KeyValuePages: Handle not having anything to show slightly better (#7353)

By disabling the pagination buttons, and showing a specific label, like Menu (https://github.com/koreader/koreader/pull/7347#issuecomment-786768640)

frontend/ui/widget/keyvaluepage.lua

@@ -625,21 +625,26 @@ function KeyValuePage:_populateItems()
     end
 
     -- update page information
-    self.page_info_text:setText(T(_("Page %1 of %2"), self.show_page, self.pages))
-    if self.pages > 1 then
-        self.page_info_text:enable()
+    if self.pages >= 1 then
+        self.page_info_text:setText(T(_("Page %1 of %2"), self.show_page, self.pages))
+        if self.pages > 1 then
+            self.page_info_text:enable()
+        else
+            self.page_info_text:disableWithoutDimming()
+        end
+        self.page_info_left_chev:show()
+        self.page_info_right_chev:show()
+        self.page_info_first_chev:show()
+        self.page_info_last_chev:show()
+
+        self.page_info_left_chev:enableDisable(self.show_page > 1)
+        self.page_info_right_chev:enableDisable(self.show_page < self.pages)
+        self.page_info_first_chev:enableDisable(self.show_page > 1)
+        self.page_info_last_chev:enableDisable(self.show_page < self.pages)
     else
+        self.page_info_text:setText(_("No items"))
         self.page_info_text:disableWithoutDimming()
     end
-    self.page_info_left_chev:show()
-    self.page_info_right_chev:show()
-    self.page_info_first_chev:show()
-    self.page_info_last_chev:show()
-
-    self.page_info_left_chev:enableDisable(self.show_page > 1)
-    self.page_info_right_chev:enableDisable(self.show_page < self.pages)
-    self.page_info_first_chev:enableDisable(self.show_page > 1)
-    self.page_info_last_chev:enableDisable(self.show_page < self.pages)
 
     UIManager:setDirty(self, function()
         return "ui", self.dimen

frontend/ui/widget/menu.lua

@@ -991,7 +991,7 @@ function Menu:updatePageInfo(select_number)
         self.page_info_last_chev:enableDisable(self.page < self.page_num)
         self.page_return_arrow:enableDisable(#self.paths > 0)
     else
-        self.page_info_text:setText(_("No choices available"))
+        self.page_info_text:setText(_("No items"))
         self.page_info_text:disableWithoutDimming()
     end
 end

plugins/statistics.koplugin/tableutil.lua

@@ -1,28 +0,0 @@
-local tableutil = {}
-
-
---http://stackoverflow.com/questions/15706270/sort-a-table-in-lua
-function tableutil.spairs(t, order)
-    -- collect the keys
-    local keys = {}
-    for k in pairs(t) do keys[#keys + 1] = k end
-
-    -- if order function given, sort by it by passing the table and keys a, b,
-    -- otherwise just sort the keys
-    if order then
-        table.sort(keys, function(a, b) return order(t, a, b) end)
-    else
-        table.sort(keys)
-    end
-
-    -- return the iterator function
-    local i = 0
-    return function()
-        i = i + 1
-        if keys[i] then
-            return keys[i], t[keys[i]]
-        end
-    end
-end
-
-return tableutil