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576 lines
30 KiB
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/doc/application-walkthrough.doc:36 -->
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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<title>Walkthrough: A Simple Application</title>
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<style type="text/css"><!--
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<table border="0" cellpadding="0" cellspacing="0" width="100%">
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<a href="index.html">
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<font color="#004faf">Home</font></a>
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<font color="#004faf">All Classes</font></a>
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<font color="#004faf">Main Classes</font></a>
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<font color="#004faf">Annotated</font></a>
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<font color="#004faf">Functions</font></a>
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</td>
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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Walkthrough: A Simple Application</h1>
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<p>
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<p> This walkthrough shows simple use of <a href="ntqmainwindow.html">TQMainWindow</a>, <a href="ntqmenubar.html">TQMenuBar</a>, <a href="ntqpopupmenu.html">TQPopupMenu</a>, <a href="ntqtoolbar.html">TQToolBar</a> and <a href="ntqstatusbar.html">TQStatusBar</a> - classes that every
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modern application window tends to use. (See also <a href="tutorial2.html">Tutorial #2</a>.)
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<p> It also illustrates some aspects of <a href="ntqwhatsthis.html">TQWhatsThis</a> (for simple help) and a
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typical <tt>main()</tt> using <a href="ntqapplication.html">TQApplication</a>.
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<p> Finally, it shows a typical print function based on <a href="ntqprinter.html">TQPrinter</a>.
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<p> <h2> The declaration of ApplicationWindow
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</h2>
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<a name="1"></a><p> Here's the header file in full:
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<p> <pre>/****************************************************************************
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** $Id: qt/application.h 3.3.8 edited Jan 11 14:37 $
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**
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** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
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**
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** This file is part of an example program for TQt. This example
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** program may be used, distributed and modified without limitation.
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**
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*****************************************************************************/
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#ifndef APPLICATION_H
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#define APPLICATION_H
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#include <<a href="qmainwindow-h.html">ntqmainwindow.h</a>>
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class TQTextEdit;
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class ApplicationWindow: public <a href="ntqmainwindow.html">TQMainWindow</a>
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{
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<a href="metaobjects.html#TQ_OBJECT">TQ_OBJECT</a>
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public:
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ApplicationWindow();
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~ApplicationWindow();
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protected:
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void closeEvent( <a href="qcloseevent.html">TQCloseEvent</a>* );
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private slots:
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void newDoc();
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void choose();
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void load( const <a href="ntqstring.html">TQString</a> &fileName );
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void save();
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void saveAs();
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void print();
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void about();
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void aboutTQt();
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private:
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<a href="ntqprinter.html">TQPrinter</a> *printer;
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<a href="ntqtextedit.html">TQTextEdit</a> *e;
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<a href="ntqstring.html">TQString</a> filename;
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};
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#endif
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</pre>
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<p> It declares a class that inherits <a href="ntqmainwindow.html">TQMainWindow</a>, with slots and private
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variables. The class pre-declaration of <a href="ntqtextedit.html">TQTextEdit</a> at the beginning
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(instead of an include) helps to speed up compilation. With this
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trick, <tt>make depend</tt> won't insist on recompiling every <tt>.cpp</tt> file that
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includes <tt>application.h</tt> when <a href="qtextedit-h.html">ntqtextedit.h</a> changes.
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<p> <a name="simplemain"></a>
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<h2> A simple main()
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</h2>
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<a name="2"></a><p> Here is <tt>main.cpp</tt> in full:
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<p> <pre>/****************************************************************************
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** $Id: qt/main.cpp 3.3.8 edited Jan 11 14:37 $
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**
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** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
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**
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** This file is part of an example program for TQt. This example
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** program may be used, distributed and modified without limitation.
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**
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*****************************************************************************/
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#include <<a href="qapplication-h.html">ntqapplication.h</a>>
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#include "application.h"
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int main( int argc, char ** argv ) {
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<a href="ntqapplication.html">TQApplication</a> a( argc, argv );
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ApplicationWindow *mw = new ApplicationWindow();
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mw-><a href="ntqwidget.html#setCaption">setCaption</a>( "TQt Example - Application" );
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<a name="x1598"></a> mw-><a href="ntqwidget.html#show">show</a>();
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<a name="x1599"></a> a.<a href="ntqobject.html#connect">connect</a>( &a, TQ_SIGNAL(<a href="ntqapplication.html#lastWindowClosed">lastWindowClosed</a>()), &a, TQ_SLOT(<a href="ntqapplication.html#quit">quit</a>()) );
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return a.<a href="ntqapplication.html#exec">exec</a>();
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}
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</pre>
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<p> Now we'll look at <tt>main.cpp</tt> in detail.
