Question

I am new to Corona and am trying to get some basic OOP going on. I have an application which requires a number of time picker widgets, and would like to be able to reuse a ‘timepicker’ class for each instance. Here’s my code so far (bare bones – timepicker.lua):

module(..., package.seeall)

local widget = require "widget"

picker = {}
picker.__index = picker

function picker.new()
    local picker_object = {}
    setmetatable(picker_object,picker)

    pickerGroup = display.newGroup()

    picker_object.theHour = 0
    picker_object.theMin = 0
    picker_object.am = true

    picker_object.increaseHrBtn = widget.newButton{
        default="gfx/up_regular.png",
        over="gfx/up_press.png",
        width=40, height=40,
        onRelease = picker.incHr
    }

    picker_object.decreaseHrBtn = widget.newButton{
        default="gfx/down_regular.png",
        over="gfx/down_press.png",
        width=40, height=40,
        onRelease = picker.decHr
    }

    picker_object.decreaseHrBtn.y = 100

    pickerGroup:insert(picker_object.increaseHrBtn.view)
    pickerGroup:insert(picker_object.decreaseHrBtn.view)

    return picker_object
end

function picker:incHr(event)
    print("inc")
end

function picker:decHr(event)
    print("dec")
end

and here is where I instantiate it:

local TimePicker = require("timepicker")
local reminderPicker1 = TimePicker.picker.new()

This gives me a functioning time picker on the screen (or the first two buttons of which, anyhow). But I want to grab the display objects of this picker and put them into my scroll view on the screen. Because the class returns an object, this can’t be inserted into the scroll view. I’m sure it’s a basic thing, but I can’t figure out what I need to do next! Can anyone help? Much appreciated.

EDIT

Posting my class, which seems to be almost there, except am having trouble accessing the variables ‘theHour’ and ‘theMin’ from within the class…

module(..., package.seeall)

local widget = require "widget"

picker = {}
picker.__index = picker

function picker.new()
    local picker_object = {}
    setmetatable(picker_object,picker)

    picker_object.theHour = 12
    picker_object.theMin = 0
    picker_object.am = true

    picker_object.increaseHrBtn = widget.newButton{
        default="gfx/up_regular.png",
        over="gfx/up_press.png",
        width=40, height=40,
        onRelease = picker.incHr
    }

    picker_object.decreaseHrBtn = widget.newButton{
        default="gfx/down_regular.png",
        over="gfx/down_press.png",
        width=40, height=40,
        onRelease = picker.decHr
    }

    picker_object.decreaseHrBtn.y = 100

    picker_object.hrText = display.newText("12", 6, 41, native.systemFont, 24)
    picker_object.hrText:setTextColor(0, 0, 0)

    picker_object.dotsText = display.newText(":", 58, 39, native.systemFont, 24)
    picker_object.dotsText:setTextColor(0, 0, 0)

    picker_object.increaseMinBtn = widget.newButton{
        default="gfx/up_regular.png",
        over="gfx/up_press.png",
        width=40, height=40,
        onRelease = picker.incMin
    }

    picker_object.increaseMinBtn.x = 100

    picker_object.decreaseMinBtn = widget.newButton{
        default="gfx/down_regular.png",
        over="gfx/down_press.png",
        width=40, height=40,
        onRelease = picker.decMin
    }
    picker_object.decreaseMinBtn.y = 100
    picker_object.decreaseMinBtn.x = 100

    picker_object.minText = display.newText("00", 86, 41, native.systemFont, 24)
    picker_object.minText:setTextColor(0, 0, 0)

    picker_object.ampmBtn = widget.newButton{
        default="gfx/blank_normal.png",
        over="gfx/blank_press.png",
        label = "AM",
        font = "Korean Calligraphy",
        fontSize = 25,
        width=58, height=58,
        onRelease = picker.toggleAmPm
    }

    picker_object.ampmBtn.x = 160
    picker_object.ampmBtn.y = 58

    return picker_object
end

function picker:getHour()
    return self.theHour
end

function picker:getMin()
    return self.theMin
end

function picker:incHr(event)
    print("inc")
    if self.theHour < 12 then
        self.theHour = self.theHour + 1
    else 
        self.theHour = 1
    end

    if self.theHour < 10 then
        picker_object.hrText.text = "0"..self.theHour
    else
        picker_object.hrText.text = self.theHour
    end
end

function picker:decHr(event)
    print("dec")
    if self.theHour > 1 then
        self.theHour = self.theHour - 1
    else 
        self.theHour = 12
    end
    if self.theHour < 10 then
        picker_object.hrText.text = "0"..self.theHour
    else
        picker_object.hrText.text = self.theHour
    end
end

function picker:incMin(event)
    print("inc")
    if self.theMin < 59 then
        self.theMin = self.theMin + 1
    else 
        self.theMin = 0
    end

    if self.theMin < 10 then
        picker_object.minText.text = "0"..self.theMin
    else
        self.minText.text = self.theMin
    end
end

function picker:decMin(event)
    print("dec")
    if self.theMin > 0 then
        self.theMin = self.theMin - 1
    else 
        self.theMin = 59
    end
    if self.theMin < 10 then
        picker_object.minText.text = "0"..self.theMin
    else
        picker_object.minText.text = self.theMin
    end
end

function picker:toggleAmPm(event)
    if self.am == true then
        self.am = false
        picker_object.ampmBtn:setLabel( "PM" )
    else
        self.am = true
        picker_object.ampmBtn:setLabel( "AM" )
    end
end

Answer 1

Ah! you had asked in your previous question right. I forgot to answer that.

Anyway you can access the display objects as
reminderPicker1.increaseHrBtn,reminderPicker1.decreaseHrBtn and so on.

Inside class methods you can access them as
self.increaseHrBtn, self.decreaseHrBtn

EDIT

Change onRelease = picker.toggleAmPm to

onRelease = function() picker_object:toggleAmPm() end 

And change picker_object.ampmBtn:setLabel( "PM" )to

self.ampmBtn:setLabel( "PM" )

DO the same for all other instances. And you’ll be fine!