Dynamically add buttons to ScrollArea

[SGaist]

Hi,

As a quick idea from your description:

• a container widget that you put in the QScrollArea,
• a QHBoxLayout on that widget.
• Add your new buttons to that horizontal layout.

What did you try ?

[andrewhopps]

@SGaist I'm pretty much lost completely as to what I'm supposed to be doing. As of right now the setup is:

• frame
  • scrollArea
    • scrollAreaContents
      • horizontalLayout
        • pushButton (x5)

I don't know what parts I need to be writing code for. I had things scrolling fine at some point last night but kept messing with different code trying to get it all working and nothing works, so back to 0 code in source.

[andrewhopps]

This post is deleted!

[SGaist]

Like I wrote, create a container widget to put in the QScrollArea using QScrollArea::setWidget.

Don't set any layout on QScrollArea, it's just wrong.

[andrewhopps]

@SGaist And is setting a layout on the container widget what I'm supposed to be doing I would assume as it now operates how I imagined? So if the container is a frame, how am I adding new buttons to that in a specific place?

For example: I want to add the button to be the 3rd widget out of the 5 or so.

[SGaist]

You can use insertWidget.

[andrewhopps]

@SGaist Okay, I'm missing something here. The only way I'm getting things to just display properly is with simple

    ui->scrollArea_2->setWidget(ui->frame_2);

Something keeps confusing me and just sends me further back into not understanding what is going on. I have my layout, and I set the layout on my container, then I added my widgets, followed by setting my scrollarea to display my container widget and the program crashes upon start. With segmentation fault at the first use of hlayout.

    QHBoxLayout *hlayout;
    ui->scrollArea_2->setWidgetResizable(true);
    ui->frame_2->setLayout(hlayout);
    hlayout->addWidget(ui->pushButton_14);
    hlayout->addWidget(ui->pushButton_16);
    hlayout->addWidget(ui->pushButton_17);
    hlayout->addWidget(ui->pushButton_18);
    hlayout->addWidget(ui->pushButton_19);
    ui->scrollArea_2->setWidget(ui->frame_2);

[hskoglund]

Hi, instead of
QHBoxLayout *hlayout;
try
QHBoxLayout *hlayout = new QHBoxLayout;

[andrewhopps]

@hskoglund said in Dynamically add buttons to ScrollArea:

QHBoxLayout *hlayout = new QHBoxLayout;

Edited:

That stopped the crashing and the order of code was off, and after rearranging to the following, everything works as originally intended. Much thanks to you both.

    QHBoxLayout *hlayout = new QHBoxLayout;
    ui->scrollArea_2->setWidget(ui->frame_2);
    ui->frame_2->setLayout(hlayout);
    ui->scrollArea_2->setWidgetResizable(true);
    hlayout->addWidget(ui->pushButton_14);
    hlayout->addWidget(ui->pushButton_16);
    hlayout->addWidget(ui->pushButton_18);
    hlayout->addWidget(ui->pushButton_19);
    hlayout->insertWidget(0, ui->pushButton_7);

[andrewhopps]

Well to expand on the previous issue, I've been able to create my buttons and such, but have no way of accessing their clicked functions. Been looking around and saw a few people saying QSignalMapper, so gave that a few tries and nothing functional. Multiple no such signals when the function I was trying to connect most definitely existed and contained just a qDebug saying it worked. I have my container populated with database items, and no clue where to be placing what within or outside of this function.

        qry->prepare("SELECT type || ' ' || number FROM Car WHERE rowid >= 2");
        if(qry->exec())
        {
            while(qry->next())
            {
            QString cName;
            cName = qry->value(0).toString();
            QPushButton *newCar = new QPushButton(cName);
            newCar->setStyleSheet("background-color: rgb(240, 240, 240);"
                                  "background-image: url(:/Resources/Images/Resources/Images/carButton.png);"
                                  "background-repeat: no-repeat;"
                                  "background-attachment: fixed;"
                                  "background-position: center;");
            newCar->setFixedSize(213, 108); 
            newCar->setIconSize(QSize(200,100)); 
            hlayout->addWidget(newCar); 
            }
        }

[J.Hilk]

@andrewhopps
hi,

I would suggest using lambdas in your case, should makes things a bit easier

...
int index = 0;
while(qry->next())
{
            .....
            QPushButton *newCar = new QPushButton(cName);
            ....
           connect(newCar, &QPushButton::clicked, newCar, [=]{newCarClicked(index});
           index++;
}

in your class you add now the function newCarClicked and handle the actions

void newCarClicked(int index{
  switch(index){
   case 0: break;
   ....
   default:break;
  }
}

[andrewhopps]

@J.Hilk Absolutely perfect! Much cleaner code than what I was attempting and trying to copy from. Thank you very much.