Qt---day4---9.20

 qt完成时钟：

 头文件：

#ifndef WIDGET_H
#define WIDGET_H
 
#include 
#include 
#include 
#include 
#include 
#include 
 
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
 
class Widget : public QWidget
{
    Q_OBJECT
 
public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
 
    void timerEvent(QTimerEvent *e) override;
    void paintEvent(QPaintEvent *event) override;
 
 
private:
    Ui::Widget *ui;
    int timer_id;
};
#endif // WIDGET_H

功能函数：

#include "widget.h"
#include "ui_widget.h"
 
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    // 构造定时器，设置超时为 1 秒
    timer_id = this->startTimer(1000);
}
 
Widget::~Widget()
{
    delete ui;
}
 
void Widget::timerEvent(QTimerEvent *e)
{
    if(e->timerId()==timer_id)
    {
        QTime sys_t=QTime::currentTime();
        QString h=sys_t.toString("hh");
        QString m=sys_t.toString("mm");
        QString s=sys_t.toString("ss");
        ui->label->setText(h);
        ui->label_2->setText(m);
        ui->label_3->setText(s);
    }
}
 
void Widget::paintEvent(QPaintEvent *event)
{
    QPainter painter(this);
    QPen pen;
    pen.setColor(QColor("black"));
    pen.setStyle(Qt::SolidLine);
    pen.setWidth(5);
    painter.setPen(pen);
    painter.translate(this->width()/2,this->height()/2);
    painter.rotate(0);
    painter.setBrush(QBrush(QColor("skyblue")));
    painter.drawEllipse(QPoint(0,0),100,100);
 
    for(int i=0;i<360;i+=30)
    {
        painter.rotate(30);
        painter.drawLine(QPoint(0,-100),QPoint(0,-90));
 
    }
    for(int i=0;i<360;i+=6)
    {
        painter.rotate(6);
        painter.drawLine(QPoint(0,-100),QPoint(0,-95));
    }
 
 
    //绘制时针
    painter.save();    // 保存当前的绘制状态
        // 将绘制的坐标原点移动到表盘的中心
    int h=ui->label->text().toInt();    // 获取当前的小时
    int m=ui->label_2->text().toInt();     // 获取当前的分钟
    double hourAngle = (h%12 + m/60.0)*30.0;  // 计算时针的角度，考虑分钟对时针的影响
    painter.rotate(hourAngle);    // 旋转坐标系，使时针指向正确的位置
    painter.setPen(QPen(Qt::black,5));    //设置笔
 
    painter.drawLine(QPoint(0,0),QPoint(0,-30));  // 绘制时针，起点是坐标原点 (0, 0)，终点是时针的末端位置
    painter.restore();       // 恢复之前保存的绘制状态，以便后续绘制
 
    //绘制分针
    painter.save();
 
    double minuteAngle = m*6.0;
    painter.rotate(minuteAngle);
    painter.setPen(QPen(Qt::red,3));        //设置笔
    painter.drawLine(QPoint(0,0),QPoint(0,-50));
    painter.restore();
 
    //绘制秒针
    painter.save();
 
    int s=ui->label_3->text().toInt();
    double secondAngle = s * 6.0;
    painter.rotate(secondAngle);
    painter.setPen(QPen(Qt::blue,2));      //设置笔
    painter.drawLine(QPoint(0,0),QPoint(0,-70));
    painter.restore();
 
    this->update();
}
 
 

测试文件：

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

 思维导图：