练习：实现一个简易闹钟

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QDateTime>
#include <QDebug>
#include <QTextToSpeech>

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = nullptr);
    ~Widget();

    void checkTime();

private slots:
    void on_startBtn_clicked();
    void on_stopBtn_clicked();
    void timerEvent(QTimerEvent *event);
    void setupBtnState();

private:
    Ui::Widget *ui;

    int timerId;
    bool alarmOn = false;
    QTextToSpeech *speech;
};

#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);

    timerId = this->startTimer(1000);
    speech = new QTextToSpeech();
}

Widget::~Widget()
{
    delete ui;
}

void Widget::timerEvent(QTimerEvent *event){
    if (event->timerId() == timerId) {
        ui->timeLabel->setText(QDateTime::currentDateTime().toString("MM-dd hh:mm:ss"));
        checkTime();
    }
}

void Widget::checkTime() {
    if (!alarmOn) {
        return;
    }

    bool hourCheck = QDateTime::currentDateTime().toString("h") == this->ui->hourEdit->text();
    bool minCheck = QDateTime::currentDateTime().toString("mm") == this->ui->minEdit->text();

    if (hourCheck && minCheck) {
        //闹钟响
        alarmOn = false;
        setupBtnState();
        speech->say(this->ui->textLabel->text());
    }
}

void Widget::setupBtnState() {
    if (alarmOn) {
        ui->startBtn->setEnabled(false);
        ui->stopBtn->setEnabled(true);
    } else {
        ui->startBtn->setEnabled(true);
        ui->stopBtn->setEnabled(false);
    }

}

void Widget::on_startBtn_clicked()
{
    alarmOn = true;
    setupBtnState();
}

void Widget::on_stopBtn_clicked()
{
    alarmOn = false;
    setupBtnState();
}

结果展示