[Qt5] Set Default Suffix

[Salads]

I made a small program that saves a file, but people who use Ubuntu say that they can't properly save the file without manually putting a file extension in the save file name. I tried using the setDefaultSuffix function though I don't see how it would fit with the getSaveFileName function that I'm using.

Here's my code for the save button:

void MainWindow::on_save_clicked()
{
    if (pngData.isEmpty())
    {
        QPixmap noSaveData(":/graphic/noSaveData.png");
        ui->preview->setStyleSheet("background: transparent ;");
        ui->preview->setPixmap(noSaveData);
        return;
    }
    QString filename = QFileDialog::getSaveFileName(this, ("Save Skin"), "C:/Users/", ("PNG Image (*.png)"));
    QFile file(filename);
    file.open(QIODevice::WriteOnly);
    file.write(pngData);
    file.close();
}

void MainWindow::on_save_clicked()
{
    if (pngData.isEmpty())
    {
        QPixmap noSaveData(":/graphic/noSaveData.png");
        ui->preview->setStyleSheet("background: transparent ;");
        ui->preview->setPixmap(noSaveData);
        return;
    }
    QString filename = QFileDialog::getSaveFileName(this, ("Save Skin"), "C:/Users/", ("PNG Image (*.png)"));
    QFile file(filename);
    file.open(QIODevice::WriteOnly);
    file.write(pngData);
    file.close();
}

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[alrawab]

QFileDialog::getSaveFileName(0,"Save Skin",QDir::homePath(),"PNG Image (*.png)");

QFileDialog::getSaveFileName(0,"Save Skin",QDir::homePath(),"PNG Image (*.png)");

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there is no C:/Users in Linux ...read The Current Directory and Other Special Paths
http://doc.qt.io/qt-4.8/QDir

[Salads]

Thanks for the tip, the save function now goes to the directory I want, however I get weird error output since I added it in:
output.jpg

QFSFileEngine::open: No file name specified
Cannot create accessible interface for object:  MainWindow(0x33fbd4, name = "MainWindow") 
Cannot create accessible interface for object:  QPushButton(0x8f4880, name = "save") 
Cannot create accessible interface for object:  MainWindow(0x33fbd4, name = "MainWindow") 
Cannot create accessible interface for object:  MainWindow(0x33fbd4, name = "MainWindow") 
Cannot create accessible interface for object:  QPushButton(0x8f4880, name = "save") 
Cannot create accessible interface for object:  QPushButton(0xa77478, name = "dLoad") 
Cannot create accessible interface for object:  QLineEdit(0xa774d8, name = "lineEdit") 
Cannot create accessible interface for object:  QPushButton(0x8f4880, name = "save") 
Cannot create accessible interface for object:  QLabel(0x8f4900, name = "preview") 
Cannot create accessible interface for object:  QPushButton(0x8f4960, name = "clear") 
Cannot create accessible interface for object:  QWidget(0xa77418, name = "centralWidget") 
Cannot create accessible interface for object:  MainWindow(0x33fbd4, name = "MainWindow") 
Cannot create accessible interface for object:  MainWindow(0x33fbd4, name = "MainWindow")

QFSFileEngine::open: No file name specified
Cannot create accessible interface for object:  MainWindow(0x33fbd4, name = "MainWindow") 
Cannot create accessible interface for object:  QPushButton(0x8f4880, name = "save") 
Cannot create accessible interface for object:  MainWindow(0x33fbd4, name = "MainWindow") 
Cannot create accessible interface for object:  MainWindow(0x33fbd4, name = "MainWindow") 
Cannot create accessible interface for object:  QPushButton(0x8f4880, name = "save") 
Cannot create accessible interface for object:  QPushButton(0xa77478, name = "dLoad") 
Cannot create accessible interface for object:  QLineEdit(0xa774d8, name = "lineEdit") 
Cannot create accessible interface for object:  QPushButton(0x8f4880, name = "save") 
Cannot create accessible interface for object:  QLabel(0x8f4900, name = "preview") 
Cannot create accessible interface for object:  QPushButton(0x8f4960, name = "clear") 
Cannot create accessible interface for object:  QWidget(0xa77418, name = "centralWidget") 
Cannot create accessible interface for object:  MainWindow(0x33fbd4, name = "MainWindow") 
Cannot create accessible interface for object:  MainWindow(0x33fbd4, name = "MainWindow")

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Everything seems to be working regardless, besides the missing extensions that Linux users have.

EDIT: The errors don't seem related to QDir, as I changed it back just to check and had the same result.

[alrawab]

its works fine if we supposed pngData is correct data type

#include <QApplication>
#include <QFileDialog>
 
int main(int argc, char **argv)
{
 QApplication app(argc,argv);
        QString filename =QFileDialog::getSaveFileName(0,"Save Skin",QDir::homePath(),"PNG Image (*.png)");
        QFile file(filename);
        file.open(QIODevice::WriteOnly);
        file.write("Foo");//change Foo to your data
 
        file.close();
        return 0;
}

#include <QApplication>
#include <QFileDialog>

int main(int argc, char **argv)
{
 QApplication app(argc,argv);
        QString filename =QFileDialog::getSaveFileName(0,"Save Skin",QDir::homePath(),"PNG Image (*.png)");
        QFile file(filename);
        file.open(QIODevice::WriteOnly);
        file.write("Foo");//change Foo to your data

        file.close();
        return 0;
}

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QPixmap::save