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2018-06-28T19:39:08Z

1版をインポートしました

2011年2月19日 (土) 16:30にwiki>Mindronesによる

2011-02-19T16:30:03Z

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{{Page/Header|2.5x|Dev:2.5/Py/API/Overview|}}

== Introduction ==
In Blender 2.5 operators are automatically registered (using a metaclass), so Blender can find them. This is normally very convenient, but when you're creating operators dynamically it might cause problems.
 
== Problems and solutions ==
Example of a normal operator declaration that is automatically registered correctly:
<source lang="python">
import bpy

class Foobar(bpy.types.Operator):
''''''
bl_idname = "foo.bar"
bl_label = "FooBar!"

def execute(self, context):
print("foobar")
return {'FINISHED'}
</source>

When you're dynamically creating operators, you might do something like this (which doesn't work):
<source lang="python">
import bpy

my_names = ["Foo", "Bar"]

def invoke(self, context, event):
print(self.bl_description)
return{'FINISHED'}

for name in my_names:
my_class = type(name, (bpy.types.Operator,), dict(bl_idname=name, bl_label=name+"!", bl_description=name))
setattr(my_class, 'invoke', invoke)
</source>
When you try to run the operator you get the error: "invalid operator call". The reason is that the automatic registering (the metaclass) is done immediately upon creating the class. So right after the line "my_class = type(...)". Adding methods or attributes after that, for example using setattr(), is too late. So the main thing to remember is: 
setattr() doesn't work with the automatic registration of operators.

Below are two ways of doing it correctly:
<source lang="python">
import bpy

my_names = ["Foo", "Bar"]

def my_invoke(self, context, event):
print(self.bl_description)
return{'FINISHED'}

for name in my_names:
class my_class(bpy.types.Operator):
bl_idname = name
bl_label = name+"!"
bl_description = name
invoke = my_invoke
</source>
<source lang="python">
import bpy

my_names = ["Foo", "Bar"]

for name in my_names:
class my_class(bpy.types.Operator):
bl_idname = name
bl_label = name+"!"
bl_description = name

def invoke(self, context, event):
print(self.bl_description)
return{'FINISHED'}
</source>

There is one final thing that might stop your script from working, and that's when the script is run as add-on. In your add-on you can't create operators from within the register() function. 
Example of code that fails when run as add-on (but works correctly when run from the text-editor):
<source lang="python">
bl_addon_info = {
"name": "FooBar",
"category": "System"}

import bpy

def create_ops():
my_names = ["Foo", "Bar"]
for name in my_names:
class my_class(bpy.types.Operator):
bl_idname = name
bl_label = name+"!"
bl_description = name

def invoke(self, context, event):
print(self.bl_description)
return{'FINISHED'}

def register():
create_ops()

def unregister():
pass

if __name__ == "__main__":
register()
</source>
The solution is to simply create the operator classes in the module itself (this way they are defined when the module is imported), not in a function definition:
<source lang="python">
bl_addon_info = {
"name": "FooBar",
"category": "System"}

import bpy

my_names = ["Foo", "Bar"]
for name in my_names:
class my_class(bpy.types.Operator):
bl_idname = name
bl_label = name+"!"
bl_description = name

def invoke(self, context, event):
print(self.bl_description)
return{'FINISHED'}

def register():
pass

def unregister():
pass

</source>
 

== Summary ==
*Don't use setattr() to set the poll/invoke/execute functions.
*Don't create operators from within the register() function.
 
== References ==
[http://lists.blender.org/pipermail/bf-committers/2010-September/028703.html Discussion on the mailinglist] 
[https://svn.blender.org/svnroot/bf-extensions/trunk/py/scripts/addons/space_view3d_copy_attributes.py Correct link to script mentioned in above discussion]

{{Page/Footer|Dev:2.5/Py/API/Overview|}}

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Yamyam: 1版 をインポートしました

2011年2月19日 (土) 16:30にwiki>Mindronesによる

Yamyam: 1版をインポートしました