feat: start and stop scanning

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

@@ -6,12 +6,16 @@ import android.app.Activity
 import android.app.AlertDialog
 import android.bluetooth.BluetoothAdapter
 import android.bluetooth.BluetoothManager
+import android.bluetooth.le.ScanCallback
+import android.bluetooth.le.ScanResult
+import android.bluetooth.le.ScanSettings
 import android.content.Context
 import android.content.DialogInterface
 import android.content.Intent
 import android.content.pm.PackageManager
 import android.os.Build
 import android.os.Bundle
+import android.util.Log
 import android.view.Menu
 import android.view.MenuItem
 import androidx.appcompat.app.AppCompatActivity
@@ -47,11 +51,27 @@ class MainActivity : AppCompatActivity() {
     private lateinit var appBarConfiguration: AppBarConfiguration
     private lateinit var binding: ActivityMainBinding
 
+    private val scanSettings = ScanSettings.Builder()
+        .setScanMode(ScanSettings.SCAN_MODE_BALANCED)
+        .build()
+
     private val bluetoothAdapter: BluetoothAdapter by lazy {
         val bluetoothManager = getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
         bluetoothManager.adapter
     }
 
+    private val bleScanner by lazy {
+        bluetoothAdapter.bluetoothLeScanner
+    }
+
+    private var isScanning = false
+        set(value) {
+            field = value
+            runOnUiThread {
+                binding.fab.setText(if (value) "Stop Scan" else "Start Scan")
+            }
+        }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         WindowCompat.setDecorFitsSystemWindows(window, false)
         super.onCreate(savedInstanceState)
@@ -66,7 +86,11 @@ class MainActivity : AppCompatActivity() {
         setupActionBarWithNavController(navController, appBarConfiguration)
 
         binding.fab.setOnClickListener { view ->
-            startBleScan()
+            if (!isScanning) {
+                startBleScan()
+            } else {
+                stopBleScan()
+            }
 //            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
 //                    .setAnchorView(R.id.fab)
 //                    .setAction("Action", null).show()
@@ -159,13 +183,34 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
+    @SuppressLint("MissingPermission")
+    val scanCallback = object : ScanCallback() {
+        override fun onScanResult(callbackType: Int, result: ScanResult) {
+            with(result.device) {
+                Log.i(
+                    "ScanCallback",
+                    "Found BLE device! Name: ${name ?: "Unnamed"}, address: $address"
+                )
+            }
+        }
+    }
+
+    @SuppressLint("MissingPermission")
     private fun startBleScan() {
         if (!hasRequiredRuntimePermissions()) {
             requestRelevantRuntimePermissions()
-        } else { /* TODO: Actually perform scan */
+        } else {
+            bleScanner.startScan(null, scanSettings, scanCallback)
+            isScanning = true
         }
     }
 
+    @SuppressLint("MissingPermission")
+    private fun stopBleScan() {
+        bleScanner.stopScan(scanCallback)
+        isScanning = false
+    }
+
     private fun Activity.requestRelevantRuntimePermissions() {
         if (hasRequiredRuntimePermissions()) {
             return

app/src/main/res/layout/activity_main.xml

@@ -21,13 +21,14 @@
 
     <include layout="@layout/content_main" />
 
-    <com.google.android.material.floatingactionbutton.FloatingActionButton
+    <com.google.android.material.floatingactionbutton.ExtendedFloatingActionButton
         android:id="@+id/fab"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_gravity="bottom|end"
         android:layout_marginEnd="@dimen/fab_margin"
         android:layout_marginBottom="16dp"
+        android:text='Scan'
         app:srcCompat="@android:drawable/stat_sys_data_bluetooth" />
 
 </androidx.coordinatorlayout.widget.CoordinatorLayout>