I have a QTreeView which is populated through a reimplementation of QFileSystemModel. As far as I know, QFileSystemModel installs a QFileSystemWatcher on the rootPath. What I'm trying to do is notify in my program when a file is being deleted directicly on the rootPath but i havent found any signal o reimplemented function which provides me that information.
My application upload some files thrugh an ftp connection and when the file is fully uploaded i remove it from the location, so i want a notification from the reimplementation of QFileSystemModel when the file is deleted directicly (not from the remove method or something similar).
I Hope you can help me. I have searched a lot on the web but I cant find anything.
Cheers.
You can use the FileSystemModel's rowsAboutToBeRemoved signal (inherited from QAbstractItemModel).
It will be fired whenever a row is removed from the model. The parent, start and end parameters allow you to get to the filename (in column 0 of the children).
Sample code:
// once you have your model set up:
...
QObject::connect(model, SIGNAL(rowsAboutToBeRemoved(const QModelIndex&, int, int)),
receiver, SLOT(toBeRemoved(const QModelIndex&, int, int)));
...
// in receiver class:
public slots:
void toBeRemoved(const QModelIndex &parent, int start, int end) {
std::cout << start << " -> " << end << std::endl;
std::cout << parent.child(start, 0).data().typeName() << std::endl;
std::cout << qPrintable(parent.child(start, 0).data().toString()) << std::endl;
}
(Using std::cout isn't good practice with Qt I think, this is just to get you started.)
The other aboutToBe... signals from QAbstractItemModel can be used for the other events that happen on the filesystem.
Related
I'm trying to use QMetaType::convert to convert a QJsonValue to another dynamic type. At first, I tested the following code with the dynamic type setting to QString, the conversion was failed.
QJsonValue value("test");
QString string;
if (!QMetaType::convert(&value, QMetaType::QJsonValue, &string, QMetaType::QString))
{
qDebug() << "failed";
}
Then, I found this static method to check whether the meta system has a registered conversion between two meta types.
qDebug() << QMetaType::hasRegisteredConverterFunction(QMetaType::QJsonValue, QMetaType::QString);
unfortunately, the result was false. Maybe QJsonValue is so complex that the conversion from QJsonValue to QString is not supported. Finally, I tried this, and the result was still false:
qDebug() << QMetaType::hasRegisteredConverterFunction(QMetaType::Int, QMetaType::Int);
It's odd, seems to be, Qt dose not implement the converter functions between basic meta types. And, users can't use QMetaType::registerConverter to register converter function between two basic meta types.
I still can't believe that Qt dosen't implement conversions between basic meta types, is there any initializtion or .pro setting I missed?
I guess you have the QMetaType system and the QVariant class to encapsulate Qt data types on the one hand, and QJsonValue to encapsulate a value in JSON on the other hand.
QMetaType::convert can deal with QVariant data only. What you can do is to extract the QVariant from your QJsonValue and then use the QMetaType system to convert your data you know being a QString.
// Your code
QJsonValue value("test");
QString string ;
if (!QMetaType::convert(&value, QMetaType::QJsonValue, &string, QMetaType::QString))
{
qDebug() << "failed";
}
// Extract the QVariant data
QVariant variant = value.toVariant() ;
// Two way to test conversion between QVariant and a type
qDebug() << "canConvert template:" << variant.canConvert<QString>() << endl
<< "canConvert parameter:" << variant.canConvert( QMetaType::QString ) ;
if( variant.canConvert<QString>() )
{
// Convert using QVariant methods
qDebug() << "QVariant toString:" << variant.toString() ;
// Convert Using QJsonValue methods
qDebug() << "QJsonValue toString:" << value.toString() ; // It's just a string representation of the data, not the actual data
}
outputs :
failed
canConvert template: true
canConvert parameter: true
QVariant toString: "test"
QJsonValue toString: "test"
PS: the QJsonValue::Type : String is different from the QVariant::Type : String (QMetaType::QString) so there is no relationship between them.
I am a beginner in ITK, VTK and Qt. I use visual studio 9.
