Ability to close all open 'MayaBaseWindow' class windows.

This can be used to clean up while closing Maya, or
opening a new Maya scene file.

Issue #222

Author: david-cattermole

python/mmSolver/ui/base_maya_window.py

@@ -149,6 +149,21 @@ def get_instance(cls):
             instance = cls.instance
         return instance
 
+    @classmethod
+    def close_all_instances(cls):
+        global ALL_CLASS_INSTANCES
+        for instance in ALL_CLASS_INSTANCES:
+            if not instance:
+                continue
+            if uiutils.isValidQtObject(instance) is False:
+                continue
+            LOG.debug("Closing: %r", instance.objectName())
+            instance.deleteLater()
+            instance.close()
+        del ALL_CLASS_INSTANCES
+        ALL_CLASS_INSTANCES = set()
+        return
+
     @classmethod
     def open_window(cls, show=True, auto_raise=True, delete=False, dock=False):
         s = time.time()
@@ -163,7 +178,11 @@ def open_window(cls, show=True, auto_raise=True, delete=False, dock=False):
             name = cls.name
             app, parent = uiutils.getParent()
             cls.instance = cls(parent=parent, name=name)
-            cls.instance.setDockableParameters(dockable=dock)
+            # Do not retain the workspaceController after the window
+            # has closed, if retain=True this causes errors when
+            # windows are closed.
+            retain = False
+            cls.instance.setDockableParameters(dockable=dock, retain=retain)
 
         # Make sure the user can see this window.
         if cls.instance.isHidden():