How to change Attribute button value without triggering its preChange and postChange command?

Question

I would like to be able to update the visuals of the picker attribute buttons when they are changed outside of the picker.
This command works fine for this.

mc.MGPickerItem(button, e=True, view=view, attributeValue=value)

The issue is that this MGPicerItem call also runs the preChange and postChange commands associated with the button id.

How can I update the picker button visuals without running the command of the button?

Answer 1

Indeed the attribute button's change command will be executed when the attribute value gets actually changed.

So if you don't wanna execute that, you need to pre-record the change command, clear it, and set the value, set back the change command.

Mabe using a python context would be a good idea. Something like:

from maya import cmds
btnId = 'attributeButton1'
viewId = cmds.MGPicker(q=True, activePickerView=True)

class AttributeButtonDisableChangeCmdCtx(object):
    def __init__(self, buttonId, viewId):
        self._btn = buttonId
        self._view= viewId
        self._preChangeCmd = ""
        self._postChangeCmd = ""

    def __enter__(self):
        self._preChangeCmd = cmds.MGPickerItem(self._btn, q=True, preChangeCommand=True, view=self._view)
        self._postChangeCmd = cmds.MGPickerItem(self._btn, q=True, postChangeCommand=True, view=self._view)
        cmds.MGPickerItem(self._btn, e=True, preChangeCommand="", view=self._view)
        cmds.MGPickerItem(self._btn, e=True, postChangeCommand="", view=self._view)

    def __exit__(self, *_, **__):
        cmds.MGPickerItem(self._btn, e=True, preChangeCommand=self._preChangeCmd, view=self._view)
        cmds.MGPickerItem(self._btn, e=True, postChangeCommand=self._postChangeCmd, view=self._view)

When you use it:

with AttributeButtonDisableChangeCmdCtx(btnId, viewId):
    cmds.MGPickerItem(btnId, e=True, atv=True, view=viewId)

Using context make it safer that the change command will be restored.