The GUI for this example is kept simple—the source code is attached with the book. It consists of two line edits (ui->from and ui->to) that allow you to enter the origin and destination of the journey. It also provides you with a combobox (ui->vehicle) that allows you to choose a mode of transportation—whether you want to drive a car, ride a bicycle, or walk—a push button (ui->search) to start the request, and a text edit, or (ui->result) to show the results.
It looks like this:
MainWindow—a subclass of QMainWindow—is the application's main class that holds two private members: m_network_manager ...
