Challenges in Building GTK Applications for Android

Oct 13, 2025 by talynt.org 75 views

Introduction

In recent years, the demand for cross-platform applications has increased significantly. Android, being one of the most popular mobile operating systems, has become a prime target for developers looking to expand their reach. However, building applications for Android can be a complex task, especially when it comes to integrating different programming languages and frameworks. In this article, we will explore the challenges of building GTK applications written in Rust for the Android backend and propose a potential solution.

Challenges in Building GTK Applications for Android

As we delve into the world of cross-platform development, we encounter several challenges that need to be addressed. In the case of building GTK applications written in Rust for the Android backend, there are two primary issues that need to be resolved:

1. Single-Pass Ninja Invocation

For Android, we want to achieve a "single-pass" ninja invocation to build the whole source+dependency tree. This means that the build process should be able to resolve all dependencies and build the application in a single step. However, as far as we understand, this is not possible with Rust, as it relies on pkg-config to resolve dependencies. This can lead to a complex and time-consuming build process.

2. Entry Point for the Application

Another challenge we face is the entry point for the application. The glue code wants to call main(int argc, char **argv, char **envp), which is the standard entry point for C applications. However, Rustc may not expose such an entry symbol by itself, requiring additional glue code to be written.

Proposed Solution: Building Rust Application as a Static Library

To overcome these challenges, we propose building the Rust application as a static library. This approach has several benefits:

Avoiding Symbol Resolving: By building the Rust application as a static library, we can avoid Rustc's symbol resolving process. This means that the build process will not be dependent on pkg-config to resolve dependencies.
Automatic Linking of Glue Code: When we build the static library, Meson can automatically link the glue code in correctly. This eliminates the need for manual intervention and ensures that the application is built correctly.

How to Build a Rust Application as a Static Library

To build a Rust application as a static library, we can follow these steps:

Step 1: Configure Meson

First, we need to configure Meson to build the Rust application as a static library. We can do this by adding the following lines to our meson.build file:

project('my_app', 'rust',
        version: '1.0',
        default_options: ['buildtype=release'],
        dependencies: ['gtk', 'glib'],
        build_type: 'static_library')

In this example, we are building a Rust application called my_app that depends on GTK and GLib. We are also specifying that the build type should be a static library.

Step 2: Write the Rust Code

Next, we need to write the Rust code for our application. We can create a new file called src/main.rs and add the following code:

use gtk::prelude::*;

fn main() {
    // Initialize GTK
    gtk::prelude::init();

    // Create a new window
    let window = gtk::Window::new(gtk::WindowType::Toplevel);

    // Show the window
    window.show();

    // Run the application
    gtk::main();
}

In this example, we are creating a simple GTK application that initializes GTK, creates a new window, and shows it.

Step 3: Build the Application

Finally, we can build the application using Meson. We can run the following command in our terminal:

meson build
ninja -C build

This will build the application in the build directory.

Conclusion

In conclusion, building GTK applications written in Rust for the Android backend can be a complex task. However, by building the Rust application as a static library, we can overcome the challenges of single-pass ninja invocation and entry point for the application. By following the steps outlined in this article, we can create a cross-platform application that runs on Android and other platforms.

Future Work

There are several areas where we can improve our solution:

Optimizing the Build Process: We can optimize the build process by using techniques such as incremental builds and caching.
Improving the Glue Code: We can improve the glue code by using more advanced techniques such as reflection and dynamic linking.
Supporting Other Platforms: We can support other platforms such as iOS and Windows by using cross-platform frameworks such as Flutter and React Native.

Introduction

In our previous article, we explored the challenges of building GTK applications written in Rust for the Android backend and proposed a potential solution by building the Rust application as a static library. However, we understand that there may be many questions and concerns regarding this approach. In this article, we will address some of the frequently asked questions and provide additional information to help you better understand the solution.

Q: What are the benefits of building the Rust application as a static library?

A: Building the Rust application as a static library has several benefits, including:

Avoiding Symbol Resolving: By building the Rust application as a static library, we can avoid Rustc's symbol resolving process. This means that the build process will not be dependent on pkg-config to resolve dependencies.
Automatic Linking of Glue Code: When we build the static library, Meson can automatically link the glue code in correctly. This eliminates the need for manual intervention and ensures that the application is built correctly.
Improved Build Performance: Building the Rust application as a static library can improve build performance by reducing the number of dependencies and build steps.

Q: How do I configure Meson to build the Rust application as a static library?

A: To configure Meson to build the Rust application as a static library, you can add the following lines to your meson.build file:

project('my_app', 'rust',
        version: '1.0',
        default_options: ['buildtype=release'],
        dependencies: ['gtk', 'glib'],
        build_type: 'static_library')

In this example, we are building a Rust application called my_app that depends on GTK and GLib. We are also specifying that the build type should be a static library.

Q: What are the requirements for building the Rust application as a static library?

A: To build the Rust application as a static library, you will need:

Rustc: You will need to have Rustc installed on your system.
Meson: You will need to have Meson installed on your system.
GTK and GLib: You will need to have GTK and GLib installed on your system.
Android SDK: You will need to have the Android SDK installed on your system.

Q: How do I build the Rust application as a static library?

A: To build the Rust application as a static library, you can follow these steps:

Configure Meson: Configure Meson to build the Rust application as a static library by adding the following lines to your meson.build file:

project('my_app', 'rust', version: '1.0', default_options: ['buildtype=release'], dependencies: ['gtk', 'glib'], build_type: 'static_library') 2. **Write the Rust Code**: Write the Rust code for your application in a file called `src/main.rs`. 3. **Build the Application**: Build the application using Meson by running the following command in your terminal: bash meson build ninja -C build

    This will build the application in the `build` directory.

**Q: What are the limitations of building the Rust application as a static library?**
--------------------------------------------------------------------------------

A: While building the Rust application as a static library has several benefits, there are also some limitations to consider:

*   **Increased Build Time**: Building the Rust application as a static library can increase build time due to the additional build steps.
*   **Increased Binary Size**: Building the Rust application as a static library can increase binary size due to the inclusion of additional dependencies.
*   **Limited Support for Dynamic Linking**: Building the Rust application as a static library may limit support for dynamic linking, which can make it more difficult to use certain libraries.

**Conclusion**
----------

In conclusion, building GTK applications written in Rust for the Android backend can be a complex task. However, by building the Rust application as a static library, we can overcome the challenges of single-pass ninja invocation and entry point for the application. By following the steps outlined in this article, we can create a cross-platform application that runs on Android and other platforms.

**Future Work**
--------------

There are several areas where we can improve our solution:

*   **Optimizing the Build Process**: We can optimize the build process by using techniques such as incremental builds and caching.
*   **Improving the Glue Code**: We can improve the glue code by using more advanced techniques such as reflection and dynamic linking.
*   **Supporting Other Platforms**: We can support other platforms such as iOS and Windows by using cross-platform frameworks such as Flutter and React Native.

By addressing these areas, we can create a more robust and maintainable solution for building GTK applications written in Rust for the Android backend.