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私の小さな変換プログラムは、私が修正して助けを必要とすることはできませんいくつかの問題があります。私は、テキストフィールドがするまでsetEditable（偽）になりたいのJava JMenuにし、JTextFieldのない文字列
- をユーザーは通貨を選択しました。ユーザーが通貨を選択するまでテキストフィールドに何も入力できないようにする
- ユーザーがjtextfieldにnumber以外を入力した場合、resultLabelはエラーメッセージを表示する必要があります。
私は最初の部分で試してみましたが、テキストフィールド全体を編集できないようにしました。
/*
*
* Currency Converter Window
* A currency converting program that accepts user defined amount
* and converts that amount in one of four currencies.
*
* Date
* @author
*
*/
import javax.swing.*;
import java.awt.event.*;
import java.awt.GridLayout;
public class CurrencyConverterWin extends JFrame
{
//three panels for the GUI
private JPanel inputPanel;
private JPanel resultPanel;
private JPanel menuPanel;
//labels that identify the fields
private JLabel promptLabel;
private JLabel resultLabel;
private JLabel selectLabel;
//menu for the list of currencies
private JMenu currencyMenu;
private JMenuBar currencyMenuBar;
//input field for user to enter currency
private JTextField inputField;
private JButton goButton;
//initial values for each currency to 1 sterling
private double euros = 1.22;
private double japaneseYen = 152.07;
private double russianRubles = 42.53;
private double usDollars = 1.55;
public CurrencyConverterWin() //constructor
{
super();
this.setSize(600, 150); //set size of the window
this.setLayout(new GridLayout(3, 1)); //split the grid with panels
this.setTitle("Currency Converter Window"); //set window title
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //close window
this.selectLabel = new JLabel("Select a currency to convert to: ", JLabel.RIGHT);
this.resultLabel = new JLabel(" ", JLabel.CENTER);
this.currencyMenu = new JMenu("(no currency selected)"); //create a menu of currencies
JMenuItem Euros = new JMenuItem("Euros"); //store the string Euros as a menu item
Euros.addActionListener(new java.awt.event.ActionListener() //add a listener to this item
{
public void actionPerformed(java.awt.event.ActionEvent evt) //listen for event
{
menuChanged(evt);
}
});
this.currencyMenu.add(Euros);
JMenuItem JapaneseYen = new JMenuItem("Japanese Yen"); //store the string Japanese Yen as a menu item
JapaneseYen.addActionListener(new java.awt.event.ActionListener() //add a listener to this item
{
public void actionPerformed(java.awt.event.ActionEvent evt)
{
menuChanged(evt);
}
});
this.currencyMenu.add(JapaneseYen);
JMenuItem RusRubbles = new JMenuItem("Russian Rubles"); //store the string russian rubles as a menu item
RusRubbles.addActionListener(new java.awt.event.ActionListener() //add a listener to this item
{
public void actionPerformed(java.awt.event.ActionEvent evt)
{
menuChanged(evt);
}
});
this.currencyMenu.add(RusRubbles);
JMenuItem USD = new JMenuItem("US Dollars"); //store the string US Dollars as a menu item
USD.addActionListener(new java.awt.event.ActionListener() //add a listener to this item
{
public void actionPerformed(java.awt.event.ActionEvent evt)
{
menuChanged(evt);
}
});
this.currencyMenu.add(USD);
currencyMenuBar = new JMenuBar(); //initialise a new menubar and add it to the currency menu
currencyMenuBar.add(currencyMenu);
this.menuPanel = new JPanel();
this.menuPanel.add(this.selectLabel);
this.menuPanel.add(this.currencyMenuBar);
this.add(this.menuPanel);
this.promptLabel = new JLabel("(select a currency first) ", JLabel.RIGHT);
this.resultLabel = new JLabel(" ", JLabel.CENTER);
this.inputField = new JTextField("", 8);
//this.amountField.setEditable(false); //need help with this part
this.goButton = new JButton("GO");
goButton.addActionListener(new java.awt.event.ActionListener()
{
public void actionPerformed(java.awt.event.ActionEvent evt)
{
buttonClicked(evt);
}
});
this.inputPanel = new JPanel();
this.inputPanel.add(this.promptLabel);
this.inputPanel.add(this.inputField);
this.inputPanel.add(this.goButton);
this.add(this.inputPanel);
this.resultPanel = new JPanel();
this.resultPanel.add(this.resultLabel);
this.add(this.resultPanel);
}
/*
* change the state of the menu bar depending on the selected currency
*/
public void menuChanged(ActionEvent e)
{
if (e.getActionCommand().equals("Euros"))
{
currencyMenu.setText("Euros");
}
if (e.getActionCommand().equals("Japanese Yen")) {
currencyMenu.setText("Japanese Yen");
}
if (e.getActionCommand().equals("Russian Rubles")) {
currencyMenu.setText("Russian Rubles");
}
if (e.getActionCommand().equals("US Dollars")) {
currencyMenu.setText("US Dollars");
}
}
/*
* Events listeners for goButton
* when the goButton is clicked it should return the user's initial value
* plus the converted amount and some predefined strings.
*/
public void buttonClicked(ActionEvent evt)
{
if(currencyMenu.getText().equals("Euros"))
{
resultLabel.setText(inputField.getText() + " in sterling is " + EurosToSterling() + " Euros.");
}
if(currencyMenu.getText().equals("Japanese Yen"))
{
resultLabel.setText(inputField.getText() + " in sterling is " + JapaneseYenToSterling() + " Japanese Yen.");
}
if(currencyMenu.getText().equals("Russian Rubles"))
{
resultLabel.setText(inputField.getText() + " in sterling is " + RussianRublesToSterling() + " Russian Rubles.");
}
if(currencyMenu.getText().equals("US Dollars"))
{
resultLabel.setText(inputField.getText() + " in sterling is " + USDollarsToSterling() + " US Dollars.");
}
}
/*
* Functions for converting currencies
* get the user entry from inputField, convert it to a
* double and multiply it by the rate of a particular
* currency to a sterling.
*/
//calculate the rate for euros
double EurosToSterling()
{
double calcTotal = Double.parseDouble(inputField.getText()) * euros;
return calcTotal;
}
//calculate the conversion rate for japanese yen
double JapaneseYenToSterling()
{
double calcTotal = Double.parseDouble(inputField.getText()) * japaneseYen;
return calcTotal;
}
//calculate the rate for russian rubles
double RussianRublesToSterling()
{
double calcTotal = Double.parseDouble(inputField.getText()) * russianRubles;
return calcTotal;
}
//calculate the rate for us dollars
double USDollarsToSterling()
{
double calcTotal = Double.parseDouble(inputField.getText()) * usDollars;
return calcTotal;
}
/*
* main method to initialise CurrencyConverterWin
*/
public static void main(String[] args)
{
CurrencyConverterWin CurConWin = new CurrencyConverterWin();
CurConWin.setVisible(true);
}
}