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<p>
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<pre> int main( int argc, char ** argv ) {
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<a href="ntqapplication.html">TQApplication</a> a( argc, argv );
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</pre>
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<p> With the above line, we create a <a href="ntqapplication.html">TQApplication</a> object with the usual
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constructor and let it
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parse <em>argc</em> and <em>argv</em>. TQApplication itself takes care of X11-specific
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command-line options like <em>-geometry</em>, so the program will automatically
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behave the way X clients are expected to.
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<p> <pre> ApplicationWindow *mw = new ApplicationWindow();
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mw-><a href="ntqwidget.html#setCaption">setCaption</a>( "TQt Example - Application" );
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<a name="x2115"></a> mw-><a href="ntqwidget.html#show">show</a>();
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</pre>
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<p> We create an <em>ApplicationWindow</em> as a top-level widget, set its window
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system caption to "Document 1", and <em>show()</em> it.
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<p> <a name="close"></a>
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<pre> a.<a href="ntqobject.html#connect">connect</a>( &a, TQ_SIGNAL(<a href="ntqapplication.html#lastWindowClosed">lastWindowClosed</a>()), &a, TQ_SLOT(<a href="ntqapplication.html#quit">quit</a>()) );
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</pre>
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<p> When the application's last window is closed, it should quit. Both
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the signal and the slot are predefined members of <a href="ntqapplication.html">TQApplication</a>.
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<p> <pre> return a.<a href="ntqapplication.html#exec">exec</a>();
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</pre>
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<p> Having completed the application's initialization, we start the main
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event loop (the GUI), and eventually return the error code
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that TQApplication returns when it leaves the event loop.
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<p> <pre> }
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</pre>
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<p> <a name="ApplicationWindow"></a>
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<h2> The Implementation of ApplicationWindow
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</h2>
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<a name="3"></a><p>
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<p> Since the implementation is quite large (almost 300 lines) we
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won't list the whole thing. (The source code is included in the
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examples/application directory.) Before we start with the constructor
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there are three <tt>#include</tt>s worth mentioning:
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<p> <pre> #include "filesave.xpm"
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#include "fileopen.xpm"
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#include "fileprint.xpm"
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</pre>
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<p> The tool buttons in our application wouldn't look good without icons!
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These icons can be found in the XPM files included above. If you ever
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moved a program to a different location and wondered why icons were
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missing afterwards you will probably agree that it is a good idea to
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compile them into the binary. This is what we are doing here.
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<p> <pre> ApplicationWindow::ApplicationWindow()
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: <a href="ntqmainwindow.html">TQMainWindow</a>( 0, "example application main window", WDestructiveClose | WGroupLeader )
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{
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</pre>
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<p> <em>ApplicationWindow</em> inherits <a href="ntqmainwindow.html">TQMainWindow</a>, the TQt class that provides
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typical application main windows, with menu bars, toolbars, etc.
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<p> <pre> printer = new <a href="ntqprinter.html">TQPrinter</a>( TQPrinter::HighResolution );
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</pre>
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<p> The application example can print things, and we chose to have a
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<a href="ntqprinter.html">TQPrinter</a> object lying around so that when the user changes a setting
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during one printing, the new setting will be the default next time.
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<p> <pre> <a href="ntqpixmap.html">TQPixmap</a> openIcon, saveIcon, printIcon;
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</pre>
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<p> For the sake of simplicity, our example only has a few commands in the
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toolbar. The above variables are used to hold an icon for each of
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them.
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<p> <pre> <a href="ntqtoolbar.html">TQToolBar</a> * fileTools = new <a href="ntqtoolbar.html">TQToolBar</a>( this, "file operations" );
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</pre>
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<p> We create a toolbar in <em>this</em> window ...