I am trying to read a DICOM series with ITK and display with VTK in QVTKWidget (Qt). I based on this code http://www.itk.org/Wiki/VTK/Examples/Cxx/IO/ReadDICOMSeries and I modified according to my needs.
when I read the series DICOM with VTK and display it in QVTKWidget it works, but when I want to read this series with ITK and display with VTK in QVTKWidget, the program displays the first image of series and when I go to the next image with the mouse wheel, the program crashes.
when I debugged, I got this error:
void VTKImageExportBase::UpdateInformationCallbackFunction(void *userData)
{
static_cast< VTKImageExportBase * >
( userData )->UpdateInformationCallback();//the error is here
}
I tried ausssi ImageToVTKImageFilter class but with the same problem.
here is my code:
void essaieAppQtVTK::drawDCMSeries(std::string folderDCM)
{
typedef unsigned short PixelType;
const unsigned int Dimension = 3;
typedef itk::Image< PixelType, Dimension > ImageType;
typedef itk::VTKImageExport<ImageType> ImageExportType;
typedef itk::ImageSeriesReader< ImageType > ReaderType;
ReaderType::Pointer reader = ReaderType::New();
typedef itk::GDCMImageIO ImageIOType;
ImageIOType::Pointer dicomIO = ImageIOType::New();
reader->SetImageIO( dicomIO );
typedef itk::GDCMSeriesFileNames NamesGeneratorType;
NamesGeneratorType::Pointer nameGenerator = NamesGeneratorType::New();
nameGenerator->SetUseSeriesDetails( true );
nameGenerator->AddSeriesRestriction("0008|0021" );
nameGenerator->SetDirectory( folderDCM);
typedef std::vector< std::string > SeriesIdContainer;
const SeriesIdContainer & seriesUID = nameGenerator->GetSeriesUIDs();
std::cout << seriesUID.size() << std::endl;
SeriesIdContainer::const_iterator seriesItr = seriesUID.begin();
SeriesIdContainer::const_iterator seriesEnd = seriesUID.end();
while( seriesItr != seriesEnd )
{
std::cout << seriesItr->c_str() << std::endl;
seriesItr++;
}
std::string seriesIdentifier;
seriesIdentifier = seriesUID.begin()->c_str();
std::cout << seriesIdentifier.c_str() << std::endl;
typedef std::vector< std::string > FileNamesContainer;
FileNamesContainer fileNames;
fileNames = nameGenerator->GetFileNames( seriesIdentifier );
reader->SetFileNames( fileNames );
try
{
reader->Update();
}
catch (itk::ExceptionObject &ex)
{
std::cout << ex << std::endl;
}
//------------------------------------------------------------------------
// ITK to VTK pipeline connection.
//------------------------------------------------------------------------
// Create the itk::VTKImageExport instance and connect it to the
// itk::CurvatureFlowImageFilter.
ImageExportType::Pointer exporter = ImageExportType::New();
exporter->SetInput(reader->GetOutput());
// Create the vtkImageImport and connect it to the
// itk::VTKImageExport instance.
vtkImageImport* importer = vtkImageImport::New();
ConnectPipelines(exporter, importer);
//------------------------------------------------------------------------
// VTK pipeline.
//------------------------------------------------------------------------
this->imageViewer= vtkImageViewer2::New();
imageViewer->SetInput(importer->GetOutput());
// slice status message
//******same code *****//
// usage hint message
//******same code *****//
// create an interactor with our own style (inherit from vtkInteractorStyleImage)
// in order to catch mousewheel and key events
//******same code *****//
// add slice status message and usage hint message to the renderer
//******same code *****//
//to display the result:
ui.qvtkWidget->SetRenderWindow(imageViewer->GetRenderWindow());
ui.qvtkWidget->GetRenderWindow()->GetInteractor()- >SetInteractorStyle(myInteractorStyle);
imageViewer->Render();
ui.qvtkWidget->update();
}
Optional: My exporter and importer are as given below:
template <typename ITK_Exporter, typename VTK_Importer>
void ConnectPipelines(ITK_Exporter exporter, VTK_Importer* importer)
{
importer->SetUpdateInformationCallback(exporter->GetUpdateInformationCallback());
importer->SetPipelineModifiedCallback(exporter->GetPipelineModifiedCallback());
importer->SetWholeExtentCallback(exporter->GetWholeExtentCallback());
importer->SetSpacingCallback(exporter->GetSpacingCallback());
importer->SetOriginCallback(exporter->GetOriginCallback());
importer->SetScalarTypeCallback(exporter->GetScalarTypeCallback());
importer->SetNumberOfComponentsCallback(exporter->GetNumberOfComponentsCallback());
importer->SetPropagateUpdateExtentCallback(exporter- >GetPropagateUpdateExtentCallback());
importer->SetUpdateDataCallback(exporter->GetUpdateDataCallback());
importer->SetDataExtentCallback(exporter->GetDataExtentCallback());
importer->SetBufferPointerCallback(exporter->GetBufferPointerCallback());
importer->SetCallbackUserData(exporter->GetCallbackUserData());
}
/**
* This function will connect the given vtkImageExport filter to
* the given itk::VTKImageImport filter.
