怎么用Qt制作简单的日期选择界面

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Qt自带的日期选择控件过于丑陋与难用，所以但凡有点小想法的人都会做一个全新的日历。

制作日历的核心难点是填充日历。以下为我的填充日历函数：

void STCalandarWidget::FillCalandar()
{
    QDate firstDay;
    firstDay.setDate(currentDate.year(), currentDate.month(), 1);
    int firstnum = firstDay.dayOfWeek();//这个月的第一天是星期几
    qDebug() << firstnum;
    QDate firstDayOfMonth = firstDay.addDays(-(firstnum - 1));//日历的第一天实际的日期
    for (int i = 0; i < 42; i++) {
        if (i < firstnum-1 || (firstDayOfMonth.month() != currentDate.month())) {//理论上只需要后半边的条件就行
            datewidgets[i]->SetDate(firstDayOfMonth.year(), firstDayOfMonth.month(), firstDayOfMonth.day(), false);
        }
        else {
            datewidgets[i]->SetDate(firstDayOfMonth.year(), firstDayOfMonth.month(), firstDayOfMonth.day(), true);
        }
        firstDayOfMonth = firstDayOfMonth.addDays(1);
    }
}

鄙人制作的日历使用起来非常简单，仅需将两个头文件和两个CPP加入到工程中，使用时的代码如下：

  calandar_ = new STCalandarWidget(this);
   connect(calandar_, SIGNAL(DateSelectSignal(QDate)), this, SLOT(HaveDateChose(QDate)));
   calandar_->exec();

当日历的日期被选择时，会发送DateSelectSignal信号，调用者写一个槽函数接受一下就可以：

void MyClass::HaveDateChose(QDate c_dates)
{
    ui.dateedit->setDate(c_dates);
    calandar_->accepted();
    calandar_->deleteLater();
}

STDateWidget.h:

#pragma once
#include <qwidget.h>
#include <QDate>
#include <QPainter>
class STDateWidget :
    public QWidget
{
    Q_OBJECT
public:
    enum Direction {
        DIR_TOP = 0,
        DIR_BOTTOM,
        DIR_LEFT,
        DIR_RIGHT
    };
 
    STDateWidget(QWidget* parrent = nullptr);
    ~STDateWidget();
    void SetDate(int year, int month, int day, bool isThisMonth);
    QDate GetCurrentDate();
    void AddNeighbor(STDateWidget* wid,Direction dir);
    void HaveGoodNeighbor(Direction dir);
    void DeleteGoodNgithbor(Direction dir);
 
 
private:
    bool isHasGoodNeighbor;
    bool canSelect;
    bool isMoveIn;
    Direction direction;
    QDate currentDate;
    QList<STDateWidget*> neighbors;
    QList<Direction>directions;
protected:
    void mouseReleaseEvent(QMouseEvent* event) ;
    void enterEvent(QEvent* event);
    void leaveEvent(QEvent* event);
    void paintEvent(QPaintEvent* event);
 
signals:
    void updateCurrentDate(QDate date);
};

STDateWidget.cpp

#include "STDateWidget.h"
#include <QMouseEvent>
#include <QLinearGradient>
STDateWidget::STDateWidget(QWidget* parrent /* = nullptr */) :QWidget(parrent)
{
    isMoveIn = false;
    //qDebug() << "make";
    //this->setGeometry(0, 0, 180, 160);
    isHasGoodNeighbor = false;
    //this->setStyleSheet("background-color:red");
}
STDateWidget::~STDateWidget()
{
}
 
void STDateWidget::SetDate(int year, int month, int day, bool isThisMonth)
{
    currentDate.setDate(year, month, day);
    canSelect = isThisMonth;
    
    update();
}
 
QDate STDateWidget::GetCurrentDate()
{
    return currentDate;
}
 
void STDateWidget::AddNeighbor(STDateWidget* wid, Direction dir)
{
    neighbors.append(wid);
    directions.append(dir);
}
 
void STDateWidget::HaveGoodNeighbor(Direction dir)
{
    isHasGoodNeighbor = true;
    direction = dir;
    update();
}
 
void STDateWidget::DeleteGoodNgithbor(Direction dir)
{
    isHasGoodNeighbor = false;
    direction = dir;
    update();
}
 
void STDateWidget::mouseReleaseEvent(QMouseEvent* event)
{
    if (canSelect) {
        emit updateCurrentDate(currentDate);
    }
    
