mainwindow中点击按钮跳转到alarm窗口没有问题，但是从alarm窗口回到主窗口，点击按钮程序为什么直接关闭了也不显示主窗口

[ameshibushi]

#ifndef ALARM_H
#define ALARM_H

#include <QWidget>

namespace Ui {
class Alarm;
}

class Alarm : public QWidget
{
Q_OBJECT

public:
explicit Alarm(QWidget *parent = 0);
~Alarm();

private slots:
void on_pushButton_back_clicked();

private:
Ui::Alarm *ui;
};

#endif // ALARM_H

#include "parameter.h"
#include "teach.h"
#include "revert.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();


private slots:
void on_pushButton_manual_clicked();

void on_pushButton_aut_clicked();

void on_pushButton_parameter_clicked();

void on_pushButton_teach_clicked();

void on_pushButton_revert_clicked();

void on_pushButton_alarm_clicked();

private:
Ui::MainWindow *ui;
Manual manual;
Automatic aut;
Alarm alarm;
Parameter para;
Teach teach;
Revert revert;

};

#endif // MAINWINDOW_H
#include "mainwindow.h"
#include "ui_mainwindow.h"


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

}

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

void MainWindow::on_pushButton_manual_clicked()
{
this->close();
manual.show();
}


void MainWindow::on_pushButton_aut_clicked()
{
this->close();
aut.show();
}

void MainWindow::on_pushButton_parameter_clicked()
{
this->close();
para.show();
}

void MainWindow::on_pushButton_teach_clicked()
{
this->close();
teach.show();
}

void MainWindow::on_pushButton_revert_clicked()
{
this->close();
revert.show();
}

void MainWindow::on_pushButton_alarm_clicked()
{
this->close();
alarm.show();
}

#include "alarm.h"
#include "ui_alarm.h"
#include "mainwindow.h"

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

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

void Alarm::on_pushButton_back_clicked()
{
this->close();
MainWindow b;
b.show();

}

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;

w.show();

return a.exec();

}

[schlafenhamster]

this->close(); 问题吧 ？ 应该 隐藏 不是 close

[ameshibushi]

已经解决了 把工程文件删除了重新运行就没问题了 真的是日狗了