Book Image

Kivy: Interactive Applications in Python

By : Roberto Ulloa
4 (1)
Book Image

Kivy: Interactive Applications in Python

4 (1)
By: Roberto Ulloa

Overview of this book

Mobiles and tablets have brought with them a dramatic change in the utility of applications. Compatibility has become essential, and this has increased the kind of interaction that users expect: gestures, multi-touches, animations, and magic pens. Kivy is an open source Python solution that covers these market needs with an easy-to-learn and rapid development approach. Kivy is growing fast and gaining attention as an alternative to the established developing platforms. Kivy: Interactive Applications in Python quickly introduces you to the Kivy development methodology. You will learn some examples of how to use many of the Kivy components, as well as understand how to integrate and combine them into big projects. This book serves as a reference guide and is organized in such a way that once finished, you will have already completed your first project. You will start by learning the Kivy Language for building User Interfaces (UI) and vector figures. We then proceed to the uses of Kivy events and properties to glue the UI with the application logic. You then go on to build an entire User Interface (UI) starting from a hand-made sketch. Furthermore, you will go on to understand how to use the canvas and drawing instructions to create different types of geometrical figures. Finally, you will be introduced to a big set of interactive and smooth features: transformations (scale, rotate, and translate), gestures, animations, scheduling tasks, and multi-touch elements. Kivy: Interactive Applications in Python expands your knowledge by introducing various components that improve the User Experience (UX). Towards the end of the book, you will be confident to utilize Kivy components and strategies to start any application or game you have in mind.
Table of Contents (13 chapters)
Kivy: Interactive Applications in Python
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Attributes, id and root


In Chapter 1, GUI Basics – Building an Interface, we distinguished between four main components for our Comic Creator: toolbox, drawing space, general options, and status bar. In this chapter these components will start to interact with each other and, therefore, we need to add some attributes to the classes of the project we created in the previous chapters. These attributes will reference different parts of the interface so they can interact. For example, the Toolbox class needs to have a reference to the DrawingSpace instance, so the ToolButton instances can draw their respective figures inside of it. The following diagram shows all the relationships that are created in the comiccreator.kv file:

Internal References of the Comic Creator

We also learned in Chapter 1, GUI Basics – Building an Interface that id lets us reference other widgets in the Kivy language.

Note

However, ids by themselves are not intended to be used outside of the Kivy language: that is the Python...