dismiss keyboard when click on expand/collapse icon or header

[sopheareachte]

I have one Textfield with InputDecoration with a listview of expandable panel.
After I click to input data in, it displays keyboard and items of expandable panel.
i put gesture detector over the scaffold to detect when onTap but it doesnt detect when I click on expand/collapse icon or header.

I want to dismiss keyboard when I click on expand/collapse icon or header.