The on-screen keyboard. No permission required.

A :text_field brings the keyboard up when tapped. It goes down again on the field's return key, when another field takes focus, when the field leaves the render tree, and on iOS via the "Done" button MobTextField adds to the keyboard toolbar. What none of those cover is the app's own idea of done — a Save button of its own, a tap on blank space, a value it has just committed. This is the call for that handler:

def handle_info({:tap, :save}, socket) do
  {:noreply, socket |> Mob.Keyboard.dismiss() |> save()}
end

It matters most for keyboard: "decimal" and "number": those iOS keyboards have no return key, so on_submit never fires for them and the toolbar button is the only built-in exit on the field itself.

A value: assigned in the same handler reaches the field, and the field's on_blur arrives, including when that handler re-renders.

iOS resigns the first responder found in any visible window of a connected scene — the view the keyboard is up for — and returns once the main thread has done it, so the handler's re-render applies to a field that is no longer focused (a focused field keeps what the user typed rather than take a new value:). Android calls MobBridge.dismissKeyboard(), which hides the soft keyboard and clears focus, in apps generated by a mob_new that has it. An older generated bridge lacks the method: the NIF returns {:error, :not_loaded} and dismiss/1 is a no-op — the field keeps its keyboard and nothing else changes. Copy the method from a freshly generated app to add it.