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[英]How do I use a directory path variable from an Action Listener from one class in another?
[英]How do I get information of the variables from one class to another Action Listener class?
這是我對兩個文件類的代碼。 為了使變量在動作偵聽器JFrame中傳輸和打印,我必須添加/修復什么? 在類型“下一步”中找到錯誤“沒有名為“(我在主類的操作偵聽器中使用的變量)的字段”
import java.awt.*; //for Dimension
import javax.swing.*; //for GUI components
public class MortgageCalculator
{
public static void main (String[] args)
{
JFrame frame = new JFrame ();
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.setSize (new Dimension (300, 250));
frame.setTitle ("Mortgage Calculator");
frame.getContentPane ().setLayout (new BorderLayout ());
frame.getContentPane ().add (new JLabel (" Personal Information"), BorderLayout.NORTH);
JPanel centerPanel = new JPanel (new GridLayout (15, 1));
centerPanel.add (new JLabel ("Full Name:"));
JTextField nameField = new JTextField ();
centerPanel.add (nameField);
centerPanel.add (new JLabel ("Your Age:"));
JTextField ageField = new JTextField ();
centerPanel.add (ageField);
centerPanel.add (new JLabel ("Yearly Income:"));
JTextField incomeField = new JTextField ();
centerPanel.add (incomeField);
centerPanel.add (new JLabel ());
centerPanel.add (new JLabel (" Mortgage Information"));
centerPanel.add (new JLabel ("Price of Property:"));
JTextField priceField = new JTextField ();
centerPanel.add (priceField);
centerPanel.add (new JLabel ("Down Payment:"));
JTextField downPayField = new JTextField ();
centerPanel.add (downPayField);
centerPanel.add (new JLabel ("Interest Rate:"));
JTextField interestRateField = new JTextField ();
centerPanel.add (interestRateField);
centerPanel.add (new JLabel ("Amortization Period (Years):"));
frame.getContentPane ().add (centerPanel, BorderLayout.CENTER);
JPanel southPanel = new JPanel (new GridLayout (5, 2));
JButton amort20 = new JButton ("20");
southPanel.add (amort20);
JButton amort25 = new JButton ("25");
southPanel.add (amort25);
JButton amort30 = new JButton ("30");
southPanel.add (amort30);
southPanel.add (new JLabel ("Payment Option:"));
southPanel.add (new JLabel ());
southPanel.add (new JLabel ());
JButton paymentWeek = new JButton ("Weekly");
southPanel.add (paymentWeek);
JButton paymentBiweek = new JButton ("Biweekly");
southPanel.add (paymentBiweek);
JButton paymentMonth = new JButton ("Monthly");
southPanel.add (paymentMonth);
//To add a blank line in frame, added three blank JLabels because it is 3 horiontal for grid layout
southPanel.add (new JLabel ());
southPanel.add (new JLabel ());
southPanel.add (new JLabel ());
southPanel.add (new JButton ("Clear Information"));
southPanel.add (new JLabel ());
JButton nextButton = new JButton ("Next");
southPanel.add (nextButton);
frame.getContentPane ().add (southPanel, BorderLayout.SOUTH);
frame.pack ();
frame.setVisible (true);
nextButton.addActionListener (new Next ());
//Gets the personal information from the text fields
int age, income, price, downPay, interestRate;
String name = nameField.getText ();
String ageText = ageField.getText ();
age = Integer.parseInt (ageText);
String incomeText = incomeField.getText ();
income = Integer.parseInt (ageText);
//Gets the mortgage information from the text fields
String priceText = priceField.getText ();
price = Integer.parseInt (ageText);
String downPayText = downPayField.getText ();
downPay = Integer.parseInt (ageText);
String interestRateText = interestRateField.getText ();
interestRate = Integer.parseInt (interestRateText);
}
}
ActionListener:
import java.awt.*; //for Dimension
import javax.swing.*; //for GUI components
import java.awt.event.*; //for MessageListener
public class Next implements ActionListener
{
public void actionPerformed (ActionEvent event)
{
//Output frame
JFrame frame2 = new JFrame ();
frame2.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame2.setSize (new Dimension (300, 250));
frame2.setTitle ("Mortgage Calculator");
frame2.getContentPane ().setLayout (new BorderLayout ());
JPanel westPanel2 = new JPanel (new GridLayout (3, 1));
JLabel nameLabel = new JLabel ("Name: " + name);
westPanel2.add (nameLabel);
JLabel ageLabel = new JLabel ("Age: " + age);
westPanel2.add (ageLabel);
JLabel incomeLabel = new JLabel ("Yearly Income: " + income);
westPanel2.add (incomeLabel);
frame2.getContentPane ().add (westPanel2, BorderLayout.WEST);
JPanel centerPanel2 = new JPanel (new GridLayout (3, 1));
JLabel priceLabel = new JLabel (" Price of property: " + price);
centerPanel2.add (priceLabel);
JLabel downPayLabel = new JLabel (" Down Payment: " + downPay);
centerPanel2.add (downPayLabel);
JLabel interestRateLabel = new JLabel (" Interest Rate: " + income);
centerPanel2.add (interestRateLabel);
frame2.getContentPane ().add (centerPanel2, BorderLayout.CENTER);
frame2.pack ();
frame2.setVisible (true);
}
}
main方法中的變量是局部變量,因此您的偵聽器將無法看到它們。
有很多方法可以解決此問題。 首先,必須使MortgageCalculator
類的狀態變量( name
等)成為成員變量,以便其他方法或類可以看到它們。 然后,給偵聽器代碼訪問這些變量的權限。 一些選項:
Next
設為MortgageCalculator
的內部類,以便它可以自動查看成員變量。 MortgageCalculator
實現ActionListener
,並將actionPerformed
方法移動到結果類中。 然后,而不是編寫nextButton.addActionListener(new Next());
,您會說nextButton.addActionListener(this);
-但僅在非靜態方法內(所以不是main
您需要在MortgageCalculator
實例上使main
調用非靜態方法)。
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