I am using QObject as a base class for a composite pattern.
Say I have a parent class File (in a contrived example) to which I am adding children of different types, HeaderSection and PageSection. File, HeaderSection and PageSection are all Sections. The constructor for Section takes a parent object which is passed through to QObject's constructor, setting the parent.
e.g:
class Section : public QObject {
Q_OBJECT
// parent:child relationship gets set by QObject
Section(QString name, Section *parent=NULL) : QObject(parent)
{ setObjectName(name);}
QString name(){return objectName();}
};
class File: public Section {
public:
// probably irrelevant to this example, but I am also populating these lists
QList<Section *> headers;
QList<Section *> pages;
};
class Header : public Section {
Header(QString name, File *file) : Section(name, file){}
};
class Page: public Section {
Body(QString name, File *file) : Section(name, file){}
};
Syntax for construction in the definition may be incorrect, apologies, I'm used to doing it outside. Anyway, when I do this:
File *file = new file();
Header *headerA = new Header("Title", file);
Header *headerB = new Header("Subtitle", file);
Page *page1 = new Page("PageOne", file);
Page *page2 = new Page("PageTwo", file);
QList<Page*> pages = file->findChildren<Page*>();
for(int i=0; i < pages.size(); i++)
qDebug() << pages.at(i)->name();
I get the following output:
Title
Subtitle
PageOne
PageTwo
What am I missing here? Surely if findChildren looked for common base classes then it would only ever return every single child of a Widget (for example), which I know it doesn't in normal use.
Also, if I iterate over the list of children returned and use dynamic_cast<Page*> on each returned child, I get the expected two Page items.
