How to Run Scripts on Android: A Complete Guide for All Levels

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Running scripts on Android is an increasingly common need among developers, tech enthusiasts, and advanced users looking to automate tasks or test specific features within their apps. However, not everyone knows where to start, what tools to use, or whether it's possible to do so without rooting the device.

In this article, we'll detail the different ways currently available to run scripts on Android devices. From simple options without special permissions to advanced methods supported by Google and built-in system tools. If you're interested in getting more out of your phone, keep reading because this guide will be very useful.

What is running a script on Android?

In simple terms, Running a script in Android means executing a set of coded instructions that perform a specific task.. These scripts can be written in various languages, such as Python, JavaScript, shell script (sh), or even WebAssembly (Wasm)Common uses include automation, app testing, simulating user actions, and more. Knowing how to run a script on Android can make many tasks easier.

Options to run scripts on Android without root

One of the common concerns when trying to run scripts on Android is root access. Not all users want or can root their device. Fortunately, there are options that don't require superuser privileges.

Applications to run scripts from Android

• SH Script RunnerThis app, available on Google Play, allows you to run scripts directly from the app. Some users report that, without root, the scripts don't execute system actions like disabling Wi-Fi or turning off the screen. However, for basic commands or user scripts, it works fine.
• Limitations without root: Many scripts fail with errors like "java.io.IOException: error=2, No such file or directory", which indicates that the script is attempting to access protected resources that are only available with root permissions.
• Functions with root: With superuser permissions, your capabilities are greatly expanded. For example, you can use commands like svc wifi disable o input keyevent 26 to turn off WiFi or the screen without locking the device (something that many screen apps can't do).

Running scripts on Android with Firebase Test Lab: Robo Scripts

Google offers through firebase test lab a powerful option to automate tests in Android apps using what they call Robo scriptsThese allow you to simulate user actions within an app and even execute system commands.

What are Robo Scripts?

They are recordings of actions on the user interface (UI) of an app These can include everything from keystrokes, text input, and screen navigation to specific execution conditions. They work alongside Firebase's Robo testing engine to automatically explore your app.

Key Advantages of Robo Scripting

• Robustness: tolerate changes in the structure of the app.
• Open end: Once the script is finished, the standard Robo auto-test can continue.
• Recordables: can be recorded from Android Studio without writing code.
• Flexible: Compatible even with apps with non-standard interface elements, such as those used in games.

What do they allow you to do?

These sequences can be used to:

• Take the app to a specific point from which to start a test.
• Simulate user flows to ensure a consistent experience.
• Run ADB commands directly as part of the test.

How to record a Robo script in Android Studio

1. Open Android Studio and go to Tools > Firebase.
2. Access the option Record Robo Script and select a device.
3. Interact with the app to record actions.
4. Save the generated JSON file.
5. Upload this file along with the APK to the Firebase console to run the test.

This process does not require advanced knowledge, so It is ideal for testers or even junior developers.

Run JavaScript scripts without WebView with JavaScriptEngine

A modern and powerful alternative offered by Android, especially useful for apps, is Use Jetpack's JavaScriptEngine libraryWith it, you can run JavaScript code without needing to use WebView, making it lighter and more efficient.

Advantages over WebView

• Lower resource consumption.
• Allows multiple independent environments (JavaScriptIsolate).
• Increased levels of security throughout, since each script runs in an isolated environment.

How JavaScriptEngine Works

You must create an instance of JavaScriptSandbox and from there derive one (or several) JavaScriptIsolate to run the code.

Basic example for adding from JavaScript:

JavaScriptIsolate jsIsolate = jsSandbox.createIsolate();
String code = "function sum(a, b) { return (a + b).toString(); }; sum(3, 4)";
ListenableFuture<String> result = jsIsolate.evaluateJavaScriptAsync(code);

The result comes as a String. Important: you cannot use the word return out of function, as it runs in global mode.

Persistence and reuse

A key advantage is that the declared variables and functions persist in the instance. This way, you can run multiple pieces of code by reusing information.

Compatibility and advanced configuration

Not all devices support all library features, so it is advisable to check with isFeatureSupported() what's available. Advanced features include:

• Passing large parameters through provideNamedData().
• Promise Support for asynchronous scripts.
• Evaluating JavaScript files from disk with evaluateJavaScriptAsync(AssetFileDescriptor).
• Error control and controlled failures , the SandboxDeadException.

Running WebAssembly Code on Android

Although less well-known, WebAssembly (Wasm) can also run on Android using this library. The best part? It's done securely in an isolated environment.

The process is similar: A byte array is passed with the Wasm code using provideNamedData() and then compiles and runs inside a JavaScript promise.

Use Google Apps Script and AppSheet

If your goal is automation or integration with Google Workspace, then you can use Google Apps Script or AppSheet:

• Script Apps: Ideal for creating custom functions, automations, menus in spreadsheets or forms.
• appsheet: Allows you to create mobile apps without writing code, using data from Google Sheets or other sources. Perfect for automating tasks without technical knowledge.

These solutions are more limited in terms of Android device control, but are useful in business or educational use cases.

Can I run Python scripts on Android?

Although it does not appear directly developed in the available resources, It is possible to run Python scripts on Android. Some apps like QPython, Pydroid 3 o Termux They allow you to run .py files without any problems. You'll need to install the appropriate app and upload your scripts there, although this option isn't as integrated with the system as the options mentioned above.

If you need to run scripts on Android, you have many options available depending on the level of complexity you require, from simple automations to deep system integrations or app validations.

Advanced possibilities and environment segmentation

In some cases, it may be necessary to run scripts in parallel without sharing context. This can be achieved by creating multiple instances of JavaScriptIsolate from the same sandbox. It is important to note that each instance is independent and they do not share variables or functions.

This approach is recommended when You need to run code in isolation or from different sources., especially in apps that work with multiple users or external integrations.

Kotlin and coroutines support

If you are developing in Kotlin, you can take advantage of coroutines to use JavaScriptEngine asynchronously with the library. kotlinx-coroutines-guavaThis allows you to integrate your script flow without blocking the user interface or using complex callbacks.

Example:

lifecycleScope.launch {
  val jsSandbox = JavaScriptSandbox.createConnectedInstanceAsync(applicationContext).await()
  val jsIsolate = jsSandbox.createIsolate()
  val result = jsIsolate.evaluateJavaScriptAsync("'Script ejecutado con éxito'").await()
  textView.text = result
}

This approach is ideal for modern developers who want to take advantage of the latest Google technologies without the hassle of threads or manual promises.

When it comes to running scripts on Android, the possibilities are many and varied. Whether through dedicated apps, official libraries provided by Google, cloud runtimes like Firebase, or automated tools like AppSheet, there's a solution for every need. The important thing is to understand the limitations of each method—especially if you're not rooted—and choose the approach that best suits your level of knowledge and the purpose of the script.