koreader/frontend/ui/widget/confirmbox.lua

--[[--
Widget that shows a confirmation alert with a message and Cancel/OK buttons.

Example:

    UIManager:show(ConfirmBox:new{
        text = _("Save the document?"),
        ok_text = _("Save"),  -- ok_text defaults to _("OK")
        ok_callback = function()
            -- save document
        end,
    })

It is strongly recommended to set a custom `ok_text` describing the action to be
confirmed, as demonstrated in the example above. No ok_text should be specified
if the resulting phrase would be longer than three words.

]]

local Blitbuffer = require("ffi/blitbuffer")
local ButtonTable = require("ui/widget/buttontable")
local CenterContainer = require("ui/widget/container/centercontainer")
local Device = require("device")
local Font = require("ui/font")
local FrameContainer = require("ui/widget/container/framecontainer")
local Geom = require("ui/geometry")
local GestureRange = require("ui/gesturerange")
local HorizontalGroup = require("ui/widget/horizontalgroup")
local HorizontalSpan = require("ui/widget/horizontalspan")
local IconWidget = require("ui/widget/iconwidget")
local InputContainer = require("ui/widget/container/inputcontainer")
local MovableContainer = require("ui/widget/container/movablecontainer")
local Size = require("ui/size")
local TextBoxWidget = require("ui/widget/textboxwidget")
local UIManager = require("ui/uimanager")
local VerticalGroup = require("ui/widget/verticalgroup")
local VerticalSpan = require("ui/widget/verticalspan")
local _ = require("gettext")
local Screen = Device.screen

local ConfirmBox = InputContainer:new{
    modal = true,
    keep_dialog_open = false,
    text = _("no text"),
    face = Font:getFace("infofont"),
    ok_text = _("OK"),
    cancel_text = _("Cancel"),
    ok_callback = function() end,
    cancel_callback = function() end,
    other_buttons = nil,
    other_buttons_first = false, -- set to true to place other buttons above Cancel-OK row
    margin = Size.margin.default,
    padding = Size.padding.default,
    dismissable = true, -- set to false if any button callback is required
    flush_events_on_show = false, -- set to true when it might be displayed after
                                  -- some processing, to avoid accidental dismissal
}

function ConfirmBox:init()
    if self.dismissable then
        if Device:isTouchDevice() then
            self.ges_events.TapClose = {
                GestureRange:new{
                    ges = "tap",
                    range = Geom:new{
                        x = 0, y = 0,
                        w = Screen:getWidth(),
                        h = Screen:getHeight(),
                    }
                }
            }
        end
        if Device:hasKeys() then
            self.key_events.Close = { {Device.input.group.Back}, doc = "cancel" }
        end
    end
    local text_widget = TextBoxWidget:new{
        text = self.text,
        face = self.face,
        width = math.floor(math.min(Screen:getWidth(), Screen:getHeight()) * 2/3),
    }
    local content = HorizontalGroup:new{
        align = "center",
        IconWidget:new{
            icon = "notice-question",
        },
        HorizontalSpan:new{ width = Size.span.horizontal_default },
        text_widget,
    }

    local buttons = {{
        text = self.cancel_text,
        callback = function()
            self.cancel_callback()
            UIManager:close(self)
        end,
    }, {
        text = self.ok_text,
        callback = function()
            self.ok_callback()
            if self.keep_dialog_open then return end
            UIManager:close(self)
        end,
    },}
    buttons = { buttons } -- single row

    if self.other_buttons ~= nil then
        -- additional rows
        local rownum = self.other_buttons_first and 0 or 1
        for i, buttons_row in ipairs(self.other_buttons) do
            local row = {}
            table.insert(buttons, rownum + i, row)
            for ___, button in ipairs(buttons_row) do
                table.insert(row, {
                    text = button.text,
                    callback = function()
                        if button.callback ~= nil then
                            button.callback()
                        end
                        if self.keep_dialog_open then return end
                        UIManager:close(self)
                    end,
                })
            end
        end
    end

    local button_table = ButtonTable:new{
        width = content:getSize().w,
        button_font_face = "cfont",
        button_font_size = 20,
        buttons = buttons,
        zero_sep = true,
        show_parent = self,
    }

    local frame = FrameContainer:new{
        background = Blitbuffer.COLOR_WHITE,
        margin = self.margin,
        radius = Size.radius.window,
        padding = self.padding,
        padding_bottom = 0, -- no padding below buttontable
        VerticalGroup:new{
            align = "left",
            content,
            -- Add same vertical space after than before content
            VerticalSpan:new{ width = self.margin + self.padding },
            button_table,
        }
    }
    self.movable = MovableContainer:new{
        frame,
    }
    self[1] = CenterContainer:new{
        dimen = Screen:getSize(),
        self.movable,
    }

    -- Reduce font size until widget fit screen height if needed
    local cur_size = frame:getSize()
    if cur_size and cur_size.h > 0.95 * Screen:getHeight() then
        local orig_font = text_widget.face.orig_font
        local orig_size = text_widget.face.orig_size
        local real_size = text_widget.face.size
        if orig_size > 10 then -- don't go too small
            while true do
                orig_size = orig_size - 1
                self.face = Font:getFace(orig_font, orig_size)
                -- scaleBySize() in Font:getFace() may give the same
                -- real font size even if we decreased orig_size,
                -- so check we really got a smaller real font size
                if self.face.size < real_size then
                    break
                end
            end
            -- re-init this widget
            self:free()
            self:init()
        end
    end
end

function ConfirmBox:onShow()
    UIManager:setDirty(self, function()
        return "ui", self[1][1].dimen
    end)
    if self.flush_events_on_show then
        -- Discard queued and coming up events to avoid accidental dismissal
        UIManager:discardEvents(true)
    end
end

function ConfirmBox:onCloseWidget()
    UIManager:setDirty(nil, function()
        return "ui", self[1][1].dimen
    end)
end

function ConfirmBox:onClose()
    -- Call cancel_callback, parent may expect a choice
    self.cancel_callback()
    UIManager:close(self)
    return true
end

function ConfirmBox:onTapClose(arg, ges)
    if ges.pos:notIntersectWith(self[1][1].dimen) then
        self:onClose()
    end
    -- Don't let it propagate to underlying widgets
    return true
end

return ConfirmBox