Kivy

Kivy is an open source Python library for developing mobile apps and other multitouch application software with a natural user interface (NUI). It can run on Android, iOS, Linux, OS X, and Windows. Distributed under the terms of the MIT license, Kivy is free and open source software.

Kivy is the main framework developed by the Kivy organization,^[2] alongside Python for Android,^[3] Kivy iOS,^[4] and several other libraries meant to be used on all platforms. In 2012, Kivy got a $5000 grant from the Python Software Foundation for porting it to Python 3.3.^[5] Kivy also supports the Raspberry Pi which was funded through Bountysource.^[6]

The framework contains all the elements for building an application such as:

• extensive input support for mouse, keyboard, TUIO, and OS-specific multitouch events,
• a graphic library using only OpenGL ES 2, and based on Vertex Buffer Object and shaders,
• a wide range of Widgets that support multitouch,
• an intermediate language (Kv)^[7] used to easily design custom Widgets.

Kivy is the evolution of the PyMT project, and is recommended for new projects.^[8]

Code example

Here is an example of the Hello world program with just one button:

from kivy.app import App
from kivy.uix.button import Button
 
class TestApp(App):
    def build(self):
        return Button(text='Hello World')
 
TestApp().run()

Kv language

The Kivy language (Kv) is a language dedicated to describing user interface and interactions. As with QML, it is possible to easily create a whole UI and attach interaction. For example, to create a Loading dialog that includes a file browser, and a Cancel / Load button, one could first create the base widget in Python, and then construct the UI in Kv.

In main.py:

class LoadDialog(FloatLayout):
    def load(self, filename): pass
    def cancel(self): pass

And in the associated Kv:

#:kivy 1.4.0
<LoadDialog>:
    BoxLayout:
        size: root.size
        pos: root.pos
        orientation: "vertical"
        FileChooserListView:
            id: filechooser
 
        BoxLayout:
            size_hint_y: None
            height: 30
            Button:
                text: "Cancel"
                on_release: root.cancel()
 
            Button:
                text: "Load"
                on_release: root.load(filechooser.path, filechooser.selection)

References

External links

• Official website