feat: make sure app is allowed to scan for bluetooth devices

.idea/deploymentTargetDropDown.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="deploymentTargetDropDown">
+    <runningDeviceTargetSelectedWithDropDown>
+      <Target>
+        <type value="RUNNING_DEVICE_TARGET" />
+        <deviceKey>
+          <Key>
+            <type value="SERIAL_NUMBER" />
+            <value value="a4566948" />
+          </Key>
+        </deviceKey>
+      </Target>
+    </runningDeviceTargetSelectedWithDropDown>
+    <timeTargetWasSelectedWithDropDown value="2023-06-14T13:19:30.001338Z" />
+  </component>
+</project>

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

@@ -3,27 +3,45 @@ package com.example.sensortestingapp
 import android.Manifest
 import android.annotation.SuppressLint
 import android.app.Activity
+import android.app.AlertDialog
 import android.bluetooth.BluetoothAdapter
 import android.bluetooth.BluetoothManager
 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 com.google.android.material.snackbar.Snackbar
+import android.view.Menu
+import android.view.MenuItem
 import androidx.appcompat.app.AppCompatActivity
+import androidx.core.app.ActivityCompat
+import androidx.core.content.ContextCompat
 import androidx.core.view.WindowCompat
 import androidx.navigation.findNavController
 import androidx.navigation.ui.AppBarConfiguration
 import androidx.navigation.ui.navigateUp
 import androidx.navigation.ui.setupActionBarWithNavController
-import android.view.Menu
-import android.view.MenuItem
-import androidx.core.content.ContextCompat
 import com.example.sensortestingapp.databinding.ActivityMainBinding
 
 private const val ENABLE_BLUETOOTH_REQUEST_CODE = 1
 
+private const val RUNTIME_PERMISSION_REQUEST_CODE = 2
+
+fun Context.hasPermission(permissionType: String): Boolean {
+    return ContextCompat.checkSelfPermission(this, permissionType) ==
+            PackageManager.PERMISSION_GRANTED
+}
+
+fun Context.hasRequiredRuntimePermissions(): Boolean {
+    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+        hasPermission(Manifest.permission.BLUETOOTH_SCAN) &&
+                hasPermission(Manifest.permission.BLUETOOTH_CONNECT)
+    } else {
+        hasPermission(Manifest.permission.ACCESS_FINE_LOCATION)
+    }
+}
+
 class MainActivity : AppCompatActivity() {
 
     private lateinit var appBarConfiguration: AppBarConfiguration
@@ -48,9 +66,10 @@ class MainActivity : AppCompatActivity() {
         setupActionBarWithNavController(navController, appBarConfiguration)
 
         binding.fab.setOnClickListener { view ->
-            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
-                    .setAnchorView(R.id.fab)
-                    .setAction("Action", null).show()
+            startBleScan()
+//            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
+//                    .setAnchorView(R.id.fab)
+//                    .setAction("Action", null).show()
         }
     }
 
@@ -94,6 +113,44 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
+    override fun onRequestPermissionsResult(
+        requestCode: Int,
+        permissions: Array<out String>,
+        grantResults: IntArray
+    ) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        when (requestCode) {
+            RUNTIME_PERMISSION_REQUEST_CODE -> {
+                val containsPermanentDenial = permissions.zip(grantResults.toTypedArray()).any {
+                    it.second == PackageManager.PERMISSION_DENIED &&
+                            !ActivityCompat.shouldShowRequestPermissionRationale(this, it.first)
+                }
+                val containsDenial = grantResults.any { it == PackageManager.PERMISSION_DENIED }
+                val allGranted = grantResults.all { it == PackageManager.PERMISSION_GRANTED }
+                when {
+                    containsPermanentDenial -> {
+                        // TODO: Handle permanent denial (e.g., show AlertDialog with justification)
+                        // Note: The user will need to navigate to App Settings and manually grant
+                        // permissions that were permanently denied
+                    }
+
+                    containsDenial -> {
+                        requestRelevantRuntimePermissions()
+                    }
+
+                    allGranted && hasRequiredRuntimePermissions() -> {
+                        startBleScan()
+                    }
+
+                    else -> {
+                        // Unexpected scenario encountered when handling permissions
+                        recreate()
+                    }
+                }
+            }
+        }
+    }
+
     @SuppressLint("MissingPermission")
     private fun promptEnableBluetooth() {
         if (!bluetoothAdapter.isEnabled) {
@@ -102,4 +159,93 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
+    private fun startBleScan() {
+        if (!hasRequiredRuntimePermissions()) {
+            requestRelevantRuntimePermissions()
+        } else { /* TODO: Actually perform scan */
+        }
+    }
+
+    private fun Activity.requestRelevantRuntimePermissions() {
+        if (hasRequiredRuntimePermissions()) {
+            return
+        }
+        when {
+            Build.VERSION.SDK_INT < Build.VERSION_CODES.S -> {
+                requestLocationPermission()
+            }
+
+            Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> {
+                requestBluetoothPermissions()
+            }
+        }
+    }
+
+    private fun requestLocationPermission() {
+
+
+        val onClick = { dialog: DialogInterface, which: Int ->
+            ActivityCompat.requestPermissions(
+                this,
+                arrayOf(Manifest.permission.ACCESS_FINE_LOCATION),
+                RUNTIME_PERMISSION_REQUEST_CODE
+            )
+        }
+
+
+        runOnUiThread {
+            val builder = AlertDialog.Builder(this)
+
+            with(builder)
+            {
+                setTitle("Location permission required")
+                setMessage(
+                    "Starting from Android M (6.0), the system requires apps to be granted " +
+                            "location access in order to scan for BLE devices."
+                )
+                setCancelable(false)
+                setPositiveButton(
+                    android.R.string.ok,
+                    DialogInterface.OnClickListener(function = onClick)
+                )
+                show()
+            }
+        }
+    }
+
+    private fun requestBluetoothPermissions() {
+
+        val onClick = { dialog: DialogInterface, which: Int ->
+            ActivityCompat.requestPermissions(
+                this,
+                arrayOf(
+                    Manifest.permission.BLUETOOTH_SCAN,
+                    Manifest.permission.BLUETOOTH_CONNECT
+                ),
+                RUNTIME_PERMISSION_REQUEST_CODE
+            )
+        }
+
+
+        runOnUiThread {
+            val builder = AlertDialog.Builder(this)
+
+            with(builder)
+            {
+                setTitle("Bluetooth permission required")
+                setMessage(
+                    "Starting from Android 12, the system requires apps to be granted " +
+                            "Bluetooth access in order to scan for and connect to BLE devices."
+                )
+                setCancelable(false)
+                setPositiveButton(
+                    android.R.string.ok,
+                    DialogInterface.OnClickListener(function = onClick)
+                )
+                show()
+            }
+        }
+
+    }
+
 }

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

@@ -28,6 +28,6 @@
         android:layout_gravity="bottom|end"
         android:layout_marginEnd="@dimen/fab_margin"
         android:layout_marginBottom="16dp"
-        app:srcCompat="@android:drawable/ic_dialog_email" />
+        app:srcCompat="@android:drawable/stat_sys_data_bluetooth" />
 
 </androidx.coordinatorlayout.widget.CoordinatorLayout>