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POMake function of root QML component callable for other components
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  1. POMake function of root QML component callable for other components
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    copied!<p>I want to show a message box, that is implemented in <strong>main.qml</strong> (as a layer above all other components). The function <code>showMessage()</code> makes the QML message box visible and sets the text. So it's possible for code in <strong>main.qml</strong> to show message boxes, but other components (not in <strong>main.qml</strong>) should be able to show message boxes, too.</p> <p>My idea so far is to create a C++ QML component that has a function <code>displayMessage()</code> which calls the <code>showMessage()</code> function of the root context (→ <strong>main.qml</strong>).</p> <p><strong>mail.qml</strong> (root component)</p> <pre><code>import QtQuick 1.0 // [...] Rectangle { id: main function showMessage(text) { // make a message area visible and set text } // [...] // message box implementation } </code></pre> <p><strong>App.qml</strong></p> <pre><code>import QtQuick 1.0 import MessageForwarder 1.0 // implemented in C++ // [...] Rectangle { id: anApp MessageForwarder { id: mf } // ← Possible without this? Component.onCompleted: mf.displayMessage("A message."); // show message // [...] } </code></pre> <p>Is it possible to create something like a static function, that would allow something like <code>MessageForwarder.displayMessage("Foo")</code>, without needing an additional instance of the <code>MessageForwarder</code> component?</p> <p>Or is there any other convenient possibility to use <code>showMessage()</code> in other components?<br> (Maybe something like the <code>Qt</code> global object?)</p> <p>Thanks!</p> <hr> <p>EDIT:</p> <p>I think I found a quite simple solution: As QML is a dynamically scoped language (→ <a href="http://doc.qt.nokia.com/4.7-snapshot/qdeclarativescope.html#component-instance-hierarchy" rel="nofollow">Qt Doc</a>) and all components are nested inside <strong>main.qml</strong>, this simply works:</p> <p><strong>main.qml</strong></p> <pre><code>import QtQuick 1.0 Rectangle { id: main QtObject { id: messageBox // nested for a more modular design function showMessage(text) { // make a message area visible and set text } } // [...] // message box implementation } </code></pre> <p><strong>App.qml</strong></p> <pre><code>import QtQuick 1.0 Rectangle { id: anApp Component.onCompleted: messageBox.showMessage("A message."); // [...] } </code></pre>
 

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