How to store QSlider position Value into .txt file?

[YDYD]

Hi all,

I would like to get my Qslider position value and store in a txt file. i did as following, my i could not obtain any value.

int h_slide1 = ui->hueSlide1->value();
QFile valueHSV("/home/pi/valueHSV/hsv.txt")
if(!valueHSV.open(QIODevice::WriteOnly| QIODevice::Text))
   return;
QTextStream hsv(&valueHSV);
hsv << h_slide1;

int h_slide1 = ui->hueSlide1->value();
QFile valueHSV("/home/pi/valueHSV/hsv.txt")
if(!valueHSV.open(QIODevice::WriteOnly| QIODevice::Text))
   return;
QTextStream hsv(&valueHSV);
hsv << h_slide1;

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is this code correct?

[anda_skoa]

That looks about right.
Did the QFile:pen() work?

Cheers,
_

[YDYD]

this can make file without error,

Will this store a value in a txt file that after i drag the slider? after i close the GUI,
i will can open the text file to see my slider value,
am i correct?
but the txt file is blank.

[Lesiok]

Value in file will be stored after the code execution. Question : how You activate this code ?

[YDYD]

Hi,
I just simply build & Run it,
i create another thread here : http://www.qtcentre.org/threads/5964...-into-txt-file

[yeye_olive]

Please do not create other threads, this only pollutes the forum. Focus on giving as much information as you can, so that we can help you effectively.

So far we have only seen a snippet of code, but we have no idea when it is executed. This may be dead code for all we know. Have you run a debugger and witnessed your snippet being executed? Another important question: what are the lifetimes of the QTextStream and QFile variables?

It would help if you posted the whole source of a minimal program reproducing the problem.

[YDYD]

I am so sorry for that.
i am doing a GUI to filter out the colour i do not want,
I would like to get value of H, S and V using slider and store these value inside a .txt file.
After that i would call these value into another function to processing and show a filter stream video,
I did use QFile and QTextStreamer, but could not get through.
below is my code

//getCam.pro
######################################################################
# Automatically generated by qmake (2.01a) Tue Jun 24 17:53:36 2014
######################################################################
CONFIG += console
 
TEMPLATE = app
TARGET = 
DEPENDPATH += .
INCLUDEPATH += .
 
# Input
HEADERS += dialog.h
FORMS += dialog.ui
SOURCES += dialog.cpp main.cpp

//getCam.pro
######################################################################
# Automatically generated by qmake (2.01a) Tue Jun 24 17:53:36 2014
######################################################################
CONFIG += console

TEMPLATE = app
TARGET = 
DEPENDPATH += .
INCLUDEPATH += .

# Input
HEADERS += dialog.h
FORMS += dialog.ui
SOURCES += dialog.cpp main.cpp

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//main.cpp
#include <QApplication>
#include "dialog.h"
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Dialog w;
    w.show();
 
    return a.exec();
}

//main.cpp
#include <QApplication>
#include "dialog.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Dialog w;
    w.show();
    
    return a.exec();
}

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//dialog.h
#ifndef DIALOG_H
#define DIALOG_H
 
#include <QDialog>
 
#include "opencv/cv.h"
#include "opencv/highgui.h"
#include <QTimer>
#include <QPixmap>
 
namespace Ui
{
    class Dialog;
}
 
class Dialog : public QDialog
{
    Q_OBJECT
 
public:
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();
 
private:
    Ui::Dialog *ui;
 
    CvCapture *cam;
    IplImage *frame,*imgHSV;
 
    QTimer *timer;
 
private slots:
    void getFrame();
    void prcFrame();
    void getValue();
};
 
#endif // DIALOG_H

//dialog.h
#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>

#include "opencv/cv.h"
#include "opencv/highgui.h"
#include <QTimer>
#include <QPixmap>

namespace Ui
{
    class Dialog;
}

class Dialog : public QDialog
{
    Q_OBJECT
    
public:
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();
    
private:
    Ui::Dialog *ui;

    CvCapture *cam;
    IplImage *frame,*imgHSV;

    QTimer *timer;

private slots:
    void getFrame();
    void prcFrame();
    void getValue();
};

#endif // DIALOG_H

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//dialog.cpp
#include "dialog.h"
#include "ui_dialog.h"
 
#include <QDebug>
#include <QFile>
#include <QTextStream>
 
Dialog::Dialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);
 
    timer = new QTimer(this);
 
    cam = cvCaptureFromCAM(-1);
 
    if(cam==NULL)
        qDebug()<<"error";
 
    timer->start(30);
    connect(timer,SIGNAL(timeout()),this,SLOT(getFrame()));
}
 
void Dialog::getFrame()
{
    frame = cvQueryFrame(cam);
    QImage image = QImage ((const uchar*)frame->imageData,frame->width,frame->height,QImage::Format_RGB888).rgbSwapped();//rgbSwapped() make color better
    ui->original->setPixmap(QPixmap::fromImage(image));
}
 
void Dialog::prcFrame()
{
    imgHSV= cvCreateImage(cvSize(frame->width,frame->height),IPL_DEPTH_8U,3);
    cvCvtColor(frame,imgHSV,CV_BGR2HSV);
 
    //threshed , get value from slider value
   // QImage filterImg = QImage ((const uchar*)imgHSV->imageData,imgHSV->width,imgHSV->height,QImage::Format_RGB888);
   // ui->filter->setPixmap(QPixmap::fromImage(filterImg));
}
 
