adding the DialerActivity

app/src/main/AndroidManifest.xml

@@ -71,6 +71,19 @@
             </intent-filter>
         </activity>
 
+        <activity
+            android:name=".activities.DialerActivity"
+            android:label="@string/dialer"
+            android:theme="@style/Theme.Transparent">
+
+            <intent-filter>
+                <action android:name="android.intent.action.CALL" />
+                <category android:name="android.intent.category.DEFAULT" />
+
+                <data android:scheme="tel" />
+            </intent-filter>
+        </activity>
+
         <activity-alias
             android:name=".activities.SplashActivity.Red"
             android:enabled="false"

app/src/main/kotlin/com/simplemobiletools/dialer/activities/DialerActivity.kt

@@ -0,0 +1,71 @@
+package com.simplemobiletools.dialer.activities
+
+import android.annotation.SuppressLint
+import android.content.Intent
+import android.net.Uri
+import android.os.Bundle
+import android.telecom.TelecomManager
+import android.view.Menu
+import com.simplemobiletools.commons.extensions.isDefaultDialer
+import com.simplemobiletools.commons.extensions.showErrorToast
+import com.simplemobiletools.commons.extensions.telecomManager
+import com.simplemobiletools.commons.extensions.toast
+import com.simplemobiletools.commons.helpers.REQUEST_CODE_SET_DEFAULT_DIALER
+import com.simplemobiletools.dialer.R
+import com.simplemobiletools.dialer.extensions.getHandleToUse
+
+class DialerActivity : SimpleActivity() {
+    private var callNumber: Uri? = null
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        if (intent.action == Intent.ACTION_CALL && intent.data != null) {
+            callNumber = intent.data
+
+            // make sure Simple Contacts is the default Phone app before initiating an outgoing call
+            if (!isDefaultDialer()) {
+                launchSetDefaultDialerIntent()
+            } else {
+                initOutgoingCall()
+            }
+        } else {
+            toast(R.string.unknown_error_occurred)
+            finish()
+        }
+    }
+
+    override fun onCreateOptionsMenu(menu: Menu): Boolean {
+        updateMenuItemColors(menu)
+        return super.onCreateOptionsMenu(menu)
+    }
+
+    @SuppressLint("MissingPermission")
+    private fun initOutgoingCall() {
+        try {
+            getHandleToUse(intent, callNumber.toString()) { handle ->
+                Bundle().apply {
+                    putParcelable(TelecomManager.EXTRA_PHONE_ACCOUNT_HANDLE, handle)
+                    putBoolean(TelecomManager.EXTRA_START_CALL_WITH_VIDEO_STATE, false)
+                    putBoolean(TelecomManager.EXTRA_START_CALL_WITH_SPEAKERPHONE, false)
+                    telecomManager.placeCall(callNumber, this)
+                }
+                finish()
+            }
+        } catch (e: Exception) {
+            showErrorToast(e)
+            finish()
+        }
+    }
+
+    override fun onActivityResult(requestCode: Int, resultCode: Int, resultData: Intent?) {
+        super.onActivityResult(requestCode, resultCode, resultData)
+        if (requestCode == REQUEST_CODE_SET_DEFAULT_DIALER) {
+            if (!isDefaultDialer()) {
+                finish()
+            } else {
+                initOutgoingCall()
+            }
+        }
+    }
+}