Corona sdk random text - text

Question

I`m have a problem because when i touch my button sometimes not appear my text... (Sorry for my English!)
Code:
function randomText(event)
display.remove(mmDis)
local a = {"Cristiano ronaldo jest najlepszy!","messi jest dobry!","lewandowski jest ok","diego lopez to bramkarz realu"}
com = (a[math.random(1,#a)])
local mmDis = display.newText(tostring(com),
display.contentWidth*0.57, display.contentHeight*0.7,
display.contentWidth*0.9, display.contentHeight*0.8, "Impact", 30)
mmDis.y=20
mmDis.x=190
mmDis:setFillColor(0, 0, 0, 1)
mmDis.anchorY = 0
end
play:addEventListener ("tap", randomText )
end
end
play:addEventListener( "touch", object )

Answer 1

Make sure you are localizing your variables properly. You need to declare "mmDis" outside your function, and then do not localize it inside the function. Something like this
local mmDis* -- this will ensure code from here on out all use the SAME "mmDis"
function randomText(event)
display.remove(mmDis)
local a = {"Cristiano ronaldo jest najlepszy!","messi jest dobry!","lewandowski jest ok","diego lopez to bramkarz realu"}
com = (a[math.random(1,#a)])
-- NOTICE how I removed the local keyword below.
-- This will ensure your code is talking about the same "mmDis"
-- you declared before your function
mmDis = display.newText(tostring(com),
display.contentWidth*0.57, display.contentHeight*0.7,
display.contentWidth*0.9, display.contentHeight*0.8, "Impact", 30)
mmDis.y=20
mmDis.x=190
mmDis:setFillColor(0, 0, 0, 1)
mmDis.anchorY = 0
end
play:addEventListener ("tap", randomText )
end
end
play:addEventListener( "touch", object )
Ultimately, the problem you were having is that you were not removing the old text off the screen because mmDis was localized inside the randomText function. Make sure you localize your variables with proper scope. Here's a good read about it http://lua-users.org/wiki/ScopeTutorial

Answer 2

local mmDis
function randomText(event)
if event.phase == "began" then
if mmDis then
display.remove(mmDis)
end
local a = {"Cristiano ronaldo jest najlepszy!","messi jest dobry!","lewandowski jest ok","diego lopez to bramkarz realu"}
local com = a[math.random(1,#a)]
mmDis = display.newText(tostring(com),
display.contentWidth*0.57, display.contentHeight*0.7,
display.contentWidth*0.9, display.contentHeight*0.8, "Impact", 30)
mmDis.y=20
mmDis.x=190
mmDis:setFillColor(0, 0, 0, 1)
mmDis.anchorY = 0
end
end
play:addEventListener ("tap", randomText )
end
end
play:addEventListener( "touch", object )
Try this and see.