B4J Question Asyncstream server client won't communicate

FreeWolF · Jan 15, 2018

Hello, I've just wrote a simple program for the communication between a Pc and an Android Phone.

The PC server side is wrote with B4J and the code is the following:

Code: Copy

Sub Process_Globals
   Private fx As JFX
   Private MainForm As Form
   Dim AStreams As AsyncStreams
   Dim Server As ServerSocket
   Dim Socket1 As Socket
   Private Label1 As Label
   Private EditText1 As TextField
   Private Label2 As Label
   Private TextField2 As TextField
End Sub

Sub AppStart (Form1 As Form, Args() As String)
   MainForm = Form1
   'MainForm.RootPane.LoadLayout("Layout1") 'Load the layout file.
   MainForm.RootPane.LoadLayout("Main")
   MainForm.Show
                           
       Server.Initialize(5500, "Server")
       Server.Listen
       Log("MyIp = " & Server.GetMyIP)
       TextField2.Text = Server.GetMyIP
       
End Sub

'Return true to allow the default exceptions handler to handle the uncaught exception.
Sub Application_Error (Error As Exception, StackTrace As String) As Boolean
   Return True
End Sub

Sub Server_NewConnection (Successful As Boolean, NewSocket As Socket)
   If Successful Then
       
       Label1.Text = "Connected"
       Socket1 = NewSocket
       'Can only use prefix mode if both sides of the connection implement the prefix protocol!!!
       AStreams.InitializePrefix(Socket1.InputStream, False, Socket1.OutputStream, "AStreams")
   Else
       Label1.Text = "Problems"
   End If
   Server.Listen
End Sub

Sub AStreams_NewData (Buffer() As Byte)
   Dim msg As String
   msg = BytesToString(Buffer, 0, Buffer.Length, "UTF8")
   EditText1.Text = msg
   Log(msg)
End Sub

Sub AStreams_Error
   Label1.Text = "Errori"
   Log("AStreams_Error")
End Sub

Sub AStreams_Terminated
   Log("AStreams_Terminated")
End Sub

'press on the Done button to send text
Sub EditText1_EnterPressed
   If AStreams.IsInitialized = False Then Return
   If EditText1.Text.Length > 0 Then
       Dim buffer() As Byte
       buffer = EditText1.Text.GetBytes("UTF8")
       AStreams.Write(buffer)
       EditText1.SelectAll
       Log("Sending: " & EditText1.Text)
   End If
End Sub

Sub Activity_Pause(UserClosed As Boolean)
   If UserClosed Then
       Log("closing")
       AStreams.Close
       Socket1.Close
   End If
End Sub

The code of the phone side, wrote in B4A is this:

Code: Copy

Sub Process_Globals
   'These global variables will be declared once when the application starts.
   'These variables can be accessed from all modules.
   Dim AStreams As AsyncStreams
   Dim Server As ServerSocket
   Dim Socket1 As Socket

End Sub

Sub Globals
   'These global variables will be redeclared each time the activity is created.
   'These variables can only be accessed from this module.

   Private EditText1 As EditText
   Private EditText2 As EditText
   Private Button1 As Button
End Sub

Sub Activity_Create(FirstTime As Boolean)
   'Do not forget to load the layout file created with the visual designer. For example:
   'Activity.LoadLayout("Layout1")
   Activity.LoadLayout("Main")
   If FirstTime Then
       Server.Initialize(5500, "Server")
       Server.Listen
       EditText2.text = Server.GetMyIP
   End If
   
   Socket1.Initialize("Socket1")
   Socket1.Connect("192.168.0.96","5500",0)
   
   If Socket1.Connected = True Then
       Button1.Text = "OK"
   Else
       Button1.Text = "KO"
   End If
   
'   EditText1.ForceDoneButton = True
'   Activity.AddView(EditText1, 10dip, 10dip, 300dip, 60dip)
End Sub

