Unlock the Power of Mobile Development with Python and Kivy
As a Python developer, have you ever wondered how to create mobile applications that can run on multiple platforms? Look no further! With the Kivy framework, you can develop platform-independent applications that compile for iOS, Android, Windows, MacOS, and Linux. In this article, we’ll take you on a step-by-step journey to create a simple random number generator app using Kivy.
Getting Started with Kivy
To begin, you’ll need a new directory for your app and Python installed on your machine. Open a new Python file and install the Kivy module from your terminal using one of the commands below. Make sure to install Kivy in a virtual environment to avoid package conflicts.
Creating the RandomNumber Class
Next, create a class that will define your app. In this example, we’ll name it RandomNumber. This class will inherit the App class from Kivy. You’ll need to import the App class by adding from kivy.app import App.
In the RandomNumber class, add a function called build, which takes a self parameter. This function will return the UI. For now, we’ll return a simple label. To do this, import Label using the line from kivy.uix.label import Label.
Outsourcing the Interface
Now, let’s outsource the interface. Create a Kivy file in your directory that will house most of your design work. Name this file the same as your class using lowercase letters and a .kv extension. Inside this file, specify the layout of your app, including elements like labels, buttons, forms, etc.
Applying the Box Layout
To keep things simple, we’ll use the box layout. This layout arranges widgets and other elements in one of two orientations: vertical or horizontal. Add three labels: one for the title RandomNumber, one to serve as a placeholder for the random number that is generated, and a Generate button that calls the generate function.
Kivy Color Values
Did you know that Kivy color values are not your typical RGB values? They are normalized to avoid issues with illumination. To convert your normal RGB values to Kivy’s convention, divide all your values by 255.
Building the Rest of the UI
In the main.py file, import the BoxLayout and edit your main.py file to return BoxLayout() in the build method. If you run this command, you should see a simple interface with the random number title, the _ placeholder, and the clickable Generate button.
Generating the Random Number Function
Now that our app is almost done, let’s create a simple function to generate random numbers when a user clicks the Generate button. To do this, import the random module and create a function or method that calls the generated number. We’ll use a range between 0 and 2000 for this demonstration.
Manually Testing the App
The only thing left to do is make sure that you call this function when the Generate button is clicked. Add the line on_press: root.generate_number() to the button selection part of your .kv file. Now, you can run this app!
Compiling Our App for Android, Windows, and iOS
Before compiling our app for Android, note that you’ll need Linux or macOS to compile your Android application. However, you don’t need a separate Linux distribution – instead, you can use a virtual machine. To compile and generate a full Android .apk application, we’ll use a tool called Buildozer.
After following these steps, you should have a simple random number generator app on your phone. Congratulations! You’ve successfully created a mobile application with Python and Kivy. Happy coding!