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<p> <pre> fileTools-><a href="ntqtoolbar.html#setLabel">setLabel</a>( "File Operations" );
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</pre>
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<p> ... and define a title for it. When a user drags the toolbar out of
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its location and floats it over the desktop, the toolbar-window will
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show "File Operations" as caption.
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<p> <pre> openIcon = TQPixmap( fileopen );
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TQToolButton * fileOpen
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= new <a href="ntqtoolbutton.html">TQToolButton</a>( openIcon, "Open File", <a href="ntqstring.html#TQString-null">TQString::null</a>,
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this, TQ_SLOT(choose()), fileTools, "open file" );
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</pre>
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<p> Now we create the first tool button for the <em>fileTools</em> toolbar
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with the appropriate icon and the tool-tip text "Open File".
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The <tt>fileopen.xpm</tt> we included at the beginning
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contains the definition of a pixmap called <em>fileopen</em>.
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We use this icon to illustrate our first tool button.
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<p> <pre> saveIcon = TQPixmap( filesave );
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TQToolButton * fileSave
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= new <a href="ntqtoolbutton.html">TQToolButton</a>( saveIcon, "Save File", TQString::null,
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this, TQ_SLOT(save()), fileTools, "save file" );
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printIcon = TQPixmap( fileprint );
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TQToolButton * filePrint
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= new <a href="ntqtoolbutton.html">TQToolButton</a>( printIcon, "Print File", TQString::null,
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this, TQ_SLOT(print()), fileTools, "print file" );
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</pre>
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<p> In a similar way we create two more tool buttons in this toolbar, each with
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appropriate icons and tool-tip text. All three buttons are connected
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to appropriate slots in this object; for example, the "Print File" button
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to <a href="#printer">ApplicationWindow::print()</a>.
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<p> <pre> (void)TQWhatsThis::whatsThisButton( fileTools );
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</pre>
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<p> The fourth button in the toolbar is somewhat peculiar: it's the one that
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provides "What's This?" help. This must be set up using a special
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function, as its mouse interface is unusual.
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<p> <pre> const char * fileOpenText = "<p><img source=\"fileopen\"> "
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"Click this button to open a <em>new file</em>.<br>"
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"You can also select the <b>Open</b> command "
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"from the <b>File</b> menu.</p>";
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TQWhatsThis::<a href="ntqwhatsthis.html#add">add</a>( fileOpen, fileOpenText );
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</pre>
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<p> With the above line we add the "What's This?" help-text to the
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<em>fileOpen</em> button...
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<p> <pre> TQMimeSourceFactory::<a href="qmimesourcefactory.html#defaultFactory">defaultFactory</a>()->setPixmap( "document-open", openIcon );
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</pre>
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<p> ... and tell the rich-text engine that when a help-text (like the one
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saved in <em>fileOpenText</em>) requests an image named "document-open", the <em>openIcon</em> pixmap is used.
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<p> <pre> const char * fileSaveText = "<p>Click this button to save the file you "
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"are editing. You will be prompted for a file name.\n"
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"You can also select the <b>Save</b> command "
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"from the <b>File</b> menu.</p>";
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TQWhatsThis::<a href="ntqwhatsthis.html#add">add</a>( fileSave, fileSaveText );
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const char * filePrintText = "Click this button to print the file you "
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"are editing.\n"
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"You can also select the Print command "
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"from the File menu.";
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TQWhatsThis::<a href="ntqwhatsthis.html#add">add</a>( filePrint, filePrintText );
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</pre>
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<p> The "What's This?" help of the remaining two buttons doesn't make use
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of pixmaps, therefore all we need to do is to add the help-text to the
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button. Be careful though: To invoke the rich-text elements in <tt>fileSaveText()</tt>, the entire string must be surrounded by <p> and
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</p>. In <tt>filePrintText()</tt>, we don't have rich-text elements, so
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this is not necessary.
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<p> <pre> <a href="ntqpopupmenu.html">TQPopupMenu</a> * file = new <a href="ntqpopupmenu.html">TQPopupMenu</a>( this );
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<a href="ntqmainwindow.html#menuBar">menuBar</a>()->insertItem( "&File", file );
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</pre>
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<p> Next we create a <a href="ntqpopupmenu.html">TQPopupMenu</a> for the <em>File</em> menu and
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add it to the menu bar. With the ampersand in front of the letter F,
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we allow the user to use the shortcut <em>Alt+F</em> to pop up this menu.
