title: iOS How to add "Done" bar to input keyboard?
body: <p><img src="https://i.stack.imgur.com/WrEn5.png" alt="enter image description here" /></p>
  <p><img src="https://i.stack.imgur.com/MgRQC.png" alt="enter image description here" /></p>
  <p>Like the two pictures, a self-window bar is above the keyboard. How to make it? Are there any third-party libraries doing it?</p>