.h文件

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QPushButton> //按钮
#include <QTextEdit> //文本
#include <QLabel>  //标签
#include <QLineEdit> //行编辑器


#include <QTimerEvent> //定时器事件类头文件
#include <QDateTime> //日期时间类
#include <QtTextToSpeech/QTextToSpeech>
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 *event) override;
signals:
        void my_signal();
public slots:
    void btn1_slots(); //启动按钮槽函数
    void btn2_slots(); //关闭按钮槽函数

private:
    Ui::Widget *ui;
    QPushButton *btn1;
    QPushButton *btn2;
    QLabel *lab;
    QTextEdit *text;
    QLineEdit *line;
    //实例化一个定时器指针
    //QTimer *timer;
    //定义一个定时器的id
    int timer_id;
    //设置一个播报员
    QTextToSpeech *speecher;
};
#endif // WIDGET_H

.cpp文件

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

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    //设置窗口的大小
    this->setFixedSize(540,410);
    //设置启动按钮
    btn1 = new QPushButton("启动",this);
    btn1->resize(70,50);
    btn1->move(340,100);
    connect(btn1,&QPushButton::clicked,this,&Widget::btn1_slots);
    //设置关闭按钮
    btn2 = new QPushButton("关闭",this);
    btn2->resize(btn1->size());
    btn2->move(btn1->x()+90,btn1->y());
    btn2->setEnabled(false);
    connect(btn2,&QPushButton::clicked,this,&Widget::btn2_slots);
    //设置定时闹钟
    lab = new QLabel("闹钟",this);
    lab->resize(310,150);
    lab->setStyleSheet("background-color:skyblue");
    //设置定的时间
    line = new QLineEdit(this);
    line->resize(160,50);
    line->move(btn1->x(),btn1->y()-70);
    //设置文本
    text = new QTextEdit(this);
    text->resize(540,270);
    text->move(lab->x(),lab->y()+180);
    text->setText("时间到了！");
    //设置播报员
    speecher = new QTextToSpeech;
    connect(this,&Widget::my_signal,[&](){
        speecher->say(this->text->toPlainText());
    });
    //定时器
    //timer = new QTimer(this);
    //将该定时的time信号连接到自定义的槽函数中
    //connect(timer,&QTime::timeout,this,&Widget::timeout_slots);
}

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

void Widget::timerEvent(QTimerEvent *event)
{
    if(event->timerId()==timer_id)
    {
        QDateTime sys_dt = QDateTime::currentDateTime();//获取当前系统日期时间
        this->lab->setText(sys_dt.toString("yyyy-MM-dd  hh:mm:ss"));
        if(sys_dt.toString("yyyy-MM-dd  hh:mm:ss") == this->line->text())
        {
            emit my_signal();
        }
    }
}

void Widget::btn1_slots()
{
    //启动定时器
    timer_id=this->startTimer(1000);
    btn2->setEnabled(true);
    btn1->setEnabled(false);
    line->setEnabled(false);
    lab->setEnabled(false);

}

void Widget::btn2_slots()
{
    this->killTimer(timer_id);
    btn2->setEnabled(false);
    btn1->setEnabled(true);
    line->setEnabled(true);
    lab->setEnabled(true);
    speecher->stop();

}