InputDialog: add :addWidget(), use it for checkboxes (#8168)

Also: Text editor now closes its keyboard when calling Find
and Go to line (which open their own keyboards) to avoid
conflicts between multiple keyboards.

frontend/apps/reader/modules/readersearch.lua

@@ -2,14 +2,11 @@ local BD = require("ui/bidi")
 local ButtonDialog = require("ui/widget/buttondialog")
 local CheckButton = require("ui/widget/checkbutton")
 local Device = require("device")
-local HorizontalGroup = require("ui/widget/horizontalgroup")
-local HorizontalSpan = require("ui/widget/horizontalspan")
 local InfoMessage = require("ui/widget/infomessage")
 local InputContainer = require("ui/widget/container/inputcontainer")
 local InputDialog = require("ui/widget/inputdialog")
 local Notification = require("ui/widget/notification")
 local UIManager = require("ui/uimanager")
-local VerticalGroup = require("ui/widget/verticalgroup")
 local logger = require("logger")
 local _ = require("gettext")
 local T = require("ffi/util").template
@@ -135,7 +132,6 @@ function ReaderSearch:onShowFulltextSearchInput()
         },
     }
 
-    -- checkboxes
     self.check_button_case = CheckButton:new{
         text = _("Case sensitive"),
         checked = not self.case_insensitive,
@@ -145,6 +141,7 @@ function ReaderSearch:onShowFulltextSearchInput()
             self.check_button_case:toggleCheck()
         end,
     }
+    self.input_dialog:addWidget(self.check_button_case)
     self.check_button_regex = CheckButton:new{
         text = _("Regular expression (hold for help)"),
         checked = self.use_regex,
@@ -157,20 +154,7 @@ function ReaderSearch:onShowFulltextSearchInput()
             UIManager:show(InfoMessage:new{ text = help_text })
         end,
     }
-
-    local checkbox_shift = math.floor((self.input_dialog.width - self.input_dialog._input_widget.width) / 2 + 0.5)
-    local check_buttons = HorizontalGroup:new{
-        HorizontalSpan:new{width = checkbox_shift},
-        VerticalGroup:new{
-            align = "left",
-            self.check_button_case,
-            not self.ui.document.info.has_pages and self.check_button_regex or nil,
-        },
-    }
-
-    -- insert check buttons before the regular buttons
-    local nb_elements = #self.input_dialog.dialog_frame[1]
-    table.insert(self.input_dialog.dialog_frame[1], nb_elements-1, check_buttons)
+    self.input_dialog:addWidget(self.check_button_regex)
 
     UIManager:show(self.input_dialog)
     self.input_dialog:onShowKeyboard()