一、开发环境

Ubuntu 20.04
QT6.0

二、新建 Qt Wigets Application 

这里的基类选择 Wigets，

pro 配置文件添加 sql 模块，需要用到 sqlite，

QT += sql

三、添加数据库连接头文件

// connection.h
#ifndef CONNECTION_H
#define CONNECTION_H#include <QMessageBox>
#include <QSqlDatabase>
#include <QSqlQuery>
#include <QSqlError>
#include <QDebug>static bool createConnection()
{QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");db.setDatabaseName(":memory:");//db.setDatabaseName("ikun.db");bool res = db.open();if (res){qDebug() << "open ikun.db ok !";}else{qDebug() << "open ikun.db fail: " << db.lastError().text();}QSqlQuery query;if(!query.exec("create table task_history(id INTEGER PRIMARY KEY AUTOINCREMENT,task_name varchar(200) not null, cost_time varchar(20) not null, create_time varchar(25) not null)")){qDebug() << "create table task_history  error: " << query.lastError().text();}return true;
}
#endif // CONNECTION_H

初始化连接到 sqlite 数据库，这里使用的内存数据库，没有持久化到磁盘，连接数据库之后创建了一个表 task_history  ，主键为 id 自增，任务事项 task_name 以及消耗时间 cost_time，

四、布局设计

一个 QLineEdit 用于输入任务事项，一个 QLCDNumber 用于计时，一个 QPlainTextEdit 用于输出日志，两个 QPushButton 用于操作开始计时和终止计时，

除了组件的布局调整，还需要在主窗体新增一个槽函数 on_Widget_customContextMenuRequested ，在添加右键菜单功能时需要用到，

五、修改 widget.h

#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>
#include <QDateTime>
#include <QTimer>
#include <QTime>
#include <QSqlQuery>
#include <QSqlError>
#include <QDebug>QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACEclass Widget : public QWidget
{Q_OBJECTpublic:Widget(QWidget *parent = nullptr);~Widget();
protected:void mousePressEvent(QMouseEvent *event);void mouseMoveEvent(QMouseEvent *event);void paintEvent(QPaintEvent *);
protected:QPoint pos;QTimer * timer;QTime * timeRecord;bool isStart;
private slots:void update_time();void on_start_btn_clicked();void get_todo_summary();void on_end_btn_clicked();void on_Widget_customContextMenuRequested(const QPoint &pos);private:Ui::Widget *ui;
};
#endif // WIDGET_H

