Connect slider and line edit??

QT-static-prgm

hey,

is there a fast way to connect a slider with a line edit??

at the moment i'm doing it that way:

#include "..\Header\SettingsWindow.h"
#include <QString>
#include <QLineEdit>
#include <QSlider>

SettingsWindow::SettingsWindow(QWidget * parent)
	: QWidget(parent)
	, ui(new Ui::SettingsWindow)
{
	ui->setupUi(this);

	setWindowFlags(Qt::Tool | Qt::NoDropShadowWindowHint);

	connect(ui->lightOff_R_LE, SIGNAL(textChanged(QString)), this, SLOT(lightOffRValueChanged(QString)));
	connect(ui->lightOff_R_S, SIGNAL(valueChanged(int)), this, SLOT(lightOffRValueChanged(int)));
}

SettingsWindow::~SettingsWindow()
{
	delete ui;
}

void SettingsWindow::lightOffRValueChanged(QString value)
{
	ui->lightOff_R_S->setValue(value.toInt());
}

void SettingsWindow::lightOffRValueChanged(int value)
{
	ui->lightOff_R_LE->setText(QString::number(value));
}

void SettingsWindow::lightOffGValueChanged(QString value)
{
	ui->lightOff_G_S->setValue(value.toInt());
}

void SettingsWindow::lightOffGValueChanged(int value)
{
	ui->lightOff_G_LE->setText(QString::number(value));
}

void SettingsWindow::lightOffBValueChanged(QString value)
{
	ui->lightOff_B_S->setValue(value.toInt());
}

void SettingsWindow::lightOffBValueChanged(int value)
{
	ui->lightOff_B_LE->setText(QString::number(value));
}

But there are 9 of these combinations, so i thought there is maybe a faster and easier way to do it

SGaist

Hi,

You can use lambdas. Or you could also use QSpinBox rather than QLineEdit and thus you could connect the two directly.

VRonin

If you can use Qt5 and C++11

connect(ui->lightOff_R_LE, &QLineEdit::textChanged, [this](const QString& val)->void{ui->lightOff_R_S->setValue(val.toInt());});
	connect(ui->lightOff_R_S, &QSlider::valueChanged,[this](const int& val)->void{ui->lightOff_R_LE->setText(locale().toString(val));});

QT-static-prgm

@VRonin do you know how do bypass this error message?

connect(ui->ambCoef, &QSpinBox::valueChanged, [this](const double& value) {emit updateAmbCoef(value); });

it says it is not clear what instance of the overloaded function valueChanged should be used

VRonin

connect(ui->ambCoef, qOverload<double>(&QDoubleSpinBox::valueChanged), [this](const double& value) {emit updateAmbCoef(value); });

or if you are using qt<5.7

connect(ui->ambCoef, ststic_cast<void (&QDoubleSpinBox::*)(double)>(&QDoubleSpinBox::valueChanged), [this](const double& value) {emit updateAmbCoef(value); });

References:
https://wiki.qt.io/New_Signal_Slot_Syntax

http://doc.qt.io/qt-5/qtglobal.html#qOverload

QT-static-prgm

@VRonin both do not work

just see you had a typo.
static_cast<void (QDoubleSpinBox::*)(double)>
instead of
static_cast<void (&QDoubleSpinBox::*)(double)>

VRonin

what is ui->ambCoef ? it's unclear here if it's a QDoubleSpinBox or a QSpinBox

QT-static-prgm

doublespinbox. I found the problem. see my edit above

SGaist

Out of curiosity, why use a lambda in that case and not signal forwarding ?

QT-static-prgm

Because it does not work. I get qstring and need into and the other way around.

SGaist

But why use QLineEdit if you are only manipulating numbers ? That makes the code uselessly complicated.