B4J Code Snippet Generate UUID in B4J

I know this is very late. But I'd like to share my working code to generate UUID in B4J. As a requirement, must select from the Library: JavaObject.

Sub GenerateUUID() As String
    Dim jObj As JavaObject
    jObj.InitializeStatic("java.util.UUID")
    Dim uuid As String = jObj.RunMethod("randomUUID", Null)
    Return uuid
End Sub

 

[Lucas Siqueira]

for b4x use:

The previous code fixed the character 8 in the first position of the fourth group of characters. Now it can be 8, 9, a, or b

Sub UUIDv4 As String
    ' Initializes a StringBuilder to construct the UUID string
    Dim sb As StringBuilder
    sb.Initialize

    ' Defines the format of the UUID with 5 groups (8, 4, 4, 4, 12 characters respectively)
    For Each stp As Int In Array(8, 4, 4, 4, 12)
        ' Adds a hyphen (-) between groups, except before the first group
        If sb.Length > 0 Then sb.Append("-")

        ' Iterates through the number of characters in each group
        For n = 1 To stp
            ' Generates a random number between 0 and 15 (hexadecimal)
            Dim c As Int = Rnd(0, 16)

            ' Converts the random number into a hexadecimal character (0-9 or a-f)
            If c < 10 Then 
                c = c + 48 ' Converts numbers 0-9 to their ASCII values (48 = '0')
            Else 
                c = c + 87 ' Converts numbers 10-15 to their ASCII values ('a'-'f', 87 is the offset)
            End If

            ' If we're at the start of the fourth group (sb.Length = 19), adjusts the first character
            ' This value must be 8, 9, a, or b, as defined by the UUID v4 specification
            If sb.Length = 19 Then
                ' Creates an array containing the possible values for the first character of the fourth group
                Dim variantArray() As String = Array As String("8", "9", "a", "b")
                ' Randomly selects one value from the array and converts it to ASCII
                c = Asc(variantArray(Rnd(0, variantArray.Length)))
            End If

            ' If we're at the start of the third group (sb.Length = 14), defines the UUID version as 4
            ' This is required by the UUID v4 specification
            If sb.Length = 14 Then 
                c = Asc("4") ' Sets the character to "4", indicating version 4
            End If

            ' Appends the generated character to the StringBuilder
            sb.Append(Chr(c))
        Next
    Next

    ' Returns the complete UUID string, converted to lowercase
    Return sb.ToString.ToLowerCase
End Sub

GUID vs UUID - Can I use GUID as UUID?

I was calling an API which requires UUID version 4 to set as one of the headers. I decided to use this website ( https://www.uuidgenerator.net/ ) API to generate the UUID which works fine. Later, I started looking for ways to generate the UUID v4 internally in the app so I came across this...

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[B4X] UUID version 4 Generator

Extracted from this Thread: https://www.b4x.com/android/forum/threads/guid-vs-uuid-can-i-use-guid-as-uuid.110970/#post-692302 Sub UUIDv4 As String Dim sb As StringBuilder sb.Initialize For Each stp As Int In Array(8, 4, 4, 4, 12) If sb.Length > 0 Then sb.Append("-") For n...

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[TILogistic]

With the solution proposed above I had problems with duplicate UUIDs.

With this one I have not had problems with duplicate UUIDs, in Java 11 or higher it generates version 4.

[B4X] UUID generator

With this UUID generator you will not have problems with duplicates, in Java 11 or higher it generates version 4. Public Sub UUID As String #If B4i Dim no As NativeObject Return no.Initialize("NSUUID").RunMethod("UUID", Null).RunMethod("UUIDString", Null).AsString #Else Dim jo As...

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