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<h1 ALIGN="CENTER">Pmw.MessageBar</h1>
<center><IMG SRC=MessageBar.gif ALT="" WIDTH=398 HEIGHT=44></center>
<dl>
<dt> <h3>Name</h3></dt><dd>
<p>Pmw.MessageBar() -
information line for displaying short messages
</p>
</dd>
<dt> <h3>Inherits</h3></dt><dd>
<a href="MegaWidget.html">Pmw.MegaWidget</a><br>
</dd>
<dt> <h3>Description</h3></dt><dd>
<p>
A message bar contains a single-line message display area. Messages
of several different types may displayed. Messages are cleared
after a period defined for each message type. Each message type
has a priority so that if the application attempts to display more
than one message at a time, the message with the highest priority
will be displayed. Messages may be accompanied by a number of
audible bells.</p>
<p> This megawidget can be used for both interactive help messages
(when the mouse enters certain widgets) and also for other general
messages.</p>
<p> To perform the help function it can cooperate with the <a href="Balloon.html">Pmw.Balloon</a>
megawidget so that the programmer (or user) can choose either
balloon help, message bar help, both or neither.</p>
<p> This megawidget supports a configurable number of message types.
The default types include <strong>'state'</strong>, <strong>'help'</strong>, <strong>'usererror'</strong> and
<strong>'systemerror'</strong>. The difference between these are the length of
time they are displayed, the number of bells that are rung and the
priority of the message. For example, the <strong>'help'</strong> message type
is lower in priority than the <strong>'usererror'</strong>, so that error
messages will always be displayed in preference to help messages
regardless of the order the messages are created. The <strong>'state'</strong>
message type is lowest in priority but has no timeout, so it
should contain messages describing the current state of the
application, such as <em>Waiting for database connection</em> or 'Waiting
for file to be unlocked'. Generally this should be set to the
empty string when the application is running normally. By default
the help messages (with message type <strong>'help'</strong>) time out after 5
seconds, so that if the cursor happens to be left over a widget,
the application state will be redisplayed after a short time.</p>
<p></p>
</dd>
<dt> <h3>Options</h3></dt><dd>
Options for this megawidget and its base
classes are described below.<p></p>
<a name=option.labelmargin></a>
<dl><dt> <strong>labelmargin
</strong></dt><dd>
Initialisation option. If the <strong>labelpos</strong> option is not <strong>None</strong>, this specifies the
distance between the <strong>label</strong> component and the rest of the
megawidget. The default is <strong>0</strong>.</p>
</dd></dl>
<a name=option.labelpos></a>
<dl><dt> <strong>labelpos
</strong></dt><dd>
Initialisation option. Specifies where to place the <strong>label</strong> component. If not
<strong>None</strong>, it should be a concatenation of one or two of the
letters <strong>'n'</strong>, <strong>'s'</strong>, <strong>'e'</strong> and <strong>'w'</strong>. The first letter
specifies on which side of the megawidget to place the label.
If a second letter is specified, it indicates where on that
side to place the label. For example, if <strong>labelpos</strong> is <strong>'w'</strong>,
the label is placed in the center of the left hand side; if
it is <strong>'wn'</strong>, the label is placed at the top of the left
hand side; if it is <strong>'ws'</strong>, the label is placed at the
bottom of the left hand side.</p>
<p> If <strong>None</strong>, a label component is not created. The default is <strong>None</strong>.</p>
</dd></dl>
<a name=option.messagetypes></a>
<dl><dt> <strong>messagetypes
</strong></dt><dd>
Initialisation option. This defines what message types are supported by the message bar
and the characteristics of those message types. It is a
dictionary where the key is a string specifying a message type and
the value is a tuple of four integers, (<em>priority</em>, <em>showtime</em>,
<em>bells</em>, <em>logmessage</em>), where <em>priority</em> is the rank of the
message type, <em>showtime</em> is the number of seconds to display
messages of this message type, <em>bells</em> is the number of audible
bells to ring and <em>logmessage</em> is a boolean
specifying whether this message should be logged for retrieval
later. Messages with a higher priority are displayed in
preference to those with lower priority. If a high priority
message times out (because it has been displayed for <em>showtime</em>
seconds), then a lower priority message may be displayed. A
<em>showtime</em> of <strong>0</strong> means that the message will never time out and
is useful for displaying messages describing the current state of
the application as opposed to messages describing events. Logging
is not currently implemented. The default is</p>
<dl><dd><pre> {
'systemerror' : (5, 10, 2, 1),
'usererror' : (4, 5, 1, 0),
'busy' : (3, 0, 0, 0),
'systemevent' : (2, 5, 0, 0),
'userevent' : (2, 5, 0, 0),
'help' : (1, 5, 0, 0),
'state' : (0, 0, 0, 0),
}</pre></dd></dl>
</dd></dl>
<a name=option.silent></a>
<dl><dt> <strong>silent
</strong></dt><dd>
If true, no audible bells will sound, regardless of the value for
<em>bells</em> defined in the <strong>messagetypes</strong> option. The default is <strong>0</strong>.</p>
</dd></dl>
<a name=option.sticky></a>
<dl><dt> <strong>sticky
</strong></dt><dd>
Initialisation option. The default is <strong>'ew'</strong>.</p>
</dd></dl>
</dd>
<dt> <h3>Components</h3></dt><dd>
Components created by this megawidget and its base
classes are described below.<p></p>
<a name=component.entry></a>
<dl><dt> <strong>entry
</strong></dt><dd>
The widget where the messages are displayed. Long messages may be
scrolled horizontally by dragging with the middle mouse button. By default, this component is a Tkinter.Entry.</p>
</dd></dl>
<a name=component.hull></a>
<dl><dt> <strong>hull
</strong></dt><dd>
This acts as the body for the entire megawidget. Other components
are created as children of the hull to further specialise this
class. By default, this component is a Tkinter.Frame.</p>
</dd></dl>
<a name=component.label></a>
<dl><dt> <strong>label
</strong></dt><dd>
If the <strong>labelpos</strong> option is not <strong>None</strong>, this component is
created as a text label for the megawidget. See the
<strong>labelpos</strong> option for details. Note that to set, for example,
the <strong>text</strong> option of the label, you need to use the <strong>label_text</strong>
component option. By default, this component is a Tkinter.Label.</p>
</dd></dl>
</dd>
<a name=methods></a>
<dt> <h3>Methods</h3></dt><dd>
Only methods specific to this megawidget are described below.
