I'm a little confused about what you are trying to do - it seems you are trying to duplicate what the action button does.
If you are using action buttons for estop and power (as toggle buttons) they will automatically change state based on linuxcnc. they also handle disabling when not available etc.
But if you do want to make your own linuxcnc aware widget (I would use a regular QToggleButton as the base widget.):
To build your own estop button, you must monitor linuxcnc state and update the button based on it. This is what the STATUS library is for.
Something like this (assuming you have imported the Status library and instantiated it globally as STATUS) :
Code:
STATUS.connect('state-estop', lambda w:self.set_estop_button(True))
STATUS.connect('state-estop-reset', lambda w: self.set_estop_button(False))
Then write a function that it calls:
Code:
def set_estop_button(self, data):
print 'estop state', data
Having widgets respond to HAL pins requires you to make a HAL pin and register it to be monitored and then it will call a function to update what ever you want to update. simple_widget.py 's LCD widget is the simplest example of a HAL pin controlled widget.
If you wish to do that in a handler file it's quite the same (no class of course, init_hal function code goes in handler's def initialized__ function)
It;s a lot easier to show then describe...
Chris M
