#include <TApplication.h>
#include <TGClient.h>
#include <TGListTree.h>

class MyMainFrame: public TGMainFrame {

private:
	TGCanvas   *fTreeCanvas;
	TGListTree *fTree;

public:
	MyMainFrame( const TGWindow *p, UInt_t w, UInt_t h );
	virtual ~MyMainFrame();

	void CloseWindow();

	//-- slots
	void OnTreeChecked(TObject*,Bool_t on);

	ClassDef(MyMainFrame,0);
};

MyMainFrame::MyMainFrame( const TGWindow *p, UInt_t w, UInt_t h )
: TGMainFrame(p,w,h)
{
	// create tree and its canvas
	fTree = new TGListTree();
	fTreeCanvas = new TGCanvas(this,200,200);
	fTree = new TGListTree(this);	
	fTree->SetCanvas( fTreeCanvas );
	fTreeCanvas->SetContainer( fTree );
	AddFrame( fTreeCanvas, new TGLayoutHints(kLHintsExpandX | kLHintsExpandY) );
	
	// add items (with checkboxes) and connect slots
	fTree->AddItem( 0, "Item1", 0,0,kTRUE );
	fTree->AddItem( 0, "Item2", 0,0,kTRUE );
	fTree->Connect( "Checked(TObject*,Bool_t)", "MyMainFrame", this, "OnTreeChecked(TObject*,Bool_t)" );
	
	// init mainwindow
	SetWindowName("Test Checked Callback of TGListTree");
	MapSubwindows();
	MapWindow();
}

MyMainFrame::~MyMainFrame()
{	
	//delete fTree;	// DELETE OR NOT?
	Cleanup();
}

void MyMainFrame::CloseWindows()
{
    DeleteWindow();
    gApplication->Terminate(0);
}

void MyMainFrame::OnTreeChecked( TObject* entry, Bool_t on )
{
	////////////////////////////////////
	// HERE IS THE PROBLEM:
	// *entry is always a null-pointer
	cout << "address of entry = " << entry << ", on = " << on << endl;
}


// named macro
void checkbox()
{
	new MyMainFrame(0, 200, 200);
}