fix Random().nextInt() error + add Game Draw

Android/TicTacToy Game/TicTacToyLocal/StartUp/app/src/main/java/com/hussein/startup/MainActivity.kt

@@ -1,3 +1,8 @@
+/*
+Notes: add the game reset and game draw, also fix the draw error when list.size <= 0 and java error (game crash) in Random().nextInt(n)
+when n <= 0 :0 that happens in the minute 5:10 on class 75.
+*/
+
 package com.hussein.startup
 
 import android.graphics.Color
@@ -15,8 +20,7 @@ class MainActivity : AppCompatActivity() {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
     }
-
-
+
     protected  fun buClick(view:View){
         val buSelected= view as Button
         var cellID=0
@@ -30,19 +34,16 @@ class MainActivity : AppCompatActivity() {
             R.id.bu7-> cellID=7
             R.id.bu8-> cellID=8
             R.id.bu9-> cellID=9
-
         }
        // Toast.makeText(this,"ID:"+ cellID, Toast.LENGTH_LONG).show()
-
         PlayGame(cellID,buSelected)
     }
-
+    
     var player1=ArrayList<Int>()
     var player2=ArrayList<Int>()
     var ActivePlayer=1
-
+    
     fun PlayGame(cellID:Int,buSelected:Button){
-
         if(ActivePlayer==1){
             buSelected.text="X"
             buSelected.setBackgroundResource(R.color.blue)
@@ -55,17 +56,12 @@ class MainActivity : AppCompatActivity() {
             player2.add(cellID)
             ActivePlayer=1
         }
-
-
         buSelected.isEnabled=false
         CheckWiner()
     }
-
-
-
+
     fun  CheckWiner(){
         var winer=-1
-
         // row 1
         if(player1.contains(1) && player1.contains(2) && player1.contains(3)){
             winer=1
@@ -74,104 +70,93 @@ class MainActivity : AppCompatActivity() {
             winer=2
         }
 
-
         // row 2
         if(player1.contains(4) && player1.contains(5) && player1.contains(6)){
             winer=1
         }
         if(player2.contains(4) && player2.contains(5) && player2.contains(6)){
             winer=2
         }
-
-
-
-
         // row 3
         if(player1.contains(7) && player1.contains(8) && player1.contains(9)){
             winer=1
         }
         if(player2.contains(7) && player2.contains(8) && player2.contains(9)){
             winer=2
         }
-
-
-
         // col 1
         if(player1.contains(1) && player1.contains(4) && player1.contains(7)){
             winer=1
         }
         if(player2.contains(1) && player2.contains(4) && player2.contains(7)){
             winer=2
         }
-
-
-
         // col 2
         if(player1.contains(2) && player1.contains(5) && player1.contains(8)){
             winer=1
         }
         if(player2.contains(2) && player2.contains(5) && player2.contains(8)){
             winer=2
         }
-
-
         // col 3
         if(player1.contains(3) && player1.contains(6) && player1.contains(9)){
             winer=1
         }
         if(player2.contains(3) && player2.contains(6) && player2.contains(9)){
             winer=2
         }
-
-
         if( winer != -1){
-
             if (winer==1){
                 Toast.makeText(this," Player 1  win the game", Toast.LENGTH_LONG).show()
+                GameReset()
             }else{
                 Toast.makeText(this," Player 2  win the game", Toast.LENGTH_LONG).show()
-
+                GameReset()
             }
-
         }
-
     }
-
-
+
     fun AutoPlay(){
-
         var emptyCells=ArrayList<Int>()
         for ( cellID in 1..9){
 
             if(!( player1.contains(cellID) || player2.contains(cellID))) {
                 emptyCells.add(cellID)
             }
         }
-
-
         val r=Random()
-        val randIndex=r.nextInt(emptyCells.size-0)+0
-        val cellID= emptyCells[randIndex]
-
-        var buSelect:Button?
-        when(cellID){
-            1-> buSelect=bu1
-            2-> buSelect=bu2
-            3-> buSelect=bu3
-            4-> buSelect=bu4
-            5-> buSelect=bu5
-            6-> buSelect=bu6
-            7-> buSelect=bu7
-            8-> buSelect=bu8
-            9-> buSelect=bu9
-            else->{
-                buSelect=bu1
+        //add this if to prevent game crash when the games draw
+        //also prevent java erro in next in when n <= 0 :0
+        if(emptyCells.size > 0){
+            val randIndex=r.nextInt(emptyCells.size-0)+0
+            val cellID= emptyCells[randIndex]
+            var buSelect:Button?
+            when(cellID){
+                1-> buSelect=bu1
+                2-> buSelect=bu2
+                3-> buSelect=bu3
+                4-> buSelect=bu4
+                5-> buSelect=bu5
+                6-> buSelect=bu6
+                7-> buSelect=bu7
+                8-> buSelect=bu8
+                9-> buSelect=bu9
+                else->{
+                    buSelect=bu1
+                }
             }
+            PlayGame(cellID,buSelect)
+        }else {
+            //This is a game draw
+            Toast.makeText(this," Game Draw!", Toast.LENGTH_LONG).show()
+            GameReset()
         }
-
-        PlayGame(cellID,buSelect)
-
     }
-
-
+
+    fun GameReset(){
+        var emptyList=ArrayList<Int>()
+        this.player1=emptyList
+        this.player2=emptyList
+        this.ActivePlayer=1
+    }
 }