Hello world¶

If you don’t know how to start with Python for Android, here is a simple tutorial for creating an UI using Kivy, and make an APK with this project.

Let’s create a simple Hello world application, with one Label and one Button.

1. Ensure you’ve correctly installed and configured the project as said in the Prerequisites

2. Create a directory named helloworld:

   mkdir helloworld
   cd helloworld
   

3. Create a file named main.py, with this content:

   import kivy
   kivy.require('1.0.9')
   from kivy.lang import Builder
   from kivy.uix.gridlayout import GridLayout
   from kivy.properties import NumericProperty
   from kivy.app import App
   
   Builder.load_string('''
   <HelloWorldScreen>:
       cols: 1
       Label:
           text: 'Welcome to the Hello world'
       Button:
           text: 'Click me! %d' % root.counter
           on_release: root.my_callback()
   ''')
   
   class HelloWorldScreen(GridLayout):
       counter = NumericProperty(0)
       def my_callback(self):
           print 'The button has been pushed'
           self.counter += 1
   
   class HelloWorldApp(App):
       def build(self):
           return HelloWorldScreen()
   
   if __name__ == '__main__':
       HelloWorldApp().run()
   

4. Go to the python-for-android directory

5. Create a distribution with kivy:

   ./distribute.sh -m kivy
   

6. Go to the newly created default distribution:

   cd dist/default
   

7. Plug your android device, and ensure you can install development application

8. Build your hello world application in debug mode:

   ./build.py --package org.hello.world --name "Hello world" \
   --version 1.0 --dir /PATH/TO/helloworld debug installd
   

9. Take your device, and start the application!

10. If something goes wrong, open the logcat by doing:

    adb logcat
    

The final debug APK will be located in bin/hello-world-1.0-debug.apk.

If you want to release your application instead of just making a debug APK, you must:

1. Generate a non-signed APK:

   ./build.py --package org.hello.world --name "Hello world" \
   --version 1.0 --dir /PATH/TO/helloworld release
   

2. Continue by reading http://developer.android.com/guide/publishing/app-signing.html