i have problem in my coding in button part. On 3-5 Every time I try run my app after it loads the first page and I tap on the button to link it to the second page it crashes , it been driving me...

i have problem in my coding in button part. On 3-5 Every time I try run my app after it loads the first page and I tap on the button to link it to the second page it crashes , it been driving me crazy. can anyone help me with my coding because whenever i click the button my app stuck and open another app. and this is android app studio.

my coding

package net.mobiledevelopment.paintcalculator;


import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import java.text.DecimalFormat;
public class MainActivity extends AppCompatActivity {


double totalFeet,heightFeet,distanceFeet;
double gallons;
String color;


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);


final EditText height = (EditText)findViewById(R.id.txtHeight);
final Spinner colors = (Spinner)findViewById(R.id.spnColors);
final EditText distance = (EditText)findViewById(R.id.txtDistance);


Button btnCompute = (Button)findViewById(R.id.btnCompute);
btnCompute.setOnClickListener(new View.OnClickListener() {




final TextView result = ((TextView)findViewById(R.id.txtResult));


@Override


public void onClick(View v) {


heightFeet = Double.parseDouble(height.getText().toString());
distanceFeet = Double.parseDouble(distance.getText().toString());
totalFeet = heightFeet * distanceFeet;
gallons = totalFeet/250;
DecimalFormat gallon = new DecimalFormat( "## , ##");
color = colors.getSelectedItem().toString();
result.setText("Color: " + color + " in " + gallon.format(gallons) +"gallons");




}
});
}
}