}
 
void STDateWidget::enterEvent(QEvent* event)
{
    isMoveIn = true;
    for (int i = 0; i < neighbors.count(); i++) {
        neighbors[i]->HaveGoodNeighbor(directions[i]);
    }
    update();
}
 
void STDateWidget::leaveEvent(QEvent* event)
{
    isMoveIn = false;
    for (int i = 0; i < neighbors.count(); i++) {
        neighbors[i]->DeleteGoodNgithbor(directions[i]);
    }
    update();
}
 
void STDateWidget::paintEvent(QPaintEvent* event)
{
    //return;
    QPainter painter(this);
    painter.save();
    int xx = 1;
    int yy = 1;
    int ww = this->geometry().width();
    int hh = this->geometry().height();
    if (isMoveIn) {
        QPen pen;
        pen.setBrush(QColor(0, 200, 250, 200));
        pen.setWidth(2);
        painter.setPen(pen);
        painter.drawRect(xx +2 ,yy +2,ww-4,hh-4);
    }
    else {
        if (isHasGoodNeighbor)
        {
            QPen pen;
            pen.setBrush(QColor(255, 255, 255, 0));
            pen.setWidth(0);
            painter.setPen(pen);
            QLinearGradient line_left_top2bottom(xx + 2, yy + 2, xx + 2, yy + hh - 6);//左。
            line_left_top2bottom.setColorAt(0.0, Qt::white);
            line_left_top2bottom.setColorAt(1.0, QColor(0, 200, 250, 100));
            QLinearGradient line_left_bottom2top( xx + 2, yy + hh - 6, xx + 2, yy + 2);//左。
            line_left_bottom2top.setColorAt(0.0, Qt::white);
            line_left_bottom2top.setColorAt(1.0, QColor(0, 200, 250, 100));
            QLinearGradient line_right_top2bottpm(xx + ww - 6, yy + 2, xx + ww - 6, yy + hh - 6);
            line_right_top2bottpm.setColorAt(0.0, Qt::white);
            line_right_top2bottpm.setColorAt(1.0, QColor(0, 200, 250, 100));
            QLinearGradient line_right_bottom2top(xx + ww - 6, yy + hh - 6, xx + ww - 6, yy + 2);
            line_right_bottom2top.setColorAt(0.0, Qt::white);
            line_right_bottom2top.setColorAt(1.0, QColor(0, 200, 250, 100));
            QLinearGradient line_top_left2right(xx + 2, yy + 2, xx + ww - 6, yy + 2);
            line_top_left2right.setColorAt(0.0, Qt::white);
            line_top_left2right.setColorAt(1.0, QColor(0, 200, 250, 100));
            QLinearGradient line_top_right2left(xx + ww - 6, yy + 2, xx + 2, yy + 2);
            line_top_right2left.setColorAt(0.0, Qt::white);
            line_top_right2left.setColorAt(1.0, QColor(0, 200, 250, 100));
            QLinearGradient line_bottom_left2right(xx + 2, yy + hh - 6, xx + ww - 6, yy + hh - 6);
            line_bottom_left2right.setColorAt(0.0, Qt::white);
            line_bottom_left2right.setColorAt(1.0, QColor(0, 200, 250, 100));
            QLinearGradient line_bottom_right2left(xx + ww - 6, yy + hh - 6, xx + 2, yy + hh - 6);
            line_bottom_right2left.setColorAt(0.0, Qt::white);
            line_bottom_right2left.setColorAt(1.0, QColor(0, 200, 250, 100));
            QRect rectTop(xx + 2, yy + 2, ww - 6, 2);
            QRect rectBottom(xx + 2, yy + hh - 4, ww - 4, 2);
            QRect rectLeft(xx + 2, yy + 2, 2, hh - 6);
            QRect rectRight(xx + ww - 4, yy + 2, 2, hh - 6);
            switch (direction)
            {
            case STDateWidget::DIR_TOP:
                painter.setBrush(QColor(0, 200, 250, 100));
                painter.drawRect(rectBottom);
                painter.setBrush(line_left_top2bottom);
                painter.drawRect(rectLeft);
                painter.setBrush(line_right_top2bottpm);
                painter.drawRect(rectRight);               
                break;
            case STDateWidget::DIR_BOTTOM:
                painter.setBrush(QColor(0, 200, 250, 100));
                painter.drawRect(rectTop);
                painter.setBrush(line_left_bottom2top);
                painter.drawRect(rectLeft);
                painter.setBrush(line_right_bottom2top);
                painter.drawRect(rectRight);
                break;
            case STDateWidget::DIR_LEFT:
                painter.setBrush(QColor(0, 200, 250, 100));
                painter.drawRect(rectRight);
                painter.setBrush(line_top_left2right);
                painter.drawRect(rectTop);
                painter.setBrush(line_bottom_left2right);
                painter.drawRect(rectBottom);
                break;
            case STDateWidget::DIR_RIGHT:
                painter.setBrush(QColor(0, 200, 250, 100));
                painter.drawRect(rectLeft);
                painter.setBrush(line_top_right2left);
                painter.drawRect(rectTop);
                painter.setBrush(line_bottom_right2left);
                painter.drawRect(rectBottom);
                break;
            default:
                break;
            }
        }
        /*   QPen pen;
           pen.setBrush(QColor(255, 255, 255, 255));
           pen.setWidth(2);
           painter.setPen(pen);
           painter.drawRect(this->geometry());*/
    }
    painter.restore();
    if (canSelect) {
        QPen pen2;
        pen2.setBrush(QColor(0, 0, 0));
        painter.setPen(pen2);
        painter.drawText(ww/2 - 10, hh/2, QString::number(currentDate.day()));
    }
    else {
        QPen pen2;
        pen2.setBrush(QColor(200, 200, 200));
        painter.setPen(pen2);
        painter.drawText(ww/2- 10, hh/2, QString::number(currentDate.day()));
    }
    //painter
}

