Introduction

To keep the code in your packages clear and manageable, it is advised to use an Integrated Development Environment (IDE) to edit your C++ code. Qt Creator is such an IDE for C++. It has the advantage of understanding your code up to some extent. This means Qt Creator can be used to, e.g., auto-complete names of variables and functions or get compilation error message in a nice way. Also, as was stated in the previous tutorial, it understands CMake, which allows it do be used to compile your project, and even run the resulting executables.

Installing Qt Creator

sudo apt-get install qtcreator


If you installed Qt Creator in the default path, you can run it by calling:

qtcreator


Caution: if you do not run Qt Creator from the terminal, the path will not be set correctly and the building of your project will fail!

Use Qt Creator for your project

Now you have installed a proper IDE, you can start to do some real programming! In previous tutorials, we created a C++ project called my_project and went through a little bit of work to get it to build using CMake. Now, that work will pay off: Qt Creator 'understands' CMake, so we can directly load the project. Simply start Qt Creator and:

1. From the home screen (Welcome tab on the left) select Open Project.
2. Navigate to the CMakeLists.txt in your project and open it.
3. Cick on "Details" for the Desktop setting and leave only the box "Default" checked. Click "Browse..." and select the build folder that you want the cmake output to be built in (e.g. myproject/build as in the previous tutorial)
4. Hit the "Configure Project" button, you should now be able to compile and run using the green "Play" button in the left bottom.
5. If QtCreator complains about a missing executable file, closing it and reopening from the terminal will likely fix this (it is a known isssue).

Qt Creator may seem daunting at first: there is a lot that you can do with it. However, we will just use some basic things, so don't worry. On the left, you see a menu with Welcome, Edit, Design, etc. You will mostly be using Edit. To the right of that, there is a window showing your project layout. You can see the name of your project, as specified in the CMakeLists.txt, you can see the CMakeLists.txt itself, and the src directory with example.cpp inside. From this point on you don't really have to leave Qt Creator any more. You can edit the source file in Qt Creator, edit the CMakeLists.txt, run CMake by right clicking the project name and selecting Run CMake, compile the project using ctrl-B and even run your program using the green 'play' button in the lower left. That's pretty awesome!

But you ain't seen nothing yet. Double click on example.cpp to edit it. Remove the #include statement at the top, and type it again, but slowly. You will see that as soon as you type the #, Qt Creator pops up a window with some suggestions. The more you type, the more specific it becomes. You can select an option using the arrow keys, and press enter or tab to confirm. This is called auto-completion and will save you a lot of typing. Continue typing. When you get to <em, you will see that Qt Creator even understands the location of header files, and auto-completes them for you.

Now lets make a mistake on purpose: misspell return and type ctrl-B to compile the project. You will see a list of issues pop up on the bottom, and a red dot besides the line that contains the error. You can double click on issues to directly jump to the error, which is especially useful if your project gets bigger.