在QLabel上点击获得的效果

一般说只在button中点击获得事件，作出相应的反应。而往往需要在QLabel上作出点击和触碰的效果。

我用qlabel做出了一个效果，当鼠标碰到label区域，label底下出现一条线，离开后线条消失。当点击label后变颜色

以下是我的代码

// label.h

#include<QLabel>

classlabel:publicQLabel

{

Q_OBJECT

public:

explicitlabel(QStringstr,QWidget*parent=0);

virtualvoidmousePressEvent(QMouseEvent*event);

voidmouseReleaseEvent(QMouseEvent*event);

voidenterEvent(QEvent*);

voidleaveEvent(QEvent*);

intcount;

voidpaintEvent(QPaintEvent*event);

boolover;

boolpress;

signals:

//自定义clicked()信号,在mousePressEvent事件发生时触发

voidclicked();

publicslots:

voidchange_color();

};

//label.cpp

#include"label.h"

#include<QMouseEvent>

#include<QPainter>

#include<QPalette>

label::label(QStringstr,QWidget*parent):

QLabel(parent)

{

QPalettepalette;

palette.setColor(QPalette::WindowText,QColor(50,255,255));

this->setText(str);

this->setPalette(palette);

setAlignment(Qt::AlignHCenter|Qt::AlignVCenter);

//this->setStyleSheet("background-color:blue");

this->setCursor(Qt::PointingHandCursor);

count=0;

press=false;

over=false;

connect(this,SIGNAL(clicked()),this,SLOT(change_color()));

}

voidlabel::mousePressEvent(QMouseEvent*event)

{

//如果单击了就触发clicked信号

if(event->button()==Qt::LeftButton)

{

//触发clicked信号

count++;

press=true;

emitclicked();

}

//将该事件传给父类处理

QLabel::mousePressEvent(event);

}

voidlabel::mouseReleaseEvent(QMouseEvent*event)

{

press=false;

update();

}

voidlabel::enterEvent(QEvent*)

{

over=true;

update();

}

voidlabel::leaveEvent(QEvent*)

{

over=false;

update();

}

voidlabel::change_color()

{

if(count%2)

this->setStyleSheet("background-color:red");

else

this->setStyleSheet("background-color:blue");

}

voidlabel::paintEvent(QPaintEvent*event)

{

QPainterpaint(this);

paint.setPen(QPen(Qt::yellow,1));

if(over)

{

paint.drawLine(5,this->height()-5,this->width()-5,this->height()-5);

}

else

{

paint.setPen(Qt::NoPen);

}

QLabel::paintEvent(event);

}

//MainWindow.h

#include<QWidget>

#include"label.h"

classMainWindow:publicQWidget

{

Q_OBJECT

public:

label*la;

explicitMainWindow(QWidget*parent=0);

~MainWindow();

};

//MainWindow.cpp

#include"mainwindow.h"

#include<QLabel>

MainWindow::MainWindow(QWidget*parent):

QWidget(parent)

{

setFixedSize(200,100);

la=newlabel("192.168.199.245",this);

la->setGeometry(50,30,100,30);

}

MainWindow::~MainWindow()

{

}

//main.cpp

#include"mainwindow.h"

#include<QApplication>

intmain(intargc,char*argv[])

{

QApplicationa(argc,argv);

MainWindoww;

w.show();

returna.exec();

}

仅供初学者参考