基于 NSOutlineView 视图 - 仅在选择时显示按钮答案

【问题标题】：NSOutlineView view based - Show button only when selected基于 NSOutlineView 视图 - 仅在选择时显示按钮
【发布时间】：2014-03-30 17:39:15
【问题描述】：

我有一个基于 NSOutlineView 视图的一列标题 + 图像/文本/按钮

我只想在选择项目时显示按钮。

我使用以下代码：

- (NSView *)outlineView:(NSOutlineView *)outlineView viewForTableColumn:(NSTableColumn *)tableColumn item:(id)item {
   ....
  SidebarTableCellView *sidebarTableCellView = [outlineView makeViewWithIdentifier:@"MainCell" owner:self];
  [sidebarTableCellView.buttonProgramme setHidden:YES];
  if (outlineView.selectedRow == [outlineView rowForItem:item])
            [sidebarTableCellView.buttonProgramme setHidden:NO];

但它不起作用，按钮总是隐藏的！我不知道是什么问题？

编辑：if 语句中的断点 => If 语句从不匹配

【问题讨论】：

标签： objective-c cocoa nsoutlineview

【解决方案1】：

我设法通过添加以下代码解决了我的问题（viewForTableColumn 没有变化）：

- (void)outlineViewSelectionDidChange:(NSNotification *)notification {

    NSNotificationCenter * center = [NSNotificationCenter defaultCenter];
    [center removeObserver:self
                      name:@"NSOutlineViewSelectionDidChangeNotification"
                    object:self.sidebarOutlineView];

    NSInteger s = [self.sidebarOutlineView selectedRow];
    NSInteger lastSelectedRow = [[self.globalVariableDictionary objectForKey:@"lastSelectedRow"] integerValue];
    [self.globalVariableDictionary setObject:[NSNumber numberWithInteger:s] forKey:@"lastSelectedRow"];

    [self.sidebarOutlineView reloadDataForRowIndexes:[NSIndexSet indexSetWithIndex:s]
                                       columnIndexes:[NSIndexSet indexSetWithIndex:0]];
    [self.sidebarOutlineView reloadDataForRowIndexes:[NSIndexSet indexSetWithIndex:lastSelectedRow]
                                       columnIndexes:[NSIndexSet indexSetWithIndex:0]];
    [self.sidebarOutlineView selectRowIndexes:[NSIndexSet indexSetWithIndex:s] byExtendingSelection:NO];

    [center addObserver:self
               selector:@selector(outlineViewSelectionDidChange:)
                   name:@"NSOutlineViewSelectionDidChangeNotification"
                 object:self.sidebarOutlineView];

    [center addObserver:self
               selector:@selector(outlineViewSelectionDidChange:)
                   name:@"NSOutlineViewSelectionDidChangeNotification"
                 object:self.sidebarOutlineView];
}

通过这样做，我们强制调用 viewForTableColumn: 当用户更改选择时。

谢谢！

【讨论】：