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    <p>The <code>QObject</code> implementation of the <a href="http://en.wikipedia.org/wiki/Composite_pattern">Composite Design Pattern</a> has been tried and tested through the many versions of Qt. </p> <p>The pattern requires that the composite object takes ownership of the children so, as long as the parenting has been done, you can be assured that the child <code>QObjects</code> will be destroyed when the parent is destroyed.</p> <p>Standard practice is to create child objects in heap memory and parent them immediately. If you don't parent immediately, you can explicitly parent using the <code>setParent()</code> function, or else parenting will be done automatically when you add the widget to a parent widget, either using <code>addWidget()</code> or <code>addLayout()</code>. </p> <p><code>QLayout</code> objects are size and layout managers of other <code>QLayouts</code> and of <code>QWidgets</code>. They don't own the objects they manage. The parent is actually the <code>QWidget</code> that the <code>QLayout</code> is the child of. </p> <p>You have a choice to create the root parent in stack memory or in heap memory. </p> <p>If you feel more comfortable with smart pointers, there are two classes that are specifically for <code>QObjects</code>: <a href="http://qt-project.org/doc/qt-5.0/qtcore/qpointer.html">QPointer</a> and <a href="http://qt-project.org/doc/qt-5.0/qtcore/qsharedpointer.html">QSharedPointer</a>. Each has their pros and cons.</p> <pre><code>#include &lt;QApplication&gt; #include &lt;QLabel&gt; #include &lt;QHBoxLayout&gt; #include &lt;QWidget&gt; int main(int argc, char **argv) { QApplication app(argc, argv); QWidget widget; // Root parent so can create as a auto-deleting object on the stack QHBoxLayout *layout = new QHBoxLayout(&amp;widget); // Create on the heap and parent immediately QLabel *label = new QLabel("label", &amp;widget); // Create on the heap and parent immediately layout-&gt;addWidget(label); // widget remains label's parent widget.setLayout(layout); // widget is changed to layout's parent if necessary, as well // as any widgets that layout manages widget.show(); return app.exec(); // layout and label are destroyed when widget is destroyed } </code></pre>
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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

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