kivy-intro

Introduction to Kivy

Mr Keyvan Hedayati

Mohammad Vahshi Bafghi

Arash Shafie Hichi Abadi

Overview

• What's Python?
• What's Kivy?
• Examples
• Installation
• Interface Design
• Hello World App
• Packaging
• Lists and Dictionaries
• SQlite
• Java classes in Kivy

Testimonial

What's Python?

• General-Purpose
• Dynamic but Strongly Typed
• High-Level
• Cross Platform
• Emphasizes on Code Readability
• Easy to learn & code

Not believing me? See it yourself

Compare it with Java "Hello Wolrd"

public class java {
    public static void main(String[] args) {
        System.out.println("Hello World");
    }
}

Lines of code for XML Serialization

Isn't that just an open-source Visual Basic?

WTF!

Who's using Python

• Youtube, Dropbox and Instagram mainly in Python
• Google, NASA, Yahoo!, CERN, PayPal/eBay, Bank of America
• OpenStack Cloud Computing Software Platform (IaaS)
• NumPy, SciPy Powerful scientific tools that compete with MATLAB
• Embedded in 3ds Max, Blender, Cinema 4D, Lightwave, Maya, GIMP, Inkscape, ArcGIS
• Installed by default in many Linux distributions
• BitTorrent, Mercurial, OpenERP, ERP5, GNU Mailman
• More Info? Read 10 Myths of Enterprise Python

Why Kivy?

Fast

• Application development
  • Agile language
• Execution speed
  • Critical functionality implemented in C
  • Uses GPU whenever it makes sense
  • Intelligent algorithms for costly operations

Flexible

• Run on a variety different devices and OSs
• Quickly adapt to new technologies
  • Windows 7 Pen & Touch
  • Apple Multi-Touch
  • HID kernel input events on Linux
  • TUIO (Tangible User Interface Objects)

Funded

• Actively developed by professionals
• Not a small, vanishing student project

Examples

Kivy showcase app

Simple application to show some of kivy features

2048

Google Play - App Store

ProcessCraft BPMN

Google Play

Flat Jewels

Google Play

Match 3

Google Play

KOGNITIVO

Google Play

Sudoku

Google Play

QPython - Python for Android

Google Play

Installation

Windows

Download the latest version

Unzip the package

Copy the kivy.bat file to the Clipboard

Open Windows explorer, and to go the address ‘shell:sendto’

You should get the special Windows directory Send To

Paste the previously copied kivy.bat file as a shortcut

Rename it to Kivy

Execute your application by right clicking on the .py file -> “Send To” -> “Kivy ”.

Linux

(Ubuntu)

• sudo add-apt-repository ppa:kivy-team/kivy
• sudo apt-get install python-kivy
• python /path/to/python/file.py

OS X

• Download the latest version from http://kivy.org/#download
• Double-click to open it
• Drag the Kivy.app into your Applications folder
• Make sure to read the Readme.txt

Interface Design

Code

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

# test.py
import kivy
from kivy.app import App

class TestApp(App):
    pass

TestApp().run()

# test.kv
Button:
    text: 'Hello world'

Just for the record, Java Hello Wolrd

package com.mkyong.android;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class HelloWorldActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        TextView text = new TextView(this);
        text.setText("Hello World");
        setContentView(text);
    }
}

GUI

Via Kivy Designer (Alpha)

A Little More Than Hello World

# =========== my.kv
<HelloWorld>:
    BoxLayout:
        Label:
            id: label
            text: 'Kivy Sample App'
        Button:
            text: 'Click Me'
            on_press: root.change_text()

# =========== my.py
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout

class MyApp(App):
    def build(self):
        return HelloWorld()

class HelloWorld(BoxLayout):
    def change_text(self):
        self.ids.label.text = 'Hello Wolrd!'

