Can I Grant Android Permissions to a C++ Only NDK Compiled Application?

Are you a C++ enthusiast looking to develop an Android application using the Native Development Kit (NDK)? Do you wonder if it’s possible to grant android permissions to your C++ only NDK compiled application? Well, wonder no more! In this comprehensive guide, we’ll dive into the world of Android permissions and explore how to grant them to your C++ application.

What are Android Permissions?

Before we dive into the juicy stuff, let’s take a step back and understand what Android permissions are. Android permissions are a set of rules that govern what an application can and cannot do on a user’s device. They’re designed to protect users from malicious apps that might access their sensitive information or perform unwanted actions.

Android permissions are categorized into two types:

• Normal Permissions: These permissions are granted to an app by default. They’re typically used for benign actions like reading the device’s screen orientation or getting the device’s current location.
• Dangerous Permissions: These permissions are not granted by default and require explicit user approval. They’re used for sensitive actions like reading contacts, making phone calls, or accessing the camera.

Why Do I Need to Grant Permissions to My C++ Application?

Now that you know what Android permissions are, you might wonder why you need to grant them to your C++ application. The reason is simple: your app needs to interact with the Android operating system and its various components to perform certain actions.

For example, if you’re developing a game that uses the device’s camera, you’ll need to request the CAMERA permission. Without it, your app won’t be able to access the camera, and your users won’t be able to take those awesome selfies or record videos.

Can I Grant Android Permissions to a C++ Only NDK Compiled Application?

The million-dollar question! The short answer is: it’s not possible to grant Android permissions directly to a C++ only NDK compiled application.

The reason is that the Android permission system is built on top of the Java-based Android API. The AndroidManifest.xml file, which is used to declare permissions, is a Java-based file that’s not compatible with C++.

So, What’s the Solution?

Don’t worry, there’s a workaround! You can create a Java-based wrapper around your C++ application using the Android NDK’s JNI (Java Native Interface) mechanism.

The idea is to create a Java-based Android application that declares the necessary permissions in the AndroidManifest.xml file. This Java-based app will then use the JNI to call your C++ code, effectively granting your C++ application the necessary permissions.

Step 1: Create a Java-Based Android Application

Create a new Android project in Android Studio, and add the necessary permissions to the AndroidManifest.xml file:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapp">

    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.RECORD_AUDIO" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

Step 2: Create a JNI Interface

Create a Java interface that will call your C++ code using the JNI mechanism:

public class MyJNI {
    public native void init();
    public native void startCamera();
    public native void stopCamera();
}

Implement the JNI interface in your C++ code:

#include <jni.h>

extern "C" {
    JNIEXPORT void JNICALL
    Java_MyJNI_init(JNIEnv *env, jobject obj) {
        // Initialize your C++ code here
    }

    JNIEXPORT void JNICALL
    Java_MyJNI_startCamera(JNIEnv *env, jobject obj) {
        // Start the camera using the native API
    }

    JNIEXPORT void JNICALL
    Java_MyJNI_stopCamera(JNIEnv *env, jobject obj) {
        // Stop the camera using the native API
    }
}

Step 3: Load the JNI Library

In your Java-based Android application, load the JNI library:

public class MainActivity extends AppCompatActivity {
    static {
        System.loadLibrary("myjni");
    }

    private MyJNI mMyJNI;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mMyJNI = new MyJNI();
        mMyJNI.init();
    }
}

That’s it! You’ve successfully granted Android permissions to your C++ only NDK compiled application using the JNI mechanism.

Conclusion

In this article, we’ve explored the world of Android permissions and how to grant them to a C++ only NDK compiled application. While it’s not possible to grant permissions directly to a C++ application, we can create a Java-based wrapper around it using the JNI mechanism.

By following the steps outlined in this article, you can ensure that your C++ application has the necessary permissions to interact with the Android operating system and its various components.

FAQs

Q: Can I grant permissions to a C++ application without using the JNI mechanism?

A: No, it’s not possible to grant permissions to a C++ application without using the JNI mechanism.

Q: How do I declare permissions in the AndroidManifest.xml file?

A: You can declare permissions in the AndroidManifest.xml file using the <uses-permission> tag.

Q: What’s the difference between normal and dangerous permissions?

A: Normal permissions are granted to an app by default, while dangerous permissions require explicit user approval.

Permission	Description
CAMERA	Allows the app to access the device’s camera.
RECORD_AUDIO	Allows the app to record audio from the device’s microphone.
READ_CONTACTS	Allows the app to read the user’s contacts.

By following the instructions outlined in this article, you can grant Android permissions to your C++ only NDK compiled application and ensure that it has the necessary privileges to interact with the Android operating system.

Frequently Asked Question

Are you curious about granting Android permissions to a C++ only NDK compiled application? Well, you’re in the right place! Here are some frequently asked questions and answers to get you started.