Qt学习—qt编写定时关机程序

大家好，又见面了，我是你们的朋友全栈君。

编写了一个简单的定时关机程序，软件界面如下。顺便记录一下所用的控件的一些简单的使用方法。程序中用到的控件主要是
QLCDNumber(数码管控件)以及QSpinBox()(滚动框控件)。

通过system()调用系统的关机命令。需要包含头文件stdlib.h。此外涉及到数码管以及滚动框显示数字时，前缀“0”的显示和消隐的问题。以下是代码。

首先是main.cpp

#include <QtGui/QApplication>

#include "mainwindow.h"

#include <QTextCodec>

int main(int argc, char *argv[])

{ 
    

 QApplication a(argc, argv);

 //Qt文本的国际化显示

 QTextCodec::setCodecForCStrings(QTextCodec::codecForName("GB18030"));

 QTextCodec::setCodecForLocale(QTextCodec::codecForName("GB18030"));

 QTextCodec::setCodecForTr(QTextCodec::codecForName("GB18030"));

 MainWindow w;

 w.show();

 return a.exec();

}

其次是mainwindow.h

#ifndef MAINWINDOW_H

#define MAINWINDOW_H

#include <QMainWindow>

#include <QDebug>

#include <QMessageBox>

#include <stdlib.h>

#include <QTimer>

#include <QString>

#include <QByteArray>

#include <QSpinBox>

namespace Ui { 
    

class MainWindow;

}

class MainWindow : public QMainWindow

{ 
    

 Q_OBJECT

public:

 explicit MainWindow(QWidget *parent = 0);

 ~MainWindow();

private slots:

 void slot_pushbutton_exec();

 void slot_pushbutton_cancel();

 void slot_count_down();

 void slot_set_hour();

 void slot_set_minute();

 void slot_set_second();

private:

 Ui::MainWindow *ui;

 QTimer timer;

 void init_sys();

};

#endif // MAINWINDOW_H

最后是mainwindow.cpp

#include "mainwindow.h"

#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :

 QMainWindow(parent),

 ui(new Ui::MainWindow)

{ 
    

 ui->setupUi(this);

 init_sys();

 QObject::connect(ui->pushButton_exec,SIGNAL(clicked()),this,SLOT(slot_pushbutton_exec()));

 QObject::connect(ui->pushButton_cancel,SIGNAL(clicked()),this,SLOT(slot_pushbutton_cancel()));

 QObject::connect(&timer,SIGNAL(timeout()),this,SLOT(slot_count_down()));

 QObject::connect(ui->spinBox_hour,SIGNAL(valueChanged(int)),this,SLOT(slot_set_hour()));

 QObject::connect(ui->spinBox_minute,SIGNAL(valueChanged(int)),this,SLOT(slot_set_minute()));

 QObject::connect(ui->spinBox_second,SIGNAL(valueChanged(int)),this,SLOT(slot_set_second()));

}

MainWindow::~MainWindow()

{ 
    

 delete ui;

}

void MainWindow::init_sys()

{ 
    

 //初始化LCD显示器

 //注：display是重载函数，当希望显示09,08,07……等数字形式时

 //采用字符串形式，可以显示前缀“0”，数字型显示会自动忽略掉0

 ui->lcdNumber_hour->display("88");

 ui->lcdNumber_minute->display("88");

 ui->lcdNumber_second->display("88");

 //设置组合框文本内容的前缀

 ui->spinBox_hour->setPrefix("0");

 ui->spinBox_minute->setPrefix("0");

 ui->spinBox_second->setPrefix("0");

 //初始化组合框文本内容

 ui->spinBox_hour->setValue(0);

 ui->spinBox_minute->setValue(0);

 ui->spinBox_second->setValue(0);

 //停止定时器

 timer.stop();

}

void MainWindow::slot_pushbutton_exec()

{ 
    

 //以索引号模式判断用户做出的选择

 int index_model = ui->comboBox_model->currentIndex();

 int index_action = ui->comboBox_action->currentIndex();

 //以当前选项文本内容判断用户做出的选择

// QString str_model = ui->comboBox_model->currentText();

// QString str_action = ui->comboBox_action->currentText();

// if(str_model = "设定时间")

 if(0==index_model) //指定关机时间模式

 { 
    

 QString second = ui->spinBox_second->text();

 QString minute = ui->spinBox_minute->text();

