I add it to string.lua and it works like you said. But, I wonder why it can’t block alphabetic characters ?
Ok.
Referring to online documentation, I see that there is no string for alphabetic characters. So I have to do it from the beginning in native.newTextField() with object.inputType. I don’t like it, but I have no other choice.
in your past reply you said " I can create a scene and print the users to the screen" can you send me an example
re: Blocking
I’m confused. I thought you wanted to allow
- alpha - abcdABCD…
- numeric - 01234…
, but ‘block’ all else.
While you can’t block key inputs, you can detect when users type them and remove them from the text string, which is effectively the same thing.
Note: object.inputType is for selecting/setting the keyboard type, not blocking inputs.
Re: example of new scene for dumping .
Sorry I don’t have the time to do that right now. Try taking a look at one of the GUI examples that comes with the simulator and/or these docs here:
Scrollview:
- Solar2D Documentation — API Reference | Libraries | widget | newScrollView
- Solar2D Documentation — API Reference | type | ScrollViewWidget
Scenes:
I’m very late to this particular party, but I’m just here to chime in regarding Lua’s io library:
What you can do to a file and how you can do it depends on how you access it via io.open(). You can open it for reading only or writing only, or you can open it for both reading and writing, etc.
Also, regarding the question of numeric, alphabetic, alphanumeric, etc. characters in Lua. It’ll be a lot easier and significantly faster to just use pattern matching:
https://www.lua.org/pil/20.2.html
For instance, if you want to ensure that a string contains only numbers, you can check it via:
local myString = "Hello World"
print( string.match(myString, "%D") ) -- prints "H"
Since string.match didn’t return nil, we know that there are non-numbers in the string. You can easily extend the pattern matching to fit all sorts of scenarios.
1 Like
hello dear friend I would like to use this function to display only the last user but I don’t know how to do it.
function m.printUsers()
for i = 1, #m._userDB do
print( "User #" .. i )
end
end
by the way I try to show the userDB.txt to screen by using Scroll view . it show all the file. I dont know how to select the content line on the file to view. for example I want to show only user name, but it show me everything " username, password and so…"
Won’t work if index > # of users
function m.printUserNameByIndex( index )
print( "User # " .. index .. " == " .. m._userDB[index] )
end
Won’t work if no users in DB
function m.printLastUserName( )
print( "Last User == " .. m._userDB[#m._userDB] )
end
I hacked a ugly example together.
Read the two steps in main.lua and follow those directions to run this example.
You’ll have to take this starting point and adjust it for your on use.
Hi !
I am working on your function some step works but I still don’t know to use some others.
for example I want to add the # of the last user in two different databases and display the result on the screen.
I mean in the UsersDB1.txt the name John is the # 9 and in the UsersDB2.txt the name peter is the # 30 . I would like to do
9+30=39 then display 39 at the screen.
I’m having trouble understanding your questions. Please spend more time formatting them for legibility and clarity.
Also, I suggest you temporarily stop work on your app. Instead, make yourself a very basic (NO GUI) testbench.
It should only include:
- The latest copy of the extension scripts.
- The latest copy of the DB module.
- main.lua
Then, in main.lua just play around with the DB module and extensions:
- manually adding users,
- changing your code,
- re-running,
- dumping the users to the console,
- …
Keep doing this till you fully understand how the extensions and modules work. You will probably find that you need to modify and/or add new functions in the DB module.
Once you have a complete understanding of the extensions/modules you can address the app.
Lastly, I will only be able answer specific questions with an example I can download and run demonstrating the problem you’re stuck on. I’ve got a full time job and do this in my spare time. So, while I like to help out I have to be careful or I’ll get no work done on my own games.
