Add WiFi scan shutdown hook for Android detector

.gitignore

@@ -1,3 +1,2 @@
 # Generated binary assets
-app/
 __pycache__/

app/src/main/java/com/example/dronedetect/DroneSignalDetector.kt

@@ -0,0 +1,29 @@
+package com.example.dronedetect
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.net.wifi.WifiManager
+import android.os.Handler
+import android.os.Looper
+
+class DroneSignalDetector(private val context: Context) {
+    private val handler = Handler(Looper.getMainLooper())
+    private val wifiManager = context.applicationContext.getSystemService(Context.WIFI_SERVICE) as WifiManager
+    private val receiver = WifiScanReceiver()
+
+    fun startScan() {
+        // TODO: implement scanning logic
+    }
+
+    fun stopScan() {
+        handler.removeCallbacksAndMessages(null)
+        context.unregisterReceiver(receiver)
+    }
+}
+
+class WifiScanReceiver : BroadcastReceiver() {
+    override fun onReceive(context: Context?, intent: Intent?) {
+        // TODO: handle scan results
+    }
+}

app/src/main/java/com/example/dronedetect/MainActivity.kt

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+package com.example.dronedetect
+
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+
+class MainActivity : AppCompatActivity() {
+    private lateinit var detector: DroneSignalDetector
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        detector = DroneSignalDetector(this)
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        detector.stopScan()
+    }
+}