CODEWITHSUNDEEP
luafile-handling
Ozitrick
Ozitrick

Reputation: 87

Stuck with I/O operations in lua

I'm trying to design a game in lua (This is my first game since I'm new to this language) Okay.. So I have run a score counter that adds up +1 on screen tap. What I want to do is I want to save the high score permanently.

I want to display the high score ('30' in this case) separately on the screen. And this is where I'm stuck. I tried tweaking with the I/O library, but this made things go more complicated. Can anyone help me with this please?

This is what I have tried:

local f1 = io.open ("scoredata.txt", "a")

function gameOver()  
disp_tempscore()

if score>highScore    -- Here initial value of highScore was 0
    then
    highScore=score
io.write (highScore)
end  

score=0     -- This turns the score 0. (There is a separate score counter that counts the score and stores in 'score')

mainScreen()
local f2 = io.open ("scoredata.txt", "r")
if f2~= nil
then
save_high = io.read(highScore)

end
    text_display2= display.newText("BEST : " .. highScore, 0, 0, "Helvetica", 90)
    text_display2.x = centerX
    text_display2.y = centerY + 80
    text_display2.alpha=1

Now here the score for 'BEST :' appears the highest score, BUT only for multiple runs at same time. What I mean to say is when I start the game in corona simulator and play the game for 5 times (suppose), then highest score shows correct data. But, when I exit simulator and restart it, the highest score vanishes and displays 0. How can I store the data (score in this case) permanently?

EDIT: (This is what I had tried last (one of the hits I tried))

local function disapp (event)                   -- An event listener that responds to "tap"

local obj = event.target
display.remove (obj)

audio.play(sound)

transition.cancel (event.target.trans)

score=score+1
curr_scoreDisp = score
scoreText.text=score

local f1 = io.open (path, "a")   --Writing score to file
if score>highScore  -- Initial value of highScore is 0
    then
    highScore=score
    f1:write(highScore)
end
io.close(f1)

Then :

local function disp_Permscore()
local f1 = io.open (path, "r")

f1:read(highScore)
    text_display2= display.newText("BEST : " .. highScore, 0, 0, "Helvetica", 90)
    text_display2.x = centerX
    text_display2.y = centerY + 80
    text_display2.alpha=1 
    io.close(f1)
end

This is another function that reads score from file and then displays it. Now? Does this help in rectifying the problem in any way?

Upvotes: 1

Views: 843

Answers (2)

Mattenii
Mattenii

Reputation: 329

You're using the file:read() function incorrectly. It takes an 'option' argument and returns what it read. Thus,

f1:read(highScore)

should be

highScore = f1:read("*n")

where the "*n" argument specifies you want to read a number.

Edit:

To prevent trouble with files not being written/read properly, try the following (untested) code:

if score > highScore then
    highScore = score
    local f1 = io.open(path, "w") -- opening in write mode erases content
    f1:write(highScore)           -- write the new highscore
    f1:close()                    -- close the file
end

for writing, and

local f1 = io.open(path, "r")     -- open the file in read mode
highScore = f1:read("*n")         -- read the saved highscore

if highScore == nil then          -- if the highscore could not be read
    --error code here (e.g. set highscore to 0, notify the user, etc.)
end

f1:close()                        -- close the file

for reading.

Upvotes: 0

Oliver
Oliver

Reputation: 29571

I think the issue is that you never write to the score file: 

io.write (highScore)

should be 

f1:write(highScore)

and you should close the file as soon as you no longer need it (will prevent loss of data due to a crash, e.g.). Also don't forget to use system.pathForFile( filename, system.DocumentsDirectory) as described in Corona docs, so the file is put in the correct location.

Upvotes: 0

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