Android Development for Beginners : Court Counter - Setting up the Methods

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.android.courtcounter.MainActivity">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Team A"
        android:gravity="center_horizontal"
        android:padding="8dp"
        />
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="0"
        android:gravity="center_horizontal"
        android:padding="8dp"
        android:id="@+id/team_a_score"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="+3 points"
        android:layout_margin="8dp"
        android:onClick="threePoints"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="+2 points"
        android:layout_margin="8dp"
        android:onClick="twoPoints"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="free throw"
        android:layout_margin="8dp"
        android:onClick="freeThrow"/>

</LinearLayout>

MainActivity.java

package com.example.android.courtcounter;

/**
 * IMPORTANT: Make sure you are using the correct package name.
 * This example uses the package name:
 * package com.example.android.courtcounter
 * If you get an error when copying this code into Android studio, update it to match teh package name found
 * in the project's AndroidManifest.xml file.
 **/

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;


public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        displayForTeamA(8);
    }
   /**
   * Increase the score for Team A by 3 point.
   */
    public void threePoints (View view){
        displayForTeamA(3);
    }
   /**
   * Increase the score for Team A by 2 point.
   */
    public void twoPoints (View view){
        displayForTeamA(2);
    }
   /**
   * Increase the score for Team A by 1 point.
   */
    public void freeThrow (View view){
        displayForTeamA(1);
    }

   /**
   * Displays the given score for Team A.
   */
    public void displayForTeamA(int score) {
        TextView scoreView = (TextView) findViewById(R.id.team_a_score);
        scoreView.setText(String.valueOf(score));
    }
   
}