Kirill Shileev wrote:
>
> Hi,
> I'd like to ask few questions concerning TG* objects:
> 1. What should be done in MyMainFrame::CloseWindow() in order to get
> from main event loop without the application been terminated?
>
void MyMainFrame::CloseWindow()
{
delete this; // delete this mainframe
gSystem->ExitLoop(); // return from TApplication::Run()
}
> 2. Is it nessesary to have the class inheriting from TQObject if i wonna
> make the signal-slot connection to it methods? Connection to non ROOT
> enable class is possible in interpreter, but i can't make this code
> operational
> as standalone.
>
You obviously don't have to inherit from TQObject if you won't make
any signal/slot connections to its methods. What is the problem in
stand alone code? Show me an example.
> 3. In guitest.C, all TGLayoutHints objects are created without making
> thiere pointers avalibale to the creator method. Does it mean that all
> TGLayoutHints objects are deleted when corresponding widgets are?
> Is it the same for TGString and TGTextBuffer? In general, is there any
> list of objects been auto deleted availbale?
In general it says in the method documentation if an object that
is passed will be adopted. If an object is adopted its ownership will
transfer to the receiving object and it will take care of deleting it.
Typically TGStrings and TGTextBuffers are adopted. However, TGFrames
and TGLayoutHints typically are not adopted since they can be reused
in different locations. To cleanup all these objects I just add them
to a TList which I delete in the dtor of the main widget. In guitest.C
see fCleanup and fTrash as two such examples.
> 4. Is it nessesary to provide layout hints for all widgets in
> TGCompositeFrame in order to assure the Layout() facility workable?
>
There is a default layout hint that will be used if you don't specify
a layout hint object in the Add() method. The properties of the default
layout hint are the ones of a default TGLayout object (created by its
default ctor).
> 5. Is it possible to use any arbitrary method of parent class (TG*
> family i mean) as a slot?
Yes, just make sure that the arguments match (exclusive the default
arguments).
> 6. How to declare my own signal?
Derive from TQObject or use the RQ_OBJECT macro and add a call like:
Emit("CloseWindow()"); // emit "CloseWindow()" signal
or
Emit("PositionChanged(Int_t)", pos);
to a method. This method will then emit the specified signal
whenever Emit() is executed.
Cheers, Fons.
--
Org: CERN, European Laboratory for Particle Physics.
Mail: 1211 Geneve 23, Switzerland
E-Mail: Fons.Rademakers@cern.ch Phone: +41 22 7679248
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