36.6. FrameWork — Interactive application framework

Platforms: Mac

The FrameWork module contains classes that together provide a framework for an interactive Macintosh application. The programmer builds an application by creating subclasses that override various methods of the bases classes, thereby implementing the functionality wanted. Overriding functionality can often be done on various different levels, i.e. to handle clicks in a single dialog window in a non-standard way it is not necessary to override the complete event handling.

Note

This module has been removed in Python 3.x.

Work on the FrameWork has pretty much stopped, now that PyObjC is available for full Cocoa access from Python, and the documentation describes only the most important functionality, and not in the most logical manner at that. Examine the source or the examples for more details. The following are some comments posted on the MacPython newsgroup about the strengths and limitations of FrameWork:

The strong point of FrameWork is that it allows you to break into the control-flow at many different places. W, for instance, uses a different way to enable/disable menus and that plugs right in leaving the rest intact. The weak points of FrameWork are that it has no abstract command interface (but that shouldn’t be difficult), that its dialog support is minimal and that its control/toolbar support is non-existent.

The FrameWork module defines the following functions:

FrameWork.Application()

An object representing the complete application. See below for a description of the methods. The default __init__() routine creates an empty window dictionary and a menu bar with an apple menu.

FrameWork.MenuBar()

An object representing the menubar. This object is usually not created by the user.

FrameWork.Menu(bar, title[, after])

An object representing a menu. Upon creation you pass the MenuBar the menu appears in, the title string and a position (1-based) after where the menu should appear (default: at the end).

FrameWork.MenuItem(menu, title[, shortcut, callback])

Create a menu item object. The arguments are the menu to create, the item title string and optionally the keyboard shortcut and a callback routine. The callback is called with the arguments menu-id, item number within menu (1-based), current front window and the event record.

Instead of a callable object the callback can also be a string. In this case menu selection causes the lookup of a method in the topmost window and the application. The method name is the callback string with 'domenu_' prepended.

Calling the MenuBar fixmenudimstate() method sets the correct dimming for all menu items based on the current front window.

FrameWork.Separator(menu)

Add a separator to the end of a menu.

FrameWork.SubMenu(menu, label)

Create a submenu named label under menu menu. The menu object is returned.

FrameWork.Window(parent)

Creates a (modeless) window. Parent is the application object to which the window belongs. The window is not displayed until later.

FrameWork.DialogWindow(parent)

Creates a modeless dialog window.

FrameWork.windowbounds(width, height)

Return a (left, top, right, bottom) tuple suitable for creation of a window of given width and height. The window will be staggered with respect to previous windows, and an attempt is made to keep the whole window on-screen. However, the window will however always be the exact size given, so parts may be offscreen.

FrameWork.setwatchcursor()

Set the mouse cursor to a watch.

FrameWork.setarrowcursor()

Set the mouse cursor to an arrow.

36.6.1. Application Objects

Application objects have the following methods, among others:

Application.makeusermenus()

Override this method if you need menus in your application. Append the menus to the attribute menubar.

Application.getabouttext()

Override this method to return a text string describing your application. Alternatively, override the do_about() method for more elaborate “about” messages.

Application.mainloop([mask[, wait]])

This routine is the main event loop, call it to set your application rolling. Mask is the mask of events you want to handle, wait is the number of ticks you want to leave to other concurrent application (default 0, which is probably not a good idea). While raising self to exit the mainloop is still supported it is not recommended: call self._quit() instead.

The event loop is split into many small parts, each of which can be overridden. The default methods take care of dispatching events to windows and dialogs, handling drags and resizes, Apple Events, events for non-FrameWork windows, etc.

In general, all event handlers should return 1 if the event is fully handled and 0 otherwise (because the front window was not a FrameWork window, for instance). This is needed so that update events and such can be passed on to other windows like the Sioux console window. Calling MacOS.HandleEvent() is not allowed within our_dispatch or its callees, since this may result in an infinite loop if the code is called through the Python inner-loop event handler.

