MDI

#include <QDialog>
#include <QSqlQuery>
#include <QSqlQueryModel>
#include <QSqlTableModel>
#include <QMdiArea>
#include <QtWidgets>
#include "login.h"
namespace Ui {
class backup;
}

class backup : public QDialog
{
    Q_OBJECT

public:
    explicit backup(QMdiArea *md,QWidget *parent = nullptr);

    ~backup();
    QVBoxLayout *vboxleft;
    QHBoxLayout *hboxMain;
    QVBoxLayout *vboxright;
    QHBoxLayout *hboxBtnHight;
    QHBoxLayout *hboxBtnLow;
    QPushButton *close;
    QLabel *text;
    QLabel *text1;
    QPushButton *btnAdd;
     QTableView *view;
     QFileSystemModel *model;
     QDir Rootdir;
     QPushButton* dell;
      QFrame *wgt;

signals:
      void repaint();

public slots:

    void createWindow();

    void addDisk();

    void restoreDisk();

    void labelClik(QString st);

    void moveTo(const QModelIndex &index);

    void dellDisk();

    //void closeEvent(QCloseEvent *event);


private:
    Ui::backup *ui;
    QMdiArea *MdiArea;

};

#endif // BACKUP_H



#include <QFileSystemModel>
#include <QDir>
#include <QDirModel>
#include <QSettings>
#include <QFileDialog>
#include <QDesktopServices>
#include <QFile>
backup::backup(QMdiArea *md, QWidget *parent) :
    QDialog(parent),
    ui(new Ui::backup)
{
       ui->setupUi(this);

MdiArea=md;



   createWindow();


}

backup::~backup()
{
    delete ui;

}

void backup::createWindow()
{
    hboxMain = new QHBoxLayout;
    vboxleft = new QVBoxLayout;
    vboxright = new QVBoxLayout;
    hboxBtnLow = new QHBoxLayout;
    hboxBtnHight = new QHBoxLayout;
    btnAdd = new QPushButton;
    close = new QPushButton;
    text = new QLabel;
    text1 = new QLabel;
    view = new QTableView;
    vboxleft->setSpacing(10);
    btnAdd->setIcon(QIcon("://plus.png"));
    btnAdd->setIconSize(QSize(25,25));
    text1->setText("Добавить диск");
    text->setText("Информация о дисках");

    hboxMain->setContentsMargins(10,10,10,10);
    hboxMain->setSpacing(20);
    hboxMain->addLayout(vboxleft);
    hboxMain->addLayout(vboxright);
    vboxleft->setContentsMargins(10,10,10,10);
    vboxleft->addLayout(hboxBtnHight);
    hboxBtnHight->addWidget(text1);
    hboxBtnHight->addWidget(btnAdd);
    vboxleft->addWidget(text);
    vboxright->addWidget(view);
    vboxright->addLayout(hboxBtnLow);
    hboxBtnLow->addWidget(close);
    setLayout(hboxMain);
   model = new QFileSystemModel;
   setStyleSheet("font-size: 14px;");
   connect(btnAdd,SIGNAL(clicked()),this,SLOT(addDisk()));
   connect(view,SIGNAL(doubleClicked(QModelIndex)),this,SLOT(moveTo(QModelIndex)));
//   Navi* n = new Navi(MdiArea);
//   connect(this,SIGNAL(repaint()),n,SLOT(repaintBackup()));
   restoreDisk();
}

void backup::addDisk()
{

    QFileDialog diag;
    diag.setFileMode(QFileDialog::Directory);
    diag.exec();
    QSettings settings("backup.ini", QSettings::IniFormat);
    settings.beginGroup("disk");
    settings.setValue(diag.directory().dirName(), diag.directory().path());
    settings.endGroup();



}

void backup::restoreDisk()
{
    QSettings settings("backup.ini", QSettings::IniFormat);
    if(settings.allKeys().isEmpty()){
    }else{
    settings.beginGroup("disk");
    QStringList key = settings.allKeys();
    for(int i=0; i<key.size();i++){
    qDebug()<<settings.value(key.at(i)).toString();
    wgt = new QFrame();
    wgt->setObjectName(QString::number(i));
    wgt->setFrameStyle(QFrame::Raised | QFrame::Sunken);
    wgt->setLineWidth(3);
    wgt->setStyleSheet("background-color: #FFFFFF; border: 1px solid #CCCCCC;\
                              border-radius: 4px; color: #555555;\
                              ");


    vboxleft->addWidget(wgt);
    QHBoxLayout* hbox = new QHBoxLayout;
    wgt->setLayout(hbox);
    QLabel* disk = new Clickable();
    disk->setText(settings.value(key.at(i),"").toString());
    hbox->addWidget(disk);
    hbox->setSpacing(10);
    dell = new QPushButton;
    //dell->setText(QString::number(i));
      dell->setObjectName(QString::number(i));
    dell->setIcon(QIcon("://clear.png"));
    dell->setIconSize(QSize(25,25));
    dell->setFixedSize(37,33);
    dell->setSizePolicy(QSizePolicy::Minimum,QSizePolicy::Minimum);
    hbox->addWidget(dell);
    connect(disk,SIGNAL(clicked(QString)),this,SLOT(labelClik(QString)));
    connect(dell,SIGNAL(clicked()),this,SLOT(dellDisk()));
     QStorageInfo hdd(settings.value(key.at(i)).toString());
     if(hdd.isReady() && hdd.isValid()){
     qDebug()<< hdd.bytesTotal()/1000/1000 <<"MB";
     qDebug()<< hdd.bytesAvailable()/1000/1000 <<"MB";
    }
     }
    settings.endGroup();
    }
    vboxleft->addStretch(1);
}

void backup::labelClik(QString st)
{


    Rootdir.setPath(st);
    model->setFilter(QDir::AllEntries);
        model->setRootPath(Rootdir.path());
        view->setModel(model);

        view->setRootIndex(model->index(Rootdir.path()));



}

void backup::moveTo(const QModelIndex &index)
{
QModelIndex currentDiscount  = view->currentIndex();
   qDebug()<<view->model()->data(view->model()->index(currentDiscount.row(),0),0).toString();
   QListView* listviw = (QListView*)sender();
   QFileInfo fileinfo= model->fileInfo(index);
   if(fileinfo.fileName()==".."){
       QDir dir = fileinfo.dir();
       dir.cdUp();
       listviw->setRootIndex( model->index(dir.absolutePath()));
   }
   else if(fileinfo.fileName()=="."){
      listviw->setRootIndex(model->index(Rootdir.path()));
   }
   else if(fileinfo.isDir()){
       listviw->setRootIndex(index);
   }
}

void backup::dellDisk()
{
    int k = dell->objectName().toInt();
    QSettings settings("backup.ini", QSettings::IniFormat);
    QStringList keys = settings.allKeys();
    settings.remove(keys.at(k));
   // вот тут нужно вызвать метод для перерисовки окна (update and repaint не  работают)
    // Mdiarea->update()(repaint()) тоже не робит
    //перерисовка subvindow откуда я это вызвал крашит всю прогу
}