How to set my QPushbutton's background?

[cspp]

the plat: Qt4.3.2,Winxp,Vc6.0
Hi all:
I want to set my QPushButton's background when i click it,
and when i click it,it will be show a QColorDialog,after i select an QColor like Qt::Red,
I will set the background of that QPushbutton Qt::Red,or select Qt::Blue,I wil set it Qt::blue.

But now I am failed.When I select some color,and use the QPalette to QPushbutton::setPalette(),but the background is not changed!

some code like this:
---------------------------------------------------------
MMywidget::listBtn_clicked()
{
QPalette palette = listColorBtn->palette();
QColor listColor = palette.color(QPalette::Button);
listColor = QColorDialog::getColor(listColor,this,tr("alarm list color set"));

if(listColor.isValid())
{
palette.setColor(QPalette::Button,listColor);
listColorBtn->setPalette(QPalette(QPalette::Button,listColor) );
listColorBtn->setAutoFillBackground(true);
tempCfg.alarmListBGColor = listColor;
}
}
---------------------------------------------------
how can I set the background correct?
thanks

[spirit]

try this

MMywidget::listBtn_clicked()
{
   QPalette palette = listColorBtn->palette();
   QColor listColor = palette.color(QPalette::Button);
   listColor = QColorDialog::getColor(listColor,this,tr("alarm list color set"));
 
   if(listColor.isValid())
   {
      palette.setColor(QPalette::Button,listColor);
      listColorBtn->setPalette(palette);
      listColorBtn->setAutoFillBackground(true);
      tempCfg.alarmListBGColor = listColor;
   }
}

MMywidget::listBtn_clicked()
{
   QPalette palette = listColorBtn->palette();
   QColor listColor = palette.color(QPalette::Button);
   listColor = QColorDialog::getColor(listColor,this,tr("alarm list color set"));

   if(listColor.isValid())
   {
      palette.setColor(QPalette::Button,listColor);
      listColorBtn->setPalette(palette);
      listColorBtn->setAutoFillBackground(true);
      tempCfg.alarmListBGColor = listColor;
   }
}

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or you can also set background using Qt Style Sheets. have a look at this example

[cspp]

thanks,it does not work also.

and if i user the QStyleSheet,can i use the QPushButton->setStyleSheet?
and if use this function,how can I make the QString styleSheet?
like this QString styleSheet = QString("QPushButton { background-color: %1; }").arg(listColor.name());
but some error when I use those code,my application wil be crashed.

Thanks

[spirit]

thanks,it does not work also.

works fine for me.
can you post compilable example?

[spirit]

using QPalette

QPalette palette = m_pbUpdateQuery->palette();
QColor listColor = palette.color(QPalette::Button);
listColor = QColorDialog::getColor(listColor,this,tr("alarm list color set"));
 
if(listColor.isValid()) {
	palette.setColor(QPalette::Button,listColor);
	m_pbUpdateQuery->setPalette(palette);
	m_pbUpdateQuery->setAutoFillBackground(true);
}

QPalette palette = m_pbUpdateQuery->palette();
QColor listColor = palette.color(QPalette::Button);
listColor = QColorDialog::getColor(listColor,this,tr("alarm list color set"));

if(listColor.isValid()) {
	palette.setColor(QPalette::Button,listColor);
	m_pbUpdateQuery->setPalette(palette);
	m_pbUpdateQuery->setAutoFillBackground(true);
}

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using Style sheet

QPalette palette = m_pbUpdateQuery->palette();
QColor listColor = palette.color(QPalette::Button);
listColor = QColorDialog::getColor(listColor,this,tr("alarm list color set"));
 
if(listColor.isValid()) {
	const QString styleSheet = QString("QPushButton {"
									"background-color: %1}").arg(listColor.name());
	m_pbUpdateQuery->setStyleSheet(styleSheet);
	m_pbUpdateQuery->setAutoFillBackground(true);
}

QPalette palette = m_pbUpdateQuery->palette();
QColor listColor = palette.color(QPalette::Button);
listColor = QColorDialog::getColor(listColor,this,tr("alarm list color set"));

if(listColor.isValid()) {
	const QString styleSheet = QString("QPushButton {"
									"background-color: %1}").arg(listColor.name());
	m_pbUpdateQuery->setStyleSheet(styleSheet);
	m_pbUpdateQuery->setAutoFillBackground(true);
}

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both methods works fine.

