UITableView: How to change cell height dynamically when a button is clicked in it? Swift

问题:

I can tell how to do this in objective-c from here, but how can I convert that to swift?

I have a UITableView with custom TableViewCells that has a UIButton called "expandButton". I am trying to figure out how to change the height of that particular cell when the expandButton for that cell is clicked.

Also, when it is clicked again, it should change back to original size. I am not familiar with ObjectiveC so please help me with this in Swift. Thanks a bunch in advance!

Here is what I have so far:

    //Declaration of variables as suggested         var shouldCellBeExpanded:Bool = false         var indexOfExpendedCell:NSInteger = -1 

Now inside the ViewController. Note: TableViewCell is the name of my custom cell.

    //Inside the ViewController         func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {      if let cell:TableViewCell = TableViewCell() {          cell.stopWatch = stopWatchBlocks[indexPath.row]          cell.expandButton.tag = indexPath.row          //Adding action to the expand button         cell.expandButton.addTarget(self, action: "expandButtonAction1:", forControlEvents: UIControlEvents.TouchUpInside)          return cell      }  } 

Now, the button action method:

    func expandButtonAction1(button:UIButton) {      button.selected = !button.selected      if button.selected {          indexOfExpendedCell = button.tag         shouldCellBeExpanded = true          self.TableView.beginUpdates()         self.TableView.reloadRowsAtIndexPaths([NSIndexPath(forItem: indexOfExpendedCell, inSection: 0)], withRowAnimation: .Automatic)         self.TableView.endUpdates()          button.setTitle("x", forState: UIControlState.Selected)     }      else if !button.selected {          indexOfExpendedCell = button.tag         shouldCellBeExpanded = false          self.TableView.beginUpdates()         self.TableView.reloadRowsAtIndexPaths([NSIndexPath(forItem: indexOfExpendedCell, inSection: 0)], withRowAnimation: .Automatic)         self.TableView.endUpdates()          button.setTitle("+", forState: UIControlState.Normal)     } } 

And Finally the HeightForRowAtIndexPath

    func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {      if shouldCellBeExpanded && indexPath.row == indexOfExpendedCell {         return 166.0     }     else { return 91.0 } } 

I think I am missing something because the cell does expand when clicked once, but it does not 'shrink' back to 91 ever!

What am I doing wrong here?

回答1:

Try not to use the selected tag as a toggle for a cell state such as this. Once a cell is selected, tapping it again will not deselect. Instead, you can just use the shouldCellBeExpanded flag:

func expandButtonAction1(button:UIButton) {      shouldCellBeExpanded = !shouldCellBeExpanded     indexOfExpendedCell = button.tag      if shouldCellBeExpanded {         self.TableView.beginUpdates()         self.TableView.endUpdates()          button.setTitle("x", forState: UIControlState.Normal)     }      else {         self.TableView.beginUpdates()         self.TableView.endUpdates()          button.setTitle("+", forState: UIControlState.Normal)     } } 

Also, from my experience the reloadRowsAtIndexPath method is unnecessary. Using the beginUpdates() and endUpdates() alone should do the trick unless you need custom animation.

文章来源: UITableView: How to change cell height dynamically when a button is clicked in it? Swift