Qt学习之旅---2.绘图，时钟小例子

学习笔记，小白可以相互学习，大佬看到能告诉咱理解不对的地方就好了。

/*********.h**********************************/#ifndef WIDGET_H#define WIDGET_H#include<QWidget>#include<QPaintEvent>#include<QPainter>#include<QPen>#include<QTimer>#include<iostream>#include<QLabel>class Widget : public QWidget{    Q_OBJECTpublic:    Widget(QWidget *parent = 0);    ~Widget();protected:    void paintEvent(QPaintEvent *event)    {        setFixedSize(500,500);        static int i = 0;        QPainter ppp(this);//定义一个画家        QPen p(QColor(Qt::red));//画笔，颜色红        p.setWidth(4);//粗细10        ppp.setPen(p);//画家拿到笔        ppp.translate(200,200);//移动中心点(移动画家的中心点位置)        //ppp.drawEllipse(QPoint(0,0),100,100);//以画家为中心点，画椭圆        ppp.rotate(i*6);//转多少度，参数为转的度数        i++;        ppp.drawLine(0,0,0,-160);//画线        //ppp.drawText(0,0,"小可爱");        static int j = 0;        QPainter ppp1(this);        QPen p1(QColor(Qt::blue));        p1.setWidth(4);        ppp1.setPen(p1);        ppp1.translate(200,200);        ppp1.rotate(j*0.5);        j++;        ppp1.drawLine(0,0,0,-120);        static int k = 0;        QPainter ppp3(this);        QPen p3(QColor(Qt::green));        p3.setWidth(6);        ppp3.setPen(p3);        ppp3.translate(200,200);        ppp3.rotate(k*0.25/60);        k++;        ppp3.drawLine(0,0,0,-80);        QPainter ppp4(this);        QPen p4(QColor(Qt::black));        p4.setWidth(4);        ppp4.setPen(p4);        ppp4.translate(200,200);        ppp4.drawEllipse(QPoint(0,0),190,190);        QPainter ppp2(this);        QPen p2(QColor(Qt::black));        p2.setWidth(20);        ppp2.setPen(p4);        ppp2.translate(200,200);        ppp2.drawPoint(0,0);        QPainter ppp5(this);        QPen p5(QColor(Qt::black));        p5.setWidth(2);        ppp5.setPen(p5);        ppp5.translate(350,350);        ppp5.translate(rand()%20,rand()%20);        ppp5.drawPixmap(0,0,QPixmap("ooopic_1504102052.ico"));//        ppp5.scale(0,0);//放大        QPainter ppp6(this);        QPen p6(QColor(Qt::black));        p6.setWidth(4);        ppp6.setPen(p6);        ppp6.translate(200,200);        int a;        QString b;        for(a = 0; a < 12 ;a++)        {            b = QString::number(a);            ppp6.drawLine(0,-180,0,-190);            ppp6.drawText(0,-165,b);            ppp6.rotate(30);        }        QPainter ppp7(this);        QPen p7(QColor(Qt::blue));        p7.setWidth(2);        ppp7.setPen(p7);        ppp7.translate(200,200);        for(a = 0; a < 60 ;a++)        {            ppp7.drawLine(0,-183,0,-190);            ppp7.rotate(6);        }        // 求时间数字        sec = i%60 - 1;        min = i/60%60;        hour = i/3600%24;        std::cout<<":"<<hour<<" :"<<min<<" :"<<" :"<<sec<<std::endl;        QString x,y,z;        x = QString::number(hour);        y = QString::number(min);        z = QString::number(sec);        QPainter ppp8(this);        QPen p8(QColor(Qt::red));        p8.setWidth(30);        ppp8.setPen(p8);        ppp8.translate(0,480);        ppp8.drawText(0,0,x);        ppp8.drawText(20,0," : ");        ppp8.drawText(40,0,y);        ppp8.drawText(60,0," : ");        ppp8.drawText(80,0,z);    }public slots:    void paint()    {        update();//人工调用    }private:    QTimer *time;    int sec,min,hour;    QLabel *lab;};#endif // WIDGET_H/********.cpp**********************************/#include "widget.h"Widget::Widget(QWidget *parent)    : QWidget(parent){    time = new QTimer;    time->start(1000);    connect(time,SIGNAL(timeout()),SLOT(paint()));}Widget::~Widget(){}

小时钟：

实现了鼠标键盘滚轮事件改变其时间

/********myclock.h*****************************/

#ifndef MYCLOCK_H#define MYCLOCK_H#include <QObject>#include <QWidget>#include <QTimer>class myclock : public QWidget{    Q_OBJECTpublic:    explicit myclock(QWidget *parent = nullptr);signals:public slots:    void setvalue(int);    void paint()    {        update();    }protected:    void paintEvent(QPaintEvent *event);private://    int pos;    int s;    QTimer *time;};#endif // MYCLOCK_H

