<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- helloscript.qdoc -->
<title>Hello Script Example | Qt Script</title>
<link rel="stylesheet" type="text/css" href="style/offline-simple.css" />
<script type="text/javascript">
document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css");
// loading style sheet breaks anchors that were jumped to before
// so force jumping to anchor again
setTimeout(function() {
var anchor = location.hash;
// need to jump to different anchor first (e.g. none)
location.hash = "#";
setTimeout(function() {
location.hash = anchor;
}, 0);
}, 0);
</script>
</head>
<body>
<div class="header" id="qtdocheader">
<div class="main">
<div class="main-rounded">
<div class="navigationbar">
<table><tr>
<td >Qt 5.12</td><td ><a href="qtscript-index.html">Qt Script</a></td><td >Hello Script Example</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right"><a href="qtscript-index.html">Qt 5.12.6 Reference Documentation</a></td>
</tr></table>
</div>
</div>
<div class="content">
<div class="line">
<div class="content mainContent">
<div class="sidebar">
<div class="toc">
<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#translating-the-application">Translating the Application</a></li>
</ul>
</div>
<div class="sidebar-content" id="sidebar-content"></div></div>
<h1 class="title">Hello Script Example</h1>
<span class="subtitle"></span>
<!-- $$$script/helloscript-description -->
<div class="descr"> <a name="details"></a>
<p>The Hello Script example shows the basic use of Qt Script: How to embed a script engine into the application, how to evaluate a script, and how to process the result of the evaluation. The example also shows how to apply internationalization to scripts.</p>
<pre class="cpp">
<span class="type">int</span> main(<span class="type">int</span> argc<span class="operator">,</span> <span class="type">char</span> <span class="operator">*</span>argv<span class="operator">[</span><span class="operator">]</span>)
{
Q_INIT_RESOURCE(helloscript);
</pre>
<p>The application will load the script file to evaluate from a resource, so we first make sure that the resource is initialized.</p>
<pre class="cpp">
<span class="type">QApplication</span> app(argc<span class="operator">,</span> argv);
<span class="type"><a href="qscriptengine.html">QScriptEngine</a></span> engine;
<span class="type">QTranslator</span> translator;
translator<span class="operator">.</span>load(<span class="string">"helloscript_la"</span>);
app<span class="operator">.</span>installTranslator(<span class="operator">&</span>translator);
engine<span class="operator">.</span>installTranslatorFunctions();
</pre>
<p>We attempt to load a translation, and install translation functions in the script engine. How to produce a translation is explained later.</p>
<pre class="cpp">
<span class="type">QPushButton</span> button;
<span class="type"><a href="qscriptvalue.html">QScriptValue</a></span> scriptButton <span class="operator">=</span> engine<span class="operator">.</span>newQObject(<span class="operator">&</span>button);
engine<span class="operator">.</span>globalObject()<span class="operator">.</span>setProperty(<span class="string">"button"</span><span class="operator">,</span> scriptButton);
</pre>
<p>A push button is created and exported to the script environment as a global variable, <code>button</code>. Scripts will be able to access properties, signals and slots of the button as properties of the <code>button</code> script object; the script object acts as a proxy to the C++ button object.</p>
<pre class="cpp">
<span class="type">QString</span> fileName(<span class="string">":/helloscript.js"</span>);
<span class="type">QFile</span> scriptFile(fileName);
scriptFile<span class="operator">.</span>open(<span class="type">QIODevice</span><span class="operator">::</span>ReadOnly);
<span class="type">QTextStream</span> stream(<span class="operator">&</span>scriptFile);
<span class="type">QString</span> contents <span class="operator">=</span> stream<span class="operator">.</span>readAll();
scriptFile<span class="operator">.</span>close();
</pre>
<p>The contents of the script file are read.</p>
<pre class="js">
button.text = qsTr('Hello World!');
button.styleSheet = 'font-style: italic';
button.show();
</pre>
<p>The script sets the <code>text</code> (note that the qTr() function is used to allow for translation) and <code>styleSheet</code> properties of the button, and calls the button's <code>show()</code> slot.</p>
<pre class="cpp">
<span class="type"><a href="qscriptvalue.html">QScriptValue</a></span> result <span class="operator">=</span> engine<span class="operator">.</span>evaluate(contents<span class="operator">,</span> fileName);
</pre>
