我正在开发一个项目，根据通话时间和通话时间来计算通话价格。一切都有效，除了计算按钮。我不确定如何制作它，所以单击“计算”按钮时，它会查找选择了哪个单选按钮并执行相应的等式。我尝试过使用循环，但它无法正常工作。
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class RateChargeGUI extends JFrame
{
private JPanel panel;
private JLabel messageLabel; //message to the user
private JTextField timeTextField; //user inputs time of call in minutes
private JPanel Buttons;
private JRadioButton DayTimeButton; //declares a new radio button called DayTimeButton
private JRadioButton EveningButton; //declares a new radio button called EveningButton
private JRadioButton Off_PeakButton; //declares a new radio button called Off_PeakButton
private ButtonGroup radioButtonGroup; //places the buttons in a group
private JButton exitButton;
private JButton calcButton;
private final int WINDOW_WIDTH = 300; //window width
private final int WINDOW_HEIGHT = 300; //window height
/**
Constructor
*/
public RateChargeGUI ()
{
//sets the text for the title bar
setTitle("Call Prices");
//sets the size of the window
setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//build a panel that will be added to the frame
buildPanel();
buildButtons();
//add the panel to the frame
add(panel);
add(Buttons, BorderLayout.SOUTH);
//display the window
setVisible(true);
}
//The buildPanel method adds a label, text field, and the buttons to the panel.
private void buildPanel()
{
messageLabel = new JLabel(" Enter Number of minutes "); //label left of the text box telling the user what to do.
timeTextField = new JTextField(10); //text field that accepts the duration of the call
DayTimeButton = new JRadioButton("Day Time"); // radio buttons for the time of day that the call is made
EveningButton = new JRadioButton("Evening");
Off_PeakButton = new JRadioButton("Off_Peak");
//add and group the radio buttons
radioButtonGroup = new ButtonGroup();
radioButtonGroup.add(DayTimeButton);
radioButtonGroup.add(EveningButton);
radioButtonGroup.add(Off_PeakButton);
//action listeners for the radio buttons that make it possible to select one of them
//DayTimeButton.addActionListener(new RadioButtonListener ());
//EveningButton.addActionListener(new RadioButtonListener ());
//Off_PeakButton.addActionListener(new RadioButtonListener ());
//create a panel and add the components to it. such as the label telling the user to enter the number of minutes
//or the radio buttons
panel = new JPanel();
panel.add(messageLabel);
panel.add(timeTextField);
panel.add(DayTimeButton);
panel.add(EveningButton);
panel.add(Off_PeakButton);
Buttons = new JPanel();
add(Buttons, BorderLayout.SOUTH);
}
private void buildButtons()
{
exitButton = new JButton("Exit");
calcButton = new JButton("Calculate");
exitButton.addActionListener(new ExitButtonListener ());
calcButton.addActionListener(new CalcButtonListener ());
Buttons.add(calcButton);
Buttons.add(exitButton);
}
/**
Private inner class that handles the event when the user clicks one of the radio buttons.
*/
private class CalcButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String input; //holds user input
double result = 0.0; //holds the conversion
input = timeTextField.getText(); //enables the text field to accept text
//Determine which radio button was selected and perform a mathmatical equation based on which button was selected.
//6AM-6PM
if (e.getSource() == DayTimeButton)
{
result = Double.parseDouble(input) * 0.20;
}
//6PM-12AM
else if (e.getSource() == EveningButton)
{
result = Double.parseDouble(input) * 0.12;
}
//12AM-6AM
else if (e.getSource() == Off_PeakButton)
{
result = Double.parseDouble(input) * 0.04;
}
if (DaytimeButton.is
//display the ammount that it will cost
JOptionPane.showMessageDialog(null, " The call price is: $ " + result);
}
}
private class ExitButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
}
//calls the ratechargegui class. The RateChargeGUI class was build above and is now being called.
public static void main(String[] args)// stringargs[] allows the program to accept arguments.
{
new RateChargeGUI();
}
}
答案 0 :(得分：1)
我的代码中没有看到任何与一天中的小时数相关的按钮的addActionListener（）方法。如果您希望事件处理程序工作，则每个单选按钮都必须附加一个actionListener。所以，你可以在某处做到这一点：
DayTimeButton.addActionListener(CalcButtonListener);
EveningButton.addActionListener(CalcButtonListener);
Off_PeakButton.addActionListener(CalcButtonListener);
此外，在Java中，变量名称必须是camelCase。类/接口名称可以以大写字母开头，但不能以变量开头。
如果您不需要处理单击其中一个单选按钮时发生的事件，但只需要单选按钮的状态，请尝试使用方法isSelected（）。你在actionPerformed中的测试看起来像这样：
if (DaytimeButton.isSelected()) {
// do stuff for this button
}
else if (EveningButton.isSelected()) {
// do stuff for this button
}
答案 1 :(得分：1)
如果仅将此侦听器应用于calcButton，它始终将成为事件源。执行操作时，您必须检查选择了哪个单选按钮。
private class CalcButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
String input; //holds user input
double result = 0.0; //holds the conversion
input = timeTextField.getText(); //enables the text field to accept text
// Determine which radio button was selected and perform a mathmatical equation based on which button was selected.
//6AM-6PM
if (DayTimeButton.isSelected()) {
result = Double.parseDouble(input) * 0.20;
}
//6PM-12AM
else if (EveningButton.isSelected()) {
result = Double.parseDouble(input) * 0.12;
}
//12AM-6AM
else if (Off_PeakButton.isSelected()) {
result = Double.parseDouble(input) * 0.04;
}
//display the ammount that it will cost
JOptionPane.showMessageDialog(null, " The call price is: $ " + result);
}
}
答案 2 :(得分：1)
你不需要为此设置循环。正如其他人指示的那样，你可以使用
ArrayList<User> users; // already contains info
private String userName;
private String pass;
private EditText userText;
private EditText passText;
private String inputUser;
private String inputPass;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
users = new ArrayList<>();
for(User user: users){
userName = user.getName();
pass = user.getPassword()'
}
// EditText where user enters the username
userText = (EditText) findViewById(R.id.username);
// EditText where user enters the password
passText = (EditText) findViewById(R.id.password);
}
public void login(View view){
inputPass = passText.getText().toString(); //password string
inputUser = userText.getText().toString(); //username string
if (inputPass.equals(pass) && (inputUser.equals(userName))) {
Toast toast = Toast.makeText(getApplicationContext(), "Login Successful!", Toast.LENGTH_LONG);
toast.show();
intent = new Intent(MainActivity.this, EnteredPage.class);
startActivity(intent);
break;
}
if (i == users.size() - 1) { //if this is the last User object
Toast toast = Toast.makeText(getApplicationContext(), "User does not exist!", Toast.LENGTH_LONG);
toast.show();
}
}
}
方法。
注意 但请注意这些。