I understood and followed your advice. I studied the modules and found the answer to many questions. But there is one that I still haven’t understood. how to remove a user using : user_db_module.removeRecordByReference( userid, password )
You can accomplish removing a user by ‘name’ + ‘pasword’ using this code:
-- Following code assumes you have already stored the name and password to remove in local variables named 'user_name' and 'user_password'
--
local rec = user_db_module.getRecordByUserID( user_name )
if ( rec ) then
if ( rec.password == user_password ) then
user_db_module.getRecordByUserID( rec )
-- you could print a message here indicating success
else
-- you could print a message here indicating failure: WRONG PASSWORD
end
else
-- you could print a message here indicating failure: USER NOT FOUND
end
Alternately, you could use existing methods in the module to write a new one:
function m.removeRecordByNamePass( name, password )
local rec = m.getRecordByUserName( name )
if ( not rec ) then
return false, "no such user"
end
if ( rec.password == password ) then
m.removeRecordByReference( rec )
return true, ""
end
return false, "wrong password"
end
Later call it like thisl
local success, reason = user_db_module.removeRecordByNamePass( user_name, user_pass )
if( success ) then
print( "User " .. user_name .. " record successfully removed" )
else
print( "User " .. user_name .. " record not removed. Reason: " .. reason )
end
Thanks for your answer, but it doesn’t work. I tried with:
function m.removeRecordByReference( rec ).
it removed the last user regardless of the name entered in the box. it seems that the
function table.removeByRef(t, obj) is incorrectly referenced.
Why would removeRecordByReference() be called without you first checking that the name matches?
That is not what I did in both examples.
The steps are:
- Try to get a record by name.
- If the record returned is nil, abort
- If the record is not nil, the name matches.
- Check that the record.password matches the one you want to delete.
- If it does, then delete the record.
- If it does not, abort.
Everything you need is in the examples above and the module provided.
If you can’t get this working, provide a copy of your modified ‘DB’ module so I can see what your code is doing.
I suggest doing all of the lookup, deletion, etc in the module.
I made one final example.
I added all the features I think a basic userDB module would need and tested them all in main.lua
There are no GUIs in this example. There is only test code showing how to use/call the module methods.
https://github.com/roaminggamer/RG_FreeStuff/raw/master/AskEd/2022/06/userDB.zip
user_db_module.lua
-- =============================================================
-- Example 'user db' management module. Add and change functions as needed.
-- =============================================================
local m = {}
-- Called once on start up to load existing user DB if any exists
-- If file does not exist yet, DB == {} by end of function
function m.init()
m._userDB = table.load("userDB.txt") or {}
end
-- Function demonstrating how to iterate over user DB list and do something with it. (In this case print it to the console.)
function m.printUsers()
for i = 1, #m._userDB do
print( "User #" .. i )
print( " > Name: " .. m._userDB[i].name )
print( " > Password: " .. m._userDB[i].password )
end
end
function m.getRecordCount( )
return #m._userDB
end
function m.getRecordByIndex( index )
if( m._userDB[index] ) then
return m._userDB[index]
else
print( "Warning: getByIndex(), invalid index " .. index )
return nil
end
end
function m.removeRecordByReference( rec )
table.removeByRef( m._userDB, rec )
table.save( m._userDB, "userDB.txt" )
end
function m.getRecordByUserName( name )
for i = 1, #m._userDB do
-- print( i, name, m._userDB[i], m._userDB[i].name, m._userDB[i].password, name == m._userDB[i].name )
if( name == m._userDB[i].name ) then
return m._userDB[i]
end
end
return nil
end
function m.nameExists( name )
for i = 1, #m._userDB do
-- print( i, name, m._userDB[i], m._userDB[i].name, m._userDB[i].password, name == m._userDB[i].name )
if( name == m._userDB[i].name ) then
return true
end
end
return false
end
function m.addUser( name, password )
local record = { name = name, password = password }
if( not m.nameExists(name) ) then
table.insert(m._userDB, record )
table.save( m._userDB, "userDB.txt" )
return true, "user record added"
end
return false, "username exists already"
end
function m.removeRecordByNamePass( name, password )
local rec = m.getRecordByUserName( name )
if ( not rec ) then
return false, "no such user"
end
if ( rec.password == password ) then
m.removeRecordByReference( rec )
return true, ""
end
return false, "wrong password"
end
return m
main.lua
io.output():setvbuf("no")
display.setStatusBar(display.HiddenStatusBar)
-- =====================================================
-- Require these just once in main.lua
require "extensions.string"
require "extensions.io"
require "extensions.table"
require "extensions.math"
require "extensions.display"
local user_db_module = require "user_db_module"
user_db_module.init()
-- =====================================================
-- Example usage of functions in module.
