B4J Question use dll to enable joystick support

ilan

Expert
Licensed User
Longtime User
hi

with this simple class, i am able to communicate with my joystick using vb2010

you can see that it is using winmm.dll

would it be possible to use b4j to communicate with winmm.dll like in this class?

B4X:
Imports System.ComponentModel
Imports System.Runtime.InteropServices

Public Class Joystick
    Inherits NativeWindow

    Private parent As Form
    Private Const MM_JOY1MOVE As Integer = &H3A0

    ' Public Event Move(ByVal joystickPosition As Point)
    Public btnValue As String
    Public Event Up()
    Public Event Down()
    Public Event Left()
    Public Event Right()

    <StructLayout(LayoutKind.Explicit)> _
    Private Structure JoyPosition
        <FieldOffset(0)> _
        Public Raw As IntPtr
        <FieldOffset(0)> _
        Public XPos As UShort
        <FieldOffset(2)> _
        Public YPos As UShort
    End Structure

    Private Class NativeMethods

        Private Sub New()
        End Sub

        ' This is a "Stub" function - it has no code in its body.
        ' There is a similarly named function inside a dll that comes with windows called
        ' winmm.dll.
        ' The .Net framework will route calls to this function, through to the dll file.
        <DllImport("winmm", CallingConvention:=CallingConvention.Winapi, EntryPoint:="joySetCapture", SetLastError:=True)> _
        Public Shared Function JoySetCapture(ByVal hwnd As IntPtr, ByVal uJoyID As Integer, ByVal uPeriod As Integer, <MarshalAs(UnmanagedType.Bool)> ByVal changed As Boolean) As Integer
        End Function

    End Class

    Public Sub New(ByVal parent As Form, ByVal joyId As Integer)
        AddHandler parent.HandleCreated, AddressOf Me.OnHandleCreated
        AddHandler parent.HandleDestroyed, AddressOf Me.OnHandleDestroyed
        AssignHandle(parent.Handle)
        Me.parent = parent
        Dim result As Integer = NativeMethods.JoySetCapture(Me.Handle, joyId, 100, True)
    End Sub

    Private Sub OnHandleCreated(ByVal sender As Object, ByVal e As EventArgs)
        AssignHandle(DirectCast(sender, Form).Handle)
    End Sub

    Private Sub OnHandleDestroyed(ByVal sender As Object, ByVal e As EventArgs)
        ReleaseHandle()
    End Sub

    Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        If m.Msg = MM_JOY1MOVE Then
            ' Joystick co-ords.
            ' (0,0) (32768,0) (65535, 0)
            '
            '
            '
            ' (0, 32768) (32768, 32768) (65535, 32768)
            '
            '
            '
            '
            ' (0, 65535) (32768, 65535) (65535, 65535)
            '
            Dim p As JoyPosition
            p.Raw = m.LParam
            ' RaiseEvent Move(New Point(p.XPos, p.YPos))
            If p.XPos > 16384 AndAlso p.XPos < 49152 Then
                ' X is near the centre line.
                If p.YPos < 6000 Then
                    ' Y is near the top.
                    RaiseEvent Up()
                ElseIf p.YPos > 59536 Then
                    ' Y is near the bottom.
                    RaiseEvent Down()
                End If
            Else
                If p.YPos > 16384 AndAlso p.YPos < 49152 Then
                    ' Y is near the centre line
                    If p.XPos < 6000 Then
                        ' X is near the left.
                        RaiseEvent Left()
                    ElseIf p.XPos > 59536 Then
                        ' X is near the right
                        RaiseEvent Right()
                    End If
                End If
            End If
        End If
        If btnValue <> m.WParam.ToString Then
            btnValue = m.WParam.ToString
        End If
        MyBase.WndProc(m)
    End Sub

End Class
 
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