How to Utilize Native C++ Code for Cross-Platform Development on Android and iOS?

What is the best way to share C++ code between Android and iOS platforms in mobile application development?

Using native C++ code for both Android and iOS allows developers to maintain a single code base, reducing duplication and improving maintainability. This guide provides a concise overview of how to accomplish this using Android's NDK (Native Development Kit) and Objective-C++ for iOS.

// Example function in C++ that can be used in both Android and iOS:
extern "C" {
    int add(int a, int b) {
        return a + b;
    }
}  
   
// In Android (Java/Kotlin) - JNI invocation:
public native int add(int a, int b);

// In iOS (Objective-C++):
#import "YourCppFile.h"

int result = add(5, 3); // Calls the C++ function from Objective-C++ code.

Causes

• The need for high-performance applications that can run efficiently on both platforms.
• Desire to maintain a single code base for easier updates and maintenance.
• The complexity of managing two different languages and frameworks (Java/Kotlin for Android and Swift/Objective-C for iOS).

Solutions

• Utilize the Android NDK to integrate C++ code within your Android application. This allows you to perform computational tasks in C++ which can be more efficient than Java or Kotlin.
• For iOS, leverage Objective-C++ (a bridge between Objective-C and C++) to incorporate C++ code into your iOS application. This allows you to call C++ functions directly from your Objective-C or Swift code.
• Organize your code in a way that separates platform-specific code from shared code, making it easier to manage and understand. Use a shared directory for C++ files and respective headers.

Mistake: Not using the correct compiler flags for C++ when building for each platform.

Solution: Make sure to specify the right flags in your build configuration files (Android.mk or CMakeLists.txt for Android and appropriate Xcode settings for iOS).

Mistake: Overlooking memory management differences between C++ and native platform languages.

Solution: Be mindful of how memory is handled in C++ and ensure proper allocation/deallocation in both environments.