Sub Activity_Resume

End Sub

Sub Server_NewConnection (Successful As Boolean, NewSocket As Socket)
   If Successful Then
       ToastMessageShow("Connected", False)
       Socket1 = NewSocket
       'Can only use prefix mode if both sides of the connection implement the prefix protocol!!!
       AStreams.InitializePrefix(Socket1.InputStream, False, Socket1.OutputStream, "AStreams")
   Else
       ToastMessageShow(LastException.Message, True)
   End If
   Server.Listen
End Sub

Sub AStreams_NewData (Buffer() As Byte)
   Dim msg As String
   msg = BytesToString(Buffer, 0, Buffer.Length, "UTF8")
   ToastMessageShow(msg, False)
   Log(msg)
End Sub

Sub AStreams_Error
   ToastMessageShow(LastException.Message, True)
   Log("AStreams_Error")
End Sub

Sub AStreams_Terminated
   Log("AStreams_Terminated")
End Sub

'press on the Done button to send text

Sub Activity_Pause(UserClosed As Boolean)
    If UserClosed Then
        Log("closing")
        AStreams.Close
        Socket1.Close
    End If
End Sub

Sub Button1_Click
   If AStreams.IsInitialized = False Then Return
   If EditText1.Text.Length > 0 Then
       Dim buffer() As Byte
       buffer = EditText1.Text.GetBytes("UTF8")
       AStreams.Write(buffer)
       EditText1.SelectAll
       Log("Sending: " & EditText1.Text)
   End If
End Sub

I can't understand why the devices don't communicate....maybe the firewall? Or I have wrote something wrong?

Erel · Jan 15, 2018

Start with this example: https://www.b4x.com/android/forum/threads/b4x-network-asyncstreams-b4xserializator.72149/

You must open the relevant port in Windows firewall if you want the Android device to connect to the PC. The other option, opening the ServerSocket on the Android device, doesn't require it.

FreeWolF · Jan 15, 2018

I had tried (with the same code) to connect the pc to the android device, but without success....

Code PC:

Code: Copy

Sub Process_Globals
   Private fx As JFX
   Private MainForm As Form
   Dim AStreams As AsyncStreams
   Dim Server As ServerSocket
   Dim Socket1 As Socket
   Private Label1 As Label
   Private EditText1 As TextField
   Private Label2 As Label
   Private TextField2 As TextField
End Sub

Sub AppStart (Form1 As Form, Args() As String)
   MainForm = Form1
   'MainForm.RootPane.LoadLayout("Layout1") 'Load the layout file.
   MainForm.RootPane.LoadLayout("Main")
   MainForm.Show
                           
       Server.Initialize(5500, "Server")
       Server.Listen
       Log("MyIp = " & Server.GetMyIP)
       TextField2.Text = Server.GetMyIP

   Socket1.Initialize("Socket1")
       Socket1.Connect("10.60.0.3","5500",0)
       
End Sub

'Return true to allow the default exceptions handler to handle the uncaught exception.
Sub Application_Error (Error As Exception, StackTrace As String) As Boolean
   Return True
End Sub

Sub Server_NewConnection (Successful As Boolean, NewSocket As Socket)
   If Successful Then
       
       Label1.Text = "Connected"
       Socket1 = NewSocket
       'Can only use prefix mode if both sides of the connection implement the prefix protocol!!!
       AStreams.InitializePrefix(Socket1.InputStream, False, Socket1.OutputStream, "AStreams")
   Else
       Label1.Text = "Problems"
   End If
   Server.Listen
End Sub

Sub AStreams_NewData (Buffer() As Byte)
   Dim msg As String
   msg = BytesToString(Buffer, 0, Buffer.Length, "UTF8")
   EditText1.Text = msg
   Log(msg)
End Sub

Sub AStreams_Error
   Label1.Text = "Errori"
   Log("AStreams_Error")
End Sub

Sub AStreams_Terminated
   Log("AStreams_Terminated")
End Sub

'press on the Done button to send text
Sub EditText1_EnterPressed
   If AStreams.IsInitialized = False Then Return
   If EditText1.Text.Length > 0 Then
       Dim buffer() As Byte
       buffer = EditText1.Text.GetBytes("UTF8")
       AStreams.Write(buffer)
       EditText1.SelectAll
       Log("Sending: " & EditText1.Text)
   End If
End Sub

