diff --git a/app/src/main/kotlin/com/tutpro/baresip/AccountListAdapter.kt b/app/src/main/kotlin/com/tutpro/baresip/AccountListAdapter.kt
index 71facfe4..306bd919 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/AccountListAdapter.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/AccountListAdapter.kt
@@ -19,8 +19,8 @@ class AccountListAdapter(private val cxt: Context, private val rows: ArrayList<A
     private val layoutInflater = LayoutInflater.from(context)
 
     private class ViewHolder(view: View?) {
-        val aorView = view?.findViewById(R.id.aor) as TextView
-        val actionView = view?.findViewById(R.id.action) as ImageButton
+        val aorView: TextView = view?.findViewById(R.id.aor)!!
+        val actionView: ImageButton = view?.findViewById(R.id.action)!!
     }
 
     override fun getView(position: Int, view: View?, parent: ViewGroup): View {
diff --git a/app/src/main/kotlin/com/tutpro/baresip/AndroidUriListAdapter.kt b/app/src/main/kotlin/com/tutpro/baresip/AndroidUriListAdapter.kt
index 9dfa84a6..b451d3fc 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/AndroidUriListAdapter.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/AndroidUriListAdapter.kt
@@ -16,9 +16,9 @@ class AndroidUriListAdapter(private val ctx: Context, private val rows: ArrayLis
     private val layoutInflater = LayoutInflater.from(context)
 
     private class ViewHolder(view: View?) {
-        val uriView = view?.findViewById(R.id.uri) as TextView
-        val messageView = view?.findViewById(R.id.message) as ImageButton
-        val callView = view?.findViewById(R.id.call) as ImageButton
+        val uriView: TextView = view?.findViewById(R.id.uri)!!
+        val messageView: ImageButton = view?.findViewById(R.id.message)!!
+        val callView: ImageButton = view?.findViewById(R.id.call)!!
     }
 
     override fun getView(position: Int, view: View?, parent: ViewGroup): View {
diff --git a/app/src/main/kotlin/com/tutpro/baresip/CallDetailsAdapter.kt b/app/src/main/kotlin/com/tutpro/baresip/CallDetailsAdapter.kt
index b5689101..8baef3ec 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/CallDetailsAdapter.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/CallDetailsAdapter.kt
@@ -2,7 +2,6 @@ package com.tutpro.baresip
 
 import android.annotation.SuppressLint
 import android.content.Context
-import android.graphics.Typeface
 import android.media.AudioAttributes
 import android.media.MediaPlayer
 import android.text.format.DateUtils
@@ -28,9 +27,9 @@ class CallDetailsAdapter(private val ctx: Context, private val rows: ArrayList<C
         context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
 
     private class ViewHolder(view: View?) {
-        val directionView = view?.findViewById(R.id.direction) as ImageView
-        val timeView = view?.findViewById(R.id.time) as TextView
-        val durationView = view?.findViewById(R.id.duration) as TextView
+        val directionView: ImageView = view?.findViewById(R.id.direction)!!
+        val timeView: TextView = view?.findViewById(R.id.time)!!
+        val durationView: TextView = view?.findViewById(R.id.duration)!!
     }
 
     @SuppressLint("SimpleDateFormat")
diff --git a/app/src/main/kotlin/com/tutpro/baresip/CallListAdapter.kt b/app/src/main/kotlin/com/tutpro/baresip/CallListAdapter.kt
index 2050b690..c2bb0298 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/CallListAdapter.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/CallListAdapter.kt
@@ -19,12 +19,12 @@ class CallListAdapter(private val ctx: Context, private val account: Account,
     private val layoutInflater = LayoutInflater.from(context)
 
     private class ViewHolder(view: View?) {
-        val textAvatarView = view?.findViewById(R.id.TextAvatar) as TextView
-        val imageAvatarView = view?.findViewById(R.id.ImageAvatar) as ImageView
-        val directionsView = view?.findViewById(R.id.directions) as LinearLayout
-        val etcView = view?.findViewById(R.id.etc) as TextView
-        val peerURIView = view?.findViewById(R.id.peer_uri) as TextView
-        val timeView = view?.findViewById(R.id.time) as TextView
+        val textAvatarView: TextView = view?.findViewById(R.id.TextAvatar)!!
+        val imageAvatarView: ImageView = view?.findViewById(R.id.ImageAvatar)!!
+        val directionsView: LinearLayout = view?.findViewById(R.id.directions)!!
+        val etcView: TextView = view?.findViewById(R.id.etc)!!
+        val peerURIView: TextView = view?.findViewById(R.id.peer_uri)!!
+        val timeView: TextView = view?.findViewById(R.id.time)!!
     }
 
     override fun getView(position: Int, view: View?, parent: ViewGroup): View {
diff --git a/app/src/main/kotlin/com/tutpro/baresip/ChatListAdapter.kt b/app/src/main/kotlin/com/tutpro/baresip/ChatListAdapter.kt
index 08e9047f..ad8ca4ea 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/ChatListAdapter.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/ChatListAdapter.kt
@@ -20,12 +20,12 @@ class ChatListAdapter(private val ctx: Context, private val account: Account, pr
     private val layoutInflater = LayoutInflater.from(context)
 
