59 lines
2.3 KiB
Python
59 lines
2.3 KiB
Python
# Created By: Virgil Dupras
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# Created On: 2011/09/09
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# Copyright 2013 Hardcoded Software (http://www.hardcoded.net)
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#
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# This software is licensed under the "BSD" License as described in the "LICENSE" file,
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# which should be included with this package. The terms are also available at
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# http://www.hardcoded.net/licenses/bsd_license
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def noop(*args, **kwargs):
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pass
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class NoopGUI:
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def __getattr__(self, func_name):
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return noop
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# A GUIObject is a cross-toolkit "model" representation of a GUI layer object, for example, a table.
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# It acts as a cross-toolkit interface to multiple what we call here a "view". That view is a
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# toolkit-specific controller to the actual view (an NSTableView, a QTableView, etc.).
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# In our GUIObject, we need a reference to that toolkit-specific controller because some actions,
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# have effects on it (for example, prompting it to refresh its data). The GUIObject is typically
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# instantiated before its "view", that is why we set it as None on init. However, the GUI
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# layer is supposed to set the view as soon as its toolkit-specific controller is instantiated.
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# When you subclass GUIObject, you will likely want to update its view on instantiation. That
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# is why we call self.view.refresh() in _view_updated(). If you need another type of action on
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# view instantiation, just override the method.
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class GUIObject:
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def __init__(self):
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self._view = None
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def _view_updated(self):
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pass #virtual
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def has_view(self):
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return (self._view is not None) and (not isinstance(self._view, NoopGUI))
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@property
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def view(self):
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return self._view
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@view.setter
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def view(self, value):
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# There's two times at which we set the view property: On initialization, where we set the
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# view that we'll use for your lifetime, and just before the view is deallocated. We need
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# to unset our view at that time to avoid calls to a deallocated instance (which means a
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# crash).
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if self._view is None:
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# Initial view assignment
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if value is None:
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return
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self._view = value
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self._view_updated()
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else:
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assert value is None
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# Instead of None, we put a NoopGUI() there to avoid rogue view callback raising an
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# exception.
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self._view = NoopGUI()
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