Connect lambda, sender argument must be string from array

[bchinfosieeuw]

How can I send a string from an array with connect using the lambda-notation? I want to send btnTest[pagecounter-1] as the first argument of the connect, but the compiler says 'no matching function for call to ...'



btnTest = new QPushButton[pagecounter];//("G", this);
btnTest[pagecounter-1].setMaximumSize(QSize(20,20));

btnTest[pagecounter-1].setObjectName(QString::number(pagecounter-1));

top->addWidget(groupBox);
top->addWidget(btnTest, pagecounter-1);
top->maximumSize();

mainLayout->addLayout(top);

QVBoxLayout *vbox = new QVBoxLayout;
groupBox->setLayout(vbox);

connect(btnTest[pagecounter-1], &QPushButton::clicked, [=] {
emit systembutton_clicked(btnTest[pagecounter-1].objectName().toInt(), 1, vbox);
});

[NameRakes]

Ok, second attempt at replying.

Is your intent to emit another signal from your slot (that is lambda)?

If so, I would create local variables for the ones you want to use (capture) in the body of the lambda. Warning: with [=] you are capturing by value!!

[d_stranz]

Your lambda syntax is wrong. It needs to be a functor:



connect(btnTest[pagecounter-1], &QPushButton::clicked, [=] () {
emit systembutton_clicked(btnTest[pagecounter-1]->objectName().toInt(), 1, vbox);


Note the parentheses following the [=]. And btnTest[pagecounter-1] is a pointer to QPushButton so needs to be dereferenced with pointer syntax.


Warning: with [=] you are capturing by value!!

Should not matter in this case, since the arguments in the lambda are pointers.

[NameRakes]

Good point! Missed the pointer aspect with my quick perusal.

[anda_skoa]

Also, from the previous thread, you don't need the emit, systembutton_clicked() is a method.

And, again also from the previous thread, are you sure you want to create an array every time the slot is called and only initialize the last entry?

Cheers,
_

[bchinfosieeuw]

I would like to initialize all the arrays in the for loop. Can you tell me how to do that?

[d_stranz]

Maybe something like:



for ( int i = 0; i < pagecounter; i++ )
{
// initialize btnTest[i]
}


You should have learned that in the first couple of weeks of your C++ class...

[bchinfosieeuw]

What I really want to do is disable the btnTest buttons when they are clicked a couple of times. But after invoking


void MyWidget::onaddbutton_clicked()
{

a second time, and then clicking on the old btnTest button of the first time, they do not get disabled. Any ideas of how to do this?

The disabling methods are placed here:


void MyWidget::systembutton_clicked(int j, int k, QVBoxLayout *vbox)
{
...
if(...){
btnTest[j].setEnabled(false);

[bchinfosieeuw]

According to the btnTest2[i].isEnabled() function the button is disabled, but in the program the btnTest2[i] remains clickable.

[anda_skoa]

You onaddbutton_clicked() creates a new array of buttons every time, maybe you disabled only one of these sets.

Cheers,
_