     private class ViewHolder(view: View?) {
-        val textAvatarView = view?.findViewById(R.id.TextAvatar) as TextView
-        val imageAvatarView = view?.findViewById(R.id.ImageAvatar) as ImageView
-        val layoutView = view?.findViewById(R.id.chat) as LinearLayout
-        val peerView = view?.findViewById(R.id.peer) as TextView
-        val infoView = view?.findViewById(R.id.info) as TextView
-        val textView = view?.findViewById(R.id.text) as TextView
+        val textAvatarView: TextView = view?.findViewById(R.id.TextAvatar)!!
+        val imageAvatarView: ImageView = view?.findViewById(R.id.ImageAvatar)!!
+        val layoutView: LinearLayout = view?.findViewById(R.id.chat)!!
+        val peerView: TextView = view?.findViewById(R.id.peer)!!
+        val infoView: TextView = view?.findViewById(R.id.info)!!
+        val textView: TextView = view?.findViewById(R.id.text)!!
     }
 
     override fun getView(position: Int, view: View?, parent: ViewGroup): View {
diff --git a/app/src/main/kotlin/com/tutpro/baresip/CodecsActivity.kt b/app/src/main/kotlin/com/tutpro/baresip/CodecsActivity.kt
index 49cba55d..845e8b9b 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/CodecsActivity.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/CodecsActivity.kt
@@ -91,7 +91,7 @@ class CodecsActivity : AppCompatActivity() {
     }
 
     private val itemTouchHelper by lazy {
-        val simpleItemTouchCallback = object : ItemTouchHelper.SimpleCallback(
+        val simpleItemTouchCallback = object : SimpleCallback(
                 UP or DOWN or START or END, RIGHT) {
 
             override fun onMove(
diff --git a/app/src/main/kotlin/com/tutpro/baresip/ContactListAdapter.kt b/app/src/main/kotlin/com/tutpro/baresip/ContactListAdapter.kt
index 6be6d5c5..3657def3 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/ContactListAdapter.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/ContactListAdapter.kt
@@ -28,10 +28,10 @@ class ContactListAdapter(private val ctx: Context, private val rows: ArrayList<C
     private var lastClick: Long = 0
 
     private class ViewHolder(view: View?) {
-        val textAvatarView = view?.findViewById(R.id.TextAvatar) as TextView
-        val imageAvatarView = view?.findViewById(R.id.ImageAvatar) as ImageView
-        val nameView = view?.findViewById(R.id.contactName) as TextView
-        val actionView = view?.findViewById(R.id.edit) as ImageButton
+        val textAvatarView: TextView = view?.findViewById(R.id.TextAvatar)!!
+        val imageAvatarView: ImageView = view?.findViewById(R.id.ImageAvatar)!!
+        val nameView: TextView = view?.findViewById(R.id.contactName)!!
+        val actionView: ImageButton = view?.findViewById(R.id.edit)!!
     }
 
     override fun getView(position: Int, view: View?, parent: ViewGroup): View {
diff --git a/app/src/main/kotlin/com/tutpro/baresip/MessageListAdapter.kt b/app/src/main/kotlin/com/tutpro/baresip/MessageListAdapter.kt
index ef43070d..ac16183d 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/MessageListAdapter.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/MessageListAdapter.kt
@@ -24,9 +24,9 @@ class MessageListAdapter(private val ctx: Context, private val peerUri: String,
     private val layoutInflater = LayoutInflater.from(context)
 
     private class ViewHolder(view: View?) {
-        val layoutView = view?.findViewById(R.id.message) as LinearLayout
-        val infoView = view?.findViewById(R.id.info) as TextView
-        val textView = view?.findViewById(R.id.text) as TextView
+        val layoutView: LinearLayout = view?.findViewById(R.id.message)!!
+        val infoView: TextView = view?.findViewById(R.id.info)!!
+        val textView: TextView = view?.findViewById(R.id.text)!!
     }
 
     override fun getView(position: Int, view: View?, parent: ViewGroup): View {
diff --git a/app/src/main/kotlin/com/tutpro/baresip/UaSpinnerAdapter.kt b/app/src/main/kotlin/com/tutpro/baresip/UaSpinnerAdapter.kt
index ff69b0b5..3f245d21 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/UaSpinnerAdapter.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/UaSpinnerAdapter.kt
@@ -15,8 +15,8 @@ class UaSpinnerAdapter(cxt: Context, private val uas: ArrayList<UserAgent>) :
     private val layoutInflater = LayoutInflater.from(context)
 
     private class ViewHolder(view: View?) {
-        val textView = view?.findViewById(R.id.spinnerText) as TextView
-        val imageView = view?.findViewById(R.id.spinnerImage) as ImageView
+        val textView: TextView = view?.findViewById(R.id.spinnerText)!!
+        val imageView: ImageView = view?.findViewById(R.id.spinnerImage)!!
     }
 
     override fun getDropDownView(position: Int, view: View?, parent: ViewGroup): View {