QT Introduction

What is QT?

• QT is a framework for building UI's.
• It makes UI's easy to make and does all the heavy lifting for us.
• soccer uses QT for all it's GUI stuff, as well as a few other things.
• (today will be a project heavy day, so get ready!)

How do we use QT?

Generate a *.ui file

• A ui file is a XML file generated by QT
• It specifies the layout of the window
• Adding buttons or changing layout is as simple as editing the UI file
• You can open or generate UI files in QtCreator (installed in your VM's)

Link the UI into your program

• You will need to program 'handlers' for actions that the UI takes
  • Ex: ButtonPressed, SelectedGroup, EnterText
• Your program can respond to these cues by modifying bits of the UI

Build Systems

• Designed to be as flexible as 'pressing run' in your IDE, while being easily shareable between programmers
• They make it easy to compile and run a large project on many platforms, which could have hundreds of dependencies

What does a Build System do?

1. Compile only files that need to be compiled
   • Don't compile files that have not changed
   • Ensure changed files get properly recompiled
2. Let your program easily interact with libraries
   • A library, such as QT, would have to be manually specified in gcc without a build system.
3. Speed up compilation by compiling independent files in parallel
4. Bring all compiled files together into one nice, runnable file!

CMake

• A C/C++ build system, very widely used
• Uses CMakeLists.txt files for configuration.
• These files can be nested (so I can copy a CMake project into mine, and automatically use their CMakeLists).

Project: Create a Simple QT App

• RoboJackets/qt-example(http://bit.ly/2fTIPfL)
• This will help you create a basic QT Gui compiled with CMake!
• This is a old project, and it might be confusing, so we'll be here to help you out.
• Let us know if you have questions.