Android Question user-defined types - conversion to array of primitive bytes

[brucePERU]

Hello

I want to send packets TCP to a server in lazarus (object pascal) from types defined in B4A. The idea is to convert it to primitive byte array

Type  TPackPosition(Hour As long, latitude As Double, longitude As double)
...
..
Dim Position as TPackPosition
Position.initialize
Position.Hour = DateTime.now
Position.Latitude = -16.46541
Position.Latitude = -70.487899

Dim obj As Object = Position
Dim buffer() as byte = obj
...
Stream.Write(buffer)

Please I need your great support,

Bruce

 

[DonManfred]

As far as i know there is no Pascal/Delphi implementation.

But using B4A/J/I you can use B4XSerializator. Here it is easy

    Dim Position As TPackPosition
    Position.initialize
    Position.Hour = DateTime.now
    Position.Latitude = -16.46541
    Position.Latitude = -70.487899
    Dim ser As B4XSerializator ' RandomAccessFile library
    ser.ConvertObjectToBytesAsync(Position,"PosType")
    wait for PosType_ObjectToBytes (Success As Boolean, Bytes() As Byte)
    Log($"PosType_ObjectToBytes(${Success},${Bytes.Length})"$)
    Dim ser As B4XSerializator
    ser.ConvertBytesToObject(Bytes)
    wait for PosType_BytesToObject (Success As Boolean, NewObject As Object)
    Log($"PosType_BytesToObject(${Success}, ${NewObject})"$)

You can use RandomAccessfile to convert the Type to bytes.

    Dim raf As RandomAccessFile
    raf.Initialize(File.DirInternal,"1.dat",False)
    raf.WriteB4XObject(Position,0)
    raf.Close

    Dim bytes() As Byte = File.ReadBytes(File.DirInternal,"1.dat")

 

[Jeffrey Cameron]

This has been discussed before for .NET -> https://www.b4x.com/android/forum/threads/serializing-deserializing-basic4android-net.32525/
I would suggest you just make a class that accepts the types and converts them to a byte stream before sending.

 

[brucePERU]

Hi DonManfred

Dim Position As TPackPosition
    Position.initialize
    Position.Hour = DateTime.now
    Position.Latitude = -16.46541
    Position.Latitude = -70.487899
    Dim ser As B4XSerializator ' RandomAccessFile library
    ser.ConvertObjectToBytesAsync(Position,"PosType")
    wait for PosType_ObjectToBytes (Success As Boolean, Bytes() As Byte)
    Log($"PosType_ObjectToBytes(${Success},${Bytes.Length})"$)

which means the content of the variable "bytes"

 

[Erel]

Best solution is to use B4J on the PC. It will make this task trivial.

which means the content of the variable "bytes"

This is the format used by B4XSerializator. You can see the source code for more information: https://github.com/AnywhereSoftware...are/b4a/randomaccessfile/B4XSerializator.java