when i use "QScreen *screen = QGuiApplication::primaryScreen()" ,i get nullptr

[_hunter]

include<iostream>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);

QScreen *screen = QGuiApplication::primaryScreen();

QString filePathName = "full-";

filePathName += QDateTime::currentDateTime().toString("yyyy-MM-dd hh-mm-ss-zzz");

filePathName += ".jpg";
if(screen == nullptr)
{
    std::cout<<"get nothing"<<std::endl;
}

}

i always get a nullptr ,i do not know why.anyone can help me.

[_hunter]

@_hunter and the os is ubuntu16.04

[J.Hilk]

@_hunter said in when i use "QScreen *screen = QGuiApplication::primaryScreen()" ,i get nullptr:

QCoreApplication

I wild guess on my side:
QCoreApplication is for applications without GUI, QGuiApplication::primaryScreen is static function, but it would at least requiere QT += gui in the pro file.

so my suggestion, change QCoreApplication to QGuiApplication.

[_hunter]

@J.Hilk thank you,this help me a lot

[aha_1980]

@_hunter If your problem is solved, please mark this topic as SOLVED too.

Thanks.