What is the significance of following constructor myView::myView(MyMainWindow* parent):QWidget(NULL)
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If I have a class
class myMainWindow: public QMainWindow() {
}
class myView: public QWidget {
myView(myMainWindow* parent);
}what is difference between three constructors
myView:myView(myMainWindow* parent): QWidget(parent) {
}or
myView:myView((myMainWindow* parent):):QWidget(NULL) {
}
or
myView:myView(myMainWindow* parent) .Could you let me know what is significance of each
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myView:myView(myMainWindow* parent): QWidget(parent) {
Give the parent to the Base class
myView:myView((myMainWindow* parent):):QWidget(NULL)
Give no parent to base class. THIS YOU SHOULD NEVER DO. EVER. not like that
if u want no parent, call like this
new myView(NULL); -
So If I have call like
class myMainWindow:QMainWindow{
}class mytableView: public QtableView {
protected:
virtual void keyPressEvent(QKeyEvent *event);};
class myView: public QWidget {
myView(A*,QString title, myMainWindow*)
private:
A* d_a;
MyMainWindow* d_parent ;
mytableView* table;
}myView::myView(Aa ,QString title,myMainWindow parent ) : d_a(a),d_parent(parent)
{
setWindowTitle(title);
table = new mytableView;
}
mytableView:keyPressEvent(QKeyEvent *event) {
...
...
}What is the problem in this code for parent child relation
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why would you ever do that ??
Just call your baseclass constructor as you should.
Its how it works and you are also free to have parent * as variable but
you should always call BaseClass constructor with the given parent.