STCalandarWidget.h

#pragma once
#include <qdialog.h>
#include "STDateWidget.h"
#include <QLabel>
#include <QPushButton>
class STCalandarWidget :
    public QDialog
{
    Q_OBJECT
public:
    STCalandarWidget(QWidget* parrent = nullptr);
    ~STCalandarWidget();
    void SetCurrentDate(int year, int month, int day);
    QDate GetCurrentDate();
private:
    void FillCalandar();
    void initLabels();
    void initCalandar();
    void init();
    QString getFormatMonth();
private:
    QLabel *weeklabels[7];
    STDateWidget *datewidgets[42];
    QPushButton *lastYearButton;
    QPushButton *lastMonthButton;
    QPushButton *nextMonthButton;
    QPushButton *nextYearButton;
    QDate currentDate;
    QLabel *cdlabel;
public slots:
    void HaveDateSelect(QDate date);
    void JumpLastYear();
    void JumpLastMonth();
    void JumpNextMonth();
    void JumpNextYear();
 
signals:
    void DateSelectSignal(QDate date);
};

STCalandarWidget.cpp:

#include "STCalandarWidget.h"
#include <QDebug>
STCalandarWidget::STCalandarWidget(QWidget* parrent /* = nullptr */) :QDialog(parrent) {
    this->setStyleSheet(QString::fromLocal8Bit("font:15px 等线; background-color:rgb(250,250,250)"));
    this->setMinimumSize(580, 450);
    this->setMaximumSize(580, 450);
    Qt::WindowFlags flags = Qt::Dialog;
    flags |= Qt::WindowCloseButtonHint;
    setWindowFlags(flags);
    init();
}
 
STCalandarWidget::~STCalandarWidget()
{
}
 
void STCalandarWidget::SetCurrentDate(int year, int month, int day)
{
    currentDate.setDate(year, month, day);
}
 
QDate STCalandarWidget::GetCurrentDate()
{
    return currentDate;
}
 
void STCalandarWidget::FillCalandar()
{
    QDate firstDay;
    firstDay.setDate(currentDate.year(), currentDate.month(), 1);
    int firstnum = firstDay.dayOfWeek();
    qDebug() << firstnum;
    QDate firstDayOfMonth = firstDay.addDays(-(firstnum - 1));
    for (int i = 0; i < 42; i++) {
        if (i < firstnum-1 || (firstDayOfMonth.month() != currentDate.month())) {
            datewidgets[i]->SetDate(firstDayOfMonth.year(), firstDayOfMonth.month(), firstDayOfMonth.day(), false);
        }
        else {
            datewidgets[i]->SetDate(firstDayOfMonth.year(), firstDayOfMonth.month(), firstDayOfMonth.day(), true);
        }
        firstDayOfMonth = firstDayOfMonth.addDays(1);
    }
}
 
void STCalandarWidget::initLabels()
{
    for (int i = 0; i < 7; i++) {
        weeklabels[i] = new QLabel(this);
        weeklabels[i]->setGeometry(35 + i*80, 50, 80, 40);
    }
    weeklabels[0]->setText("Mon");
    weeklabels[1]->setText("Tue");
    weeklabels[2]->setText("Wed");
    weeklabels[3]->setText("Thu");
    weeklabels[4]->setText("Fri");
    weeklabels[5]->setText("Sat");
    weeklabels[6]->setText("Sun");
}
 