-- =====================================================
--
print( " ******************* EXAMPLE STARTED RUNNING ")
--
print( "\n ******************* ")
print( "Users in DB " .. tostring( user_db_module.getRecordCount() ) )
user_db_module.printUsers()
--
print( "\n ******************* ")
local success
local reason
success, reason = user_db_module.addUser( "Bob", "mypass123" )
print( success, reason )
success, reason = user_db_module.addUser( "Sue", "mypass456" )
print( success, reason )
success, reason = user_db_module.addUser( "Bob", "mypass789" )
print( success, reason )
user_db_module.printUsers()
--
print( "\n ******************* ")
local function test_find( name )
local rec = user_db_module.getRecordByUserName( name )
print("Try to get " .. name .. "'s record")
if( rec ) then
print( "Found it: " )
table.print_r( rec ) -- print_r() from extensions/table.lua
else
print( "Not found!" )
end
end
test_find( "Sue" ) -- This should produce a record
test_find( "Bill" ) -- There is no Bill
--
print( "\n ******************* ")
local function test_remove( name, pass )
local success, reason = user_db_module.removeRecordByNamePass( name, pass )
print( "Tried to remove user: " .. name .. " password: " .. pass )
print( success, reason )
end
test_remove( "Bill", "funkyMonkey" ) -- No Bill
test_remove( "Sue", "funkyMonkey" ) -- Wrong password
test_remove( "Sue", "mypass456" ) -- Will delete Sue
test_remove( "Sue", "mypass456" ) -- No Sue (we just deleted her record
test_remove( "Bob", "mypass123" ) -- Bye, bye Bob... now no users in DB.
user_db_module.printUsers()
Please check my model and see what I did wrong.
in main.lu ----Run the add user function first to add some user before running remove user function.
Model.zip (18.0 KB)
Fixed copy: https://github.com/roaminggamer/RG_FreeStuff/raw/master/AskEd/2022/06/Model_fixed.zip
Steps taken to fix:
-
Replaced your user_db_module.lua with the one from here: https://github.com/roaminggamer/RG_FreeStuff/raw/master/AskEd/2022/06/userDB.zip
-
Replaced this code (in remove.lua):
-- Rule A1 - Length >= 4
if( string.len(userid) < 4 ) then
labelReturnStatus1.text = "invalid password (too short)!"
-- Clear warning label and save new user record
else
labelReturnStatus1.text = ""
labelReturnStatus2.text = userid .. " successfully removed"
local success, reason = user_db_module.removeRecordByNamePass( userid, password )
if( success ) then
print( "User " .. userid .. " record successfully removed" )
else
print( "User " .. userid .. " record not removed. Reason: " .. reason )
end
with this:
-- Rule A1 - Length >= 4
if( string.len(userid) < 4 ) then
labelReturnStatus1.text = "invalid password (too short)!"
else
local success, reason = user_db_module.removeRecordByNamePass( userid, password )
if( success ) then
print( "User " .. userid .. " record successfully removed" )
else
print( "User " .. userid .. " record not removed. Reason: " .. reason )
end
labelReturnStatus1.text = userid
labelReturnStatus2.text = reason
Okay it’s fixed the problem was the user_db_module. I just replace it by the new one and it works !
please check the corrected file to continue help me in my project.
Corrected model.zip (18.6 KB)
I posted a fix above.
Tip: I’d suggest taking great care to maintain clean code or your project will become hard to understand and work with.
I noticed a lot of unnecessary blank lines and incorrect indentation levels.
I also noticed this:
-- 1 Initialize the local copy of the DB
local user_db_module = require "scripts.user_db_module"
user_db_module.init()
-- 1. Run this a few times first and add some names...
--local Add user = require "scripts.example"
-- 2. ...then comment out above and run this....
-- Basic dump of names list to scrollview
local scroll_example = require "scripts.scroll_example"
-- 1. Run this to remove some names...
local remove = require "scripts.remove"
which should have been more like this:
-- 1 Initialize the local copy of the DB
local user_db_module = require "scripts.user_db_module"
user_db_module.init()
-- 2. Run this a few times first and add some names...
require "scripts.example"
-- 3. ...then comment out above and run this....
-- Basic dump of names list to scrollview
-- require "scripts.scroll_example"
-- 4. Run this to remove some names...
--require "scripts.remove"