How to show the Keyboard automatically for a Textfield in Flutter

You can use the autofocus:true property of the TextField:

Whether this text field should focus itself if nothing else is already focused.

So whenever the widget appears on screen, if theres nothing else with the keyboard focus, the focus will automatically be directed to it, thus opening the keyboard.

TextField(TextEditingController: controller, 
         focusNode: focusNode,
         autofocus:true)