How to reveal string one letter at a time? - lua

Question

I'm learning from a book, and this is the assignment question i'm working on:
Create an app that asks for the users name and then displays the name down the side of the screen, one letter at a time.
Clarify what i'm trying trying to do: Have users name fade in one at a time vertically. Example: Adam "A" would appear after 1 second , "d" would appear after 3 seconds under the displayed A, "a" would appear after 5 seconds under the displayed d, "m" would appear after 7 seconds under the displayed a. The visuals would have a sort of domino effect.When they appear they would stay displayed on screen.
So far i'm able to get the user's name and display it side ways. Have it fade it in within 2 seconds. I'm stuck on how to get the letters to fade in one letter at a time.
function submit ()
print( "connect" )
userName = userNameField.text
display_userName = display.newText( userName, display.contentWidth-20, display.contentHeight/2 )
display_userName.rotation = 90
display_userName.alpha = 0
userNameField: removeSelf( )
greeting:removeSelf( )
submitButton:removeSelf( )
transition.fadeIn( display_userName, {time = 2000} )
Please let me know if you need to see more of my code.

Answer 1

You can do it in a simple way as below:
local myString = "Adam" -- Create your string
local positionCount = 0 -- initialize a variable to determine letter position
local function displayData()
positionCount = positionCount + 1
if(positionCount<=string.len(myString))then
-- if positionCount is less than or equal to letters in 'myString'
local letter = string.sub(myString, positionCount, positionCount) -- get the current letter
local letterLabel = display.newText(letter,20,20*positionCount,nil,20) -- place the letter
letterLabel.alpha = 0;
-- display the label and update the function after the completion of transition
transition.to(letterLabel,{time=1000,alpha=1,onComplete=displayData})
end
end
displayData()
Keep Coding.................... :)

Answer 2

Here is the code snippet for storing every character in a table.
Initialise a variable:
check =0;
Here splitWord is an table to store each character of string. and variable "yourStringForOneLetter" is your string variable for splitting. "string.sub" will split string into words using for loop.
if(check==wordSize) then
check=1
end
local wordSize = string.len(yourStringForOneLetter)
splitWord = {}
for i=check, check do
splitWord[i] = string.sub(yourStringForOneLetter, i, i)
check= check +1;
end