基於視圖的「源列表」NSOutlineView不顯示項目的圖標和標題

Question

將基於單元格的NSOutlineView更改爲基於視圖後，它不顯示文件系統樹的圖標和標題。這裏我的代碼：

- (void)outlineView:(NSOutlineView *)outlineView willDisplayCell:(id)cell forTableColumn:(NSTableColumn *)tableColumn item:(id)item { 
    if ([[tableColumn identifier] isEqualToString:@"name"]) 
     return [(ImageAndTextCell *)cell setTextFieldImage:[item icon]]; 
} 

- (id)outlineView:(NSOutlineView *)outlineView objectValueForTableColumn:(NSTableColumn *)tableColumn byItem:(id)item { 
    return [((ConstructorFSEntity *)item) title]; 
} 

- (NSView *)outlineView:(NSOutlineView *)outlineView viewForTableColumn:(NSTableColumn *)tableColumn item:(id)item { 
    if ([item isKindOfClass:[FSEntity class]]) { 
     return [outlineView makeViewWithIdentifier:@"HeaderCell" owner:self]; 
    } else { 
     return [outlineView makeViewWithIdentifier:@"DataCell" owner:self]; 
    } 
} 

我還有一個問題。如何將枚舉項目（文件系統項目的數組）放到單元格「DataCell」和「HeaderCell」中作爲父文件夾（組）並聲明爲標題（例如，@「根文件夾」）和路徑班上。因爲現在以前的基於視圖的方法僅在「HeaderCell」或「DataCell」中顯示枚舉項，並且當我嘗試將某個值分配給「HeaderCell」時，應用程序崩潰。你能幫助我嗎？

Answer 1

要顯示的項目名稱和圖標，你只需要改變這個方法

- (NSView *)outlineView:(NSOutlineView *)outlineView viewForTableColumn:(NSTableColumn *)tableColumn item:(id)item

如下：

- (NSView *)outlineView:(NSOutlineView *)outlineView viewForTableColumn:(NSTableColumn *)tableColumn item:(id)item { 
    if (![item isKindOfClass:[FSEntity class]]) { 
     return [outlineView makeViewWithIdentifier:@"HeaderCell" owner:self]; 
    } else { 
     NSTableCellView *cellView = [outlineView makeViewWithIdentifier:@"DataCell" owner:self]; 
     [(ImageAndTextCell *)cellView.textField.cell setTextFieldImage:[item icon]]; 
     cellView.textField.stringValue = [((FSEntity *)item) title]; 
     return cellView; 
    } 
}