UITableViewCell，两个单元格都获得了附件视图(UITableViewCell, two cells are both getting an accessory view)

UITableViewCell，两个单元格都获得了附件视图(UITableViewCell, two cells are both getting an accessory view)

情况：当用户选择单元格时，会向该单元格添加一个按钮。 当他们选择一个新单元格时，该按钮将从前一个单元格中删除并添加到新单元格中。 这样可行。 问题是当更多数据添加到表中时。 所以假设有20个单元格，然后我再添加20个单元格。 然后我选择第一个单元格，但是按钮被添加到单元格1 AND单元格21.选择委托方法仅注册被选择的第一个单元格。

从我的didSelectRowAtIndexPath方法：

if (self.selectedCell) { self.selectedCell.accessoryView = nil; self.selectedCell = nil; } UIButton *downloadButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; [downloadButton setTitle:@"Download" forState:UIControlStateNormal]; [downloadButton setFrame:CGRectMake(0, 0, 130, 34)]; self.selectedCell = [self.tableView cellForRowAtIndexPath:indexPath]; self.selectedCell.accessoryView = downloadButton; [self.selectedCell setNeedsDisplay];

在我的方法中，我向表格添加了更多数据：

if(self.selectedCell){ self.selectedCell.accessoryView = nil; self.selectedCell = nil; } [self.tableView reloadData]; [self.tableView setNeedsLayout];

Situation: When a user selects a cell, a button is added to that cell. When they select a new cell, the button is removed from the previous cell and added to the new cell. That works. The problem is when more data is added to the table. So lets say there are 20 cells, then I add another 20 cells. I then select the first cell, however the button is added to cell 1 AND cell 21. The select delegate method only registers the first one being selected though.

From my didSelectRowAtIndexPath method:

if (self.selectedCell) { self.selectedCell.accessoryView = nil; self.selectedCell = nil; } UIButton *downloadButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; [downloadButton setTitle:@"Download" forState:UIControlStateNormal]; [downloadButton setFrame:CGRectMake(0, 0, 130, 34)]; self.selectedCell = [self.tableView cellForRowAtIndexPath:indexPath]; self.selectedCell.accessoryView = downloadButton; [self.selectedCell setNeedsDisplay];

In my method that adds more data to the table I end with:

if(self.selectedCell){ self.selectedCell.accessoryView = nil; self.selectedCell = nil; } [self.tableView reloadData]; [self.tableView setNeedsLayout];

最满意答案

细胞被重复使用。 在你的cellForRowAtIndexPath: ，你忘了清除accessoryView 。 当细胞被重复使用时， accessoryView视图会出现。

我喜欢的一种技术是在tableView:willDisplayCell:forRowAtIndexPath:设置accessoryView tableView:willDisplayCell:forRowAtIndexPath: . 在将单元格放在屏幕上之前调用它。 然后你可以这样做：

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath { if (cell.isSelected) { cell.accessoryView = self.downloadButton; // No reason to create a new one every time, right? } else { cell.accessoryView = nil; } }

Cells are reused. In your cellForRowAtIndexPath:, you're forgetting to clear accessoryView. When the cell is reused, the accessoryView comes along.

A technique I like is to set the accessoryView in tableView:willDisplayCell:forRowAtIndexPath:. This is called right before the cell is put on the screen. You can then do something like:

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath { if (cell.isSelected) { cell.accessoryView = self.downloadButton; // No reason to create a new one every time, right? } else { cell.accessoryView = nil; } }