FEM: use python base constraint class, constraint self weight

src/Mod/Fem/femguiobjects/_ViewProviderFemConstraintSelfWeight.py

@@ -28,51 +28,11 @@ __url__ = "http://www.freecadweb.org"
 #  \ingroup FEM
 #  \brief FreeCAD FEM Constraint SelfWeight ViewProvider
 
-import FreeCAD
-import FreeCADGui
-import FemGui  # needed to display the icons in TreeView
-
-False if FemGui.__name__ else True  # flake8, dummy FemGui usage
+from . import ViewProviderFemConstraint
 
 
-class _ViewProviderFemConstraintSelfWeight:
+class _ViewProviderFemConstraintSelfWeight(ViewProviderFemConstraint.ViewProxy):
     "A View Provider for the FemConstraintSelfWeight object"
-    def __init__(self, vobj):
-        vobj.Proxy = self
 
     def getIcon(self):
         return ":/icons/fem-constraint-selfweight.svg"
-
-    def attach(self, vobj):
-        self.ViewObject = vobj
-        self.Object = vobj.Object
-
-    def updateData(self, obj, prop):
-        return
-
-    def onChanged(self, vobj, prop):
-        return
-
-    def setEdit(self, vobj, mode=0):
-        # avoid edit mode by return False
-        # https://forum.freecadweb.org/viewtopic.php?t=12139&start=10#p161062
-        return False
-
-    def doubleClicked(self, vobj):
-        guidoc = FreeCADGui.getDocument(vobj.Object.Document)
-        # check if another VP is in edit mode
-        # https://forum.freecadweb.org/viewtopic.php?t=13077#p104702
-        if not guidoc.getInEdit():
-            guidoc.setEdit(vobj.Object.Name)
-        else:
-            from PySide.QtGui import QMessageBox
-            message = "Active Task Dialog found! Please close this one before opening  a new one!"
-            QMessageBox.critical(None, "Error in tree view", message)
-            FreeCAD.Console.PrintError(message + "\n")
-        return True
-
-    def __getstate__(self):
-        return None
-
-    def __setstate__(self, state):
-        return None

src/Mod/Fem/femobjects/_FemConstraintSelfWeight.py

@@ -27,10 +27,17 @@ __url__ = "http://www.freecadweb.org"
 #  \ingroup FEM
 #  \brief FreeCAD FEM constraint self weight object
 
+from . import FemConstraint
 
-class _FemConstraintSelfWeight:
+
+class _FemConstraintSelfWeight(FemConstraint.Proxy):
     "The FemConstraintSelfWeight object"
+
+    Type = "Fem::ConstraintSelfWeight"
+
     def __init__(self, obj):
+        super(_FemConstraintSelfWeight, self).__init__(obj)
+
         obj.addProperty(
             "App::PropertyFloat",
             "Gravity_x",
@@ -52,8 +59,3 @@ class _FemConstraintSelfWeight:
         obj.Gravity_x = 0.0
         obj.Gravity_y = 0.0
         obj.Gravity_z = -1.0
-        obj.Proxy = self
-        self.Type = "Fem::ConstraintSelfWeight"
-
-    def execute(self, obj):
-        return