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diff --git a/doc/html/tutorial2-07.html b/doc/html/tutorial2-07.html new file mode 100644 index 0000000..6298a38 --- /dev/null +++ b/doc/html/tutorial2-07.html @@ -0,0 +1,112 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> +<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/doc/tutorial2.doc:969 --> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>File Handling</title> +<style type="text/css"><!-- +fn { margin-left: 1cm; text-indent: -1cm; } +a:link { color: #004faf; text-decoration: none } +a:visited { color: #672967; text-decoration: none } +body { background: #ffffff; color: black; } +--></style> +</head> +<body> + +<table border="0" cellpadding="0" cellspacing="0" width="100%"> +<tr bgcolor="#E5E5E5"> +<td valign=center> + <a href="index.html"> +<font color="#004faf">Home</font></a> + | <a href="classes.html"> +<font color="#004faf">All Classes</font></a> + | <a href="mainclasses.html"> +<font color="#004faf">Main Classes</font></a> + | <a href="annotated.html"> +<font color="#004faf">Annotated</font></a> + | <a href="groups.html"> +<font color="#004faf">Grouped Classes</font></a> + | <a href="functions.html"> +<font color="#004faf">Functions</font></a> +</td> +<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>File Handling</h1> + + +<p> +<p> (Extracts from <tt>chartform_files.cpp</tt>.) +<p> <h2> Reading Chart Data +</h2> +<a name="1"></a><p> + +<pre> void ChartForm::load( const <a href="qstring.html">QString</a>& filename ) + { + <a href="qfile.html">QFile</a> file( filename ); + if ( !file.<a href="qfile.html#open">open</a>( <a href="qfile.html#open">IO_ReadOnly</a> ) ) { + <a href="qmainwindow.html#statusBar">statusBar</a>()->message( QString( "Failed to load \'%1\'" ). + arg( filename ), 2000 ); + return; + } + + init(); // Make sure we have colours + m_filename = filename; + <a href="qtextstream.html">QTextStream</a> ts( &file ); + Element element; + int errors = 0; + int i = 0; + <a name="x2592"></a> while ( !ts.<a href="qtextstream.html#eof">eof</a>() ) { + ts >> element; + if ( element.isValid() ) + m_elements[i++] = element; +</pre><pre> <a name="x2590"></a> file.<a href="qfile.html#close">close</a>(); +</pre> +<p> <pre> <a href="qwidget.html#setCaption">setCaption</a>( QString( "Chart -- %1" ).arg( filename ) ); + updateRecentFiles( filename ); + + drawElements(); + m_changed = FALSE; + } +</pre> +<p> Loading a data set is very easy. We open the file and create a text +stream. While there's data to read we stream an element into <tt>element</tt> and if it is valid we insert it into the <tt>m_elements</tt> vector. +All the detail is handled by the <tt>Element</tt> class. Then we close +the file and update the caption and the recent files list. Finally we +draw the chart and mark it as unchanged. +<p> <h2> Writing Chart Data +</h2> +<a name="2"></a><p> <pre> void ChartForm::fileSave() + { +</pre><pre> <a href="qfile.html">QFile</a> file( m_filename ); + <a name="x2591"></a> if ( !file.<a href="qfile.html#open">open</a>( <a href="qfile.html#open">IO_WriteOnly</a> ) ) { + <a href="qmainwindow.html#statusBar">statusBar</a>()->message( QString( "Failed to save \'%1\'" ). + arg( m_filename ), 2000 ); + return; + } + <a href="qtextstream.html">QTextStream</a> ts( &file ); + for ( int i = 0; i < MAX_ELEMENTS; ++i ) + if ( m_elements[i].isValid() ) + ts << m_elements[i]; + + file.<a href="qfile.html#close">close</a>(); + + <a href="qwidget.html#setCaption">setCaption</a>( QString( "Chart -- %1" ).arg( m_filename ) ); + <a href="qmainwindow.html#statusBar">statusBar</a>()->message( QString( "Saved \'%1\'" ).arg( m_filename ), 2000 ); + m_changed = FALSE; + } +</pre> +<p> Saving data is equally easy. We open the file and create a text +stream. We then stream every valid element to the text stream. All the +detail is handled by the <tt>Element</tt> class. +<p> <p align="right"> +<a href="tutorial2-06.html">« Canvas Control</a> | +<a href="tutorial2.html">Contents</a> | +<a href="tutorial2-08.html">Taking Data »</a> +</p> +<p> +<!-- 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>Qt 3.3.8</div> +</table></div></address></body> +</html> |