Added broadcast receiver and listener to toggle usb connected/disconnected icon in action bar.

app/src/main/java/com/example/hpos/data/DataHolder.kt

@@ -1,8 +1,12 @@
 package com.example.hpos.data
 
+import androidx.lifecycle.MutableLiveData
 import com.example.hpos.data.model.TestRightDeviceConstants
 
 object DataHolder {
+//    var usbConnected: Boolean = false
+    val usbConnected = MutableLiveData(false)
+
     var isStoragePermissionGranted = false
     var isAppFolderCreated = false
     var appFolderPath = ""

app/src/main/java/com/example/hpos/presentation/MainActivity.kt

@@ -1,10 +1,20 @@
 package com.example.hpos.presentation
 
+import android.content.BroadcastReceiver
+import android.content.Context
 import android.content.Intent
+import android.content.IntentFilter
+import android.hardware.usb.UsbManager
 import android.os.Bundle
+import android.view.Gravity
+import android.view.Menu
 import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
+import androidx.core.content.ContextCompat
+import androidx.core.view.get
 import androidx.lifecycle.ViewModelProvider
+import com.example.hpos.R
+import com.example.hpos.data.DataHolder
 import com.example.hpos.databinding.ActivityMainBinding
 import com.example.hpos.presentation.testRight.TestRightActivity
 import com.example.hpos.util.MyViewModelFactory
@@ -17,8 +27,23 @@ class MainActivity : AppCompatActivity()
     private lateinit var binding: ActivityMainBinding
     private lateinit var viewModel: MainViewModel
 
+    private var myMenu: Menu? = null
+
     private val TAG = "MainActivity"
 
+    private var mUsbReceiver: BroadcastReceiver = object : BroadcastReceiver() {
+        override fun onReceive(context: Context?, intent: Intent) {
+            val action = intent.action
+            if (UsbManager.ACTION_USB_DEVICE_DETACHED == action) {
+                DataHolder.usbConnected.value = false
+//                Toast.makeText(context, "Detached", Toast.LENGTH_SHORT).show()
+            } else if (UsbManager.ACTION_USB_DEVICE_ATTACHED == action) {
+                DataHolder.usbConnected.value = true
+//                Toast.makeText(context, "Attached", Toast.LENGTH_SHORT).show()
+            }
+        }
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         binding = ActivityMainBinding.inflate(layoutInflater)
@@ -32,6 +57,11 @@ class MainActivity : AppCompatActivity()
 //        supportActionBar?.setDisplayHomeAsUpEnabled(true)
 
         setupListeners()
+
+        val filter = IntentFilter()
+        filter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED)
+        filter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED)
+        registerReceiver(mUsbReceiver, filter)
     }
 
     private fun setupListeners() {
@@ -44,7 +74,22 @@ class MainActivity : AppCompatActivity()
         binding.cvItem2.setOnClickListener {
             Toast.makeText(this, "To be Implemented", Toast.LENGTH_SHORT).show()
         }
+
+        DataHolder.usbConnected.observe(this){
+            if (it){
+                myMenu?.get(0)?.icon = ContextCompat.getDrawable(this, R.drawable.ic_baseline_usb_24)
+            } else {
+                myMenu?.get(0)?.icon = ContextCompat.getDrawable(this, R.drawable.ic_baseline_usb_off_24)
+                Toast.makeText(this, "USB NOT CONNECTED", Toast.LENGTH_SHORT).show()
+            }
+        }
     }
 
+    override fun onCreateOptionsMenu(menu: Menu?): Boolean {
+        menuInflater.inflate(R.menu.my_menu, menu)
+        myMenu = menu
+        DataHolder.usbConnected.value = DataHolder.usbConnected.value
+        return true
+    }
 
 }

app/src/main/java/com/example/hpos/presentation/testRight/TestRightActivity.kt

@@ -8,6 +8,7 @@ import android.hardware.usb.UsbManager
 import android.os.Bundle
 import android.os.IBinder
 import android.util.Log
+import android.view.Gravity
 import android.view.Menu
 import android.view.MenuItem
 import android.widget.Toast
@@ -23,6 +24,7 @@ import com.example.hpos.util.MyViewModelFactory
 import com.hoho.android.usbserial.driver.UsbSerialDriver
 import com.hoho.android.usbserial.driver.UsbSerialProber
 
