hi
when i clicked "Create Dir" button...
Why is this program not working?

QDir.jpg

Qt Code: 
  1. #ifndef MAINWINDOW_H
  2. #define MAINWINDOW_H
  3.  
  4. #include <QMainWindow>
  5. #include <QDirModel>
  6.  
  7. namespace Ui {
  8. class MainWindow;
  9. }
  10.  
  11. class MainWindow : public QMainWindow
  12. {
  13.     Q_OBJECT
  14.  
  15. public:
  16.     explicit MainWindow(QWidget *parent = 0);
  17.     ~MainWindow();
  18.  
  19. private slots:
  20.     void on_pushButton_clicked();
  21.  
  22.     void on_pushButton_2_clicked();
  23.  
  24. private:
  25.     Ui::MainWindow *ui;
  26.     QDirModel *model ;
  27.  
  28. };
  29.  
  30. #endif // MAINWINDOW_H
To copy to clipboard, switch view to plain text mode 

Qt Code: 
  1. #include "mainwindow.h"
  2. #include "ui_mainwindow.h"
  3. #include <QInputDialog>
  4. #include <QString>
  5.  
  6. MainWindow::MainWindow(QWidget *parent) :
  7.     QMainWindow(parent),
  8.     ui(new Ui::MainWindow)
  9. {
  10.     ui->setupUi(this);
  11.     model = new QDirModel(this) ;
  12.     model->setReadOnly(false);
  13.     model->setSorting(QDir::DirsFirst |QDir::Name | QDir::IgnoreCase);
  14.     ui->treeView->setModel(model);
  15. }
  16.  
  17. MainWindow::~MainWindow()
  18. {
  19.     delete ui;
  20. }
  21.  
  22. void MainWindow::on_pushButton_clicked()
  23. {
  24.     //Create
  25.     QModelIndex index = ui->treeView->currentIndex();
  26.     if(!index.isValid())
  27.         return;
  28.     QString name = QInputDialog::getText(this,"Name","Enter a name :");
  29.     if(!name.isEmpty())
  30.         return ;
  31.     model->mkdir(index,name);
  32. }
  33.  
  34. void MainWindow::on_pushButton_2_clicked()
  35. {
  36.     //Delete
  37. }
To copy to clipboard, switch view to plain text mode