title: Flutter How to always hide keyboard when click on TextField but keep focus(Keep show cursor)
body: <p>I can't control keyboard show or hide, In my project I need to always hide keyboard but keep focused to display my custom keyboard(a widget).</p>
  <p><strong>This is I want</strong></p>
  <p><img src="https://i.stack.imgur.com/gmu15.png" alt="" /></p>
  <p><strong>And this is my problem</strong></p>
  <p><img src="https://i.stack.imgur.com/wusaC.png" alt="" /></p>