Progress bar works as a timer

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

 package com.example.quickmax
 
+import android.os.Build
 import android.os.Bundle
 import android.os.CountDownTimer
 import android.widget.TextView
@@ -10,6 +11,7 @@ import kotlinx.android.synthetic.main.activity_main.*
 class MainActivity : AppCompatActivity() {
 
     private lateinit var answerSet: AnswerSet
+    private val timeToSolve = 4000
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -52,9 +54,13 @@ class MainActivity : AppCompatActivity() {
         startActivity(intent)
     }
 
-    private val timer = object : CountDownTimer(4000, 1000) {
+    private val timer = object : CountDownTimer(timeToSolve.toLong(), 100) {
         override fun onTick(millisUntilFinished: Long) {
-//            tv_time_left.text = (millisUntilFinished / 1000).toString()
+            val progress = ((timeToSolve - millisUntilFinished).toFloat() / timeToSolve) * 100
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
+                bar_time_left.setProgress(progress.toInt(), true)
+            else
+                bar_time_left.progress = progress.toInt()
         }
 
         override fun onFinish() {

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

@@ -25,14 +25,13 @@
             app:layout_constraintTop_toTopOf="parent">
 
             <ProgressBar
+                android:id="@+id/bar_time_left"
                 style="?android:attr/progressBarStyleHorizontal"
                 android:layout_width="match_parent"
                 android:layout_height="32dp"
                 android:layout_gravity="center"
-                android:indeterminate="true"
-                android:indeterminateTint="#FFFFFF"
-                android:progressTint="#FF9800"
-                android:progressTintMode="src_atop" />
+                android:max="100"
+                android:indeterminate="false" />
 
         </FrameLayout>