Usage of QMessageBox in consol application

[Please_Help_me_D]

Hi,

I'm able to use QMessageBox in consol application as:

        QMessageBox msgBox;
        msgBox.setIcon(QMessageBox::Critical);
        msgBox.setWindowTitle("Error");
        msgBox.setText("file can't be less than 600 bytes!");
        msgBox.exec();

But this takes 5 lines of code and to reduce the code I want to use it in form:

QMessageBox::critical(this, "Error", "file can't be less than 600 bytes!");

But in this case I get error:
readsegy.cpp:87:9: error: no matching function for call to 'critical'
qmessagebox.h:194:27: note: candidate function not viable: no known conversion from 'ReadSegy *' to 'QWidget *' for 1st argument

I understand that the problem is in the first parameter this but is there a way to use QMessageBox "inline" style?

[Christian Ehrlicher]

You can pass a nullptr if you don't have a parent.

[Pablo J. Rogina]

@Please_Help_me_D said in Usage of QMessageBox in consol application:

is there a way to use QMessageBox "inline" style?

Yes, using it properly :-)

Documentation is your friend here.

First parameter of such static method is a QWidget object, which the compiler is clearly letting you know about:

qmessagebox.h:194:27: note: candidate function not viable: no known conversion from 'ReadSegy *' to 'QWidget *' for 1st argument

So, could your please show the declaration of your ReadSegy class?

[Please_Help_me_D]

@Pablo-J-Rogina thank you for answer. This part of documentation I don't understand how to use it. Mostly I don't understand where can I get parent in my case.
here it is:

class ReadSegy
{
private:
    QString segyFile;
    QString hdfFile;
    QStringList groupName = {"/TRACES_USTK", "/TRACES_STK", "/MODEL", "/HEADERS"};
    QFile *qFile;
    quint64 segySize, nTrc;
    hid_t file_id, group_id[2];
    htri_t objExist;
    QString segyEndian, segyFormat, txtEncoding;
    quint16_le dataFormatCode_le;
    quint16_be dataFormatCode_be;
    quint16 dataFormatCode, dataFormatBytes, nSamp;
    quint8 compressLevel;
    bool compressDataFlag;
    char txtHdr[3200];


public:
    ReadSegy(QString segyFile, QString hdfFile, QString *txtEncoding, QString *segyEndian, QString *segyFormat, bool compressDataFlag, quint8 compressLevel); // Constructor
    void readTxtHdr(char txtHdr[]);
    void readBinHdr();
    void readTraces();
};
``

[Pablo J. Rogina]

@Please_Help_me_D said in Usage of QMessageBox in consol application:

where can I get parent in my case.

Maybe the problem isn't where to get the parent from, but to get the proper class of parent.

class ReadSegy
{
...
}

Clearly your ReadSegy class is not a subclass of QWidget, and you already know that the 1st parameter to pass to the QMessage static method must be a Qwidget (or any of its descendents...), right?

[Please_Help_me_D]

@Pablo-J-Rogina yes, I'm beginner in C++ programming but as I understand first parameter should be subclass of QWidget. In GUI application I can pass first parameter as this but in consol app... ?

[Christian Ehrlicher]

You can pass a nullptr if you don't have a parent.

[Please_Help_me_D]

@Christian-Ehrlicher that works! thank you!