added handler for non-existent products

app/src/main/java/org/foxarmy/barcodescannerforemployees/Requester.kt

@@ -15,7 +15,12 @@ class Requester constructor(var siteName: String, var endpoint: String) {
         val stringRequest = object: StringRequest(
             Method.POST, url, { resp ->
             run {
-                response = resp
+                response =
+                if (resp == "") {
+                    "Not found 404"
+                } else {
+                    resp
+                }
             }
         },
             {

app/src/main/java/org/foxarmy/barcodescannerforemployees/activities/AddAbstractProductActivity.kt

@@ -128,6 +128,12 @@ class AddAbstractProductActivity : AppCompatActivity() {
                     thread {
                         // Я сам в ахуях какой это костыль, пока хз как фиксить, потом придумаю :))
                         while (requester.response == "") { }
+                        if (requester.response == "Not found 404") {
+                            runOnUiThread {
+                                Toast.makeText(this, "Product not found. Please, try again or type manually", Toast.LENGTH_LONG).show()
+                            }
+                            return@thread
+                        }
                         abstractProduct = Parser().parse(requester.response)
                         requester.response = ""
                         runOnUiThread {