*/
template <typename VTK_Exporter, typename ITK_Importer>
void ConnectPipelines(VTK_Exporter* exporter, ITK_Importer importer)
{
importer->SetUpdateInformationCallback(exporter->GetUpdateInformationCallback());
importer->SetPipelineModifiedCallback(exporter->GetPipelineModifiedCallback());
importer->SetWholeExtentCallback(exporter->GetWholeExtentCallback());
importer->SetSpacingCallback(exporter->GetSpacingCallback());
importer->SetOriginCallback(exporter->GetOriginCallback());
importer->SetScalarTypeCallback(exporter->GetScalarTypeCallback());
importer->SetNumberOfComponentsCallback(exporter->GetNumberOfComponentsCallback());
importer->SetPropagateUpdateExtentCallback(exporter->GetPropagateUpdateExtentCallback());
importer->SetUpdateDataCallback(exporter->GetUpdateDataCallback());
importer->SetDataExtentCallback(exporter->GetDataExtentCallback());
importer->SetBufferPointerCallback(exporter->GetBufferPointerCallback());
importer->SetCallbackUserData(exporter->GetCallbackUserData());
}
Maybe there is a fault at the Pipline between ITK and VTK, please please can help me to find a solution for this problem, I spent two weeks looking for a solution but all methods have failed, maybe there has another method to bind ITK and VTK apart ImageToVTKImageFilter class. I count on your help. thank you in advance.
I faced same error at the same point you showed inside void VTKImageExportBase::UpdateInformationCallbackFunction function I was using ImageToVTKImageFilter for conversion. What I was missing is update of ITK pipeline before connecting it to VTK viewer. In ITK to VTK pipeline connection part your code is also missing same thing. So use:
exporter->SetInput(reader->GetOutput());
exporter->Update();
then go for further.
While coding a seemingly simple part of a Qt application that would run a subprocess and read data from its standard output, I have stumbled upon a problem that has me really puzzled. The application should read blocks of data (raw video frames) from the subprocess and process them as they arrive:
start a QProcess
gather data until there is enough for one frame
process the frame
return to step 2
The idea was to implement the processing loop using signals and slots – this might look silly in the simple, stripped-down example that I provide below, but seemed entirely reasonable within the framework of the original application. So here we go:
app::app() {
process.start("cat /dev/zero");
buffer = new char[frameLength];
connect(this, SIGNAL(wantNewFrame()), SLOT(readFrame()), Qt::QueuedConnection);
connect(this, SIGNAL(frameReady()), SLOT(frameHandler()), Qt::QueuedConnection);
emit wantNewFrame();
}
I start here a trivial process (cat /dev/zero) so that we can be confident that it will not run out of data. I also make two connections: one starts the reading when a frame is needed and the other calls a data handling function upon the arrival of a frame. Note that this trivial example runs in a single thread so the connections are made to be of the queued type to avoid infinite recursion. The wantNewFrame() signal initiates the acquisition of the first frame; it gets handled when the control returns to the event loop.
bool app::readFrame() {
qint64 bytesNeeded = frameLength;
qint64 bytesRead = 0;
char* ptr = buffer;
while (bytesNeeded > 0) {
process.waitForReadyRead();
bytesRead = process.read(ptr, bytesNeeded);
if (bytesRead == -1) {
qDebug() << "process state" << process.state();
qDebug() << "process error" << process.error();
qDebug() << "QIODevice error" << process.errorString();
QCoreApplication::quit();
break;
}
ptr += bytesRead;
bytesNeeded -= bytesRead;
}
if (bytesNeeded == 0) {
emit frameReady();
return true;
} else
return false;
}
Reading the frame: basically, I just stuff the data into a buffer as it arrives. The frameReady() signal at the end announces that the frame is ready and in turn causes the data handling function to run.
void app::frameHandler() {
static qint64 frameno = 0;
qDebug() << "frame" << frameno++;
emit wantNewFrame();
}
A trivial data processor: it just counts the frames. When it is done, it emits wantNewFrame() to start the reading cycle anew.