void STCalandarWidget::initCalandar()
{
    for (int i = 0; i < 42; i++) {
        datewidgets[i] = new STDateWidget(this);
        datewidgets[i]->setGeometry(10 + i % 7 * 80, 80 + i / 7 * 60, 80, 60);
        connect(datewidgets[i], SIGNAL(updateCurrentDate(QDate)), this, SLOT(HaveDateSelect(QDate)));
    }
    for (int i = 0; i < 42; i++) {
        if (i / 7 == 0 ) {//第一排
            if (i % 7 == 0) {//第一个
                datewidgets[i]->AddNeighbor(datewidgets[i + 1], STDateWidget::DIR_RIGHT);
            }
            else if (i % 7 == 6) {//最后一个
                datewidgets[i]->AddNeighbor(datewidgets[i - 1], STDateWidget::DIR_LEFT);
            }
            else {
                datewidgets[i]->AddNeighbor(datewidgets[i + 1], STDateWidget::DIR_RIGHT);
                datewidgets[i]->AddNeighbor(datewidgets[i - 1], STDateWidget::DIR_LEFT);
            }
            datewidgets[i]->AddNeighbor(datewidgets[i + 7], STDateWidget::DIR_BOTTOM);
        }
        else if (i / 7 == 5) {//最后一排
            if (i % 7 == 0) {//第一个
                datewidgets[i]->AddNeighbor(datewidgets[i + 1], STDateWidget::DIR_RIGHT);
            }
            else if (i % 7 == 6) {//最后一个
                datewidgets[i]->AddNeighbor(datewidgets[i - 1], STDateWidget::DIR_LEFT);
            }
            else {
                datewidgets[i]->AddNeighbor(datewidgets[i + 1], STDateWidget::DIR_RIGHT);
                datewidgets[i]->AddNeighbor(datewidgets[i - 1], STDateWidget::DIR_LEFT);
            }
            datewidgets[i]->AddNeighbor(datewidgets[i - 7], STDateWidget::DIR_TOP);
        }
        else
        {
            if (i % 7 == 0) {//第一个
                datewidgets[i]->AddNeighbor(datewidgets[i + 1], STDateWidget::DIR_RIGHT);
            }
            else if (i % 7 == 6) {//最后一个
                datewidgets[i]->AddNeighbor(datewidgets[i - 1], STDateWidget::DIR_LEFT);
            }
            else {
                datewidgets[i]->AddNeighbor(datewidgets[i + 1], STDateWidget::DIR_RIGHT);
                datewidgets[i]->AddNeighbor(datewidgets[i - 1], STDateWidget::DIR_LEFT);
            }
            datewidgets[i]->AddNeighbor(datewidgets[i - 7], STDateWidget::DIR_TOP);
            datewidgets[i]->AddNeighbor(datewidgets[i + 7], STDateWidget::DIR_BOTTOM);
        }
    }
    FillCalandar();
}
 
void STCalandarWidget::init()
{
    currentDate = QDate::currentDate();
    lastYearButton = new QPushButton(this);
    lastYearButton->setGeometry(10, 10, 100, 30);
    lastYearButton->setText("<<");
 
    lastMonthButton = new QPushButton(this);
    lastMonthButton->setGeometry(120, 10, 100, 30);
    lastMonthButton->setText("<");
 
    cdlabel = new QLabel(this);
    cdlabel->setGeometry(255, 10, 100, 40);
    cdlabel->setText(getFormatMonth());
 
    nextMonthButton = new QPushButton(this);
    nextMonthButton->setGeometry(360, 10, 100, 30);
    nextMonthButton->setText(">");
 
    nextYearButton = new QPushButton(this);
    nextYearButton->setGeometry(470, 10, 100, 30);
    nextYearButton->setText(">>");
 
    connect(lastYearButton, SIGNAL(clicked()), this, SLOT(JumpLastYear()));
    connect(lastMonthButton, SIGNAL(clicked()), this, SLOT(JumpLastMonth()));
    connect(nextMonthButton, SIGNAL(clicked()), this, SLOT(JumpNextMonth()));
    connect(nextYearButton, SIGNAL(clicked()), this, SLOT(JumpNextYear()));
    initLabels();
    initCalandar();
}
QString STCalandarWidget::getFormatMonth()
{
    QString ans = "";
    ans += QString::number(currentDate.year());
    ans += QString::fromLocal8Bit("年");
    ans += QString::number(currentDate.month());
    ans += QString::fromLocal8Bit("月");
    return ans;
}
void STCalandarWidget::HaveDateSelect(QDate date)
{
    qDebug() << date;
    emit DateSelectSignal(date);
}
void STCalandarWidget::JumpLastYear()
{
    currentDate = currentDate.addYears(-1);
    FillCalandar();
    cdlabel->setText(getFormatMonth());
}
 
void STCalandarWidget::JumpLastMonth()
{
    currentDate = currentDate.addMonths(-1);
    FillCalandar();
    cdlabel->setText(getFormatMonth());
}
 
void STCalandarWidget::JumpNextMonth()
{
    currentDate = currentDate.addMonths(1);
    FillCalandar();
    cdlabel->setText(getFormatMonth());
}
 
void STCalandarWidget::JumpNextYear()
{
    currentDate = currentDate.addYears(1);
    FillCalandar();
    cdlabel->setText(getFormatMonth());
}