Weird behavior when filter QFileSystemModel by proxy

[stereoMatching]

#include <QtCore>
#include <QtGui>

class fileProxy : public QSortFilterProxyModel
{
Q_OBJECT

public:
explicit fileProxy(QObject *parent = 0) : QSortFilterProxyModel(parent), selectDirs_(true), selectFiles_(true) {}

public slots:
void setSelectDirs(bool enable) { selectDirs_ = enable; }
void setSelectFiles(bool enable) { selectFiles_ = enable; }

protected:
bool filterAcceptsRow(int source_row, const QModelIndex &source_parent) const
{
QModelIndex index = sourceModel()->index(source_row, 0, source_parent);
QFileSystemModel *source = static_cast<QFileSystemModel*>(sourceModel());
QFileInfo info = source->fileInfo(index);

if(info.isDir() && selectDirs_) return true;

if(info.isFile() && selectFiles_) return true;

return false;
}

private:
bool selectDirs_;
bool selectFiles_;

};

class Proxy2 : public QWidget
{
Q_OBJECT

public:
Proxy2()
{
model_ = new QFileSystemModel(this);

normalProxy_ = new QSortFilterProxyModel(this);
normalProxy_->setSourceModel(model_);

proxy_ = new fileProxy(this);
proxy_->setSourceModel(model_);

treeView_ = new QTreeView(this);
treeView_->setModel(normalProxy_);
treeView_->setRootIndex(normalProxy_->mapFromSource(model_->setRootPath("")));

tableView_ = new QTableView(this);
tableView_->setModel(proxy_);

connect(treeView_, SIGNAL(clicked(QModelIndex)), this, SLOT(changeTableRootIndex(QModelIndex)));

QCheckBox *dirBox = new QCheckBox(this);
QCheckBox *fileBox = new QCheckBox(this);

dirBox->setText("Dir");
fileBox->setText("file");
dirBox->setCheckState(Qt::Checked);
fileBox->setCheckState(Qt::Checked);
connect(dirBox, SIGNAL(clicked(bool)), proxy_, SLOT(setSelectDirs(bool)));
connect(fileBox, SIGNAL(clicked(bool)), proxy_, SLOT(setSelectFiles(bool)));

QHBoxLayout *layout = new QHBoxLayout(this);
layout->addWidget(treeView_);
layout->addWidget(tableView_);
layout->addWidget(dirBox);
layout->addWidget(fileBox);

setLayout(layout);
}

public slots:
void changeTableRootIndex(QModelIndex const &index)
{
QModelIndex sourceIndex = normalProxy_->mapToSource(index);
tableView_->setRootIndex(proxy_->mapFromSource(sourceIndex));
}

private:
QFileSystemModel *model_;
QSortFilterProxyModel *normalProxy_;
fileProxy *proxy_;
QTableView *tableView_;
QTreeView *treeView_;
};

inline int testProxy2(QApplication &app)
{
Proxy2 p2;
p2.show();

return app.exec();
}


I hope the fileProxy will filter the files according to the checkstate of the check box
But the results are pretty weird

1 : It would not filter out the files or directories instantly, I have to switch between different directories or drives
of the treeView
2 : Even I did switch the directories or drives, there is no guarantee the fileProxy will filter out the directories or
files

What kind of mistakes do I make?
Thanks a lot

Added after 4 minutes:

I narrow the problem a little bit
If I remove line 22, neglect all of the check box and change the codes to


if(info.isFile() && selectFiles_) return true;


The TableView will never show anything
How could I show the files(only files)to the users?
Thanks a lot