# Create an AIDL server

* [x] Create implementation of main AIDL file, add register callback methods, keep track of all callback.

```kotlin
// CalculatorImpl.kt
package com.tejpratapsingh.aidlserver.aidl

import com.tejpratapsingh.aildlib.ICalculator
import com.tejpratapsingh.aildlib.ICalculatorCallback
import java.util.concurrent.CopyOnWriteArrayList

object CalculatorImpl : ICalculator.Stub() {

    private const val TAG = "CalculatorImpl"

    private val callbacks: CopyOnWriteArrayList<ICalculatorCallback> = CopyOnWriteArrayList()

    override fun registerListener(cb: ICalculatorCallback) {
        callbacks.addIfAbsent(cb)
    }

    override fun unRegisterListener(cb: ICalculatorCallback) {
        callbacks.remove(cb)
    }

    override fun add(a: Int, b: Int) {
        callbacks.forEach {
            it.onAdded(a + b)
        }
    }
}
```

* [x] Expose the AIDL using a service

```kotlin
// CalculatorService.kt
package com.tejpratapsingh.aidlserver.aidl

import android.app.Service
import android.content.Intent
import android.os.IBinder

class CalculatorService : Service() {
    override fun onBind(intent: Intent): IBinder {
        return CalculatorImpl
    }
}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://notes.tejpratapsingh.com/_/android-tips/aidl/aidl-with-callback/create-an-aidl-server.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.