Sub Activity_Pause(UserClosed As Boolean)
   If UserClosed Then
       Log("closing")
       AStreams.Close
       Socket1.Close
   End If
End Sub

Code Phone:

Code: Copy

Sub Process_Globals
   'These global variables will be declared once when the application starts.
   'These variables can be accessed from all modules.
   Dim AStreams As AsyncStreams
   Dim Server As ServerSocket
   Dim Socket1 As Socket

End Sub

Sub Globals
   'These global variables will be redeclared each time the activity is created.
   'These variables can only be accessed from this module.

   Private EditText1 As EditText
   Private EditText2 As EditText
   Private Button1 As Button
End Sub

Sub Activity_Create(FirstTime As Boolean)
   'Do not forget to load the layout file created with the visual designer. For example:
   'Activity.LoadLayout("Layout1")
   Activity.LoadLayout("Main")
   If FirstTime Then
       Server.Initialize(5500, "Server")
       Server.Listen
       EditText2.text = Server.GetMyIP
   End If
   
   Socket1.Initialize("Socket1")
   Socket1.Connect("192.168.0.96","5500",0)
   
   If Socket1.Connected = True Then
       Button1.Text = "OK"
   Else
       Button1.Text = "KO"
   End If
   
'   EditText1.ForceDoneButton = True
'   Activity.AddView(EditText1, 10dip, 10dip, 300dip, 60dip)
End Sub

Sub Activity_Resume

End Sub

Sub Server_NewConnection (Successful As Boolean, NewSocket As Socket)
   If Successful Then
       ToastMessageShow("Connected", False)
       Socket1 = NewSocket
       'Can only use prefix mode if both sides of the connection implement the prefix protocol!!!
       AStreams.InitializePrefix(Socket1.InputStream, False, Socket1.OutputStream, "AStreams")
   Else
       ToastMessageShow(LastException.Message, True)
   End If
   Server.Listen
End Sub

Sub AStreams_NewData (Buffer() As Byte)
   Dim msg As String
   msg = BytesToString(Buffer, 0, Buffer.Length, "UTF8")
   ToastMessageShow(msg, False)
   Log(msg)
End Sub

Sub AStreams_Error
   ToastMessageShow(LastException.Message, True)
   Log("AStreams_Error")
End Sub

Sub AStreams_Terminated
   Log("AStreams_Terminated")
End Sub

'press on the Done button to send text

Sub Activity_Pause(UserClosed As Boolean)
    If UserClosed Then
        Log("closing")
        AStreams.Close
        Socket1.Close
    End If
End Sub

Sub Button1_Click
   If AStreams.IsInitialized = False Then Return
   If EditText1.Text.Length > 0 Then
       Dim buffer() As Byte
       buffer = EditText1.Text.GetBytes("UTF8")
       AStreams.Write(buffer)
       EditText1.SelectAll
       Log("Sending: " & EditText1.Text)
   End If
End Sub

At this poit I think I have to open the port onward and forward on the pc, but unfortunately the pc is on a lan and the firewall is controlled by the admin

Erel · Jan 15, 2018

Start with running the example as is.

OliverA · Jan 15, 2018

You should really start with the example that @Erel has linked to (as I just was Ninja'd by @Erel). The other thing I noticed is that neither device is on the same IP network. It may be that IT block's intra-network communications within your organization or within these two networks. But you really won't find out, nor can anyone help you without testing a functioning code set first (which @Erel links to).

FreeWolF · Jan 15, 2018

Ok, I will try, thanks a lot to all for the replies!

B4J Question Asyncstream server client won't communicate

FreeWolF

Active Member

Erel

B4X founder

FreeWolF

Active Member

Erel

B4X founder

OliverA

Expert

FreeWolF

Active Member

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