This is it. For completeness, I'll also post the header file and main() here.
app.h:
#include <QDebug>
#include <QCoreApplication>
#include <QProcess>
class app : public QObject
{
Q_OBJECT
public:
app();
~app() { delete[] buffer; }
signals:
void wantNewFrame();
void frameReady();
public slots:
bool readFrame();
void frameHandler();
private:
static const quint64 frameLength = 614400;
QProcess process;
char* buffer;
};
main.cpp:
#include "app.h"
int main(int argc, char** argv)
{
QCoreApplication coreapp(argc, argv);
app foo;
return coreapp.exec();
}
And now for the bizarre part. This program processes a random number of frames just fine (I've seen anything from fifteen to more than thousand) but eventually stops and complains that the QProcess had crashed:
$ ./app
frame 1
...
frame 245
frame 246
frame 247
process state 0
process error 1
QIODevice error "Process crashed"
Process state 0 means "not running" and process error 1 means "crashed". I investigated into it and found out that the child process receives a SIGPIPE – i.e., the parent had closed the pipe on it. But I have absolutely no idea of where and why this happens. Does anybody else?
The code is a bit weird looking (not using the readyRead signal and instead relying on delayed signals/slots). As you pointed out in the discussion, you've already seen the thread on the qt-interest ML where I asked about a similar problem. I've just realized that I, too, used the QueuedConnection at that time. I cannot explain why it is wrong -- the queued signals "should work", in my opinion. A blind shot is that the invokeMethod which is used by the Qt's implementation somehow races with your signal delivery so that you empty your read buffer before Qt gets a chance to process the data. This would mean that Qt will ultimately read zero bytes and (correctly) interpret that as an EOF, closing the pipe.
I cannot find the referenced "Qt task 217111" anymore, but there is a couple of reports in their Jira about waitForReadyRead not working as users expect, see e.g. QTBUG-9529.
I'd bring this to the Qt's "interest" mailing list anmd stay clear of the waitFor... family of methods. I agree that their documentation deserves updating.
Mouse button clicki am trying to create an automatic mouse click event at a particular co ordinate.
This source code moves the mouse pointer to the co ordinate region but it is not clicking.
please help me to solve this problem or suggest any new idea to automate mouse click event.
Note: i am using QT 3.0.3
void mMouseClickFunction()
{
QWidget *d = QApplication::desktop()->screen();
int w=d->width(); // returns desktop width
int h=d->height();
printf("w=%d\nh=%d\n",w,h);
int x,y;
printf("Enter the points...\n");
scanf("%d%d",&x,&y);
QApplication::desktop()->cursor().setPos(x,y);
QPoint pt(x,y);
std::cout << pt.x() << " " << pt.y() << std::endl;
QMouseEvent *e = new QMouseEvent(QEvent::MouseButtonPress, pt,Qt::LeftButton, 0);
QApplication::sendEvent(d, e);
std::cout << "in contentsMousePressEvent"<< e->x() << " " << e->y() << std::endl;
QMouseEvent *p = new QMouseEvent(QEvent::MouseButtonRelease, pt,Qt::LeftButton, 0);
QApplication::sendEvent(d, p);
std::cout << "in contentsMouseReleaseEvent"<< p->x() << " " << p->y() << std::endl;
}
QApplication::sendEvent sends an event internal to the QApplication, not a system wide event. You probably need to be system specific to send out an event like that. Here is the function call for windows:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms646310(v=vs.85).aspx
But even with that kind of call, you will be limited to certain windows, unless you have UIAccess to be true, and your program is a signed application located in the right part of the harddrive.
EDIT: Here is a page that has some examples for sending input in Linux:
http://www.linuxquestions.org/questions/programming-9/simulating-a-mouse-click-594576/
Hope that helps.
I have the following scenario:
QProcess*p;
// later
p->start();
//later
p->terminate(); // there might be unread data in stdout
//later
p->start();
I read the process stdout. After I call p->start() the second time, could there still be unread data left in the stdout buffers from the first p->start()? That would be a problem for me. Do I need to flush the buffers or something?
Okay, I've checked the sources. The QProcess::start() method explicitly clears both output buffers, so it should be okay, at least in this sense:
void QProcess::start(const QString &program, const QStringList &arguments, OpenMode mode)
{
Q_D(QProcess);
if (d->processState != NotRunning) {
qWarning("QProcess::start: Process is already running");
return;
}
#if defined QPROCESS_DEBUG
qDebug() << "QProcess::start(" << program << "," << arguments << "," << mode << ")";
#endif
d->outputReadBuffer.clear();
d->errorReadBuffer.clear();
I still think it's a bad style to reuse the same object, though.