Application.asyncevents(onoff)

Call this method with a nonzero parameter to enable asynchronous event handling. This will tell the inner interpreter loop to call the application event handler async_dispatch whenever events are available. This will cause FrameWork window updates and the user interface to remain working during long computations, but will slow the interpreter down and may cause surprising results in non-reentrant code (such as FrameWork itself). By default async_dispatch will immediately call our_dispatch but you may override this to handle only certain events asynchronously. Events you do not handle will be passed to Sioux and such.

The old on/off value is returned.

Application._quit()

Terminate the running mainloop() call at the next convenient moment.

Application.do_char(c, event)

The user typed character c. The complete details of the event can be found in the event structure. This method can also be provided in a Window object, which overrides the application-wide handler if the window is frontmost.

Application.do_dialogevent(event)

Called early in the event loop to handle modeless dialog events. The default method simply dispatches the event to the relevant dialog (not through the DialogWindow object involved). Override if you need special handling of dialog events (keyboard shortcuts, etc).

Application.idle(event)

Called by the main event loop when no events are available. The null-event is passed (so you can look at mouse position, etc).

36.6.2. Window Objects

Window objects have the following methods, among others:

Window.open()

Override this method to open a window. Store the Mac OS window-id in self.wid and call the do_postopen() method to register the window with the parent application.

Window.close()

Override this method to do any special processing on window close. Call the do_postclose() method to cleanup the parent state.

Window.do_postresize(width, height, macoswindowid)

Called after the window is resized. Override if more needs to be done than calling InvalRect.

Window.do_contentclick(local, modifiers, event)

The user clicked in the content part of a window. The arguments are the coordinates (window-relative), the key modifiers and the raw event.

Window.do_update(macoswindowid, event)

An update event for the window was received. Redraw the window.

Window.do_activate(activate, event)

The window was activated (activate == 1) or deactivated (activate == 0). Handle things like focus highlighting, etc.

36.6.3. ControlsWindow Object

ControlsWindow objects have the following methods besides those of Window objects:

ControlsWindow.do_controlhit(window, control, pcode, event)

Part pcode of control control was hit by the user. Tracking and such has already been taken care of.

36.6.4. ScrolledWindow Object

ScrolledWindow objects are ControlsWindow objects with the following extra methods:

ScrolledWindow.scrollbars([wantx[, wanty]])

Create (or destroy) horizontal and vertical scrollbars. The arguments specify which you want (default: both). The scrollbars always have minimum 0 and maximum 32767.

ScrolledWindow.getscrollbarvalues()

You must supply this method. It should return a tuple (x, y) giving the current position of the scrollbars (between 0 and 32767). You can return None for either to indicate the whole document is visible in that direction.

ScrolledWindow.updatescrollbars()

Call this method when the document has changed. It will call getscrollbarvalues() and update the scrollbars.

ScrolledWindow.scrollbar_callback(which, what, value)

Supplied by you and called after user interaction. which will be 'x' or 'y', what will be '-', '--', 'set', '++' or '+'. For 'set', value will contain the new scrollbar position.

ScrolledWindow.scalebarvalues(absmin, absmax, curmin, curmax)

Auxiliary method to help you calculate values to return from getscrollbarvalues(). You pass document minimum and maximum value and topmost (leftmost) and bottommost (rightmost) visible values and it returns the correct number or None.

ScrolledWindow.do_activate(onoff, event)

Takes care of dimming/highlighting scrollbars when a window becomes frontmost. If you override this method, call this one at the end of your method.

ScrolledWindow.do_postresize(width, height, window)

Moves scrollbars to the correct position. Call this method initially if you override it.

ScrolledWindow.do_controlhit(window, control, pcode, event)

Handles scrollbar interaction. If you override it call this method first, a nonzero return value indicates the hit was in the scrollbars and has been handled.

36.6.5. DialogWindow Objects

DialogWindow objects have the following methods besides those of Window objects:

DialogWindow.open(resid)

Create the dialog window, from the DLOG resource with id resid. The dialog object is stored in self.wid.

DialogWindow.do_itemhit(item, event)

Item number item was hit. You are responsible for redrawing toggle buttons, etc.