adding some handling to rejecting calls

app/src/main/kotlin/com/simplemobiletools/contacts/pro/activities/CallActivity.kt

@@ -7,6 +7,7 @@ import android.app.NotificationManager
 import android.app.PendingIntent
 import android.content.Intent
 import android.os.Bundle
+import android.telecom.Call
 import android.widget.RemoteViews
 import androidx.core.app.NotificationCompat
 import com.simplemobiletools.commons.extensions.notificationManager
@@ -15,6 +16,7 @@ import com.simplemobiletools.commons.extensions.updateTextColors
 import com.simplemobiletools.commons.helpers.isOreoPlus
 import com.simplemobiletools.contacts.pro.R
 import com.simplemobiletools.contacts.pro.helpers.ACCEPT_CALL
+import com.simplemobiletools.contacts.pro.helpers.CallManager
 import com.simplemobiletools.contacts.pro.helpers.DECLINE_CALL
 import com.simplemobiletools.contacts.pro.receivers.CallActionReceiver
 import kotlinx.android.synthetic.main.activity_call.*
@@ -33,6 +35,8 @@ class CallActivity : SimpleActivity() {
         updateTextColors(call_holder)
         initButtons()
         showNotification()
+        CallManager.registerCallback(getCallCallback())
+        updateCallState(CallManager.getState())
     }
 
     override fun onDestroy() {
@@ -41,7 +45,10 @@ class CallActivity : SimpleActivity() {
     }
 
     private fun initButtons() {
-        call_decline.setOnClickListener { }
+        call_decline.setOnClickListener {
+            endCall()
+        }
+
         call_accept.setOnClickListener { }
 
         call_toggle_microphone.setOnClickListener {
@@ -68,6 +75,25 @@ class CallActivity : SimpleActivity() {
         call_toggle_microphone.setImageDrawable(getDrawable(drawable))
     }
 
+    private fun updateCallState(state: Int) {
+        when (state) {
+            Call.STATE_DISCONNECTED -> endCall()
+        }
+    }
+
+    private fun endCall() {
+        CallManager.reject()
+        finish()
+    }
+
+    @SuppressLint("NewApi")
+    fun getCallCallback() = object : Call.Callback() {
+        override fun onStateChanged(call: Call, state: Int) {
+            super.onStateChanged(call, state)
+            updateCallState(state)
+        }
+    }
+
     @SuppressLint("NewApi")
     private fun showNotification() {
         val channelId = "simple_contacts_call"

app/src/main/kotlin/com/simplemobiletools/contacts/pro/helpers/CallManager.kt

@@ -0,0 +1,34 @@
+package com.simplemobiletools.contacts.pro.helpers
+
+import android.annotation.SuppressLint
+import android.telecom.Call
+
+// inspired by https://github.com/Chooloo/call_manage
+@SuppressLint("NewApi")
+class CallManager {
+    companion object {
+        var call: Call? = null
+
+        fun reject() {
+            if (call != null) {
+                if (call!!.state == Call.STATE_RINGING) {
+                    call!!.reject(false, null)
+                } else {
+                    call!!.disconnect()
+                }
+            }
+        }
+
+        fun registerCallback(callback: Call.Callback) {
+            if (call != null) {
+                call!!.registerCallback(callback)
+            }
+        }
+
+        fun getState() = if (call == null) {
+            Call.STATE_DISCONNECTED
+        } else {
+            call!!.state
+        }
+    }
+}

app/src/main/kotlin/com/simplemobiletools/contacts/pro/receivers/CallActionReceiver.kt

@@ -3,9 +3,13 @@ package com.simplemobiletools.contacts.pro.receivers
 import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
+import com.simplemobiletools.contacts.pro.helpers.CallManager
+import com.simplemobiletools.contacts.pro.helpers.DECLINE_CALL
 
 class CallActionReceiver : BroadcastReceiver() {
     override fun onReceive(context: Context, intent: Intent) {
-
+        when (intent.action) {
+            DECLINE_CALL -> CallManager.reject()
+        }
     }
 }

app/src/main/kotlin/com/simplemobiletools/contacts/pro/services/CallService.kt

@@ -1,13 +1,25 @@
 package com.simplemobiletools.contacts.pro.services
 
+import android.content.Intent
 import android.os.Build
 import android.telecom.Call
 import android.telecom.InCallService
 import androidx.annotation.RequiresApi
+import com.simplemobiletools.contacts.pro.activities.CallActivity
+import com.simplemobiletools.contacts.pro.helpers.CallManager
 
 @RequiresApi(Build.VERSION_CODES.M)
 class CallService : InCallService() {
     override fun onCallAdded(call: Call) {
         super.onCallAdded(call)
+        val intent = Intent(this, CallActivity::class.java)
+        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+        startActivity(intent)
+        CallManager.call = call
+    }
+
+    override fun onCallRemoved(call: Call) {
+        super.onCallRemoved(call)
+        CallManager.call = null
     }
 }

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

@@ -44,7 +44,8 @@
     <androidx.constraintlayout.widget.ConstraintLayout
         android:id="@+id/ongoing_call_holder"
         android:layout_width="match_parent"
-        android:layout_height="match_parent">
+        android:layout_height="match_parent"
+        android:visibility="gone">
 
         <ImageView
             android:id="@+id/call_toggle_microphone"
@@ -104,8 +105,7 @@
     <androidx.constraintlayout.widget.ConstraintLayout
         android:id="@+id/incoming_call_holder"
         android:layout_width="match_parent"
-        android:layout_height="match_parent"
+        android:layout_height="match_parent">
-        android:visibility="gone">
 
         <ImageView
             android:id="@+id/call_decline"