OpenOffice Calc macro to add pie chart - macros

Question

I am trying to insert a piechart in open-office using macro. But the code shows error:
Line:
Dim oDiagram As New com.sun.star.chart.PieDiagram
Error:
"Object not accessible. Invalid reference."
I am unable to figure out why. Kindly help. Here is my complete macro code:
Sub Macro1
Dim oRange as Object
Dim oRangeAddress(1) As New com.sun.star.table.CellRangeAddress
Dim oDiagram As New com.sun.star.chart.PieDiagram
Dim oRect As New com.sun.star.awt.Rectangle
Dim cTitle as String
oRange = thisComponent.getCurrentSelection.getRangeAddress
oSheets = ThisComponent.getSheets()
oSheet = oSheets.getByIndex(0)
oCharts = oSheet.Charts
oRect.Width = 10000
oRect.Height = 10000
oRect.X = 8000
oRect.Y = 1000
oRangeAddress(0).Sheet = oRange.Sheet
oRangeAddress(0).StartColumn = 0
oRangeAddress(0).StartRow = 0
oRangeAddress(0).EndColumn = 1
oRangeAddress(0).EndRow = 2
cTitle = "Test Results"
oCharts.addNewByName(cTitle,oRect,oRangeAddress(),TRUE, TRUE)
oChart = oCharts.getByName(cTitle).embeddedObject
oChart.Diagram = oDiagram
oChart.HasMainTitle = True
oChart.Title.String = cTitle
End Sub
Here is the input sheet data:

Answer 1

You can't instantiate a com.sun.star.chart.PieDiagram directly, independent of an already-existing chart. Instead, you'll have to create the chart first, and then create a PieDiagram. Thus, to make the macro work, do the following:
remove the line Dim oDiagram As New com.sun.star.chart.PieDiagram
change the line oChart.Diagram = oDiagram to oChart.Diagram = oChart.createInstance("com.sun.star.chart.PieDiagram").
This results in the following code (i've tested this with OpenOffice.org Calc 4.1.0 on Win7):
Sub Macro1
Dim oRange as Object
Dim oRangeAddress(1) As New com.sun.star.table.CellRangeAddress
Dim oRect As New com.sun.star.awt.Rectangle
Dim cTitle as String
oRange = thisComponent.getCurrentSelection.getRangeAddress
oSheets = ThisComponent.getSheets()
oSheet = oSheets.getByIndex(0)
oCharts = oSheet.Charts
oRect.Width = 10000
oRect.Height = 10000
oRect.X = 8000
oRect.Y = 1000
oRangeAddress(0).Sheet = oRange.Sheet
oRangeAddress(0).StartColumn = 0
oRangeAddress(0).StartRow = 0
oRangeAddress(0).EndColumn = 1
oRangeAddress(0).EndRow = 2
cTitle = "Test Results"
oCharts.addNewByName(cTitle,oRect,oRangeAddress(),TRUE, TRUE)
oChart = oCharts.getByName(cTitle).embeddedObject
oChart.Diagram = oChart.createInstance("com.sun.star.chart.PieDiagram")
oChart.HasMainTitle = True
oChart.Title.String = cTitle
End Sub
Running the macro should give the following result:
NB: The macro won't run on LibreOffice Calc; it only works with OpenOffice.org Calc. I think this a LibreOffice bug, since i coudn't find any differences in the API of OOo and LO.