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<p> <pre> file-><a href="ntqmenudata.html#insertItem">insertItem</a>( "&New", this, TQ_SLOT(newDoc()), CTRL+Key_N );
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</pre>
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<p> Its first entry is connected to the (yet to be implemented) slot <tt>newDoc()</tt>. When the user chooses this <em>New</em> entry (e.g. by typing the
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letter N as marked by the ampersand) or uses the
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<em>Ctrl+N</em> accelerator, a new editor-window will pop up.
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<p> <pre> int id;
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id = file-><a href="ntqmenudata.html#insertItem">insertItem</a>( openIcon, "&Open...",
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this, TQ_SLOT(choose()), CTRL+Key_O );
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file-><a href="ntqmenudata.html#setWhatsThis">setWhatsThis</a>( id, fileOpenText );
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id = file-><a href="ntqmenudata.html#insertItem">insertItem</a>( saveIcon, "&Save",
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this, TQ_SLOT(save()), CTRL+Key_S );
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file-><a href="ntqmenudata.html#setWhatsThis">setWhatsThis</a>( id, fileSaveText );
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id = file-><a href="ntqmenudata.html#insertItem">insertItem</a>( "Save &As...", this, TQ_SLOT(saveAs()) );
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file-><a href="ntqmenudata.html#setWhatsThis">setWhatsThis</a>( id, fileSaveText );
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</pre>
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<p> We populate the <em>File</em> menu with three more commands (<em>Open</em>, <em>Save</em> and
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<em>Save As</em>), and set "What's This?" help for them. Note in particular
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that "What's This?" help and pixmaps are used in both the toolbar (above)
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and the menu bar (here). (See <a href="ntqaction.html">TQAction</a> and the <tt>examples/action</tt>
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example for a shorter and easier approach.)
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<p> <pre> file-><a href="ntqmenudata.html#insertSeparator">insertSeparator</a>();
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</pre>
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<p> Then we insert a separator, ...
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<p> <pre> id = file-><a href="ntqmenudata.html#insertItem">insertItem</a>( printIcon, "&Print...",
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this, TQ_SLOT(print()), CTRL+Key_P );
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file-><a href="ntqmenudata.html#setWhatsThis">setWhatsThis</a>( id, filePrintText );
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file-><a href="ntqmenudata.html#insertSeparator">insertSeparator</a>();
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file-><a href="ntqmenudata.html#insertItem">insertItem</a>( "&Close", this, TQ_SLOT(<a href="ntqwidget.html#close">close</a>()), CTRL+Key_W );
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file-><a href="ntqmenudata.html#insertItem">insertItem</a>( "&Quit", tqApp, TQ_SLOT( <a href="ntqapplication.html#closeAllWindows">closeAllWindows</a>() ), CTRL+Key_Q );
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</pre>
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<p> ... the <em>Print</em> command with "What's This?" help, another separator and
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two more commands (<em>Close</em> and <em>Quit</em>) without "What's This?" and pixmaps.
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In case of the <em>Close</em> command, the signal is connected
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to the <em>close()</em> slot of the respective <em>ApplicationWindow</em> object whilst
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the <em>Quit</em> command affects the entire application.
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<p> Because <em>ApplicationWindow</em> is a <a href="ntqwidget.html">TQWidget</a>, the <em>close()</em> function
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triggers a call to <a href="#closeEvent">closeEvent()</a> which we
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will implement later.
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<p> <a name="common_constructor"></a>
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<pre> <a href="ntqmainwindow.html#menuBar">menuBar</a>()->insertSeparator();
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</pre>
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<p> Now that we have done the File menu we shift our focus back to the
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menu bar and insert a separator. From now on further menu bar entries
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will be aligned to the right if the windows system style requires it.
