Convert PDF Documents to TXT Documents  

val cPDFConvert = CPDFConverterTxt(context, uri, "")
val params = CPDFConvertTxtOptions()
val result: ConvertError = cPDFConvert.convert(outputDir, outputfilename, params, pageArrays, 
onHandle = onHandleCal, 
onProgress = onProgressCal, 
onPost = onPostCal)