Qt-interest Archive, March 2008
Instant apply windows
Message 1 in thread
Hi list,
Is there a way to implement instant apply windows[*] in Qt?
My configuration window has several linedits, I tried to play with
editingFinished() signal, but without any success.
The problem is that editingFinished() doesn't receive the current
contents of a lineedit. Here is a snippet from my code:
QList<QLineEdit*> leList;
leList << lineEdit_1
<< lineEdit_2
<< lineEdit_3
<< lineEdit_4;
QList<QString> values;
values << lineEdit_1->text()
<< lineEdit_2->text()
<< lineEdit_3->text()
<< lineEdit_4->text();
signalMapper = new QSignalMapper(this);
for (int i = 0; i < 4; i++)
{
connect(leList[i], SIGNAL(editingFinished()), signalMapper,
SLOT(map()));
signalMapper->setMapping(leList[i], values[i]);
}
connect(signalMapper, SIGNAL(mapped(QString)),
this, SIGNAL(editingFinished(QString)));
connect(this, SIGNAL(editingFinished(QString)),
this, SLOT(writeSettings(QString)));
I believe something is wrong with mapping to ïtext() properties of a
lineedit, but what is the right way of doing this?
The other drawback of this method is that I can't get the
sender(lineedit) of a signal in my ïwriteSettings slot. How to overcome
this?
Thanks for any feedback.
[*]
http://library.gnome.org/devel/hig-book/stable/windows-utility.html.en#windows-instant-apply
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Message 2 in thread
On sÃndag den 2. Marts 2008, Nikolay Derkach wrote:
> Is there a way to implement instant apply windows[*] in Qt?
Of course. You just need to figure out how.
You should not use a signal mapper for this problem. Instead, do this:
foreach(QLineEdit* le, leList)
connect(le, SIGNAL(editingFinished(const QString&)),
this, SLOT(writeSettings(const QString&)));
In your writeSettings slot, you can call sender() and find out which of the
line edits have changed the text.
A QSignalMapper object is good when you want to parameterize a set of widgets.
For example, you have 10 buttons, and you want to have a single slot that
just takes an int as argument, and this int tells which of the buttons was
pressed.
I hope this helps.
Bo.
> My configuration window has several linedits, I tried to play with
> editingFinished() signal, but without any success.
>
> The problem is that editingFinished() doesn't receive the current
> contents of a lineedit. Here is a snippet from my code:
>
> QList<QLineEdit*> leList;
> leList << lineEdit_1
> << lineEdit_2
> << lineEdit_3
> << lineEdit_4;
>
> QList<QString> values;
> values << lineEdit_1->text()
> << lineEdit_2->text()
> << lineEdit_3->text()
> << lineEdit_4->text();
>
> signalMapper = new QSignalMapper(this);
> for (int i = 0; i < 4; i++)
> {
> connect(leList[i], SIGNAL(editingFinished()), signalMapper,
> SLOT(map()));
> signalMapper->setMapping(leList[i], values[i]);
> }
>
> connect(signalMapper, SIGNAL(mapped(QString)),
> this, SIGNAL(editingFinished(QString)));
>
> connect(this, SIGNAL(editingFinished(QString)),
> this, SLOT(writeSettings(QString)));
>
> I believe something is wrong with mapping to ïtext() properties of a
> lineedit, but what is the right way of doing this?
>
> The other drawback of this method is that I can't get the
> sender(lineedit) of a signal in my ïwriteSettings slot. How to overcome
> this?
>
> Thanks for any feedback.
>
>
> [*]
> http://library.gnome.org/devel/hig-book/stable/windows-utility.html.en#wind
>ows-instant-apply
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Message 3 in thread
Hi Bo,
Thanks for your reply.
2008/3/3, Bo Thorsen <bo@xxxxxxxxxxxxxxxxxxxxx>:
>
> On søndag den 2. Marts 2008, Nikolay Derkach wrote:
> > Is there a way to implement instant apply windows[*] in Qt?
>
>
> Of course. You just need to figure out how.
>
> You should not use a signal mapper for this problem. Instead, do this:
>
> foreach(QLineEdit* le, leList)
> connect(le, SIGNAL(editingFinished(const QString&)),
> this, SLOT(writeSettings(const QString&)));
The problem is that editingFinished() method has no parameters. That's why I
had tried using QSignalMapper to add a QString option. Is there any simple
way to overload editingFinished()?
In your writeSettings slot, you can call sender() and find out which of the
> line edits have changed the text.
>
> A QSignalMapper object is good when you want to parameterize a set of
> widgets.
> For example, you have 10 buttons, and you want to have a single slot that
> just takes an int as argument, and this int tells which of the buttons was
> pressed.
I believe this is exactly my case. Probably I misunderstand something?
--
[ signature omitted ]
Message 4 in thread
On mandag den 3. Marts 2008, Nikolay Derkach wrote:
> Hi Bo,
>
> Thanks for your reply.
>
> 2008/3/3, Bo Thorsen <bo@xxxxxxxxxxxxxxxxxxxxx>:
> > On søndag den 2. Marts 2008, Nikolay Derkach wrote:
> > > Is there a way to implement instant apply windows[*] in Qt?
> >
> > Of course. You just need to figure out how.
> >
> > You should not use a signal mapper for this problem. Instead, do this:
> >
> > foreach(QLineEdit* le, leList)
> > connect(le, SIGNAL(editingFinished(const QString&)),
> > this, SLOT(writeSettings(const QString&)));
>
> The problem is that editingFinished() method has no parameters. That's why
> I had tried using QSignalMapper to add a QString option. Is there any
> simple way to overload editingFinished()?
No. When I wrote it, I assumed you had this one set.
Instead, do this:
QLineEdit* lineEdit = qobject_cast<QLineEdit*>(sender());
QString text = lineEdit->text();
Bo.
> In your writeSettings slot, you can call sender() and find out which of the
>
> > line edits have changed the text.
> >
> > A QSignalMapper object is good when you want to parameterize a set of
> > widgets.
> > For example, you have 10 buttons, and you want to have a single slot that
> > just takes an int as argument, and this int tells which of the buttons
> > was pressed.
>
> I believe this is exactly my case. Probably I misunderstand something?
--
[ signature omitted ]
Message 5 in thread
2008/3/3, Bo Thorsen <bo@xxxxxxxxxxxxxxxxxxxxx>:
>
> On mandag den 3. Marts 2008, Nikolay Derkach wrote:
> > Hi Bo,
> >
> > Thanks for your reply.
> >
> > 2008/3/3, Bo Thorsen <bo@xxxxxxxxxxxxxxxxxxxxx>:
> > > On søndag den 2. Marts 2008, Nikolay Derkach wrote:
> > > > Is there a way to implement instant apply windows[*] in Qt?
> > >
> > > Of course. You just need to figure out how.
> > >
> > > You should not use a signal mapper for this problem. Instead, do this:
> > >
> > > foreach(QLineEdit* le, leList)
> > > connect(le, SIGNAL(editingFinished(const QString&)),
> > > this, SLOT(writeSettings(const QString&)));
> >
> > The problem is that editingFinished() method has no parameters. That's
> why
> > I had tried using QSignalMapper to add a QString option. Is there any
> > simple way to overload editingFinished()?
>
>
> No. When I wrote it, I assumed you had this one set.
>
> Instead, do this:
>
> QLineEdit* lineEdit = qobject_cast<QLineEdit*>(sender());
> QString text = lineEdit->text();
>
>
> Bo.
Thanks again. Works like a charm!
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