index.lxp@lxpwrap=x5388_252ehtm.htm
来自「GUI Programming with Python」· HTM 代码 · 共 576 行 · 第 1/2 页
HTM
576 行
<table border="0" cellspacing="0" cellpadding="3" width="100%"><tr><td> <div align="center" id="bldcontent"> <a href="../default.htm"><img src="../images/opendocs.png" width="63" height="76" border="0"></a> <br> <div class="symbol">Your OpenSource Publisher™</div> </div> </td></tr></table> <div align="center" class="author"> <a href="../products.lxp">Products</a> | <a href="../wheretobuy.lxp">Where to buy</a> | <a href="../bookstore.lxp">Retailers</a> | <a href="../faq.lxp">FAQ</a> | <a href="../writeforus.lxp">Write for Us.</a> | <a href="#contact">Contact Us.</a> </div> <table border="0" cellspacing="3" cellpadding="0" width="100%"><tr><td width="100%"> <div class="content"> <table border="0" cellspacing="2" cellpadding="0" width="100%"><tr><td width="100%"> <div align="center"><H4 CLASS="AUTHOR"><A NAME="AEN5">Boudewijn Rempt</A><br><a href="../../https@secure.linuxports.com/opendocs/default.htm"><img src=odpyqt125.png></a><br>ISBN: 0-97003300-4-4<br><a href="../../https@secure.linuxports.com/opendocs/default.htm">Available from bookstores everywhere or you can order it here.</a><p>You can download the source files for the book <a href="pyqtsrc.tgz">(code / eps) here.</a><hr></div> <HTML><HEAD><TITLE>The Document Manager</TITLE><METANAME="GENERATOR"CONTENT="Modular DocBook HTML Stylesheet Version 1.72"><LINKREL="HOME"TITLE="GUI Programming with Python: QT Edition"HREF="book1.htm"><LINKREL="UP"TITLE="A More Complex Framework: Multiple Documents, Multiple Views"HREF="c5288.htm"><LINKREL="PREVIOUS"TITLE="Document/View Manager"HREF="x5339.htm"><LINKREL="NEXT"TITLE="Document"HREF="x5451.htm"></HEAD><BODYCLASS="SECT1"BGCOLOR="#FFFFFF"TEXT="#000000"LINK="#0000FF"VLINK="#840084"ALINK="#0000FF"><DIVCLASS="NAVHEADER"><TABLESUMMARY="Header navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><THCOLSPAN="3"ALIGN="center">GUI Programming with Python: QT Edition</TH></TR><TR><TDWIDTH="10%"ALIGN="left"VALIGN="bottom"><A accesskey="P" href="index.lxp@lxpwrap=x5339_252ehtm.htm">Prev</A></TD><TDWIDTH="80%"ALIGN="center"VALIGN="bottom">Chapter 15. A More Complex Framework: Multiple Documents, Multiple Views</TD><TDWIDTH="10%"ALIGN="right"VALIGN="bottom"><A accesskey="N" href="index.lxp@lxpwrap=x5451_252ehtm.htm">Next</A></TD></TR></TABLE><HRALIGN="LEFT"WIDTH="100%"></DIV><DIVCLASS="SECT1"><H1CLASS="SECT1">The Document Manager</A></H1><P>The <TTCLASS="CLASSNAME">DocManager</TT> class is one of the more complex classes discussed in this book. </P><DIVCLASS="EXAMPLE"></A><P><B>Example 15-2. The document manager class</B></P><PRECLASS="PROGRAMLISTING">""" docmanager.py — manager class for document/view mappingscopyright: (C) 2001, Boudewijn Remptemail: boud@rempt.xs4all.nl"""from qt import *TRUE=1FALSE=0class DocManagerError(Exception):passclass NoSuchDocumentError(DocManagerError): ERR = "Document %s with title %s is not managed by this DocumentManager" def __init__(self, document): self.errorMessage = ERR % (str(document), document.title(), str()) def __repr__(self): return self.errorMessage def __str__(self): return self.errorMessageclass DocumentsRemainingError(DocManagerError): def __init__(self, document): self.errorMessage = "There are still documents remaining." def __repr__(self): return self.errorMessage def __str__(self): return self.errorMessage </PRE></DIV><P>If you have a complex class like the document manager, it is often useful to create a few specific exception classes. You can still <TTCLASS="FUNCTION">raise</TT> exceptions that will be mere messages in a string — but these have been deprecated since Python 2.0. For the document manager we have a small hierarchy of exceptions, with a base exception (<TTCLASS="CLASSNAME">DocManagerError</TT>), and two specific exceptions, <TTCLASS="CLASSNAME">NoSuchDocumentError</TT> and <TTCLASS="CLASSNAME">DocumentsRemainingError</TT>. The first exception is raised when an attempt is made to delete a document which is not managed by the document manager. This can happen when you need more than one document manager, for instance. The second is raised when an attempt is made to delete all open documents, but one or more of them could not be closed.</P><PRECLASS="PROGRAMLISTING">class DocManager(QObject): """ The DocManager manages the creation and removal of documents and views. """ def __init__(self, parent, viewManager = None): QObject.__init__(self) self._viewToDocMap = {} self._docToViewMap = {} self._parent=parent if viewManager: self._viewManager = viewManager else: self._viewManager = parent </PRE><P>Two very simple datastructures manage all the information in the document manage. The first is <TTCLASS="VARNAME">_viewToDocMap</TT>, which maps documents to views (one document can be associated with a list of views). The other datastructure, <TTCLASS="VARNAME">_docToViewMap</TT>, maps views to documents. Note the single underscore before the variable names; this indicates that you shouldn't try to use the variable outside its class, in this case <TTCLASS="CLASSNAME">DocManager</TT>. The <TTCLASS="VARNAME">viewManager</TT> is the object that collects all views and shows them in the application letterbox between toolbars and statusbars.</P><PRECLASS="PROGRAMLISTING"> def numberOfDocuments(self): return len(self._docToViewMap) def numberOfViews(self): return len(self._viewToDocMap) def views(self, document): return self._docToViewMap[document] def _createView(self, document, viewClass): view = viewClass(self._viewManager, document, None, QWidget.WDestructiveClose) view.installEventFilter(self._parent) if self._viewToDocMap == {}: view.showMaximized() else: view.show() if self._docToViewMap.has_key(document): index = len(self._docToViewMap[document]) + 1 else: index = 1 view.setCaption(document.title() + " %s" % index) return view </PRE><P>The function <TTCLASS="FUNCTION">_createView(self, document, viewClass)</TT> not only maps views to documents, but also creates the view objects. Note the <TTCLASS="VARNAME">QWidget.WDestructiveClose</TT> flag — if this is not passed to the <TTCLASS="CLASSNAME">QWidget</TT>-derived view class, the view will not disappear from the screen when⌨️ 快捷键说明
复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?