spinbox input add rows ??

[n-2204]

how to add rows based on spinbox input ?
i have qtableviiew so when user enter number in spinbox number. of rows should be added how to do this ?
as i can add row using 2 ways on button click

1.
add row{
 model->insertRow(model->rowCount(QModelIndex()));
}
2.
QList<QStandardItem*> newRow;
QStandardItem* item1 = new QStandardItem(QString(""));
newRow.append(item1);
model->appendRow(newRow);

how to do ??
thanks in advance

[JonB]

@n-2204
Either way, get the number value from the spin box and do a loop that many times to add multiple rows? There is also a insertRows(int row, int count, const QModelIndex &parent = QModelIndex()) to insert multiple rows at a time.

[artwaw]

@n-2204
https://doc.qt.io/qt-5/signalsandslots.html

Connect to the valueChanged(int) signal https://doc.qt.io/Qt-5/qspinbox.html#valueChanged

It is up to you to figure out if value has increased or decreased but you can figure it out using rowCount()

[n-2204]

@artwaw
this is not working why??

QObject::connect(ui.spinBox, SIGNAL(valueChanged(int)), ui.tableView, SLOT(setTableRows()));
void tool::setTableRows()
{
int rows = ui.spinBox->value();
model->setRowCount(rows);
}

[Christian Ehrlicher]

@n-2204 said in spinbox input add rows ??:

this is not working why??

Because you did something wrong.
I would guess ui.tableView is not the correct receiver.

Use the new signal/slot syntax to catch such errors during compile time.

[n-2204]

tried after change ui.tableview to model but not working

    QObject:: connect(ui.spinBox, SIGNAL(valueChanged(int)), model, SLOT(setTableRows())); 
void tool::setTableRows()
{
     int rows = ui.spinBox->value();
model->setRowCount(rows);
}

or tried using insertrows also not working

   QObject:: connect(ui.spinBox, SIGNAL(valueChanged(int)), model, SLOT(setTableRows())); 
 void tool::setTableRows()
{
int noofrows = ui.spinBox->value();
for (int i = 0;i < noofrows;++i)
{
    model->insertRows(i, model->rowCount(QModelIndex()));
}
}

[JonB]

@n-2204
First, put in debug/print statements just to see if slot called, instead of relying on seeing row count increase.

Secondly, you have

 QObject:: connect(ui.spinBox, SIGNAL(valueChanged(int)), model, SLOT(setTableRows())); 

but

 void tool::setTableRows()

Is model of class tool? Because if not you are not connecting the slot.

If you followed @Christian-Ehrlicher's suggestion of changing to new signal/slot syntax and never used SIGNAL/SLOT() macros you would find out, and your coding would be better....

And finally I doubt you really intend

model->insertRows(i, model->rowCount(QModelIndex()));

Why rowCount() as the number of rows to add?? I would have thought given your loop you would want 1 there. You are confusing insertRows() to add multiple rows without a loop versus a loop to add one row at a time....

[n-2204]

@JonB yes tool is my class

model = new QStandardItemModel(10, 13, this)
ui.tableView->setModel(model);

[JonB]

@n-2204
You seem to have:

    QObject:: connect(ui.spinBox, SIGNAL(valueChanged(int)), model, SLOT(setTableRows())); 
void tool::setTableRows()

You have just said that model is of type QStandardItemModel.

But setTableRows() is a method of tool.

And earlier you had:

QObject::connect(ui.spinBox, SIGNAL(valueChanged(int)), ui.tableView, SLOT(setTableRows()));

which had the same issue,

For the third time, if you followed https://wiki.qt.io/New_Signal_Slot_Syntax you would get compile-time help preventing you doing what you are trying to do.

[VRonin]

I suspect the 3rd argument might be this. You can at least put the connect inside a Q_ASSUME() so you get a runtime crash in debug mode if the connect fails

[n-2204]

yes, thanks using this works
but what happening is i added 10 rows and when i change value in spinbox to 1 then no. of rows in table also changing to 1

so i think using loop this prblm will be solved

int noofrows = ui.spinBox->value();
   for (int i = 0;i < noofrows;i++)
{
   model->insertRows(i,noofrows);
}

if use this loop when i enter 1 in spinbox it adds two rows ?

[JonB]

@n-2204
I already told you about that earlier.

And finally I doubt you really intend

model->insertRows(i, model->rowCount(QModelIndex()));

Why rowCount() as the number of rows to add?? I would have thought given your loop you would want 1 there. You are confusing insertRows() to add multiple rows without a loop versus a loop to add one row at a time....

EITHER a for loop with insertRow(), OR no for loop and insertRows(). You really should be able to understand this.

Put some qDebug() statements in to see for yourself what is going on. That is what debugging is about.

[n-2204]

ok understood
thank you all

[n-2204]

 tooll::tool(QWidget* parent)
: QMainWindow(parent)
  {
  ui.setupUi(this);
 model = new QStandardItemModel(10, 13, this)
 ui.tableView->setModel(model);
 connect(ui.spinBox, SIGNAL(valueChanged(int)), model, 
 SLOT(setTableRows())); 
}
void tool::setTable2Rows()
   { 
 int noofrows2 = ui.spinBox_2->value();
 for (int i = 0;i < noofrows2;++i)
  {
      model2->insertRow(i);
    //qDebug() << i;
}
}

when i am using new signal/slot why i am getting error
(Error (active) E0304 no instance of overloaded function)

 connect(ui.spinBox, &QSpinBox::valueChanged, this,&tool::setTableRows);
connect( sender, &Sender::valueChanged,    receiver, &Receiver::updateValue);

[jsulm]

@n-2204 Please post whole error message. Does your tooll class have setTableRows slot? I'm asking because I only see setTable2Rows()

[n-2204]

yes slot setTablerow() is also there

 void tool::setTableRows()
{ 
int noofrows = ui.spinBox->value();
for (int i = 0;i < noofrows;++i)
{
  model->insertRow(i);
//qDebug() << i;
} 

c++ no instance of overloaded function matches the argument list argument types are: (QSpinBox *, <unknown-type>, tooll , void (tool::)())
Severity Code Description Project File Line Suppression State Detail Description
Error (active) E0304 no instance of overloaded function "tool::connect" matches the argument list tool C:\User\source\repos\tool\tooll.cpp 265 argument types are: (QSpinBox *, <unknown-type>, tool , void (tool::)())

[VRonin]

@n-2204 said in spinbox input add rows ??:

tooll::tool(QWidget* parent)

????

What's the name of the class? tooll or tool? looks like a big mess here

[Christian Ehrlicher]

@n-2204 said in spinbox input add rows ??:

c++ no instance of overloaded function matches the argument list argument types are: (QSpinBox *, <unknown-type>, tooll , void (tool::)())

How about taking a single look into the documentation? The problem is exactly explained there.

Simply writing something without understanding what you're doing doesn't help you at all.

[n-2204]

thanks for sharing ref doc, its done

 connect(ui.spinBox, QOverload<int>::of(&QSpinBox::valueChanged), 
         this, &tool::setTableRows);

[n-2204]

what changes need to do to end the row at end of row, now when i enter value in spinbox row is adding in top but i need to add the row at end how to do ?

 void tool::setTableRows()
{
int noofrows = ui.spinBox->value();
for (int i = 0;i < noofrows;++i)
{
   model->insertRow(i);
}
 }
connect(ui.spinBox, QOverload<int>::of(&QSpinBox::valueChanged), 
         this, &tool::setTableRows);