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>

class label :public QLabel

{

    Q_OBJECT

public:

    explicit label(QString str,QWidget *parent = 0);

    virtual void mousePressEvent(QMouseEvent *event);

    void mouseReleaseEvent(QMouseEvent *event);

    void enterEvent(QEvent *);

    void leaveEvent(QEvent *);

    int count;

    void paintEvent(QPaintEvent *event);

    bool over;

    bool press;

signals:

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

    void clicked();

public slots:

    void change_color();

};

//label.cpp

#include "label.h"

#include <QMouseEvent>

#include <QPainter>

#include <QPalette>

label::label(QString str,QWidget *parent) :

    QLabel(parent)

{

    QPalette palette;

    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()));

}

void label::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;

        emit clicked();

    }

    //将该事件传给父类处理

    QLabel::mousePressEvent(event);

}

void label:: mouseReleaseEvent(QMouseEvent *event)

{

   press = false;

   update();

}

void label::enterEvent(QEvent *)

{

    over =true;

    update();

}

void label::leaveEvent(QEvent *)

{

    over = false;

    update();

}

void label::change_color()

{

    if(count%2)

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

    else

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

}

void label::paintEvent(QPaintEvent *event)

{

    QPainter paint(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"
class MainWindow : public QWidget
{
    Q_OBJECT
    
public:
    label *la;
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
};

//MainWindow.cpp

#include "mainwindow.h"
#include <QLabel>
MainWindow::MainWindow(QWidget *parent) :
    QWidget(parent)
{
    setFixedSize(200,100);
    la =new label("192.168.199.245",this);
    la->setGeometry(50,30,100,30);
}
MainWindow::~MainWindow()
{
}

//main.cpp

#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    
    return a.exec();
}

仅供初学者参考