+
 class TestRightActivity : AppCompatActivity() {
 
     private lateinit var binding: ActivityTestRightBinding
@@ -79,27 +81,21 @@ class TestRightActivity : AppCompatActivity() {
         setSupportActionBar(binding.myToolbar)
         supportActionBar?.setDisplayHomeAsUpEnabled(true)
 
-        // Connected or not connected icon with livetime status using live data
-
-            // Todo: uncomment it
-//        connectUsb(false)
+        setupListener()
 
+        connectUsb(false)
     }
 
-    override fun onCreateOptionsMenu(menu: Menu?): Boolean {
-        menuInflater.inflate(R.menu.my_menu, menu)
-        myMenu = menu
-//        menu?.get(0)?.icon = ContextCompat.getDrawable(this, R.drawable.ic_baseline_circle_24)
-        return true
-    }
-
-    override fun onOptionsItemSelected(item: MenuItem) = when (item.itemId) {
-        R.id.action_usb -> {
-            Toast.makeText(this, "USB Connected", Toast.LENGTH_SHORT).show()
-            myMenu?.get(0)?.icon = ContextCompat.getDrawable(this, R.drawable.ic_baseline_usb_off_24)
-            true
+    private fun setupListener() {
+        DataHolder.usbConnected.observe(this){
+            if (it){
+                myMenu?.get(0)?.icon = ContextCompat.getDrawable(this, R.drawable.ic_baseline_usb_24)
+            } else {
+                myMenu?.get(0)?.icon = ContextCompat.getDrawable(this, R.drawable.ic_baseline_usb_off_24)
+//                val myToast = Toast.makeText(this, "USB is Detached", Toast.LENGTH_SHORT)
+                Toast.makeText(this, "USB is Detached", Toast.LENGTH_SHORT).show()
+            }
         }
-        else -> {super.onOptionsItemSelected(item)}
     }
 
 //    private fun testing() {
@@ -178,6 +174,32 @@ class TestRightActivity : AppCompatActivity() {
         }
     }
 
+    fun onUsbError(msg: String) {
+        Toast.makeText(this, msg, Toast.LENGTH_SHORT).show()
+//        Snackbar.make(binding.clParent, msg, Snackbar.LENGTH_LONG)
+//            .setAction("CLOSE") { Toast.makeText(this, "Will soon", Toast.LENGTH_SHORT).show() }
+//            .setActionTextColor(resources.getColor(R.color.white))
+//            .show()
+
+        if (!isFinishing)
+            onBackPressed()
+    }
+
+    override fun onCreateOptionsMenu(menu: Menu?): Boolean {
+        menuInflater.inflate(R.menu.my_menu, menu)
+        myMenu = menu
+        return true
+    }
+
+//    override fun onOptionsItemSelected(item: MenuItem) = when (item.itemId) {
+//        R.id.action_usb -> {
+////            Toast.makeText(this, "USB Connected", Toast.LENGTH_SHORT).show()
+////            myMenu?.get(0)?.icon = ContextCompat.getDrawable(this, R.drawable.ic_baseline_usb_off_24)
+//            true
+//        }
+//        else -> {super.onOptionsItemSelected(item)}
+//    }
+
     override fun onDestroy() {
         super.onDestroy()
         if (viewModel.isServiceConnected) {
@@ -187,18 +209,5 @@ class TestRightActivity : AppCompatActivity() {
         }
     }
 
-    fun onUsbError(msg: String) {
-        Toast.makeText(this, msg, Toast.LENGTH_SHORT).show()
-//        Snackbar.make(binding.flMain, msg, Snackbar.LENGTH_LONG)
-//            .setAction("CLOSE", object : View.OnClickListener {
-//                override fun onClick(p0: View?) {
-//                    TODO("Not yet implemented")
-//                }
-//            })
-//            .setActionTextColor(resources.getColor(R.color.holo_red_light))
-//            .show()
-        if (!isFinishing)
-            onBackPressed()
-    }
 
 }

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

@@ -6,6 +6,7 @@
     xmlns:tools="http://schemas.android.com/tools">
 
     <androidx.constraintlayout.widget.ConstraintLayout
+        android:id="@+id/cl_parent"
         android:layout_width="match_parent"
         android:layout_height="match_parent">