Creating a GUI using Qt - c++

Question

Is it possible to create user interfaces using the Qt framework without utilizing the Qt Creator program? It seems that when using this program half of the work must be done by you anyway, so why not learn how it works more fundamentally (insofar as the Qt API is concerned) and implement the programs yourself?
It seems that Qt implements XML files and does a lot of heavy lifting for you when using the creator program (i.e. automatically including class member functions, etc). I have previously implemented GUIs in Java and did not have to dabble in XML. Does Java handle this behind the scenes, or does Qt approach the problem differently?

Answer 1

Qt has more than way to create a GUI. There is the old QtWidgets module which works with "classical" desktop UI widgets and has a C++ API. The XML file is just a convenient way to describe your interface, qmake will generate C++ headers from the XMLs and generate a lot of the boilerplate for you.
If you prefer, you can do all the work yourself entirely in C++ by instantiating the various QWidget subclasses (QMainWindow, QLabel, etc.) and using their APIs.
(I'm not familiar enough with Java to answer that part of the question.)
However, I suggest you to take a look at Qt Quick which allows for a better and more modern way to deal with GUIs, and gives you a lot more freedom. (It's also a lot easier and faster to work with.)
If you want more details on either of them, just write a comment :)

Answer 2

Yes it is possible. I am not going to make any statement on what is the best way because I do not even know how to use Qt Creator. Personally, I just use a text editor to create the source files. I have done that for ten years. I also agree with you on understanding API and structuring of the code.

Answer 3

Yes, here's the code for how to create a simple window and a button.
#include <QApplication>
#include <QPushButton>
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QPushButton *quitButton = new QPushButton("Quit", 0);
connect(quitButton, SIGNAL(clicked()), &app, SLOT(quit()));
return 0;
}
A good Qt tutorial:
http://meetingcpp.com/index.php/br/items/an-introduction-into-qt-part-ii.html

Answer 4

QtCreator, if using g++ compiler:
When there are errors in code, allow right-click on errors list then Show Outputs (O shortcut)… and you can see g++ command with all options:
g++ -c -pipe -g -std=gnu++0x -Wall -W -D_REENTRANT -fPIC -D_GLIBCXX_USE_CXX11_ABI=0 -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I../my-project -I. -I../../../anaconda3/include/qt -I../../../anaconda3/include/qt/QtWidgets -I../../../anaconda3/include/qt/QtGui -I../../../anaconda3/include/qt/QtCore -I. -I. -I../../../anaconda3/mkspecs/linux-g++ -o mainwindow.o ../my-project/mainwindow.cpp
So it only creates a MakeFile in build-your-project-title-Debug (or Release). If you edit it, you have all informations:
MAKEFILE = Makefile
####### Compiler, tools and options
CC = gcc
CXX = g++
DEFINES = -D_GLIBCXX_USE_CXX11_ABI=0 -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB
CFLAGS = -pipe -g -Wall -W -D_REENTRANT -fPIC $(DEFINES)
CXXFLAGS = -pipe -g -std=gnu++0x -Wall -W -D_REENTRANT -fPIC $(DEFINES)
INCPATH = -I../sans_titre -I. -I../../../anaconda3/include/qt -I../../../anaconda3/include/qt/QtWidgets -I../../../anaconda3/include/qt/QtGui -I../../../anaconda3/include/qt/QtCore -I. -I. -I../../../anaconda3/mkspecs/linux-g++
…
You can reproduce it or just use QtCreator to define this MakeFile first then run under CLI with:
make