android: add support for 3rd party dictionary apps

frontend/apps/reader/modules/readerdictionary.lua

@@ -298,6 +298,56 @@ If you'd like to change the order in which dictionaries are queried (and their r
             }
         }
     }
+    if Device:canExternalDictLookup() then
+        local function genExternalDictItems()
+            local items_table = {}
+            for i, v in ipairs(Device:getExternalDictLookupList()) do
+                local setting = v[1]
+                local dict_name = v[2]
+                local is_enabled = v[3]
+                table.insert(items_table, {
+                    text = dict_name,
+                    checked_func = function()
+                        return setting == G_reader_settings:readSetting("external_dict_lookup_method")
+                    end,
+                    enabled_func = function()
+                        return is_enabled == true
+                    end,
+                    callback = function()
+                        G_reader_settings:saveSetting("external_dict_lookup_method", v[1])
+                    end,
+                })
+            end
+            return items_table
+        end
+        table.insert(menu_items.dictionary_settings.sub_item_table, 1, {
+            text = _("Use external dictionary"),
+            checked_func = function()
+                return G_reader_settings:isTrue("external_dict_lookup")
+            end,
+            callback = function()
+                G_reader_settings:flipNilOrFalse("external_dict_lookup")
+            end,
+        })
+        table.insert(menu_items.dictionary_settings.sub_item_table, 2, {
+            text_func = function()
+                local display_name = _("none")
+                local ext_id = G_reader_settings:readSetting("external_dict_lookup_method")
+                for i, v in ipairs(Device:getExternalDictLookupList()) do
+                    if v[1] == ext_id then
+                        display_name = v[2]
+                        break
+                    end
+                end
+                return T(_("Dictionary: %1"), display_name)
+            end,
+            enabled_func = function()
+                return G_reader_settings:isTrue("external_dict_lookup")
+            end,
+            sub_item_table = genExternalDictItems(),
+            separator = true,
+        })
+    end
 end
 
 function ReaderDictionary:onLookupWord(word, box, highlight, link)
@@ -710,6 +760,11 @@ function ReaderDictionary:stardictLookup(word, dict_names, fuzzy_search, box, li
         })
     end
 
+    if Device:canExternalDictLookup() and G_reader_settings:isTrue("external_dict_lookup") then
+        Device:doExternalDictLookup(word, G_reader_settings:readSetting("external_dict_lookup_method"))
+        return
+    end
+
     if fuzzy_search then
         self:showLookupInfo(word)
     end

frontend/device/android/device.lua

@@ -40,6 +40,21 @@ local function getCodename()
     return codename
 end
 
+local EXTERNAL_DICTS_AVAILABILITY_CHECKED = false
+local EXTERNAL_DICTS = require("device/android/dictionaries")
+local function getExternalDicts()
+    if not EXTERNAL_DICTS_AVAILABILITY_CHECKED then
+        EXTERNAL_DICTS_AVAILABILITY_CHECKED = true
+        for i, v in ipairs(EXTERNAL_DICTS) do
+            local package = v[4]
+            if android.isPackageEnabled(package) then
+                v[3] = true
+            end
+        end
+    end
+    return EXTERNAL_DICTS
+end
+
 local Device = Generic:new{
     isAndroid = yes,
     model = android.prop.product,
@@ -57,6 +72,21 @@ local Device = Generic:new{
         if not link or type(link) ~= "string" then return end
         return android.openLink(link) == 0
     end,
+    canExternalDictLookup = yes,
+    getExternalDictLookupList = getExternalDicts,
+    doExternalDictLookup = function (self, text, method)
+        local params = nil
+        for i, v in ipairs(getExternalDicts()) do
+            if v[1] == method then
+                package = v[4]
+                action = v[5]
+                break
+            end
+        end
+        android.dictLookup(text, package, action)
+    end,
+
+
     --[[
     Disable jit on some modules on android to make koreader on Android more stable.
 
@@ -86,6 +116,7 @@ function Device:init()
                 or ev.code == C.APP_CMD_WINDOW_REDRAW_NEEDED then
                 this.device.screen:_updateWindow()
             elseif ev.code == C.APP_CMD_RESUME then
+                EXTERNAL_DICTS_AVAILABILITY_CHECKED = false
                 local new_file = android.getIntent()
                 if new_file ~= nil and lfs.attributes(new_file, "mode") == "file" then
                     -- we cannot blit to a window here since we have no focus yet.

frontend/device/android/dictionaries.lua

@@ -0,0 +1,15 @@
+return { --[[ supported android dictionary applications.
+
+Most of them should support Intent.ACTION_SEND, Intent.ACTION_SEARCH or
+Intent.ACTION_PROCESS_TEXT. Some applications implement their custom intents. ]]--
+
+    { "Aard2", "Aard2", false, "itkach.aard2", "aard2" },
+    { "Alpus", "Alpus", false, "com.ngcomputing.fora.android", "search" },
+    { "ColorDict", "ColorDict", false, "com.socialnmobile.colordict", "colordict" },
+    { "Fora", "Fora Dict", false, "com.ngc.fora", "search" },
+    { "GoldenFree", "GoldenDict Free", false, "mobi.goldendict.android.free", "send" },
+    { "GoldenPro", "GoldenDict Pro", false, "mobi.goldendict.android.pro", "send" },
+    { "Kiwix", "Kiwix", false, "org.kiwix.kiwixmobile", "text" },
+    { "Mdict", "Mdict", false, "cn.mdict", "send" },
+    { "QuickDic", "QuickDic", false, "de.reimardoeffinger.quickdic", "quickdic" },
+}

frontend/device/generic/device.lua

@@ -71,6 +71,7 @@ local Device = {
 
     canOpenLink = no,
     openLink = no,
+    canExternalDictLookup = no,
 }
 
 function Device:new(o)