Programmatically set editable/active QLineEdit (like when user double click on it)

Please_Help_me_D · wrote on 27 Sept 2020, 02:52

Hi,

I have QLineEdit. I'm trying to do the following:
after user finishes editing (presses 'enter' or mouse click somwhere or something) I check if it is ok and if it is not ok then I want to select all text in lineEdit and show ToolTip.
The problem is that I cant programmatically set lineEdit editable/active (like when user double clicks on it).

How can I do that? Simply calling lineEdit->selectAll() doesn't work.

Christian Ehrlicher · 27 Sept 2020, 11:39

@Please_Help_me_D said in Programmatically set editable/active QLineEdit (like when user double click on it):

imply calling lineEdit->selectAll() doesn't work.

It does work.
Setting the focus can be done with QWidget::setFocus()

SGaist · wrote on 27 Sept 2020, 09:09

Hi,

Why not use a validator so your users cannot enter invalid values ?

Please_Help_me_D · 27 Sept 2020, 11:55

@Christian-Ehrlicher I completely forgot to notice that my QLineEdit is a delegate. So to edit something in it I need firstly double-click on it.
In this way setFocus and selectAll doesn't work as I expect.

@SGaist I use validator but after user finishes editing I need to additionally check if the full file name is available and unique (filename is a string from lineEdit).

mrjj · 27 Sept 2020, 12:02

@Please_Help_me_D
Hi
The view can do it.
https://doc.qt.io/qt-5/qabstractitemview.html#edit

Please_Help_me_D · 27 Sept 2020, 13:01

@mrjj thank you
is it possible to get view from my delegate inherited from QStyledItemDelegate?

Christian Ehrlicher · 27 Sept 2020, 13:12

@Please_Help_me_D said in Programmatically set editable/active QLineEdit (like when user double click on it):

is it possible to get view from my delegate inherited from QStyledItemDelegate?

Why do you need it? Add a validator as @SGaist suggested and you're fine. Or overwrite QStyledItemDelegate::setModelData() and do your checks there.

Please_Help_me_D · wrote on 27 Sept 2020, 13:12

@Christian-Ehrlicher I think validator can't help in this case.
What I'm doing:
I have a QLineEdit where user writes name of a file. Well file name can't have some symbols like ?<>/* etc. So I set QRegularExpressionValidator to check symbols.
Besides there are already files in the folder that have their names. After user finishes editing I must check whether new filename is unique or not. If not then I want that QLineEdit stays active and show tooltip like FileName is not unique.

Do I need to add all the file names in the folder to the regular expression and set it to validator?

Christian Ehrlicher · wrote on 27 Sept 2020, 14:38

QLineEdit has some signals which are emitted when the content changes.

Please_Help_me_D · 27 Sept 2020, 17:18

Can't understand how to perform the idea I described above.
The problem was that QStyledItemDelegate::setModelData is invoked before QLineEdit editing finished. I checked that with QAbstractItemView::isPersistentEditorOpen(const QModelIndex &index) const. Thus at the moment when I need to open lineEdit for editing it is already opened but soon will be closed :)
That means that QAbstractItemView::openPersistentEditor(const QModelIndex &index) won't help.

And QAbstractItemView I get from parent of my model wich is available from QStyledItemDelegate

Now I solved my problem in the following way:
beside Validator I also added completer with file-name list that are in the folder. So when user fills lineEditor he can see what file-names already in the folder. I hope that is enough for now

SGaist · 27 Sept 2020, 19:41

You need your users to enter the path of an existing file ?

Christian Ehrlicher · wrote on 27 Sept 2020, 17:18

@Please_Help_me_D said in Programmatically set editable/active QLineEdit (like when user double click on it):

Can't understand how to perform the idea I described above.

See QLineEdit::textChanged()

JonB · wrote on 27 Sept 2020, 17:39

@Please_Help_me_D
Using the QFileDialog to get a filename from the user for either reading from a writing to (whichever of those you want) is an awful lot easier than displaying existing filenames or writing validators if it can suit your situation?

Please_Help_me_D · 28 Sept 2020, 08:22

@SGaist here is the picture. I have hdf5 container somewhere on the disk (say D:\MyProject\DATA\raw_le.h5). This container contains many datasets that should have unique names. And from this point of view we can look at this like we have a folder raw_le.h5 and files in this folder that should have unique names. When I edit itemData in my proxy model I actually change the name of a file in the raw_le.h5 folder.
Ok with validator I can check if there is no restricted symbols in file-name but I also need to check if final itemData (item name/file name) is unique.
I wanted that when user finishes editing delegated lineEdit and the final name is not unique I wanted that the lineEdit stays active and a toolTip appears with message Filename is not valid! and user continues to correct the filename without reDOubleClick on item.

@Christian-Ehrlicher probably you are right. Probably I need to check uniqueness of a file when typing and not when editingFinished.

JonB · wrote on 28 Sept 2020, 08:22

@Please_Help_me_D said in Programmatically set editable/active QLineEdit (like when user double click on it):

@Christian-Ehrlicher probably you are right. Probably I need to check uniqueness of a file when typing and not when editingFinished.

Yes, if you want to stay in editing mode, instead of exiting it and then having to restart, your validator should check for a unique file as the user types and reject the input if not. Then the editingFinished() signal will not be emitted on a duplicate filename.