[cspp]

The example:
main.cpp

#include <QApplication>
#include <QTranslator>
#include <QLocale>
#include <QLibraryInfo>
 
#include "dialog.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
 
    QString translatorFileName = QLatin1String("qt_");
    translatorFileName += QLocale::system().name();
    QTranslator *translator = new QTranslator(&app);
    if (translator->load(translatorFileName, QLibraryInfo::location(QLibraryInfo::TranslationsPath)))
        app.installTranslator(translator);
 
    Dialog dialog;
    return dialog.exec();
}

#include <QApplication>
#include <QTranslator>
#include <QLocale>
#include <QLibraryInfo>

#include "dialog.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QString translatorFileName = QLatin1String("qt_");
    translatorFileName += QLocale::system().name();
    QTranslator *translator = new QTranslator(&app);
    if (translator->load(translatorFileName, QLibraryInfo::location(QLibraryInfo::TranslationsPath)))
        app.installTranslator(translator);

    Dialog dialog;
    return dialog.exec();
}

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dialog.h

#ifndef DIALOG_H
#define DIALOG_H
 
#include <QDialog>
 
class QCheckBox;
class QLabel;
class QErrorMessage;
 
class Dialog : public QDialog
{
    Q_OBJECT
 
public:
    Dialog(QWidget *parent = 0);
 
private slots:
    void setColor();
 
private:
    QCheckBox *native;
	QPushButton *colorButton;
    QLabel *colorLabel;
    QErrorMessage *errorMessageDialog;
 
    QString openFilesPath;
};
 
#endif

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>

class QCheckBox;
class QLabel;
class QErrorMessage;

class Dialog : public QDialog
{
    Q_OBJECT

public:
    Dialog(QWidget *parent = 0);

private slots:
    void setColor();

private:
    QCheckBox *native;
	QPushButton *colorButton;
    QLabel *colorLabel;
    QErrorMessage *errorMessageDialog;

    QString openFilesPath;
};

#endif

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dialog.cpp

#include <QtGui>
#include "dialog.h"
 
Dialog::Dialog(QWidget *parent)
    : QDialog(parent)
{
    colorLabel = new QLabel;
    colorButton = new QPushButton(tr("QColorDialog::get&Color()"));
 
    connect(colorButton, SIGNAL(clicked()), this, SLOT(setColor()));
 
    QGridLayout *layout = new QGridLayout;
    layout->setColumnStretch(1, 1);
    layout->setColumnMinimumWidth(1, 250);
    layout->addWidget(colorButton, 0, 0);
    layout->addWidget(colorLabel, 0, 1);
    setLayout(layout);
 
    setWindowTitle(tr("Standard Dialogs"));
}
 
void Dialog::setColor()
{
    QColor color = QColorDialog::getColor(Qt::green, this);
    if (color.isValid()) {
        colorLabel->setText(color.name());
        colorLabel->setPalette(QPalette(color));
        colorLabel->setAutoFillBackground(true);
 
		QPalette palette = colorButton->palette();
		palette.setColor(QPalette::Button,color);
		colorButton->setPalette(palette);
		colorButton->setAutoFillBackground(true);
    }
}

#include <QtGui>
#include "dialog.h"

Dialog::Dialog(QWidget *parent)
    : QDialog(parent)
{
    colorLabel = new QLabel;
    colorButton = new QPushButton(tr("QColorDialog::get&Color()"));

    connect(colorButton, SIGNAL(clicked()), this, SLOT(setColor()));

