QListWidget doesn't highlights selected item :(

Stramonium

Hello!

When I select item or row, everything works fine, but the item remains not highlighted. Abstract from code:

@
ui->listWidget->setSelectionMode(QAbstractItemView::SingleSelection);
ui->listWidget->setCurrentRow(0);
this->on_listWidget_clicked(ui->listWidget->currentIndex()); // Everything works here.
ui->listWidget->currentItem()->setSelected(TRUE);
ui->listWidget->currentItem()->isSelected(); // returns true here!
ui->listWidget->show();
@

Please help me to find solution!

[edit: added missing coding tags SGaist]

SGaist

Hi,

You should at least add which version of Qt you are using and which OS you are running. Also how are you populating your QListWidget ?

Ebrahim Karimi

I have the same issue
I'm trying to build a cross platform application so appreciate any suggestion or recommendation about either code style or any OS specific details
My OS is Ubuntu 19.04
QT version 5.13
I created a custom widget class:

class MyObjectWidget : public QWidget,public QListWidgetItem{

    Q_OBJECT
    
     public:
         explicit MyObjectWidget(QPointer<MyObject> obj,QListWidget *parent = nullptr,int type=0);
               QSize sizeHint()const override;
          QPointer<MyObject> getObj();
              QVariant data(int role=Qt::ItemDataRole::DisplayRole)const override;
     private:
           Ui::MyObjectWidget *ui;
           QPointer<MyObject> myobj;
}

and in my .cpp:

MyObjectWidget::MyObjectWidget(QPointer<MyObject> obj, QListWidget *parent, int type) :
    QWidget (parent),
    QListWidgetItem(parent,type),
    ui(new Ui::MyObjectWidget),
    myobj(obj)
{
    ui->setupUi(this);
    this->ui->progressBar->setValue(getObj()->getIntVal());
    this->ui->lbl_name->setText(getMyObj()->getName());
}


QPointer<MyObject>MyObjectWidget::getObj()
{
    return this->myobj;
}

QSize MyObjectWidget::sizeHint() const
{
    return QWidget::sizeHint();
}

QVariant MyObjectWidget::data(int role) const
{
    if(role==Qt::ItemDataRole::SizeHintRole){
        return QWidget::sizeHint();
    }else if(role == Qt::ItemDataRole::BackgroundRole){
        return QVariant(palette().highlight()); // even made sure :(
    }
    return QVariant();
}

and for population i have a custom QListWidget:


class MyObjectListWidget : public QListWidget
{
public:
    MyObjectListWidget(QWidget *parent=nullptr);

    bool addObj(QPointer<MyObjectWidget> object);

private:
    QList<QPointer<MyObjectWidget>> widgets;
};

in .cpp :


bool MyObjectListWidget::addObj(QPointer<MyObjectWidget> object)
{
    addItem(object);
    qDebug()<<object->flags().testFlag(Qt::ItemFlag::ItemIsSelectable);
    widgets.push_back(object);
    return true;
}

it's a little tricky this way but i believe its possible to make it work, right?

Christian Ehrlicher

Why do you derive from QListWidgetItem and QWidget? Why do you think this is needed and what do you gain?

Ebrahim Karimi

@Christian-Ehrlicher i wanted to use qt designer to generate the UI so i thought i would be a good solution, any suggestion?

Christian Ehrlicher

@Ebrahim-Karimi said in QListWidget doesn't highlights selected item :(:

i wanted to use qt designer to generate the UI so i thought i would be a good solution, any suggestion?

I don't see any relation between designer and your code above, sorry.

Ebrahim Karimi

@Christian-Ehrlicher its ok bro but this is killing me how can i solve the highlight thing? :'(

Ebrahim Karimi

@SGaist I believe you are a QT Ninja, can you help me with this?

Ebrahim Karimi

OMG!
Stupid,
i totally forgot to remove previous style sheets on all the related widgets

mrjj

@Ebrahim-Karimi
Hi
Glad you found the issue.
It's one of the main reasons that many use just 1 stylesheet we set on Application
so it affects all widgets in the app.

Im not sure i understand the
class MyObjectWidget : public QWidget,public QListWidgetItem
Design.

Since you can use any widget with
https://doc.qt.io/qt-5/qlistwidget.html#setItemWidget
to set on any item - so I would just make them as completely normal widgets with
.h/.cpp and UI file and then use this like that.

Ebrahim Karimi

@mrjj please correct me if i'm wrong
if i don't inherit QListWidgetItem i have to create another raw QListWidgetItem and add it to the QListWidget then setItemWidget(QListWidgetItem *rawItem, QWidget *myCustomWidget) right?
so i decided instead of creating two objects, i can inherit both in one class and create only one object and use that one for both addItem and setItemWidget methods

mrjj

@Ebrahim-Karimi
Hi
Yes, that is the normal way. Also so the Widget is owned and handled by
the QListWidget like its items.

I understand your rationale for then combining them into one class but
if you then reuse the Widgets in another context, they are also half a QListWidgetItem and if you later wanted to use the View version of the List widget with a custom model, then the QListWidgetItem part is also not needed.

Overall, in OOP we use inheritance when we have something we can say "is a"
and i think what i find odd with it - is that we say the QListWidgetItem is now a QWidget which means it can no longer be copied and radically changed the
expected contract of items. Like you could new a MyObjectWidget and place it on a form.

But I dont think any part of Qt, include proxies will try to copy QListWidgetItems, so I dont think it will come back and haunt you :)

So my comment was more out of o.O surprise of such a combination than
out of fear or experience - that it will burn💥 later.