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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<title>Qt 4.8: QML Tutorial 1 - Basic Types</title>
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<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#walkthrough">Walkthrough</a></li>
<li class="level2"><a href="#import">Import</a></li>
<li class="level2"><a href="#rectangle-element">Rectangle element</a></li>
<li class="level2"><a href="#text-element">Text element</a></li>
<li class="level2"><a href="#viewing-the-example">Viewing the example</a></li>
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<h1 class="title">QML Tutorial 1 - Basic Types</h1>
<span class="subtitle"></span>
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<div class="descr"> <a name="details"></a>
<p>This first program is a very simple "Hello world" example that introduces some basic QML concepts. The picture below is a screenshot of this program.</p>
<p class="centerAlign"><img src="images/declarative-tutorial1.png" alt="" /></p><p>Here is the QML code for the application:</p>
<pre class="qml"> import QtQuick 1.0
<span class="type"><a href="qml-rectangle.html">Rectangle</a></span> {
<span class="name">id</span>: <span class="name">page</span>
<span class="name">width</span>: <span class="number">500</span>; <span class="name">height</span>: <span class="number">200</span>
<span class="name">color</span>: <span class="string">"lightgray"</span>
<span class="type"><a href="qml-text.html">Text</a></span> {
<span class="name">id</span>: <span class="name">helloText</span>
<span class="name">text</span>: <span class="string">"Hello world!"</span>
<span class="name">y</span>: <span class="number">30</span>
<span class="name">anchors</span>.horizontalCenter: <span class="name">page</span>.<span class="name">horizontalCenter</span>
<span class="name">font</span>.pointSize: <span class="number">24</span>; <span class="name">font</span>.bold: <span class="number">true</span>
}
}</pre>
<a name="walkthrough"></a>
<h2>Walkthrough</h2>
<a name="import"></a>
<h3>Import</h3>
<p>First, we need to import the types that we need for this example. Most QML files will import the built-in QML types (like <a href="qml-rectangle.html">Rectangle</a>, <a href="qml-image.html">Image</a>, ...) that come with Qt, using:</p>
<pre class="qml"> import QtQuick 1.0</pre>
<a name="rectangle-element"></a>
<h3>Rectangle element</h3>
<pre class="qml"> <span class="type"><a href="qml-rectangle.html">Rectangle</a></span> {
<span class="name">id</span>: <span class="name">page</span>
<span class="name">width</span>: <span class="number">500</span>; <span class="name">height</span>: <span class="number">200</span>
<span class="name">color</span>: <span class="string">"lightgray"</span></pre>
<p>We declare a root element of type <a href="qml-rectangle.html">Rectangle</a>. It is one of the basic building blocks you can use to create an application in QML. We give it an <tt>id</tt> to be able to refer to it later. In this case, we call it "page". We also set the <tt>width</tt>, <tt>height</tt> and <tt>color</tt> properties. The <a href="qml-rectangle.html">Rectangle</a> element contains many other properties (such as <tt>x</tt> and <tt>y</tt>), but these are left at their default values.</p>
<a name="text-element"></a>
<h3>Text element</h3>
<pre class="qml"> <span class="type"><a href="qml-text.html">Text</a></span> {
<span class="name">id</span>: <span class="name">helloText</span>
<span class="name">text</span>: <span class="string">"Hello world!"</span>
<span class="name">y</span>: <span class="number">30</span>
<span class="name">anchors</span>.horizontalCenter: <span class="name">page</span>.<span class="name">horizontalCenter</span>
<span class="name">font</span>.pointSize: <span class="number">24</span>; <span class="name">font</span>.bold: <span class="number">true</span>
}</pre>
<p>We add a <a href="qml-text.html">Text</a> element as a child of the root Rectangle element that displays the text 'Hello world!'.</p>
<p>The <tt>y</tt> property is used to position the text vertically at 30 pixels from the top of its parent.</p>
<p>The <tt>anchors.horizontalCenter</tt> property refers to the horizontal center of an element. In this case, we specify that our text element should be horizontally centered in the <i>page</i> element (see <a href="qml-anchor-layout.html#anchor-layout">Anchor-Based Layout</a>).</p>
<p>The <tt>font.pointSize</tt> and <tt>font.bold</tt> properties are related to fonts and use the <a href="qdeclarativeintroduction.html#dot-properties">dot notation</a>.</p>
<a name="viewing-the-example"></a>
<h3>Viewing the example</h3>
<p>To view what you have created, run the <a href="qmlviewer.html">QML Viewer</a> tool (located in the <tt>bin</tt> directory) with your filename as the first argument. For example, to run the provided completed Tutorial 1 example from the install location, you would type:</p>
<pre class="cpp"> bin<span class="operator">/</span>qmlviewer $QTDIR<span class="operator">/</span>examples<span class="operator">/</span>declarative<span class="operator">/</span>tutorials<span class="operator">/</span>helloworld<span class="operator">/</span>tutorial1<span class="operator">.</span>qml</pre>
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