Implement going to the previous serviceitem.

openlp/core/ui/slidecontroller.py

@@ -1174,7 +1174,8 @@ class SlideController(QtWidgets.QWidget, LogMixin, RegistryProperties):
         if not self.service_item:
             return
         if self.service_item.is_command():
-            past_end = Registry().execute('%s_next' % self.service_item.name.lower(), [self.service_item, self.is_live])
+            past_end = Registry().execute('{text}_next'.format(text=self.service_item.name.lower()),
+                                          [self.service_item, self.is_live])
             # Check if we have gone past the end of the last slide
             if self.is_live and past_end and past_end[0]:
                 if wrap is None:
@@ -1211,9 +1212,17 @@ class SlideController(QtWidgets.QWidget, LogMixin, RegistryProperties):
         if not self.service_item:
             return
         if self.service_item.is_command():
-            Registry().execute('{text}_previous'.format(text=self.service_item.name.lower()),
-                               [self.service_item, self.is_live])
-            if self.is_live:
+            before_start = Registry().execute('{text}_previous'.format(text=self.service_item.name.lower()),
+                                              [self.service_item, self.is_live])
+            # Check id we have tried to go before that start slide
+            if self.is_live and before_start and before_start[0]:
+                print('detected before start!')
+                if self.slide_limits == SlideLimits.Wrap:
+                    self.on_slide_selected_index([self.preview_widget.slide_count() - 1])
+                elif self.is_live and self.slide_limits == SlideLimits.Next:
+                    self.keypress_queue.append(ServiceItemAction.PreviousLastSlide)
+                    self._process_queue()
+            elif self.is_live:
                 self.update_preview()
         else:
             row = self.preview_widget.current_slide_number() - 1

openlp/plugins/presentations/lib/impresscontroller.py

@@ -46,6 +46,18 @@ from openlp.plugins.presentations.lib.presentationcontroller import Presentation
 if is_win():
     from win32com.client import Dispatch
     import pywintypes
+    uno_available = False
+    try:
+        service_manager = Dispatch('com.sun.star.ServiceManager')
+        service_manager._FlagAsMethod('Bridge_GetStruct')
+        XSlideShowListenerObj = service_manager.Bridge_GetStruct('com.sun.star.presentation.XSlideShowListener')
+
+        class SlideShowListenerImport(XSlideShowListenerObj.__class__):
+            pass
+    except (AttributeError, pywintypes.com_error):
+        class SlideShowListenerImport(object):
+            pass
+    
     # Declare an empty exception to match the exception imported from UNO
 
     class ErrorCodeIOException(Exception):
@@ -58,6 +70,9 @@ else:
         from com.sun.star.task import ErrorCodeIOException
         from com.sun.star.presentation import XSlideShowListener
 
+        class SlideShowListenerImport(unohelper.Base, XSlideShowListener):
+            pass
+
         uno_available = True
     except ImportError:
         uno_available = False
@@ -504,8 +519,10 @@ class ImpressDocument(PresentationDocument):
             notes.append(note)
         self.save_titles_and_notes(titles, notes)
 
+        if is_win():
+            property_object = self.controller.manager.Bridge_GetStruct('com.sun.star.beans.PropertyValue')
 
-class SlideShowListener(unohelper.Base, XSlideShowListener):
+class SlideShowListener(SlideShowListenerImport):
     """
     Listener interface to receive global slide show events.
     """

openlp/plugins/presentations/lib/messagelistener.py

@@ -203,8 +203,10 @@ class Controller(object):
             return
         if not self.activate():
             return
-        self.doc.previous_step()
+        ret = self.doc.previous_step()
         self.poll()
+        print('previous returning: %d' % ret)
+        return ret
 
     def shutdown(self):
         """
@@ -435,11 +437,12 @@ class MessageListener(object):
         """
         is_live = message[1]
         if is_live:
-            self.live_handler.previous()
+            ret = self.live_handler.previous()
             if Settings().value('core/click live slide to unblank'):
                 Registry().execute('slidecontroller_live_unblank')
+            return ret
         else:
-            self.preview_handler.previous()
+            return self.preview_handler.previous()
 
     def shutdown(self, message):
         """

openlp/plugins/presentations/lib/powerpointcontroller.py

@@ -468,12 +468,16 @@ class PowerpointDocument(PresentationDocument):
         Triggers the previous slide on the running presentation.
         """
         log.debug('previous_step')
+        # if we are at the presentations start we can't go further back, just return True
+        if self.presentation.SlideShowWindow.View.GetClickIndex() == 0 and self.get_slide_number() == 1:
+            return True
         try:
             self.presentation.SlideShowWindow.View.Previous()
         except (AttributeError, pywintypes.com_error):
             log.exception('Caught exception while in previous_step')
             trace_error_handler(log)
             self.show_error_msg()
+        return False
 
     def get_slide_text(self, slide_no):
         """

openlp/plugins/presentations/lib/presentationcontroller.py

@@ -246,15 +246,17 @@ class PresentationDocument(object):
     def next_step(self):
         """
         Triggers the next effect of slide on the running presentation. This might be the next animation on the current
-        slide, or the next slide
+        slide, or the next slide.
+        Returns True if we stepped beyond the slides of the presentation
         """
         return False
 
     def previous_step(self):
         """
         Triggers the previous slide on the running presentation
+        Returns True if we stepped beyond the slides of the presentation
         """
-        pass
+        return False
 
     def convert_thumbnail(self, image_path, index):
         """