change handler to coroutine

Author: isaidamier

BluetoothLeChat/app/build.gradle

@@ -54,6 +54,7 @@ android {
 dependencies {
     implementation fileTree(dir: "libs", include: ["*.jar"])
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.5.1'
     implementation 'androidx.core:core-ktx:1.3.2'
     implementation 'androidx.fragment:fragment-ktx:1.3.4'
     implementation 'androidx.activity:activity-ktx:1.3.0-alpha08'

BluetoothLeChat/app/src/main/java/com/example/bluetoothlechat/scan/DeviceScanViewModel.kt

@@ -19,15 +19,14 @@ import android.app.Application
 import android.bluetooth.BluetoothAdapter
 import android.bluetooth.BluetoothDevice
 import android.bluetooth.le.*
-import android.os.Handler
-import android.os.Looper
 import android.os.ParcelUuid
 import android.util.Log
 import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import com.example.bluetoothlechat.bluetooth.SERVICE_UUID
 import com.example.bluetoothlechat.scan.DeviceScanViewState.*
+import kotlinx.coroutines.*
 
 
 private const val TAG = "DeviceScanViewModel"
@@ -84,8 +83,10 @@ class DeviceScanViewModel(app: Application) : AndroidViewModel(app) {
             _viewState.value = ActiveScan
 
             // Stop scanning after the scan period
-            Handler(Looper.myLooper()!!).postDelayed({ stopScanning() }, SCAN_PERIOD)
-
+            CoroutineScope(Dispatchers.Main).launch {
+                delay(SCAN_PERIOD)
+                stopScanning()
+            }
             // Kick off a new scan
             scanCallback = DeviceScanCallback()
             scanner?.startScan(scanFilters, scanSettings, scanCallback)