For a description of its inherited methods, see the
manual for its base class
<strong><a href="MegaWidget.html#methods">Pmw.MegaWidget</a></strong>.
In addition, methods from the
<strong>Tkinter.Entry</strong> class
are forwarded by this megawidget to the
<strong>entry</strong> component.
<p></p>
<a name=method.helpmessage></a>
<dl><dt> <strong>helpmessage</strong>(<em>text</em>)</dt><dd>
A convenience method to display <em>text</em> in the message bar
according to the characteristics defined by the <strong>help</strong> message type.
Equivalent to <code>message('help', text)</code>.</p>
</dd></dl>
<a name=method.message></a>
<dl><dt> <strong>message</strong>(<em>type</em>, <em>text</em>)</dt><dd>
Display <em>text</em> in the message bar according to the characteristics
defined by the <em>type</em> message type, as discussed under
<strong>messagetypes</strong>.</p>
</dd></dl>
<a name=method.resetmessages></a>
<dl><dt> <strong>resetmessages</strong>(<em>type</em>)</dt><dd>
Clear the <em>type</em> message and all message types with a lower
priority, except permanent messages, such as <strong>state</strong>. This is
useful to clear the <strong>busy</strong> message and any outstanding event and
help messages.</p>
</dd></dl>
</dd>
<dt> <h3>Example</h3></dt><dd>
The image at the top of this manual is a snapshot
of the window (or part of the window) produced
by the following code.<p></p>
<pre>
class Demo:
def __init__(self, parent):
# Create and pack the MessageBar.
self._messagebar = Pmw.MessageBar(parent,
entry_width = 40,
entry_relief='groove',
labelpos = 'w',
label_text = 'Status:')
self._messagebar.pack(side = 'bottom', fill = 'x',
expand = 1, padx = 10, pady = 10)
# Create and pack the ScrolledListBox to change the MessageBar.
self.box = Pmw.ScrolledListBox(parent,
listbox_selectmode='single',
items=('state', 'help', 'userevent', 'systemevent',
'usererror', 'systemerror', 'busy',),
label_text='Message type',
labelpos='n',
selectioncommand=self.selectionCommand)
self.box.pack(fill = 'both', expand = 'yes', padx = 10, pady = 10)
self._index = 0
self._stateCounter = 0
def selectionCommand(self):
sels = self.box.getcurselection()
if len(sels) > 0:
self._index = self._index + 1
messagetype = sels[0]
if messagetype == 'state':
self._stateCounter = (self._stateCounter + 1) % 3
text = stateMessages[self._stateCounter]
if text != '':
text = text + ' (' + messagetype + ')'
self._messagebar.message('state', text)
else:
text = messages[messagetype]
text = text + ' (' + messagetype + ')'
self._messagebar.message(messagetype, text)
if messagetype == 'busy':
Pmw.showbusycursor()
self.box.after(2000)
Pmw.hidebusycursor()
self._messagebar.resetmessages('busy')
text = 'All files successfully removed'
text = text + ' (userevent)'
self._messagebar.message('userevent', text)
messages = {
'help': 'Save current file',
'userevent': 'Saving file "foo"',
'busy': 'Busy deleting all files from file system ...',
'systemevent': 'File "foo" saved',
'usererror': 'Invalid file name "foo/bar"',
'systemerror': 'Failed to save file: file system full',
}
stateMessages = {
0: '',
1: 'Database is down',
2: 'Waiting for reply from database',
}
</pre>
</dd>
</dl>
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Pmw 1.3 -
7 Aug 2007
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