Assume the existence of the following Java GUI application. There are two text f

Question

Assume the existence of the following Java GUI application. There are two text fields for user input. The first JTextField variable is named voltage and is used to input a voltage value in volts. The second JTextField variable named resistance is used to input a resistance value in ohms. All input values and calculations use floating point values. The user clicks a JButton to perform a calculation. One JButton called current causes the program to calculate and display the current flowing through the resistor, I = V / R. Another JButton called power causes the program to calculate the power being dissipated by the resistor, P = V * V / R. The result of the selected calculation is displayed in an output text area variable named output. The output string should say something like this:

Explanation / Answer

GUITest.java

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextArea;
import javax.swing.JTextField;


public class GUITest {

/**
* @param args
*/
JFrame frame;
JLabel voltageLabel;
JLabel resistanceLabel;
JTextField volatge;
JTextField resistance;
JButton currentButton;
JButton powerButton;
JTextArea output;
public GUITest() {
frame = new JFrame("Current / Power Calculator");
voltageLabel = new JLabel("Voltage:");
resistanceLabel = new JLabel("Resistance:");
volatge = new JTextField(10);
resistance = new JTextField(10);
currentButton = new JButton("Calculate Current");
powerButton = new JButton("Calculate Power");
output = new JTextArea(5, 40);

frame.setLayout(new FlowLayout(FlowLayout.CENTER));
frame.add(voltageLabel);
frame.add(volatge);
frame.add(resistanceLabel);
frame.add(resistance);
frame.add(currentButton);
frame.add(powerButton);
frame.add(output);
frame.setSize(400, 200);
frame.setVisible(true);

currentButton.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
double v = Double.parseDouble(volatge.getText());
double r = Double.parseDouble(resistance.getText());
output.setText(v + " volts dropped across " + r + " ohms creates current of " + v/r + " amps");
}
});
powerButton.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
double v = Double.parseDouble(volatge.getText());
double r = Double.parseDouble(resistance.getText());
output.setText(v + " volts dropped across " + r + " ohms creates power of " + (v*v)/r + " watts");
}
});

}
public static void main(String[] args) {
// TODO Auto-generated method stub
new GUITest();
}

}

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