Add single file stage 4 hello world. Move all other stage 4 steps by 1.

Author: jonathanrocher

stage4.0_hello_world_application/main.py

@@ -0,0 +1,84 @@
+""" Hello world as a single file Pyface application
+"""
+
+from traitsui.api import InstanceEditor, Item, ModelView, View
+from traits.api import HasStrictTraits, Instance, Str
+
+from pyface.tasks.api import Task, TasksApplication, TaskFactory, \
+    TraitsTaskPane
+
+
+class HelloWorldModel(HasStrictTraits):
+
+    content = Str
+
+    def _content_default(self):
+        return "Hello World!"
+
+
+class HelloWorldView(ModelView):
+    model = Instance(HelloWorldModel, ())
+
+    def traits_view(self):
+        return View(
+            Item("model.content")
+        )
+
+
+class HelloWorldPane(TraitsTaskPane):
+
+    #: The unique id of the task.
+    id = "pycasa.hello_world_pane"
+
+    #: The human-readable name of the task.
+    name = "Message Viewer Pane"
+
+    hello_world_view = Instance(HelloWorldView, ())
+
+    def traits_view(self):
+        return View(
+            Item("hello_world_view", editor=InstanceEditor(), style="custom",
+                 show_label=False)
+        )
+
+
+class HelloWorldTask(Task):
+
+    #: The unique id of the task.
+    id = "pycasa.hello_world_task"
+
+    #: The human-readable name of the task.
+    name = "Message Viewer Task"
+
+    def create_central_pane(self):
+        """ Create the central pane: the script editor.
+        """
+        return HelloWorldPane()
+
+
+class PycasaApplication(TasksApplication):
+    """ An application to say hello.
+    """
+    id = "pycasa_application"
+
+    name = "Pycasa"
+
+    description = "An example Tasks application that explores image files."
+
+    def _task_factories_default(self):
+        return [
+            TaskFactory(
+                id='pycasa.hello_world_task',
+                name="Hello World Editor",
+                factory=HelloWorldTask
+            )
+        ]
+
+
+def main():
+    app = PycasaApplication()
+    app.run()
+
+
+if __name__ == '__main__':
+    main()