用于在自定义uitableview单元格中输入的自定义键盘

I have a view which contains a tableview, (i call this view the EquationView, and its controller the EquationViewController). The table view cells are custom cells with a label and a textfield, representing a variable and its value, receptively. I have been able to get my custom keyboard to apear when editing begins in the textfield. I have a view which contains a tableview, (i ca