Add key event handler for keyboard

itemcontroller.lua

@@ -480,6 +480,19 @@ local PAGES = {
 
     local keyboardList = Padding:new{
       onClick = ignoreClick,
+      onKey = function(elem, keyCode, held)
+        if keyCode == keys.backspace then
+          pageState.filter = fitText(pageState.filter, math.max(0, #pageState.filter - 1))
+          pageState.reloadState()
+          return true
+        end
+        return false
+      end,
+      onChar = function(elem, charCode)
+        pageState.filter = pageState.filter..charCode
+        pageState.reloadState()
+        return true
+      end,
       bgColor = KEYBOARD_BG_COLOR,
       left = KEYBOARD_HPAD,
       right = KEYBOARD_HPAD,