MyApp().run()

Run on PC

Run on Android

Packaging

Android

(Manual)

• Install Linux, Java, Jinja2
• Download Android NDK, SDK
• Download latest Android platform
• Download python-for-android
• Build a distribution
• Build the APK of your application
• Install the debug apk to your device
• Enjoy! (your aunt spirits)

Android

(Automatic)

• Using Buildozer pip install buildozer buildozer init
• Edit buildozer.spec for App Name, Version, Perms, etc. buildozer android debug deploy run
• Bouns Step - If you're on linux adb logcat | grep python

Android

(If you can't use your neighbor's uncensored Internet and/or using Windows)

• Download Virtual Disk
• Install VirtualBox, Import Disk Image and Run Virtual Machine
• Build a distribution ./distribute.sh -m "kivy"
• Build project ./build.py --dir ~/kivy/examples/demo/touchtracer \ --package org.demo.touchtracer \ --name "Kivy Touchtracer" --version 1.1.0 debug installd
• Install it on your device adb install -r bin/KivyTouchtracer-1.1.0-debug.apk

Android

(Vahid's favorite, Cloud!)

buildozer.io

Kivy Launcher

• Install from Google Play
• Put your app in /sdcard/kivy/yourapplication
• yourapplication should be a directory containing

  main.py     # Your main application file
  android.txt # Some info Kivy requires about your app on android

• The file android.txt must contain

  title=<Application Title>
  author=<Your Name>
  orientation=<portrait|landscape>

You can package your app for Windows, Linux, MacOSX, IOS

(But I'm not going through it)

List

• Dynamic Size
• No Type Enforcement
• Some methods: append, index, insert, pop, remove, reverse, sort

Examples

my_list = ['K1', 3.14, str]
my_list.append(1)
my_list.append(10)
my_list.append(15)
my_list.remove(3.14)
print len(my_list)     # 5
print my_list          # ['K1', str, 1, 10, 15]
print my_list[0]       # K1

Dictionary

• Key-Value Data Structure
• Uses Hash-Map For Fast Access

Examples

founded_year = {
    'Google': 2998,
    'Mi©ro$oft': 1975,
    'Apple': 1976,
    'Facebook': 2004
}
founded_year['Google'] = 1998
print founded_year['Apple'] # 1976
print founded_year          # {'Google': 1998, 'Mi©ro$oft': 1975, 'Apple': 1976, 'Facebook': 2004}
print founded_year.keys()   # ['Google', 'Mi©ro$oft', 'Apple', 'Facebook']

Simple for arrays

company_info = {
    'Google': {'founded_year': 1998, 'ceo': 'Larry Page', 'employees': 55030},
    'Mi©ro$oft': {'founded_year': 1975, 'ceo': 'Satya Nadella', 'employees': 128076},
    'Apple': {'founded_year': 1976, 'ceo': 'Tim Cook', 'employees': 98000},
    'Facebook': {'founded_year': 2004, 'ceo': 'Mark Zuckerberg', 'employees': 8348},
}

Code

This code can be cleaner

self.cols = 8
for company, info in company_info.items():
    self.add_widget(Label(text='Name: '))
    self.add_widget(Label(text=company))
    self.add_widget(Label(text='Founded Year: '))
    self.add_widget(Label(text=info['founded_year']))
    self.add_widget(Label(text='CEO: '))
    self.add_widget(Label(text=info['ceo']))
    self.add_widget(Label(text='Employees: '))
    self.add_widget(Label(text=info['employees']))

Run

SQlite

• In-Process
• Self-Contained
• Serverless
• Zero-Configuration
• Transactional

Intro

import sqlite3

db = sqlite3.connect('db.sqlite')
db.execute('INSERT INTO members VALUES ("Gholi", "Kheshtak Zade")').commit()
members = db.execute('SELECT * FROM members').fetchall()

Simple for database

Data

CREATE TABLE companies (company_name TEXT, founded_year TEXT, ceo TEXT, employees TEXT);
INSERT INTO companies VALUES ('Google', 1998, 'Larry Page', 55030);
INSERT INTO companies VALUES ('Mi©ro$oft', 1975, 'Satya Nadella', 128076);
INSERT INTO companies VALUES ('Apple', 1976, 'Tim Cook', 98000);
INSERT INTO companies VALUES ('Facebook', 2004, 'Mark Zuckerberg', 8348);

Code

db = sqlite3.connect('db.sqlite')
company_info = db.execute('SELECT * FROM companies').fetchall()
self.cols = 8
for company in company_info:
    self.add_widget(Label(text='Name: '))
    self.add_widget(Label(text=company[0]))
    self.add_widget(Label(text='Founded Year: '))
    self.add_widget(Label(text=company[1]))
    self.add_widget(Label(text='CEO: '))
    self.add_widget(Label(text=company[2]))
    self.add_widget(Label(text='Employees: '))
    self.add_widget(Label(text=company[3]))

Run