    QGridLayout *layout = new QGridLayout;
    layout->setColumnStretch(1, 1);
    layout->setColumnMinimumWidth(1, 250);
    layout->addWidget(colorButton, 0, 0);
    layout->addWidget(colorLabel, 0, 1);
    setLayout(layout);

    setWindowTitle(tr("Standard Dialogs"));
}

void Dialog::setColor()
{
    QColor color = QColorDialog::getColor(Qt::green, this);
    if (color.isValid()) {
        colorLabel->setText(color.name());
        colorLabel->setPalette(QPalette(color));
        colorLabel->setAutoFillBackground(true);

		QPalette palette = colorButton->palette();
		palette.setColor(QPalette::Button,color);
		colorButton->setPalette(palette);
		colorButton->setAutoFillBackground(true);
    }
}

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[cspp]

and if I set the add this code:

colorButton->setFlat(true);

colorButton->setFlat(true);

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the button's background wiil be set.
but I don't want to set the flat true!

[spirit]

still works fine

[spirit]

and if I set the add this code:

colorButton->setFlat(true);

colorButton->setFlat(true);

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the button's background wiil be set.
but I don't want to set the flat true!

I did change flatness of a button, just compiled your example and it works.

[spirit]

btw, I tested on Qt 4.5.0, which version of Qt do you use?
PS. also read this, maybe you already know this.

[cspp]

QMake version 2.01a
Using Qt version 4.3.2 in D:\Qt\4.3.2\lib

[spirit]

QMake version 2.01a
Using Qt version 4.3.2 in D:\Qt\4.3.2\lib

maybe this is a bug in this Qt version, try to compile you code with older Qt version.

[cspp]

In my example,I use the setStyleSheet,it works well.But in my application,it will be crashed!
I have no idea

the crash infomation is:

Qt has caught an exception thrown from an event handler. Throwing
exceptions from an event handler is not supported in Qt. You must
reimplement QApplication::notify() and catch all exceptions there.

Qt has caught an exception thrown from an event handler. Throwing
exceptions from an event handler is not supported in Qt. You must
reimplement QApplication::notify() and catch all exceptions there.

In my application,I have a framework,it will be load some QLibrary,in the
Lib,it wil create some widget,like QPushButton,like the listColorBtn.
and now when I setStyleSheet in listColorBtn,it crashed!

[cspp]

maybe this is a bug in this Qt version, try to compile you code with older Qt version.

I compiled my code in QT4.5,
it works well.

I think it just some Bug in Qt4.3.2!

[spirit]

yup, I don't remember the task number, but it was on the tracker.

[cookie1909]

I followed the exact code to update the QPalette to change the QPushButton's color but it never showed the color. I compiled my code for Qt 4.5.3 on *both* Unix/X11 and Qt-Embedded, none worked I tried Qt Designer as well, color's not shown either. It works with style sheet, but what I'm trying to have a blinking button that changes colors ever 0.5s, and just that eats up 95% CPU consumption! Admittedly we don't have a very powerful one so I was hoping using QPalette would help the performance.

Anyhow, do you guys have any more ideas? I do have a style sheet applied at the top level Form, but it should be overwritten when I update palette for a particular button, right?

Thanks in advance.

[spirit]

can you show us you code?

[sophister]

I've gor a question.
I use the following codes to change the background color of QLabel, but it doesn't work!

QPalette pale = ui->label->palette();
      pale.setColor(QPalette::Window, listColor);
      ui->label->setAutoFillBackground(true);
      ui->label->setText(listColor.name());

QPalette pale = ui->label->palette();
      pale.setColor(QPalette::Window, listColor);
      ui->label->setAutoFillBackground(true);
      ui->label->setText(listColor.name());

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While if I use

ui->label->setPalette(QPalette(listColor));

ui->label->setPalette(QPalette(listColor));

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it works.
why??

