Timer is stopped after answering

app/src/main/java/com/example/quickmax/MainActivity.kt

@@ -17,23 +17,7 @@ class MainActivity : AppCompatActivity() {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
         addRadioButtons()
-        setTimer()
-    }
-
-    private fun setTimer() {
-        object : CountDownTimer(4000, 1000) {
-            override fun onTick(millisUntilFinished: Long) {
-                tv_time_left.text = (millisUntilFinished / 1000).toString()
-            }
-
-            override fun onFinish() {
-                makeRadioButtonsUncheckable()
-                supportFragmentManager
-                    .beginTransaction()
-                    .add(R.id.main_layout, TimeIsOverFragment.newInstance(), "time_is_over")
-                    .commitAllowingStateLoss()
-            }
-        }.start()
+        timer.start()
     }
 
     private fun addRadioButtons() {
@@ -47,6 +31,9 @@ class MainActivity : AppCompatActivity() {
     }
 
     private fun processAnswer(answer: Int) {
+        timer.cancel()
+        makeRadioButtonsUncheckable()
+
         val responseFragment: Fragment = if (numberSet.isCorrect(answer)) {
             ResponseCorrectFragment.newInstance()
         } else
@@ -56,7 +43,6 @@ class MainActivity : AppCompatActivity() {
             .beginTransaction()
             .add(R.id.main_layout, responseFragment, "response")
             .commitAllowingStateLoss()
-        makeRadioButtonsUncheckable()
     }
 
     private fun makeRadioButtonsUncheckable() {
@@ -64,4 +50,18 @@ class MainActivity : AppCompatActivity() {
             radio_group[i].isClickable = false
         }
     }
+
+    private val timer = object : CountDownTimer(4000, 1000) {
+        override fun onTick(millisUntilFinished: Long) {
+            tv_time_left.text = (millisUntilFinished / 1000).toString()
+        }
+
+        override fun onFinish() {
+            makeRadioButtonsUncheckable()
+            supportFragmentManager
+                .beginTransaction()
+                .add(R.id.main_layout, TimeIsOverFragment.newInstance(), "time_is_over")
+                .commitAllowingStateLoss()
+        }
+    }
 }

app/src/main/java/com/example/quickmax/ResponseCorrectFragment.kt

@@ -4,6 +4,7 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import android.widget.ImageButton
 import androidx.fragment.app.Fragment
 
 class ResponseCorrectFragment: Fragment() {
@@ -17,6 +18,14 @@ class ResponseCorrectFragment: Fragment() {
     override fun onCreateView(inflater: LayoutInflater,
                               container: ViewGroup?,
                               savedInstanceState: Bundle?): View? {
-        return inflater.inflate(R.layout.fragment_response_correct, container, false)
+        val view = inflater.inflate(R.layout.fragment_response_correct, container, false)
+        view.findViewById<ImageButton>(R.id.btn_next).setOnClickListener { reloadActivity() }
+        return view
+    }
+
+    private fun reloadActivity() {
+        val intent = activity?.intent
+        activity?.finish()
+        activity?.startActivity(intent)
     }
 }
\ No newline at end of file

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

@@ -7,11 +7,10 @@
     app:layout_constraintStart_toStartOf="parent"
     android:background="#4CAF50"
     xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
-    xmlns:tools="http://schemas.android.com/tools">
+    xmlns:app="http://schemas.android.com/apk/res-auto">
 
     <ImageButton
-        android:id="@+id/imageButton"
+        android:id="@+id/btn_next"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginTop="8dp"

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

@@ -10,6 +10,7 @@
     app:layout_constraintStart_toStartOf="parent">
 
     <ImageButton
+        android:id="@+id/btn_next"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginTop="8dp"