MainActivity.java

package com.example.connect3;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import androidx.gridlayout.widget.GridLayout;;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;


public class MainActivity extends AppCompatActivity {

    // 0=yellow, 1=red
    int activePlayer = 0;
    //game is active or not
    boolean gameIsActive=true;

    // 2 means unplayed

    int[] gameState = {2,2,2,2,2,2,2,2,2};
    int [][] winnningPositions={{0,1,2},{3,4,5},{6,7,8},{0,3,6},{1,4,7},{2,5,8},{0,4,8},{2,4,6}};
    public void dropIn(View view)
    {
        ImageView counter = (ImageView) view;
        int tappedCounter = Integer.parseInt(counter.getTag().toString());

        if (gameState[tappedCounter]==2 && gameIsActive)
        {
            gameState[tappedCounter]=activePlayer;
            counter.setTranslationY(-1000f);
            if(activePlayer==0)
            {
                counter.setImageResource(R.drawable.yellow);
                activePlayer=1;
            }
            else
            {
                counter.setImageResource(R.drawable.red);
                activePlayer=0;
            }
            counter.animate().translationYBy(1000f).rotation(360).setDuration(300);
            for (int[] winningPosition: winnningPositions)
            {
                if (gameState[winningPosition[0]]==gameState[winningPosition[1]]&&gameState[winningPosition[1]]==gameState[winningPosition[2]]
                        &&gameState[winningPosition[0]]!=2)
                {
                    //someone has won
                    gameIsActive=false;
                    String winner = "Red";
                    if (gameState[winningPosition[0]]==0)
                    {
                        winner="Yellow";
                    }


                    TextView winnerMessage = (TextView) findViewById(R.id.winnerMessage);
                    winnerMessage.setText(winner + " has won!");
                    LinearLayout layout = (LinearLayout)findViewById(R.id.playAgainLayout);
                    layout.setVisibility(View.VISIBLE);
                }
                else
                {
                    boolean gameIsOver = true;
                    for (int counterState : gameState)
                    {
                        if (counterState == 2)
                        {
                            gameIsOver=false;
                        }
                    }
                    if (gameIsOver)
                    {
                        TextView winnerMessage = (TextView) findViewById(R.id.winnerMessage);
                        winnerMessage.setText("Draw !");
                        LinearLayout layout = (LinearLayout)findViewById(R.id.playAgainLayout);
                        layout.setVisibility(View.VISIBLE);
                    }

                }
            }
        }


    }
    public void playAgain(View view)
    {
        gameIsActive=true;
        LinearLayout layout = (LinearLayout)findViewById(R.id.playAgainLayout);
        layout.setVisibility(View.INVISIBLE);
        activePlayer = 0;

        for ( int i = 0;i<gameState.length;i++)
        {
            gameState[i]=2;

        }
        GridLayout gridLayout = (GridLayout) findViewById(R.id.gridLayout);
        for (int i = 0; i<gridLayout.getChildCount();i++)
        {
            ((ImageView)gridLayout.getChildAt(i)).setImageResource(0);
        }
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}