Not able to get screen resolution with QDesktopWidget.

Ahti

Why doesn't the following code display the screen resolution :

  QMessageBox* EyeCare::constructMessageBox(QWidget *parent,QMessageBox *message,
                                  int x,int y,int w,int h,
                                  QString style){
    message = new QMessageBox(parent) ;
    message->setGeometry(x,y,w,h);
    message->setStyleSheet(style);
    return message ;
}

void EyeCare::setupSimpleAndErrorMessage(){

    showSimpleMessage = constructMessageBox(this,showSimpleMessage,400,400,0,0
                                            ,"color:#D3D3D3;background-color:rgb(32,52,60);"
                                             "font: 75 bold 12pt Arial;") ;
}

    QDesktopWidget widget ;
    setupSimpleAndErrorMessage() ;
    QRect screenSize = widget.availableGeometry(widget.primaryScreen());
    showSimpleMessage->setText("Height: " + screenSize.height()  );
    showSimpleMessage->show();

Instead of displaying the height. It displays the current location of my qt project.
what is wrong with it ??
please help...

hskoglund

Hi, try this:

QDesktopWidget* widget = qApp->desktop();
setupSimpleAndErrorMessage() ;
QRect screenSize = widget->availableGeometry(widget->primaryScreen());
showSimpleMessage->setText("Height: " + screenSize.height()  );
showSimpleMessage->show();

Ahti

@hskoglund Still displaying the location of my qt project. :(

hskoglund

Hmm, I tested the code like this: created a new empty Widgets app, then modified mainwindow.cpp so it looks like this:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "QDesktopWidget"  // <-- added
#include "qdebug.h"        // <-- added

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

// added these 3 lines:
    QDesktopWidget* widget = qApp->desktop();
    QRect screenSize = widget->availableGeometry(widget->primaryScreen());
    qDebug() << "Height: " << screenSize.height();
}

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

Debug output shows height of my desktop (minus 30 because of Windows 7's taskbar)

Ahti

@hskoglund okay mine displays 1030 which means it subtracts 50 because of windows 10 taskbar. But why doesn't it display the same if use QMessageBox ? does your display it using QMessageBox ??

SGaist

Hi,

Did you update your code following @hskoglund suggestions ? If so, can you post the new version ?

Ahti

@SGaist yes but i removed it because now i am facing a new problem and here its.