如何在Swift中向TableView添加自定义单元格?

I am very new to iOS programming and I am currently trying to use an add button in my navigation bar to add a new row to my table view. Each cell in the table is a custom cell with a UITextfield. When I run my program in the simulator my first cell shows up, but when I try to add another one the tableView becomes a black screen (but the navigation bar still stays on the screen). Please help!I am very new to iOS programming and I am curre