[cookie1909]

Here's my code:

mywindow.h (ui_form.h was generated using Qt Designer, it's huge so I won't put it here)

#ifndef MYWINDOW_H
#define MYWINDOW_H
 
#include <QMainWindow>
#include <QColor>
#include "ui_form.h"
 
class MyWindow1 : public QMainWindow
{
    Q_OBJECT 
 
    public:
        MyWindow1(const Ui::Form& ui);
        ~MyWindow1() {}
 
        void setTimer(int ms);
 
    public slots:
        void blink() ;
 
    private:
        Ui::Form mUi;
        QColor mColor;
};
 
#endif

#ifndef MYWINDOW_H
#define MYWINDOW_H

#include <QMainWindow>
#include <QColor>
#include "ui_form.h"

class MyWindow1 : public QMainWindow
{
    Q_OBJECT 

    public:
        MyWindow1(const Ui::Form& ui);
        ~MyWindow1() {}

        void setTimer(int ms);

    public slots:
        void blink() ;

    private:
        Ui::Form mUi;
        QColor mColor;
};

#endif

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mywindow.cpp

#include <QPalette>
#include <QIcon>
#include <QtCore/QTimer>
#include "mywindow.h"
 
MyWindow1::MyWindow1(const Ui::Form& ui) : QMainWindow()
{
    mUi = ui;
    mUi.setupUi(this);
    mColor = Qt::red;
}
 
void MyWindow1::setTimer(int ms)
{
    if (!mUi.pushButton_114)
        printf("setTimer: invalid button\n");
 
    QTimer *timer = new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(blink()));
    timer->start(ms);
}
 
void MyWindow1::blink()
{
    if (!mUi.pushButton_114)
    {
        printf("Invalid button\n");
        return;
    }
 
    if (mColor == Qt::green)
        mColor = Qt::red;
    else
        mColor = Qt::green;
 
    // DOES NOT WORK
    QPalette p = mUi.pushButton_114->palette();
    p.setColor(QPalette::Button, mColor);
    mUi.pushButton_114->setPalette(p);
    mUi.pushButton_114->setAutoFillBackground(true);    
 
#if 0   
    // THIS WORKS
    QString style = mUi.pushButton_114->styleSheet();
    if (style.contains("green"))
    {   
        mUi.pushButton_114->setStyleSheet(
                QString::fromUtf8("background-color: red;"));
    }
    else
    {
        mUi.pushButton_114->setStyleSheet(
                QString::fromUtf8("background-color: green;"));
    }
#endif
}

#include <QPalette>
#include <QIcon>
#include <QtCore/QTimer>
#include "mywindow.h"

MyWindow1::MyWindow1(const Ui::Form& ui) : QMainWindow()
{
    mUi = ui;
    mUi.setupUi(this);
    mColor = Qt::red;
}

void MyWindow1::setTimer(int ms)
{
    if (!mUi.pushButton_114)
        printf("setTimer: invalid button\n");

    QTimer *timer = new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(blink()));
    timer->start(ms);
}

void MyWindow1::blink()
{
    if (!mUi.pushButton_114)
    {
        printf("Invalid button\n");
        return;
    }

    if (mColor == Qt::green)
        mColor = Qt::red;
    else
        mColor = Qt::green;
  
    // DOES NOT WORK
    QPalette p = mUi.pushButton_114->palette();
    p.setColor(QPalette::Button, mColor);
    mUi.pushButton_114->setPalette(p);
    mUi.pushButton_114->setAutoFillBackground(true);    
        
#if 0   
    // THIS WORKS
    QString style = mUi.pushButton_114->styleSheet();
    if (style.contains("green"))
    {   
        mUi.pushButton_114->setStyleSheet(
                QString::fromUtf8("background-color: red;"));
    }
    else
    {
        mUi.pushButton_114->setStyleSheet(
                QString::fromUtf8("background-color: green;"));
    }
#endif
}

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main.cpp

#include <QApplication>
#include "mywindow.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Ui::Form ui; 
    MyWindow1 *widget = new MyWindow1(ui);
    widget->setTimer(500);
    widget->show();
    return app.exec();
}

#include <QApplication>
#include "mywindow.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Ui::Form ui; 
    MyWindow1 *widget = new MyWindow1(ui);
    widget->setTimer(500);
    widget->show();
    return app.exec();
}

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