Prompt Title: Broadcast Receiver

To implement a BroadcastReceiver in Kotlin for handling USB connection events, such as ACTION_USB_ACCESSORY_ATTACHED, ACTION_USB_ACCESSORY_DETACHED, ACTION_USB_DEVICE_ATTACHED, and ACTION_USB_DEVICE_DETACHED, follow these steps:

Step 1: Implement the BroadcastReceiver

First, create a Kotlin class that extends BroadcastReceiver and override the onReceive method to handle the different USB actions.

kotlinCopy code
import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.hardware.usb.UsbManager

class UsbBroadcastReceiver : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {
        when (intent.action) {
            UsbManager.ACTION_USB_ACCESSORY_ATTACHED -> {
                // Handle USB accessory attached
            }
            UsbManager.ACTION_USB_ACCESSORY_DETACHED -> {
                // Handle USB accessory detached
            }
            UsbManager.ACTION_USB_DEVICE_ATTACHED -> {
                // Handle USB device attached
            }
            UsbManager.ACTION_USB_DEVICE_DETACHED -> {
                // Handle USB device detached
            }
        }
    }
}

Step 2: Dynamically Register the BroadcastReceiver

Since Android 8.0 (API level 26), you must register the BroadcastReceiver dynamically if you are listening for implicit broadcasts. Do this in an Activity or Service where you need to monitor USB connection changes.

kotlinCopy code
import android.content.IntentFilter
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle

class YourActivity : AppCompatActivity() {

    private lateinit var usbBroadcastReceiver: UsbBroadcastReceiver

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_your)

        // Initialize the BroadcastReceiver
        usbBroadcastReceiver = UsbBroadcastReceiver()
    }

    override fun onStart() {
        super.onStart()
        // Create an IntentFilter and register the receiver
        IntentFilter().apply {
            addAction(UsbManager.ACTION_USB_ACCESSORY_ATTACHED)
            addAction(UsbManager.ACTION_USB_ACCESSORY_DETACHED)
            addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED)
            addAction(UsbManager.ACTION_USB_DEVICE_DETACHED)
            registerReceiver(usbBroadcastReceiver, this)
        }
    }

    override fun onStop() {
        super.onStop()
        // Unregister the receiver to avoid memory leaks
        unregisterReceiver(usbBroadcastReceiver)
    }
}

Best Practices

• Lifecycle Awareness: Register the receiver in onStart() and unregister it in onStop() to align the receiver's lifecycle with the activity, preventing unnecessary resource consumption when the activity is not visible.
• USB Permission Handling: If your application needs to communicate with the USB device or accessory, remember to request permission from the user using UsbManager.requestPermission().
• Use UsbManager: Utilize the UsbManager class to obtain details about the USB device or accessory. This is crucial for determining whether your application can interact with the device and how it should respond to its connection or disconnection.

By adhering to these steps and best practices, you can effectively manage USB connection events in your Kotlin-based Android application.