头文件中主要定义了计时器的成员属性与成员方法、鼠标事件、绘画事件以及对应的槽方法，

六、修改 widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <qpainter.h>
#include <QMouseEvent>
#include <QPaintEvent>
#include <QMessageBox>
#include <QMenu>
#include <QSqlQueryModel>
#include <QTableView>
#include <QDateTime>
#include <QScreen>Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);this->setWindowFlag(Qt::FramelessWindowHint);this->setAttribute(Qt::WA_TranslucentBackground);this->setWindowFlags(windowFlags() | Qt::WindowStaysOnTopHint);// initthis->isStart = false;this->timer = new QTimer;this->timeRecord = new QTime(0, 0, 0);// connect timer and SLOT functionconnect(this->timer,SIGNAL(timeout()),this,SLOT(update_time()));//  menuthis->setContextMenuPolicy(Qt::CustomContextMenu);
}Widget::~Widget()
{delete ui;
}void Widget::mousePressEvent(QMouseEvent* ev)
{if(ev->button()==Qt::LeftButton){pos=ev->pos();}
}void Widget::mouseMoveEvent(QMouseEvent*ev)
{if(ev->buttons()==Qt::LeftButton){int x,y;x=ev->pos().x()-pos.x();y=ev->pos().y()-pos.y();this->move(this->x()+x,this->y()+y);}
}void Widget::paintEvent(QPaintEvent *)
{QPainter painter(this);QPixmap pixmap;pixmap.load(QString("../MyPet/image/pikakun.png"));painter.drawPixmap(0, 0, 128, 128, pixmap);
}void Widget::on_start_btn_clicked()
{if(this->ui->todo_line->text().trimmed().length()  == 0 ){QMessageBox::warning(this, tr("warning"), tr("please input todo first!"), QMessageBox::Yes);this->ui->todo_line->setFocus();return;}this->ui->todo_line->setEnabled(false);this->ui->last_log->setPlainText(QString("Mission " +  this->ui->todo_line->text().trimmed() + " is timing..."));if(!this->isStart){this->timer->start(128);this->ui->start_btn->setText(QString("Pause"));}else{this->timer->stop();this->ui->start_btn->setText(QString("Continue"));}this->isStart = !this->isStart;
}void Widget::update_time()
{// timer add 1 secs, and then display*this->timeRecord = this->timeRecord->addMSecs(128);this->ui->timer->display(this->timeRecord->toString(QString("hh:mm:ss.zzz")));
}void Widget::on_end_btn_clicked()
{// stop timerthis->timer->stop();// show logthis->ui->last_log->setPlainText(QString(this->ui->todo_line->text() +" Cost Time "  +this->timeRecord->toString(QString("hh:mm:ss.zzz"))));// save dbQSqlDatabase::database().transaction();QSqlQuery query;query.prepare(QString("insert into task_history(task_name, cost_time, create_time ) ""values(:task_name, :cost_time,:create_time)"));query.bindValue(":task_name", this->ui->todo_line->text());query.bindValue(":cost_time", this->timeRecord->toString(QString("hh:mm:ss.zzz")));QDateTime dt =QDateTime::currentDateTime();// format yyyy//MM/dd hh:mm:s.zzzQString create_time = dt.toString("yyyy-MM-dd hh:mm:ss.zzz");query.bindValue(":create_time", create_time);if(!query.exec()){qDebug() << "insert into task_history error: " <<  query.lastError().text();}QSqlDatabase::database().commit();// reset displaythis->timeRecord->setHMS(0,0,0);this->ui->timer->display(this->timeRecord->toString(QString("hh:mm:ss.zzz")));this->isStart = false;this->ui->start_btn->setText(QString("Start"));// reset todo_linethis->ui->todo_line->clear();this->ui->todo_line->setEnabled(true);this->ui->todo_line->setFocus();
}void Widget::get_todo_summary()
{QSqlQueryModel *model = new QSqlQueryModel(this);model->setQuery("select * from task_history");model->setHeaderData(0, Qt::Horizontal, tr("ID"));model->setHeaderData(1, Qt::Horizontal, tr("Task"));model->setHeaderData(2, Qt::Horizontal, tr("Time"));model->setHeaderData(3, Qt::Horizontal, tr("LogTime"));QTableView *view = new QTableView;view->setWindowTitle(QString("summary"));view->setModel(model);// must after setModelview->setColumnWidth(1,250);view->setColumnWidth(3,150);QSize *min_size = new QSize;min_size->setWidth(620);min_size->setHeight(400);view->setMinimumSize(*min_size);QScreen *screen = QApplication::primaryScreen();QSize screenSize = screen->size();view->move(( screenSize.width() - min_size->width() ) / 2 , ( screenSize.height() - view->height() ) / 2 );view->show();// free memdelete min_size;
}void Widget::on_Widget_customContextMenuRequested(const QPoint &pos)
{QMenu *menu = new QMenu(this);QAction *summary = new QAction( QIcon(QString("../MyPet/image/pikakun.png")),tr("summary"), this);menu->addAction(summary);connect(summary, SIGNAL(triggered()), this, SLOT(get_todo_summary()));menu->exec(cursor().pos());
}

七、修改 main.cpp

初始化数据库连接，并将窗口移动至屏幕的中间位置，

#include "widget.h"
#include "connection.h"
#include <QApplication>
#include <QLocale>
#include <QTranslator>
#include <QScreen>int main(int argc, char *argv[])
{QApplication a(argc, argv);if (!createConnection()){return 1;}QTranslator translator;const QStringList uiLanguages = QLocale::system().uiLanguages();for (const QString &locale : uiLanguages) {const QString baseName = "MyPet_" + QLocale(locale).name();if (translator.load(":/i18n/" + baseName)) {a.installTranslator(&translator);break;}}Widget w;QScreen *screen = QApplication::primaryScreen();QSize screenSize = screen->size();w.move(( screenSize.width() - w.width() ) / 2 , ( screenSize.height() - w.height() ) / 2 );w.show();return a.exec();
}

八、效果演示

1、输入需要计时的事项后，点击“Start”按钮开始计时

2、开始计时后，“Start”按钮会变成“Pause”按钮，点击该按钮会暂停计时

3、暂停后，“Pause”按钮会变成“Continue”按钮，点击该按钮会继续计时

4、点击“End”按钮后，停止计时，并记录事项耗时到 sqlite 数据库中

5、右键有“Summary”菜单，点击后可以看到事项汇总

特别注意，如果需要将数据从内存中持久化到硬盘，则修改 connection.h，

# 保存在内存，注释这行
// db.setDatabaseName(":memory:");# 保存在 ikun.db，添加这行
db.setDatabaseName("ikun.db");