joshua 2009-07-29 14:03:37