Solved QTreeWidget with LineEdit to filter and search element in my tree

[coilo]

Hello guys,

I am new to the world of Qt. I am trying to do a filter for my QTreeWidget. I have a list of items in my tree and I would like to use a search input (with a LineEdit) to find my item from my list.
Here the pic of my GUI so that you can better understand :

So when I write a letter in my LineEdit i would like to show only items who started with this letter.
But unfortunately i have no idea how to deal with it.

If someone can help me, thank you very much.

[CP71]

@coilo
Hi.
Never done!
As the first idea I think:

QList<QTreeWidgetItem*> list;

list = MyQTreeWidget->findChildren<QTreeWidgetItem*>();

Then foreach in the list to find text that contains your substring, then select QTreeWidgetItem

Unique doubt, I'm not sure that list has the correct order, you must check

[VRonin]

Instead of using QTreeWidget split the model and the view (QStandardItemModel+QTreeView)
Then you can just use a QSortFilterProxyModel in-between to do the filtering

[coilo]

@CP71
Hmmm i am going to try your solution ! Thanks for the help

[coilo]

@VRonin
The problem is that I have already used this tree for other functions. So I would like to avoid redoing everything and keep the QTreeWidget format. But yeah you're right, I don't think that the QtreeWidget format is the most appropriate :(

[CP71]

@coilo
You are welcome.
Please, write the result of your test, so I know if it is a good way for future
Thanks

[coilo]

@CP71
Yes of course no problem !
But i have some issues here, i am a beginner with Qt, i am trying your solution the function contains does not exist with QTreeWidgetItem.
Here is my code :

void MainWindow::on_lineEdit_textChanged(const QString &arg1)
{
QList<QTreeWidgetItem*> list;
list= ui->treeWidget->findChildren<QTreeWidgetItem*>();

foreach (QTreeWidgetItem* myitem,list)
{
    if(myitem->contains(arg1))
    { 
        list.append(myitem);
    }
}

}

Thanks again ! =)

[CP71]

@coilo
try
https://doc.qt.io/qt-5/qtreewidgetitem.html#text

[SGaist]

Hi,

For the searching part, no need to complicate stuff, QTreeWidget has you covered with findItems.

[CP71]

@coilo
as @SGaist says

https://stackoverflow.com/questions/29694416/qtreewidgetitem-find-child-by-text

I'm sure that my first idea is not a good way! :(

[coilo]

This post is deleted!

[JonB]

@coilo said in QTreeWidget with LineEdit to filter and search element in my tree:

ui->treeWidget->clear(); //i would like to delete all element (but only the view not the data)

You won't be able to do this. In a QTreeWidget it manages the data and the displayed items itself, you cannot have one without the other. As someone said earlier, the best way to really do this is with your own QTreeView plus a QSortFilterProxyModel, which would achieve what you want, but you have said you have reasons for not wanting to change over.

If you are going to stick with your QTreeWidget you will need to clear its current members and then re-add the desired new items from sublist into your ui->treeWidget, not just call ui->treeWidget->setCurrentItem() (which only selects an existing item already in a QTreeWidget).

Note also: you find items recursively, but you only produce a "flat" sublist. If doing it this way you will need to code whatever to re-add the old items in the correct hierarchy/parentage.

[VRonin]

Disclaimer

This is not the advised solution, the correct one is to use QStandardItemModel+QSortFilterProxyModel+QTreeView.

---

Since you are already hacking, might as well hack properly.

• Create a QTreeView right next to your QTreeWidget.
• Add a private QSortFilterProxyModel* m_proxy; member to MainWindow
• in the MainWindow constructor add:

m_proxy  = new QSortFilterProxyModel(this);
m_proxy->setSourceModel(ui->treeWidget->model());
ui->treeView->setModel(m_proxy);
ui->treeWidget->hide();

• on_lineEdit_textChanged becomes:

void MainWindow::on_lineEdit_textChanged(const QString &arg1)
{
    m_proxy->setFilterRegularExpression(arg1);
}

[coilo]

Hmmm ok i tried what you suggested me and it works yeah ! But i will consider changing my QTreeWidget into QStandardItemModel+QSortFilterProxyModel+QTreeView to do it properly in the future.

Thanks a lot guys !