 QString hour = ui->spinBox_hour->text();

 QString cmd = "at "+hour+":"+minute+":"+second+" ";

 switch(index_action)

 { 
    

 case 0: //关机指令

 cmd = cmd + "shutdown -s";

 break;

 case 1: //注销指令

 cmd = cmd + "shutdown -l";

 break;

 case 2: //重启指令

 cmd = cmd + "shutdown -r";

 break;

 }

 //将QString类对象转换为char*类型

 char* ch;

 QByteArray ba = cmd.toLatin1();

 ch=ba.data();

 system(ch); //执行shell命令

 }

 else if(1==index_model) //倒计时关机模式

 { 
    

 int delay = ui->spinBox_hour->value()*3600 +

 ui->spinBox_minute->value()*60 +

 ui->spinBox_second->value();

 QString cmd = "";

 switch(index_action)

 { 
    

 case 0: //关机指令

 cmd = "shutdown -s -t "+QString::number(delay);

 break;

 case 1: //注销指令

 cmd = "shutdown -l -t "+QString::number(delay);

 break;

 case 2: //重启指令

 cmd = "shutdown -r -t "+QString::number(delay);

 break;

 }

 char* ch;

 QByteArray ba = cmd.toLatin1();

 ch=ba.data();

 system(ch);

 //当显示的数字的位数为一位时，需要加上前缀“0”,以达到09，08……的效果

 //当显示的数字为两位数时，则需要屏蔽掉前缀“0”。

 //设置LCD显示小时

 if(ui->spinBox_hour->value()<=9&&ui->spinBox_hour->value()>=0)

 ui->lcdNumber_hour->display("0"+QString::number(ui->spinBox_hour->value()));

 else

 ui->lcdNumber_hour->display(QString::number(ui->spinBox_hour->value()));

 //设置LCD显示分钟

 if(ui->spinBox_minute->value()<=9&&ui->spinBox_minute->value()>=0)

 ui->lcdNumber_minute->display("0"+QString::number(ui->spinBox_minute->value()));

 else

 ui->lcdNumber_minute->display(QString::number(ui->spinBox_minute->value()));

 //设置LCD显示秒

 if(ui->spinBox_second->value()<=9&&ui->spinBox_second->value()>=0)

 ui->lcdNumber_second->display("0"+QString::number(ui->spinBox_second->value()));

 else

 ui->lcdNumber_second->display(QString::number(ui->spinBox_second->value()));

 timer.start(1*1000);

 }

}

void MainWindow::slot_pushbutton_cancel()

{ 
    

 system("shutdown -a");

 init_sys();

}

void MainWindow::slot_count_down()

{ 
    

 int hour = ui->lcdNumber_hour->value();

 int minute = ui->lcdNumber_minute->value();

 int second = ui->lcdNumber_second->value();

 second--;

 if(second<0)

 { 
    

 second = 59;

 minute--;

 if(minute<0)

 { 
    

 minute = 59;

 hour--;

 if(hour<0)

 { 
    

 hour = 0;

 }

 }

 }

 if(hour<=9&&hour>=0)

 ui->lcdNumber_hour->display("0"+QString::number(hour));

 else

 ui->lcdNumber_hour->display(QString::number(hour));

 if(minute<=9&&minute>=0)

 ui->lcdNumber_minute->display("0"+QString::number(minute));

 else

 ui->lcdNumber_minute->display(QString::number(minute));

 if(second<=9&&second>=0)

 ui->lcdNumber_second->display("0"+QString::number(second));

 else

 ui->lcdNumber_second->display(QString::number(second));

}

void MainWindow::slot_set_hour()

{ 
    

 if(ui->spinBox_hour->value()>9)

 { 
    

 ui->spinBox_hour->setPrefix("");

 }

 else

 { 
    

 ui->spinBox_hour->setPrefix("0");

 }

}

void MainWindow::slot_set_minute()

{ 
    

 if(ui->spinBox_minute->value()>9)

 { 
    

 ui->spinBox_minute->setPrefix("");

 }

 else

 { 
    

 ui->spinBox_minute->setPrefix("0");

 }

}

void MainWindow::slot_set_second()

{ 
    

 if(ui->spinBox_second->value()>9)

 { 
    

 ui->spinBox_second->setPrefix("");

 }

 else

 { 
    

 ui->spinBox_second->setPrefix("0");

 }

}