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<p> <pre> <a href="ntqpopupmenu.html">TQPopupMenu</a> * help = new <a href="ntqpopupmenu.html">TQPopupMenu</a>( this );
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<a href="ntqmainwindow.html#menuBar">menuBar</a>()->insertItem( "&Help", help );
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help-><a href="ntqmenudata.html#insertItem">insertItem</a>( "&About", this, TQ_SLOT(about()), Key_F1 );
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help-><a href="ntqmenudata.html#insertItem">insertItem</a>( "About &TQt", this, TQ_SLOT(aboutTQt()) );
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help-><a href="ntqmenudata.html#insertSeparator">insertSeparator</a>();
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help-><a href="ntqmenudata.html#insertItem">insertItem</a>( "What's &This", this, TQ_SLOT(<a href="ntqmainwindow.html#whatsThis">whatsThis</a>()), SHIFT+Key_F1 );
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</pre>
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<p> We create a <em>Help</em> menu, add it to the menu bar, and insert a few
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commands. Depending on the style it will appear on the right hand
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side of the menu bar or not.
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<p> <pre> e = new <a href="ntqtextedit.html">TQTextEdit</a>( this, "editor" );
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e-><a href="ntqwidget.html#setFocus">setFocus</a>();
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<a href="ntqmainwindow.html#setCentralWidget">setCentralWidget</a>( e );
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</pre>
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<p> Now we create a simple text-editor, set the initial focus to it,
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and make it the window's central widget.
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<p> <a href="ntqmainwindow.html#centralWidget">TQMainWindow::centralWidget</a>() is the heart of the entire application:
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It's what menu bar, statusbar and toolbars are all arranged around. Since
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the central widget is a text editing widget, we can now reveal that
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our simple application is a text editor. :)
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<p> <pre> <a href="ntqmainwindow.html#statusBar">statusBar</a>()->message( "Ready", 2000 );
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</pre>
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<p> We make the statusbar say "Ready" for two seconds at startup, just to
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tell the user that the window has finished initialization and can be
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used.
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<p> <pre> <a href="ntqwidget.html#resize">resize</a>( 450, 600 );
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</pre>
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<p> Finally it's time to resize the new window to a a nice default size.
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<p> <pre> }
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</pre>
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<p> We have now finished with the constructor. Now we'll deal with the
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destructor.
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<p> <pre> ApplicationWindow::~ApplicationWindow()
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{
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delete printer;
|
|
}
|
|
</pre>
|
|
<p> The only thing an <em>ApplicationWindow</em> widget needs to do in its
|
|
destructor is to delete the printer it created. All other objects are
|
|
child widgets, which TQt will delete when appropriate.
|
|
<p> Now our task is to implement all the slots mentioned in the header file
|
|
and used in the constructor.
|
|
<p> <a name="newDoc()"></a>
|
|
<pre> void ApplicationWindow::newDoc()
|
|
{
|
|
ApplicationWindow *ed = new ApplicationWindow;
|
|
ed-><a href="ntqwidget.html#setCaption">setCaption</a>("TQt Example - Application");
|
|
ed-><a href="ntqwidget.html#show">show</a>();
|
|
}
|
|
</pre>
|
|
<p> This slot, connected to the <em>File|New</em> menu item, simply creates a
|
|
new <em>ApplicationWindow</em> and shows it.
|
|
<p> <a name="choose()"></a>
|
|
<pre> void ApplicationWindow::choose()
|
|
{
|
|
<a href="ntqstring.html">TQString</a> fn = TQFileDialog::<a href="ntqfiledialog.html#getOpenFileName">getOpenFileName</a>( TQString::null, TQString::null,
|
|
this);
|
|
if ( !fn.<a href="ntqstring.html#isEmpty">isEmpty</a>() )
|
|
load( fn );
|
|
else
|
|
<a href="ntqmainwindow.html#statusBar">statusBar</a>()->message( "Loading aborted", 2000 );
|
|
}
|
|
</pre>
|
|
<p> The <em>choose()</em> slot is connected to the <em>Open</em> menu item and
|
|
tool button. With a little help from <a href="ntqfiledialog.html#getOpenFileName">TQFileDialog::getOpenFileName</a>(), it
|
|
asks the user for a file name and then either loads that file or gives an
|
|
error message in the statusbar.
