Developing Qt applications

This recipe will show how to build, run, and debug a graphical Qt application using Qt Creator.

Getting ready

Before launching Qt Creator, we check whether we are able to build and launch a Qt application manually. We will build a Qt hello world application. Here is the code for qt_hello_world.cpp:

#include <QApplication> 
#include <QPushButton> 
 
 int main(int argc, char *argv[]) 
 { 
     QApplication app(argc, argv); 
 
     QPushButton hello("Hello world!"); 
 
     hello.show(); 
     return app.exec(); 
 } 

To build it, we use the SDK installed, as described previously:

$ . /opt/poky/2.4/environment-setup-cortexa9hf-neon-poky-linux-gnueabi
$ qmake -project
$ qmake

This uses qmake to create a project file and a Makefile file with all the relevant code files in the directory. We can now build with the following command:

$ make

Note

The previous build will fail with the following error:qt_hello_world.cpp:1:10: fatal error: QApplication: No such file or directory...