[COLOR="#FFFF00"]void Dialog::getValue()
{
    int h_slide1 = ui->hueSlide1->value();
    QFile valueHSV("/home/pi/valueHSV/hsv.txt");
    if(!valueHSV.open(QIODevice::WriteOnly|QIODevice::Text))
    {
        qDebug() << "cannot open file for writing"<<endl;
        return;
    }
    QTextStream hsv(&valueHSV);
    hsv <<h_slide1;
    qDebug() << "Value=" << h_slide1;
    valueHSV.close();
 
}[/COLOR]
 
 
Dialog::~Dialog()
{
    timer->stop();
    cvReleaseCapture(&cam);
 
    delete ui;
}

//dialog.cpp
#include "dialog.h"
#include "ui_dialog.h"

#include <QDebug>
#include <QFile>
#include <QTextStream>

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

    timer = new QTimer(this);

    cam = cvCaptureFromCAM(-1);

    if(cam==NULL)
        qDebug()<<"error";

    timer->start(30);
    connect(timer,SIGNAL(timeout()),this,SLOT(getFrame()));
}

void Dialog::getFrame()
{
    frame = cvQueryFrame(cam);
    QImage image = QImage ((const uchar*)frame->imageData,frame->width,frame->height,QImage::Format_RGB888).rgbSwapped();//rgbSwapped() make color better
    ui->original->setPixmap(QPixmap::fromImage(image));
}

void Dialog::prcFrame()
{
    imgHSV= cvCreateImage(cvSize(frame->width,frame->height),IPL_DEPTH_8U,3);
    cvCvtColor(frame,imgHSV,CV_BGR2HSV);

    //threshed , get value from slider value
   // QImage filterImg = QImage ((const uchar*)imgHSV->imageData,imgHSV->width,imgHSV->height,QImage::Format_RGB888);
   // ui->filter->setPixmap(QPixmap::fromImage(filterImg));
}

[COLOR="#FFFF00"]void Dialog::getValue()
{
    int h_slide1 = ui->hueSlide1->value();
    QFile valueHSV("/home/pi/valueHSV/hsv.txt");
    if(!valueHSV.open(QIODevice::WriteOnly|QIODevice::Text))
    {
        qDebug() << "cannot open file for writing"<<endl;
        return;
    }
    QTextStream hsv(&valueHSV);
    hsv <<h_slide1;
    qDebug() << "Value=" << h_slide1;
    valueHSV.close();

}[/COLOR]


Dialog::~Dialog()
{
    timer->stop();
    cvReleaseCapture(&cam);

    delete ui;
}

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//compile output
04:45:50: Running steps for project getCam...
 
04:45:50: Configuration unchanged, skipping qmake step.
 
04:45:50: Starting: "/usr/bin/make" -w
 
make: Entering directory `/home/pi/qt/getCam'
 
/usr/bin/qmake-qt4 -spec /usr/share/qt4/mkspecs/linux-g++ -o Makefile getCam.pro
 
make: Leaving directory `/home/pi/qt/getCam'
 
make: Entering directory `/home/pi/qt/getCam'
 
g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -I. -I/usr/local/include/opencv -o dialog.o dialog.cpp
 
g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -I. -I/usr/local/include/opencv -o main.o main.cpp
 
/usr/bin/moc-qt4 -DQT_WEBKIT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -I. -I/usr/local/include/opencv dialog.h -o moc_dialog.cpp
 
g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -I. -I/usr/local/include/opencv -o moc_dialog.o moc_dialog.cpp
 
g++ -Wl,-O1 -o getCam dialog.o main.o moc_dialog.o -L/usr/lib/arm-linux-gnueabihf /usr/local/lib/libopencv_core.so /usr/local/lib/libopencv_highgui.so /usr/local/lib/libopencv_ml.so /usr/local/lib/libopencv_imgproc.so -lQtGui -lQtCore -lpthread
 
make: Leaving directory `/home/pi/qt/getCam'
 
04:47:35: The process "/usr/bin/make" exited normally.

//compile output
04:45:50: Running steps for project getCam...

04:45:50: Configuration unchanged, skipping qmake step.

04:45:50: Starting: "/usr/bin/make" -w

make: Entering directory `/home/pi/qt/getCam'

/usr/bin/qmake-qt4 -spec /usr/share/qt4/mkspecs/linux-g++ -o Makefile getCam.pro

make: Leaving directory `/home/pi/qt/getCam'

make: Entering directory `/home/pi/qt/getCam'

g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -I. -I/usr/local/include/opencv -o dialog.o dialog.cpp

g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -I. -I/usr/local/include/opencv -o main.o main.cpp

/usr/bin/moc-qt4 -DQT_WEBKIT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -I. -I/usr/local/include/opencv dialog.h -o moc_dialog.cpp

g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -I. -I/usr/local/include/opencv -o moc_dialog.o moc_dialog.cpp

g++ -Wl,-O1 -o getCam dialog.o main.o moc_dialog.o -L/usr/lib/arm-linux-gnueabihf /usr/local/lib/libopencv_core.so /usr/local/lib/libopencv_highgui.so /usr/local/lib/libopencv_ml.so /usr/local/lib/libopencv_imgproc.so -lQtGui -lQtCore -lpthread

make: Leaving directory `/home/pi/qt/getCam'

04:47:35: The process "/usr/bin/make" exited normally.

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and this is the pic of GUI design
snapshot1.jpg

Please advise

regards
YDYD

[anda_skoa]

Could you point out where you call getValue()? I can't seem to find it.

Cheers,
_

[YDYD]

Regarding above title, i am doing a GUI to filter out the colour i do not want,
I would like to get value of H, S and V using slider and store these value inside a .txt file.
After that i would call these value into another function to processing and show a filter stream video,
I did use QFile and QTextStreamer, but could not get through.

Here is a photo of my GUI,
snapshot1.jpg
Please advise,