[UX] Navigation settings for all devices (#4680)

Before multiswipes and the gesture manager this was impractical on touch-only devices, but no more!

Also includes some minor textual clarifications on some of the settings.

frontend/apps/reader/modules/readergesture.lua

@@ -24,6 +24,7 @@ local action_strings = {
     page_jmp_fwd_10 = _("Forward 10 pages"),
     page_jmp_fwd_1 = _("Next page"),
     skim = _("Skim"),
+    back = _("Back"),
     previous_location = _("Back to previous location"),
     latest_bookmark = _("Go to latest bookmark"),
 
@@ -101,6 +102,7 @@ function ReaderGesture:init()
         multiswipe_east_north = "history",
         multiswipe_south_north = "skim",
         multiswipe_south_west = "show_frontlight_dialog",
+        multiswipe_west_south = "back",
         multiswipe_west_east_west = "open_previous_document",
         multiswipe_east_north_west = "zoom_contentwidth",
         multiswipe_south_east_north = "zoom_contentheight",
@@ -242,6 +244,7 @@ function ReaderGesture:buildMenu(ges, default)
         {"page_jmp_fwd_10", not self.is_docless},
         {"page_jmp_fwd_1", not self.is_docless},
         {"skim", not self.is_docless},
+        {"back", true},
         {"previous_location", not self.is_docless},
         {"latest_bookmark", not self.is_docless, true},
 
@@ -506,6 +509,8 @@ function ReaderGesture:gestureAction(action)
         self:pageUpdate(-1)
     elseif action == "skim" then
         self.ui:handleEvent(Event:new("ShowSkimtoDialog"))
+    elseif action == "back" then
+        self.ui:handleEvent(Event:new("Back"))
     elseif action == "previous_location" then
         self.ui:handleEvent(Event:new("GoBackLink"))
     elseif action == "latest_bookmark" then

frontend/ui/elements/common_settings_menu_table.lua

@@ -165,15 +165,23 @@ if Device:isTouchDevice() then
     }
 end
 
-if Device:hasKeys() then
+common_settings.navigation = {
-    common_settings.navigation = {
     text = _("Navigation"),
+}
+local back_to_exit_str = {
+    prompt = {_("Prompt"), _("prompt")},
+    always = {_("Always"), _("always")},
+    disable ={_("Disable"), _("disable")},
+}
+common_settings.back_to_exit = {
+    text_func = function()
+        local back_to_exit = G_reader_settings:readSetting("back_to_exit") or "prompt"
+        return T(_("Back to exit (%1)"),
+                 back_to_exit_str[back_to_exit][2])
+    end,
     sub_item_table = {
         {
-                text = _("Back key to exit KOReader"),
+            text = back_to_exit_str.prompt[1],
-                sub_item_table = {
-                    {
-                        text = _("Prompt"),
             checked_func = function()
                 local setting = G_reader_settings:readSetting("back_to_exit")
                 return setting == "prompt" or setting == nil
@@ -183,7 +191,7 @@ if Device:hasKeys() then
             end,
         },
         {
-                        text = _("Always"),
+            text = back_to_exit_str.always[1],
             checked_func = function()
                 return G_reader_settings:readSetting("back_to_exit")
                            == "always"
@@ -193,7 +201,7 @@ if Device:hasKeys() then
             end,
         },
         {
-                        text = _("Disable"),
+            text = back_to_exit_str.disable[1],
             checked_func = function()
                 return G_reader_settings:readSetting("back_to_exit")
                            == "disable"
@@ -203,15 +211,19 @@ if Device:hasKeys() then
             end,
         },
     },
-            },
+}
-            {
+common_settings.back_in_filemanager = {
-                text = _("Back key in file browser"),
+    text = _("Back in file browser"),
     sub_item_table = {
         {
-                        text = _("Default"),
+            text_func = function()
+                local back_to_exit = G_reader_settings:readSetting("back_to_exit") or "prompt"
+                return T(_("Back to exit (%1)"),
+                         back_to_exit_str[back_to_exit][2])
+            end,
             checked_func = function()
-                            return G_reader_settings:readSetting("back_in_filemanager")
+                local back_in_filemanager = G_reader_settings:readSetting("back_in_filemanager")
-                                       == "default"
+                return back_in_filemanager == nil or back_in_filemanager == "default"
             end,
             callback = function()
                 G_reader_settings:saveSetting("back_in_filemanager", "default")
@@ -228,8 +240,8 @@ if Device:hasKeys() then
             end,
         },
     },
-            },
+}
-            {
+common_settings.enable_back_history = {
     text = _("Enable back history"),
     checked_func = function()
         return G_reader_settings:nilOrTrue("enable_back_history")
@@ -237,8 +249,9 @@ if Device:hasKeys() then
     callback = function()
         G_reader_settings:flipNilOrTrue("enable_back_history")
     end,
-            },
+}
-            {
+if Device:hasKeys() then
+    common_settings.invert_page_turn_buttons = {
         text = _("Invert page turn buttons"),
         checked_func = function()
             return G_reader_settings:isTrue("input_invert_page_turn_keys")
@@ -247,10 +260,9 @@ if Device:hasKeys() then
             G_reader_settings:flipNilOrFalse("input_invert_page_turn_keys")
             Device:invertButtons()
         end,
-            },
-        }
     }
 end
+
 common_settings.document = {
     text = _("Document"),
     sub_item_table = {

frontend/ui/elements/filemanager_menu_order.lua

@@ -41,6 +41,13 @@ local order = {
         "battery",
         "mass_storage_settings",
     },
+    navigation = {
+        "back_to_exit",
+        "back_in_filemanager",
+        "enable_back_history",
+        "----------------------------",
+        "invert_page_turn_buttons",
+    },
     network = {
         "network_wifi",
         "network_proxy",

frontend/ui/elements/reader_menu_order.lua

@@ -61,6 +61,13 @@ local order = {
         "battery",
         "mass_storage_settings",
     },
+    navigation = {
+        "back_to_exit",
+        "back_in_filemanager",
+        "enable_back_history",
+        "----------------------------",
+        "invert_page_turn_buttons",
+    },
     network = {
         "network_wifi",
         "network_proxy",