Trap presentation errors when OpenOffice.org is not installed

bzr-revno: 892

openlp/plugins/presentations/lib/impresscontroller.py

@@ -41,10 +41,15 @@ from openlp.core.lib import resize_image
 
 if os.name == u'nt':
     from win32com.client import Dispatch
+    import pywintypes
 else:
-    import uno
-    from com.sun.star.beans import PropertyValue
-
+    try:
+        import uno
+        from com.sun.star.beans import PropertyValue
+        uno_available = True
+    except ImportError:
+        uno_available = False
+        
 from PyQt4 import QtCore
 
 from presentationcontroller import PresentationController, PresentationDocument
@@ -78,9 +83,7 @@ class ImpressController(PresentationController):
         if os.name == u'nt':
             return self.get_com_servicemanager() is not None
         else:
-            # If not windows, and we've got this far then probably
-            # installed else the import uno would likely have failed
-            return True
+            return uno_available
 
     def start_process(self):
         """
@@ -322,7 +325,10 @@ class ImpressDocument(PresentationDocument):
         Returns true if screen is blank
         """
         log.debug(u'is blank OpenOffice')
-        return self.control.isPaused()
+        if self.control:
+            return self.control.isPaused()
+        else:
+            return False
 
     def stop_presentation(self):
         log.debug(u'stop presentation OpenOffice')