/*************widget.h***************************************/

#ifndef WIDGET_H#define WIDGET_H#include <QWidget>#include<QSlider>#include"myclock.h"#include<QMouseEvent>#include<QKeyEvent>#include<QWheelEvent>#include<QTimer>#include<QLCDNumber>class Widget : public QWidget{    Q_OBJECTpublic:    Widget(QWidget *parent = 0);    ~Widget();public slots:    void shownum(int num);private:    myclock *clock;    QSlider *sd;    int click;    QLCDNumber *lcd;protected:    void mousePressEvent(QMouseEvent *event);    void wheelEvent(QWheelEvent *event);    void keyPressEvent(QKeyEvent *event);};#endif // WIDGET_H

/******************myclock.cpp********************/

#include "myclock.h"#include<QWidget>#include<QPaintEvent>#include<QPainter>#include<QString>#include<QDebug>#include<QBrush>myclock::myclock(QWidget *parent) : QWidget(parent){    //update();    s = 0;    time = new QTimer;    time->start(1000);    connect(time,SIGNAL(timeout()),SLOT(paint()));}void myclock::setvalue(int i){    s = i;    update();}void myclock::paintEvent(QPaintEvent *event){    setFixedSize(600,600);    QPainter pp(this);    QBrush b(QColor(Qt::yellow));    QPen p(QColor(Qt::black));    p.setWidth(4);    pp.setPen(p);    pp.translate(this->width()/2,this->height()/2);    pp.drawEllipse(QPoint(0,0),200,200);    QPainter pp1(this);    QPen p1(QColor(Qt::black));    p1.setWidth(4);    pp1.setPen(p1);    pp1.translate(this->width()/2,this->height()/2);    for(int i = 0;i < 12 ;i++)    {        pp1.drawLine(0,-190,0,-200);        pp1.drawText(0,-170,QString::number(i));        pp1.rotate(30);    }    QPainter pp2(this);    QPen p2(QColor(Qt::black));    p2.setWidth(2);    pp2.setPen(p2);    pp2.translate(this->width()/2,this->height()/2);    for(int j = 0;j < 60 ;j++)    {        pp2.drawLine(0,-193,0,-200);        pp2.rotate(6);    }    QPainter pp5(this);    QPen p5(QColor(Qt::green));    p5.setWidth(6);    pp5.setPen(p5);    pp5.translate(this->width()/2,this->height()/2);    pp5.rotate(s*0.25/60);    pp5.drawLine(0,0,0,-70);    QPainter pp4(this);    QPen p4(QColor(Qt::blue));    p4.setWidth(5);    pp4.setPen(p4);    pp4.translate(this->width()/2,this->height()/2);    pp4.rotate(s*0.5);    pp4.drawLine(0,0,0,-120);    QPainter pp3(this);//定义一个画家    QPen p3(QColor(Qt::red));//画笔，颜色红    p3.setWidth(4);//粗细10    pp3.setPen(p3);//画家拿到笔    pp3.translate(this->width()/2,this->height()/2);    pp3.rotate(s*6);    pp3.drawLine(0,0,0,-170);    s++;    qDebug()<<"s ="<<s;}

/************widget.cpp************************************************/

#include "widget.h"#include <QVBoxLayout>#include<QDebug>int now = 0;Widget::Widget(QWidget *parent)    : QWidget(parent){    click = 0;    lcd = new QLCDNumber;    lcd->setMinimumHeight(45);    sd = new QSlider(this);    sd->setOrientation(Qt::Horizontal);    sd->setRange(0,864399);    clock = new myclock(this);    clock->setFixedSize(300,300);    QVBoxLayout *vbox = new QVBoxLayout;    vbox->addWidget(clock);    vbox->addWidget(lcd);    vbox->addWidget(sd);    setLayout(vbox);    connect(sd,SIGNAL(valueChanged(int)),clock,SLOT(setvalue(int)));    connect(sd,SIGNAL(valueChanged(int)),this,SLOT(shownum(int)));}void Widget::shownum(int num){    now = num;    lcd->display(num);}void Widget::mousePressEvent(QMouseEvent *event){    if( Qt::LeftButton == event->button())    {        click++;        int c = click + now;        sd->setValue(c);        if(c == 864399)        {            click = 0;            sd->setValue(1*click);        }    }    else if( Qt::RightButton == event->button())    {        click--;        sd->setValue(1*click);        if(click == 0)        {            click = 359;            sd->setValue(1*click);        }    }}void Widget::wheelEvent(QWheelEvent *event){    if( Qt::WA_TranslucentBackground == event->delta())    {        click++;        sd->setValue(1*click);        if(click == 359)        {            click = 0;            sd->setValue(1*click);        }    }    else if( -120 == event->delta())    {        click--;        sd->setValue(1*click);        if(click == 0)        {            click = 359;            sd->setValue(1*click);        }    }}void Widget::keyPressEvent(QKeyEvent *event){    if( (Qt::Key_Up == event->key()) || (Qt::Key_Right == event->key()))    {        click++;        sd->setValue(1*click);        if(click == 359)        {            click = 0;            sd->setValue(1*click);        }    }    else if( (Qt::Key_Down == event->key()) || (Qt::Key_Left == event->key()))    {        click--;        sd->setValue(1*click);        if(click == 0)        {            click = 359;            sd->setValue(1*click);        }    }}Widget::~Widget(){}