I am using android studio along with java coding to produce an app that easily splits a restaurant bill for a group of people. My problem is that I am getting a divide by zero error and cannot figure out how to fix it.

 SecondActivity.java import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.RadioButton; import android.widget.TextView; import android.widget.Toast; import java.text.DecimalFormat; public class SecondActivity extends Activity { int billTotals; int groupSize; double percentTotal; double individualTotal; int groupsSize; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_second); final EditText billTotal = (EditText) findViewById(R.id.billTotal); final EditText groupSize = (EditText) findViewById(R.id.groupSize); final RadioButton tenPercent = (RadioButton) findViewById(R.id.txtTenPercent); final RadioButton fifteenPercent = (RadioButton) findViewById(R.id.txtFifteenPercent); final RadioButton eighteenPercent = (RadioButton) findViewById(R.id.txtEighteenPercent); final RadioButton twentyPercent = (RadioButton) findViewById(R.id.txtTwentyPercent); final TextView result = (TextView) findViewById(R.id.txtResult); Button convert = (Button) findViewById(R.id.btnConvert); convert.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { billTotals = (int) Double.parseDouble(billTotal.getText().toString()); groupsSize = (int) Double.parseDouble(groupSize.getText().toString()); DecimalFormat tenth = new DecimalFormat("#.#"); if (tenPercent.isChecked()) { int percentTotal = (int) ((billTotals * .1) + billTotals); individualTotal = percentTotal / groupsSize; result.setText(tenth.format("$ " + individualTotal)); } else { Toast.makeText(SecondActivity.this, "Please Complete Missing Criteria", Toast.LENGTH_LONG).show(); } if (fifteenPercent.isChecked()) { int percentTotal = (int) ((billTotals * .15) + billTotals); individualTotal = percentTotal / groupsSize; result.setText(tenth.format("$ " + individualTotal)); } else { Toast.makeText(SecondActivity.this, "Please Complete Missing Criteria", Toast.LENGTH_LONG).show(); } if (eighteenPercent.isChecked()) { int percentTotal = (int) ((billTotals * .18) + billTotals); individualTotal = percentTotal / groupsSize; result.setText(tenth.format("$ " + individualTotal)); } else { Toast.makeText(SecondActivity.this, "Please Complete Missing Criteria", Toast.LENGTH_LONG).show(); } if (twentyPercent.isChecked()) { int percentTotal = (int) ((billTotals * .2) + billTotals); individualTotal = percentTotal / groupsSize; result.setText(tenth.format("$ " + individualTotal)); } else { Toast.makeText(SecondActivity.this, "Please Complete Missing Criteria", Toast.LENGTH_LONG).show(); } } }); } } 

activity_second.xml

xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout 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"> <TextView  android:id="@+id/txtBill"  android:layout_width="200dp"  android:layout_height="60dp"  android:layout_marginEnd="8dp"  android:layout_marginStart="16dp"  android:layout_marginTop="16dp"  android:text="@string/txtBill"  android:textSize="40sp"  app:layout_constraintEnd_toStartOf="@+id/billTotal"  app:layout_constraintHorizontal_bias="0.23"  app:layout_constraintStart_toStartOf="parent"  app:layout_constraintTop_toTopOf="parent" /> <TextView  android:id="@+id/txtGroupSize"  android:layout_width="200dp"  android:layout_height="60dp"  android:layout_marginEnd="8dp"  android:layout_marginStart="16dp"  android:layout_marginTop="16dp"  android:text="@string/txtGroupSize"  android:textSize="40sp"  app:layout_constraintEnd_toStartOf="@+id/groupSize"  app:layout_constraintHorizontal_bias="0.229"  app:layout_constraintStart_toStartOf="parent"  app:layout_constraintTop_toBottomOf="@+id/txtBill" /> <EditText  android:id="@+id/billTotal"  android:layout_width="209dp"  android:layout_height="wrap_content"  android:layout_marginEnd="40dp"  android:layout_marginTop="16dp"  android:ems="10"  android:hint="@string/hint"  android:inputType="numberDecimal"  android:textSize="30sp"  app:layout_constraintEnd_toEndOf="parent"  app:layout_constraintTop_toTopOf="parent" /> <EditText  android:id="@+id/groupSize"  android:layout_width="209dp"  android:layout_height="wrap_content"  android:layout_marginEnd="40dp"  android:layout_marginTop="16dp"  android:ems="10"  android:hint="@string/hint"  android:inputType="number"  android:textSize="30sp"  app:layout_constraintEnd_toEndOf="parent"  app:layout_constraintTop_toBottomOf="@+id/billTotal" /> <Spinner  android:id="@+id/txtQuality"  android:layout_width="519dp"  android:layout_height="75dp"  android:layout_marginEnd="8dp"  android:layout_marginStart="8dp"  android:layout_marginTop="28dp"  android:entries="@array/txtQuality"  android:textSize="30sp"  app:layout_constraintEnd_toEndOf="parent"  app:layout_constraintHorizontal_bias="0.507"  app:layout_constraintStart_toStartOf="parent"  app:layout_constraintTop_toBottomOf="@+id/groupSize" /> <RadioGroup  android:id="@+id/txtTipPercent"  android:layout_width="114dp"  android:layout_height="211dp"  android:layout_marginEnd="8dp"  android:layout_marginStart="8dp"  android:layout_marginTop="25dp"  app:layout_constraintEnd_toEndOf="parent"  app:layout_constraintStart_toStartOf="parent"  app:layout_constraintTop_toBottomOf="@+id/txtQuality"> <RadioButton  android:id="@+id/txtTenPercent"  android:layout_width="100dp"  android:layout_height="wrap_content"  android:layout_weight="1"  android:text="@string/tenPercent"  android:textSize="25sp" /> <RadioButton  android:id="@+id/txtFifteenPercent"  android:layout_width="100dp"  android:layout_height="wrap_content"  android:layout_weight="1"  android:text="@string/fifteenPercent"  android:textSize="25sp" /> <RadioButton  android:id="@+id/txtEighteenPercent"  android:layout_width="100dp"  android:layout_height="wrap_content"  android:layout_weight="1"  android:text="@string/eighteenPercent"  android:textSize="25sp" /> <RadioButton  android:id="@+id/txtTwentyPercent"  android:layout_width="100dp"  android:layout_height="wrap_content"  android:layout_weight="1"  android:text="@string/twentyPercent"  android:textSize="25sp" /> RadioGroup> <TextView  android:id="@+id/txtResult"  android:layout_width="317dp"  android:layout_height="85dp"  android:layout_marginEnd="8dp"  android:layout_marginStart="8dp"  android:layout_marginTop="25dp"  android:textSize="30sp"  app:layout_constraintEnd_toEndOf="parent"  app:layout_constraintHorizontal_bias="0.501"  app:layout_constraintStart_toStartOf="parent"  app:layout_constraintTop_toBottomOf="@+id/btnConvert" /> <Button  android:id="@+id/btnConvert"  android:layout_width="276dp"  android:layout_height="50dp"  android:layout_marginEnd="8dp"  android:layout_marginStart="8dp"  android:layout_marginTop="8dp"  android:text="@string/btnConvert"  android:textSize="25sp"  app:layout_constraintEnd_toEndOf="parent"  app:layout_constraintStart_toStartOf="parent"  app:layout_constraintTop_toBottomOf="@+id/txtTipPercent" /> android.support.constraint.ConstraintLayout>