cocoa - 关于 NSoutlineView 和 WriteItem |拖放问题

Question

为了处理拖放，已完成以下操作，

-(void)InitMyOutlineView{
 - - - - -  - - - - - - - -  -- - - - - - - -  -
 - - - - - - - - - - - - - -- -- - - - - - - - - 
[pMyOutlineView registerForDraggedTypes:
     [NSArray arrayWithObject:NSStringPboardType]];

/* I tried both Yes and No */   
[pMyOutlineView setDraggingSourceOperationMask:NSDragOperationEvery forLocal:NO];
- - - -  -- - - - - - -- - - - - - - -- - - - - - 
- -- -- - - - - -- - - - - - - - - - -  - -- - - - 
}

WriteItem方法如下，

- (BOOL)outlineView:(NSOutlineView *)outlineView writeItems:(NSArray *)items toPasteboard:(NSPasteboard *)pboard{
    [self log:@"write Items"];
    NSString *pStr = [NSString stringWithFormat:@"this is the temp string "];
       [pboard declareTypes:[NSArray arrayWithObject:NSStringPboardType] owner:self];
       [pboard setString:pStr forType:NSStringPboardType];
       [self log:@"returning YES"];
       return YES;
}

现在我期望控制权将到达 AcceptDrop 方法，但断点没有击中那里，并且在 Log/gdb 中获取以下日志

2011-02-04 16:21:25.435 MyApp[2006:a0f] write Items
2011-02-04 16:21:25.437 MyApp[2006:a0f] returning YES
2011-02-04 16:21:25.439 MyApp[2006:a0f] *** -[NSCFArray initWithObjects:count:]: attempt to insert nil object at objects[0]

并且控制没有到达acceptDrop方法，

当我启用“异常时停止”时，以下是停止时的调用堆栈，

#0  0x981b94e6 in objc_exception_throw
#1  0x96ed34cf in -[__NSPlaceholderArray initWithObjects:count:]
#2  0x96efaaa3 in +[NSArray arrayWithObject:]
#3  0x92316dfd in -[NSOutlineView _columnsForDragImage]
#4  0x923f1e32 in -[NSTableView _doImageDragUsingRowsWithIndexes:event:pasteboard:source:slideBack:startRow:]
#5  0x91fea16a in -[NSTableView _performDragFromMouseDown:]
#6  0x91fe89b9 in -[NSTableView mouseDown:]
#7  0x91fe864e in -[NSOutlineView mouseDown:]
#8  0x91f86c68 in -[NSWindow sendEvent:]
#9  0x91e9f817 in -[NSApplication sendEvent:]
#10 0x91e332a7 in -[NSApplication run]
#11 0x91e2b2d9 in NSApplicationMain

让我再更新一件事，在我的大纲 View 中，我有自定义单元格，它只不过是我正在使用的 Mac ImageTextCell 接口(interface)文件。

任何人都可以指导我，我做错了什么

亲切的问候罗汉

Answer 1

[myoutlineView setOutlineColoumn:firstColumn] 丢失，当我添加时，它就开始工作了