|
|
<p> <pre> void ApplicationWindow::load( const <a href="ntqstring.html">TQString</a> &fileName )
|
|
{
|
|
<a href="ntqfile.html">TQFile</a> f( fileName );
|
|
if ( !f.<a href="ntqfile.html#open">open</a>( <a href="ntqfile.html#open">IO_ReadOnly</a> ) )
|
|
return;
|
|
|
|
<a href="ntqtextstream.html">TQTextStream</a> ts( &f );
|
|
e-><a href="ntqtextedit.html#setText">setText</a>( ts.<a href="ntqtextstream.html#read">read</a>() );
|
|
e-><a href="ntqtextedit.html#setModified">setModified</a>( FALSE );
|
|
<a href="ntqwidget.html#setCaption">setCaption</a>( fileName );
|
|
<a href="ntqmainwindow.html#statusBar">statusBar</a>()->message( "Loaded document " + fileName, 2000 );
|
|
}
|
|
</pre>
|
|
<p> This function loads a file into the editor. When it's done, it sets the
|
|
window system caption to the file name and displays a success message in
|
|
the statusbar for two seconds. With files that exist but are not
|
|
readable, nothing happens.
|
|
<p> <a name="save()"></a>
|
|
<pre> void ApplicationWindow::save()
|
|
{
|
|
if ( filename.isEmpty() ) {
|
|
saveAs();
|
|
return;
|
|
}
|
|
|
|
<a href="ntqstring.html">TQString</a> text = e-><a href="ntqtextedit.html#text">text</a>();
|
|
<a href="ntqfile.html">TQFile</a> f( filename );
|
|
if ( !f.<a href="ntqfile.html#open">open</a>( <a href="ntqfile.html#open">IO_WriteOnly</a> ) ) {
|
|
<a href="ntqmainwindow.html#statusBar">statusBar</a>()->message( TQString("Could not write to %1").arg(filename),
|
|
2000 );
|
|
return;
|
|
}
|
|
|
|
<a href="ntqtextstream.html">TQTextStream</a> t( &f );
|
|
t << text;
|
|
f.<a href="ntqfile.html#close">close</a>();
|
|
</pre>
|
|
<p> As its name suggests, this function saves the current file. If no
|
|
filename has been specified so far, the <a href="#saveAs()">saveAs()</a> function is called. Unwritable files cause the <em>ApplicationWindow</em> object to provide an error-message in the statusbar.
|
|
Note that there is more than one way to do this:
|
|
compare the above <tt>statusBar()->message()</tt> line with the equivalent
|
|
code in the <tt>load()</tt> function.
|
|
<p> <pre> e-><a href="ntqtextedit.html#setModified">setModified</a>( FALSE );
|
|
</pre>
|
|
<p> Tell the editor that the contents haven't been edited since the last
|
|
save. When the user does some further editing and wishes to close the
|
|
window without explicit saving, <a href="#closeEvent">ApplicationWindow::closeEvent()</a> will ask about it.
|
|
<p> <pre> <a href="ntqwidget.html#setCaption">setCaption</a>( filename );
|
|
</pre>
|
|
<p> It may be that the document was saved under a different name than the
|
|
old caption suggests, so we set the window caption just to be sure.
|
|
<p> <pre> <a href="ntqmainwindow.html#statusBar">statusBar</a>()->message( TQString( "File %1 saved" ).arg( filename ), 2000 );
|
|
}
|
|
</pre>
|
|
<p> With a message in the statusbar, we inform the user that the file
|
|
was saved successfully.
|
|
<p> <a name="saveAs()"></a>
|
|
<pre> void ApplicationWindow::saveAs()
|
|
{
|
|
<a href="ntqstring.html">TQString</a> fn = TQFileDialog::<a href="ntqfiledialog.html#getSaveFileName">getSaveFileName</a>( TQString::null, TQString::null,
|
|
this );
|
|
if ( !fn.<a href="ntqstring.html#isEmpty">isEmpty</a>() ) {
|
|
filename = fn;
|
|
save();
|
|
} else {
|
|
<a href="ntqmainwindow.html#statusBar">statusBar</a>()->message( "Saving aborted", 2000 );
|
|
}
|
|
}
|
|
</pre>
|
|
<p> This function asks for a new name, saves the document under that name,
|
|
and implicitly changes the window system caption to the new name.
