Thread: How plugin works? need fully understand plugin

Originally Posted by efun

I have read some plugin source code and also write several simple plugins, but still can not fully understand plugin. So raise my questions here:

1)RR may load many plugin when it starts, so there are many methods with same name. For example, if has 3 plugins, it will have 3 ProcessCommand method. How does RR handle this(multi-methods with same name)? It will execute each method one by one?

2) Public Function ProcessCommand(ByVal CMD As String, ByVal frm As Object) As Integer
It seems that CMD should be defined as ByRef, since it may be modified in the method.

3)Public Function ReturnLabel(ByVal LBL As String, ByVal FMT As String) As String
When will the method be called? for example, I write my code in ReturnLabel which will return the label text based on the label code. But It seems that the method was never called. I have to set the label taxt via COM interface:
RRExtension.SDK.Execute("SETLABEL;PDC_DISTANCE;" & bean.getMinDist())

4)Public Function ReturnSlider(ByVal SLD As String) As Long
So I set the value in this method. But the sliders(pdc_sensor_a,b,c,d) were not changed. I can not find the set command via COM interface too.

Code:

    Public Function ReturnSlider(ByVal SLD As String) As Long

        'This tells RR that the Slider was not processed in this plugin
        ReturnSlider = -1

        Select Case LCase(SLD)

            Case "pdc_sensor_a"
                ReturnSlider = Int(327.68 * statusHolder.getPdcStatusBean.getDistRL1())
                If ReturnSlider > 65536 Then ReturnSlider = 65536

            Case "pdc_sensor_b"
                ReturnSlider = Int(327.68 * statusHolder.getPdcStatusBean.getDistRL2())
                If ReturnSlider > 65536 Then ReturnSlider = 65536

            Case "pdc_sensor_c"
                ReturnSlider = Int(327.68 * statusHolder.getPdcStatusBean.getDistRL3())
                If ReturnSlider > 65536 Then ReturnSlider = 65536

            Case "pdc_sensor_d"
                ReturnSlider = Int(327.68 * statusHolder.getPdcStatusBean.getDistRL4())
                If ReturnSlider > 65536 Then ReturnSlider = 65536

        End Select

    End Function

1. yes it calls each plugins processcommand one after the other.

2. It is allowed that the CMD should change in the plugin, so byval is fine.

3. again labels get called in each plugin one by one. (don't use com interface, just sdk.execute(<etc>) from your plugin.

4. Make sure sliders are integers (which in your example you have)

Originally Posted by Enforcer

1. yes it calls each plugins processcommand one after the other.

2. It is allowed that the CMD should change in the plugin, so byval is fine.

3. again labels get called in each plugin one by one. (don't use com interface, just sdk.execute(<etc>) from your plugin.

4. Make sure sliders are integers (which in your example you have)

2. ByVal will not return back the modified CMD. The modified comand will not execute based on my test. After chaning to ByRef, the command works well

3. Yes, I use SDK.execute to set the label text (I may make a misktake between SDK and COM interface). My question is that the ReturnLabel() was never called. I must use SDK.execute("SETLABEL;...") outside of the RRExtension class. So when will the ReturnLabel() be called? Is it useless since I can use SDK.execute?

4. the sliders are integers. Even I hardcode the value(for example,65535), the sliders were not showed. So how to control the silder from application code?

the offical plugin SDK which is included in the LATEST installer

Public Function ProcessCommand(CMD As String, frm As Object) As Integer

which is byRef! and thats what it should be

look in the RRExtension Plugin Examples directory for the latest sdk

The plugin code you looked at likely was changed to BYVAL by choice so he could change the variable without affecting RR.

1) RR calls the process command method of each plugin using the object reference of each plugin.

2) As it's been said, the original code is ByRef

3) This method will be called whenever RR needs to translate the label codes into text. It will pass you the label code and the format (if any), and if your plugin has that label defined and return its text, then it will show in RR's skin. If the label isn't defined in your plugin, it's likely internal or on another plugin -- otherwise it will show blank.

4) As long as you define those slider codes in the skin, it should request your plugin for the value of the sliders you defined and set them in the skin.

Bear in mind none of the above will work if your plugin isn't registered or isn't setup to be loaded by RR (X definition or plugins.txt of some skins).

Thanks guino. so how often the plugin will be called? I mean the interval. Based on my observation, the plugin will be called every 2 seconds. It is too long for me. For the label, I can refresh it when need via SDK.execute(SETLABEL;xxx), but how to refresh the silders?

Here is guino's suggestion. I have tried and it works very well. The silders was updated every 1/4s and CPU% is under 4%.

'// Defined in RRExtension class
Public Shared curForm As Object

'// The first line in ProcessCommand function
curForm = frm

'//Anywhere I want to update the sliders
If RRExtension.curForm IsNot Nothing Then RRExtension.curForm.updatesliders()

Everything in the skin refreshes according to the screenrefresh= setting in RR.INI -- the default is every 1 second. Setlabel will force an update to a label at request, however sliders are only updated when the screen refreshes, however it should be possible for you store the current screen form object (passed with processcommand at the execution of EVERY command -- including LOAD commands) basically, you would declare a curform object in the plugin like:

(Right below "option explicit" or anywhere globally in your project
Dim CurForm as Object

Then in ProcessCommand() function:

(right before "select case"
set curform = frm

Then whenever you'd need to update the sliders, you could call (from anywhere): curform.updatesliders

Bear in mind:
-I've never tried anything like the above before -- but I don't see why it shouldn't work
-The more you call setlabel/updatesliders, the higher CPU load you'll generate.. and updatesliders can be very cpu intensive.

Let me know,
Guino.