[Solved]Combobox index using as input for function

BobMarly

I have different files and i want based on the index/name of the combobox that the file i use changes. i have something like this now, but it does not work:
@MWidget::MWidget(QWidget *parent) :
QWidget(parent),
ui(new Ui::MWidget)
{
ui->setupUi(this);
connect(ui->comboBox,SIGNAL(currentIndexChanged(int)),this,SLOT(on_comboBox_currentIndexChanged(int)));

QStringList List;
List<<"C:\\Airfoils\\a18.dat"<<"C:\\Airfoils\\a18sm.dat"<<"C:\\Airfoils\\a63a108c.dat"<<"C:/Airfoils/ag03.dat";

//read file for drawing
QFile file&#40;List[index]&#41;;

void MWidget::on_comboBox_currentIndexChanged(int index)
{
switch (index) {
case 0 :
ui->comboBox->currentIndexChanged(0);
break;
case 1 :
ui->comboBox->currentIndexChanged(1);
break;
}@
I cut out irrelevant code parts, since without the input form the combobox the loading from files works, based on the order of which they are in the list. I also want to do this for about 1500 files..

Jeroentjehome

Hi,
Your ui->combobox->currentIndexChanged is a SIGNAL! Not a slot, you it can be compiled, but not called! Why don't you connect both comboboxes to each other?
@
connect(ui->comboBox1, SIGNAL(currentIndexChanged(in),
ui->comboBox2, SLOT(setCurrentIndex(int)) );
@
Or something like that?

BobMarly

I only want one combobox..just a combobox with a lot of options, and for each option it should call the file belonging to that, so it will draw something with the coordinates of that file.. (nieuw @ Qt)

Jeroentjehome

Hmm,
Oke,
Use the slot currentIndexChanged(), and connect to a slot. In that slot you are able to do anything you like. Like reading files, updating GUI elements etc etc,
Ben jij NL?
Welkom trouwens!

Jeroentjehome

Also, don't you want just a single QFile and a QStringList to hold the file names? Then you could generate a slot that will update the QFile and sends a signal to "read that file" and update on screen. Since your a noob, let's give some code:
@
// hpp file:
class ...
private:
QFile* m_File_p;
QStringList m_MyFileList;
...
}
//cpp file
MWidget::MWidget(QWidget* parent) : QWidget(parent), ui(new Ui::MWidget)
{
// File your m_MyFileList;

ReadFile&#40;MyFileList.at(0&#41;);

connect(ui->comboBox, SIGNAL(currentIndexChanged(int)),
this, SLOT(ChangeFile(int));
}

void MWidget::ChangeFile(int NewIndex_i)
{
if (NewIndex_i < MyFileList.count())
{
// New file to read, may also be done via signal/slots!
ReadFile(MyFileList.at(NewIndex));
}
}

void MWidget::ReadFile(QString NewFileName)
{
m_File_p = new QFile (NewFileName);
if (m_File_p != NULL)
{
if ( (m_File_p.exists() == true) &&
(m_File_p.open(QIODEVICE::ReadWrite) == true) )
{
// Do your read file stuff
}
m_File_p.flush();
m_File_p.close();
// Release memory again.
delete m_File_p;
}
}
@

BobMarly

Dank je!. I tried implementing your code into mine but it does not work..
@MWidget::MWidget(QWidget *parent) :
QWidget(parent),
ui(new Ui::MWidget)
{
ui->setupUi(this);
ReadFile(MyFileList.at(0));
connect(ui->comboBox,SIGNAL(currentIndexChanged(int)),this,SLOT(ChangeFile(int)));
}

void MWidget::ChangeFile(int NewIndex)
{ MyFileList<<"C:\Airfoils\a18.dat"<<"C:\Airfoils\a18sm.dat"<<"C:\Airfoils\a63a108c.dat"<<"C:/Airfoils/ag03.dat";
if(NewIndex<MyFileList.count())
{
ReadFile(MyFileList.at(NewIndex));
}
}

void MWidget::ReadFile(QString NewFileName)
{QFile m_File_p(NewFileName);

if (!m_File_p->open(QIODevice::ReadOnly | QIODevice::Text))
    return ;
QTextStream in(&m_File_p);
QString line = in.readLine();
bool blnFirstLine =true;
float flScale = 640;
while (!line.isNull())
{

    if(blnFirstLine)
    {
        blnFirstLine=false;
    }else{

        QStringList coordinates = line.split(",", QString::SkipEmptyParts );

        if( coordinates.count() == 2 )
        {
            bool checkX;
            float x = coordinates.at(0).trimmed().toFloat( &checkX )*flScale+100;
            bool checkY;
            float y = coordinates.at(1).trimmed().toFloat( &checkY )*(-1)*flScale+100;

            if( checkX && checkY )
                polyPoints  << QPointF(x,y);
        }
    }


    line = in.readLine();
}
m_File_p.flush();
m_File_p.close();
delete m_File_p;

}

//![6]
@

BobMarly

It gives an error message :"QList index out of range" and then closes..also the delete function gives errors..

NicuPopescu

bq. Also where do i load my files now as i did before in stringlist?

as far as I see, in MWidget's constructor and MyFileList must be a member of it ... but you could keep the file names directly in combo box as data by using:

@ comboBox->setItemData(0,QVariant(filename),Qt::UserRole);@

BobMarly

The program is working!! Only still need to remove the previous drawn item(which would probably work if the delete works i guess??)

BobMarly

How do i remove the previously drawn item( that was drawn via selection in the combobox) when i select a new one? now all images are written on top of each other because it remembers all previous selections..