<p>The script is evaluated. Note that the file name is passed as the (optional) second parameter; this makes it possible for the script engine to produce a meaningful backtrace if something goes wrong, and makes the qTr() function be able to resolve the translations that are associated with this script.</p>
<pre class="cpp">
<span class="keyword">if</span> (result<span class="operator">.</span>isError()) {
<span class="type">QMessageBox</span><span class="operator">::</span>critical(<span class="number">0</span><span class="operator">,</span> <span class="string">"Hello Script"</span><span class="operator">,</span>
<span class="type">QString</span><span class="operator">::</span>fromLatin1(<span class="string">"%0:%1: %2"</span>)
<span class="operator">.</span>arg(fileName)
<span class="operator">.</span>arg(result<span class="operator">.</span>property(<span class="string">"lineNumber"</span>)<span class="operator">.</span>toInt32())
<span class="operator">.</span>arg(result<span class="operator">.</span>toString()));
<span class="keyword">return</span> <span class="operator">-</span><span class="number">1</span>;
}
</pre>
<p>If the result is an Error object (e.g. the script contained a syntax error, or tried to call a function that doesn't exist), we obtain the line number and string representation of the error and display it in a message box.</p>
<pre class="cpp">
<span class="keyword">return</span> app<span class="operator">.</span>exec();
}
</pre>
<p>If the evaluation went well, the application event loop is entered.</p>
<a name="translating-the-application"></a>
<h2 id="translating-the-application">Translating the Application</h2>
<p>The Qt Script internalization support builds on what Qt already provides for C++; see the Hello tr() Example for an introduction.</p>
<p>Since we haven't made the translation file <code>helloscript_la.qm</code>, the source text is shown when we run the application ("Hello world!").</p>
<p>To generate the translation file, run <code>lupdate</code> as follows:</p>
<pre class="cpp">
lupdate helloscript<span class="operator">.</span>js <span class="operator">-</span>ts helloscript_la<span class="operator">.</span>ts
</pre>
<p>You should now have a file <code>helloscript_la.ts</code> in the current directory. Run <code>linguist</code> to edit the translation:</p>
<pre class="cpp">
linguist helloscript_la<span class="operator">.</span>ts
</pre>
<p>You should now see the text "helloscript.js" in the top left pane. Double-click it, then click on "Hello world!" and enter "Orbis, te saluto!" in the <b>Translation</b> pane (the middle right of the window). Don't forget the exclamation mark!</p>
<p>Click the <b>Done</b> checkbox and choose <b>File|Save</b> from the menu bar. The TS file will no longer contain</p>
<pre class="cpp">
<span class="operator"><</span>translation type<span class="operator">=</span><span class="char">'unfinished'</span><span class="operator">></span><span class="operator"><</span><span class="operator">/</span>translation<span class="operator">></span>
</pre>
<p>but instead will have</p>
<pre class="cpp">
<span class="operator"><</span>translation<span class="operator">></span>Orbis<span class="operator">,</span> te saluto<span class="operator">!</span><span class="operator"><</span><span class="operator">/</span>translation<span class="operator">></span>
</pre>
<p>To see the application running in Latin, we have to generate a QM file from the TS file. Generating a QM file can be achieved either from within <i>Qt Linguist</i> (for a single TS file), or by using the command line program <code>lrelease</code> which will produce one QM file for each of the TS files listed in the project file. Generate <code>hellotr_la.qm</code> from <code>hellotr_la.ts</code> by choosing <b>File|Release</b> from <i>Qt Linguist</i>'s menu bar and pressing <b>Save</b> in the file save dialog that pops up. Now run the <code>helloscript</code> program again. This time the button will be labelled "Orbis, te saluto!".</p>
<p>Files:</p>
<ul>
<li><a href="qtscript-script-helloscript-helloscript-js.html">script/helloscript/helloscript.js</a></li>
<li><a href="qtscript-script-helloscript-helloscript-pro.html">script/helloscript/helloscript.pro</a></li>
<li><a href="qtscript-script-helloscript-helloscript-qrc.html">script/helloscript/helloscript.qrc</a></li>
<li><a href="qtscript-script-helloscript-main-cpp.html">script/helloscript/main.cpp</a></li>
</ul>
</div>
<!-- @@@script/helloscript -->
</div>
</div>
</div>
</div>
</div>
<div class="footer">
<p>
<acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd.
Documentation contributions included herein are the copyrights of
their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property
of their respective owners. </p>
</div>
</body>
</html>
distrib
>
Mageia
>
7
>
armv7hl
>
media
>
core-updates
>
by-pkgid
>
32e951f007f30f654c2e19437a4aa0ce
>
files
>
95
