Qt事件--数字时钟

实验：

1）用Timer显示时间

2）用Timer定时

3）鼠标左键按下控件可随意在桌面上拖动

main.cpp

#include <qapplication.h>
#include "form2.h"

int main( int argc, char ** argv )
{
    QApplication a( argc, argv );
    Form2 w;
    w.show();
	
    a.connect( &a, SIGNAL( lastWindowClosed() ), &a, SLOT( quit() ) );
    return a.exec();
}

form2.cpp

/****************************************************************************
** Form implementation generated from reading ui file 'form2.ui'
**
** Created by: The User Interface Compiler ($Id: qt/main.cpp   3.3.6   edited Aug 31 2005 $)
**
** WARNING! All changes made in this file will be lost!
****************************************************************************/

#include "form2.h"

#include <qvariant.h>
#include <qlcdnumber.h>
#include <qlayout.h>
#include <qtooltip.h>
#include <qwhatsthis.h>
#include <qimage.h>
#include <qpixmap.h>
#include<qtimer.h>
#include<qdatetime.h>
#include <qpoint.h> 

/*
 *  Constructs a Form2 as a child of 'parent', with the
 *  name 'name' and widget flags set to 'f'.
 *
 *  The dialog will by default be modeless, unless you set 'modal' to
 *  TRUE to construct a modal dialog.
 */
DigiClock::DigiClock(QWidget * parent, const char * name)
	: QLCDNumber(parent,name)
{

	QPalette p = palette();
	p.setColor(QPalette::Normal, QColorGroup::Background, Qt::blue);
	setPalette(p);

	QTimer *timer = new QTimer(this);
	connect(timer,SIGNAL(timeout()),SLOT(showTime()));
	timer->start(1000);

	showColon = true;
	showTime();
}
void DigiClock::showTime()
{
	QTime time = QTime::currentTime();
	QString text = time.toString("hh:mm");
	if(showColon)
	{
		text[2] = ':';
		showColon = false;
	}
	else
	{
		text[2] = ' ';
		showColon = true;
	}	
	display(text);
}

Form2::Form2( QWidget* parent, const char* name, bool modal, WFlags fl )
    : QDialog( parent, name, modal, fl )
{	setMouseTracking (true);	
    if ( !name )
	setName( "Form2" );
    lCDNumber2 = new DigiClock( this, "lCDNumber2");
    lCDNumber2->setGeometry( QRect( 0, 0, 370, 70 ) );
    languageChange();
    resize( QSize(369, 70).expandedTo(minimumSizeHint()) );
    clearWState( WState_Polished );
	LbuttonFlag = false;
}

/*
 *  Destroys the object and frees any allocated resources
 */
Form2::~Form2()
{
    // no need to delete child widgets, Qt does it all for us
}

/*
 *  Sets the strings of the subwidgets using the current
 *  language.
 */
void Form2::languageChange()
{
    setCaption( tr( "Form2" ) );
}

void Form2::mousePressEvent(QMouseEvent *e)
{
	if(e->button()==QMouseEvent::LeftButton)
	{
		dragPositon = e->globalPos()-frameGeometry().topLeft();
		LbuttonFlag = true;
		e->accept();
	}
}
void Form2::mouseReleaseEvent(QMouseEvent * e)
{
		LbuttonFlag = false;
}

void Form2::mouseMoveEvent(QMouseEvent *e)
{
	if(LbuttonFlag)
	{
		move(e->globalPos()-dragPositon);
		qDebug("gx=%d,gy%d,x=%d,y=%d",e->globalX(),e->globalY(),dragPositon.x(),dragPositon.y());
		e->accept();
	}
}