|
|
<p> <a name="printer"></a>
|
|
<p> <pre> void ApplicationWindow::print()
|
|
{
|
|
printer-><a href="ntqprinter.html#setFullPage">setFullPage</a>( TRUE );
|
|
if ( printer-><a href="ntqprinter.html#setup">setup</a>(this) ) { // printer dialog
|
|
<a href="ntqmainwindow.html#statusBar">statusBar</a>()->message( "Printing..." );
|
|
<a href="ntqpainter.html">TQPainter</a> p;
|
|
if( !p.<a href="ntqpainter.html#begin">begin</a>( printer ) ) { // paint on printer
|
|
<a href="ntqmainwindow.html#statusBar">statusBar</a>()->message( "Printing aborted", 2000 );
|
|
return;
|
|
}
|
|
|
|
<a href="ntqpaintdevicemetrics.html">TQPaintDeviceMetrics</a> metrics( p.<a href="ntqpainter.html#device">device</a>() );
|
|
int dpiy = metrics.<a href="ntqpaintdevicemetrics.html#logicalDpiY">logicalDpiY</a>();
|
|
int margin = (int) ( (2/2.54)*dpiy ); // 2 cm margins
|
|
<a href="ntqrect.html">TQRect</a> view( margin, margin, metrics.<a href="ntqpaintdevicemetrics.html#width">width</a>() - 2*margin, metrics.<a href="ntqpaintdevicemetrics.html#height">height</a>() - 2*margin );
|
|
<a href="ntqsimplerichtext.html">TQSimpleRichText</a> richText( TQStyleSheet::<a href="ntqstylesheet.html#convertFromPlainText">convertFromPlainText</a>(e-><a href="ntqtextedit.html#text">text</a>()),
|
|
TQFont(),
|
|
e-><a href="ntqtextedit.html#context">context</a>(),
|
|
e-><a href="ntqtextedit.html#styleSheet">styleSheet</a>(),
|
|
e-><a href="ntqtextedit.html#mimeSourceFactory">mimeSourceFactory</a>(),
|
|
view.<a href="ntqrect.html#height">height</a>() );
|
|
richText.<a href="ntqsimplerichtext.html#setWidth">setWidth</a>( &p, view.<a href="ntqrect.html#width">width</a>() );
|
|
int page = 1;
|
|
do {
|
|
richText.<a href="ntqsimplerichtext.html#draw">draw</a>( &p, margin, margin, view, colorGroup() );
|
|
view.<a href="ntqrect.html#moveBy">moveBy</a>( 0, view.<a href="ntqrect.html#height">height</a>() );
|
|
p.<a href="ntqpainter.html#translate">translate</a>( 0 , -view.<a href="ntqrect.html#height">height</a>() );
|
|
p.<a href="ntqpainter.html#drawText">drawText</a>( view.<a href="ntqrect.html#right">right</a>() - p.<a href="ntqpainter.html#fontMetrics">fontMetrics</a>().width( TQString::<a href="ntqstring.html#number">number</a>( page ) ),
|
|
view.<a href="ntqrect.html#bottom">bottom</a>() + p.<a href="ntqpainter.html#fontMetrics">fontMetrics</a>().ascent() + 5, TQString::number( page ) );
|
|
if ( view.<a href="ntqrect.html#top">top</a>() - margin >= richText.<a href="ntqsimplerichtext.html#height">height</a>() )
|
|
break;
|
|
printer-><a href="ntqprinter.html#newPage">newPage</a>();
|
|
page++;
|
|
} while (TRUE);
|
|
|
|
<a href="ntqmainwindow.html#statusBar">statusBar</a>()->message( "Printing completed", 2000 );
|
|
} else {
|
|
<a href="ntqmainwindow.html#statusBar">statusBar</a>()->message( "Printing aborted", 2000 );
|
|
}
|
|
}
|
|
</pre>
|
|
<p> <em>print()</em> is called by the <em>File|Print</em> menu item and the <em>filePrint</em>
|
|
tool button.
|
|
<p> We present the user with the print setup dialog, and abandon printing
|
|
if they cancel.
