diff --git a/app/src/main/kotlin/com/simplemobiletools/smsmessenger/extensions/Context.kt b/app/src/main/kotlin/com/simplemobiletools/smsmessenger/extensions/Context.kt
index 5b4609f3..18bc4878 100644
--- a/app/src/main/kotlin/com/simplemobiletools/smsmessenger/extensions/Context.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/smsmessenger/extensions/Context.kt
@@ -34,10 +34,10 @@ import com.simplemobiletools.smsmessenger.interfaces.MessagesDao
 import com.simplemobiletools.smsmessenger.models.*
 import com.simplemobiletools.smsmessenger.receivers.DirectReplyReceiver
 import com.simplemobiletools.smsmessenger.receivers.MarkAsReadReceiver
+import me.leolin.shortcutbadger.ShortcutBadger
 import java.io.FileNotFoundException
 import java.util.*
 import kotlin.collections.ArrayList
-import me.leolin.shortcutbadger.ShortcutBadger
 
 val Context.config: Config get() = Config.newInstance(applicationContext)
 
@@ -894,13 +894,13 @@ fun Context.getFileSizeFromUri(uri: Uri): Long {
     }
 }
 
-fun Context.dialNumber(phoneNumber: String, callback: () -> Unit = fun() {}) {
+fun Context.dialNumber(phoneNumber: String, callback: (() -> Unit)? = null) {
     Intent(Intent.ACTION_DIAL).apply {
         data = Uri.fromParts("tel", phoneNumber, null)
 
         try {
             startActivity(this)
-            callback()
+            callback?.invoke()
         } catch (e: ActivityNotFoundException) {
             toast(R.string.no_app_found)
         } catch (e: Exception) {