|
|
<p> We create a <a href="ntqsimplerichtext.html">TQSimpleRichText</a> object and give it the text. This object
|
|
is able to format the text nicely as one long page. We achieve
|
|
pagination by printing one paper page's worth of text from the
|
|
TQSimpleRichText page at a time.
|
|
<p> Now let's see what happens when a user wishes to <em>close()</em>
|
|
an <em>ApplicationWindow</em>.
|
|
<p> <a name="closeEvent"></a>
|
|
<pre> void ApplicationWindow::<a href="ntqwidget.html#closeEvent">closeEvent</a>( <a href="qcloseevent.html">TQCloseEvent</a>* ce )
|
|
{
|
|
</pre>
|
|
<p> This event gets to process window system close events. A close event is
|
|
subtly different from a hide event: hide often means "iconify" whereas
|
|
close means that the window is going away for good.
|
|
<p> <pre> if ( !e-><a href="ntqtextedit.html#isModified">isModified</a>() ) {
|
|
ce-><a href="qcloseevent.html#accept">accept</a>();
|
|
return;
|
|
}
|
|
</pre>
|
|
<p> If the text hasn't been edited, we just accept the event. The window
|
|
will be closed, and because we used the <em>WDestructiveClose</em> <a href="ntqt.html#WidgetFlags">widget flag</a> in the <a href="#ApplicationWindow"><i>ApplicationWindow()</i> constructor</a>,
|
|
the widget will be deleted.
|
|
<p> <pre> switch( TQMessageBox::<a href="ntqmessagebox.html#information">information</a>( this, "TQt Application Example",
|
|
"Do you want to save the changes"
|
|
" to the document?",
|
|
"Yes", "No", "Cancel",
|
|
0, 1 ) ) {
|
|
</pre>
|
|
<p> Otherwise we ask the user: What do you want to do?
|
|
<p> <pre> case 0:
|
|
save();
|
|
ce-><a href="qcloseevent.html#accept">accept</a>();
|
|
break;
|
|
</pre>
|
|
<p> If they want to save and then exit, we do that.
|
|
<p> <pre> case 1:
|
|
ce-><a href="qcloseevent.html#accept">accept</a>();
|
|
break;
|
|
</pre>
|
|
<p> If the user doesn't want to exit, we ignore the close event (there is
|
|
a chance that we can't block it but we try).
|
|
<p> <pre> case 2:
|
|
default: // just for sanity
|
|
ce-><a href="qcloseevent.html#ignore">ignore</a>();
|
|
break;
|
|
</pre>
|
|
<p> The last case -- the user wants to abandon the edits and exit -- is very
|
|
simple.
|
|
<p> <pre> }
|
|
}
|
|
</pre>
|
|
<p> Last but not least we implement the slots used by the help menu entries.
|
|
<p> <pre> void ApplicationWindow::about()
|
|
{
|
|
TQMessageBox::<a href="ntqmessagebox.html#about">about</a>( this, "TQt Application Example",
|
|
"This example demonstrates simple use of "
|
|
"TQMainWindow,\nTQMenuBar and TQToolBar.");
|
|
}
|
|
|
|
void ApplicationWindow::aboutTQt()
|
|
{
|
|
TQMessageBox::<a href="ntqmessagebox.html#aboutTQt">aboutTQt</a>( this, "TQt Application Example" );
|
|
}
|
|
</pre>
|
|
<p> These two slots use ready-made "about" functions to provide some
|
|
information about this program and the GUI toolkit it uses. (Although you
|
|
don't need to provide an About TQt in your programs, if you use TQt for free
|
|
we would appreciate it if you tell people what you're using.)
|
|
<p> That was all we needed to write a complete, almost useful application with
|
|
nice help-functions, almost as good as the "editors" some computer vendors
|
|
ship with their desktops, and in less than 300 lines of code!
|
|
<p> <p>See also <a href="step-by-step-examples.html">Step-by-step Examples</a>.
|
|
|
|
<!-- eof -->
|
|
<p><address><hr><div align=center>
|
|
<table width=100% cellspacing=0 border=0><tr>
|
|
<td>Copyright © 2007
|
|
<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
|
|
<td align=right><div align=right>TQt 3.3.8</div>
|
|
</table></div></address></body>
|
|
</html>
|