的Java Swing：管理整數/與聽衆和J *字段

Question

EDITED

我可能只是盯着屏幕WAYYY太久雙打，但我覺得有必要提出這個問題，去之前睡覺incase我的deli妄仍然是真的...

我遇到的問題是我試圖從JTextField textField得到一個int/double並將其轉換爲（n）int/double稍後使用一個偵聽器，在從偵聽器中檢索它之後... ListenForText實現KeyListener，特別是KeyTyped，通過toString（）獲取並將其存儲在一個String txtFldAmnt中。之後，如果複製到編輯器，我將把Integer.parseInt（txtFldAmnt）的結果存儲到fldAmnt（fldAmnt = Integer.pareseInt（txtFldAmnt））LINE 99中。一旦將其轉換爲int，我希望能夠操作它，然後再次使用它，在LINE 173處，在新窗口中顯示fldAmnt。老實說，我並不在意它是顯示一個int還是String，但我知道一個String是JTextField所必需的。我錯過了什麼魔法？總是歡迎回答，但我更喜歡有機會學習。此外，由於我是相當新到Java，題外話指針，批評和實現這個代碼更好的方法是很大的歡迎:)

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.*; 


public class GUI extends JFrame{ 

/** 
* wtf is the serial version UID = 1L 
*/ 
private static final long serialVersionUID = 1L; 
private JButton wdBtn; 
private JButton dpBtn; 
private JButton xferBtn; 
private JButton balBtn; 
private JRadioButton chkRadio; 
private JRadioButton savRadio; 
private JTextField textField; 
private static String txtFldAmnt; 
private static int fldAmnt = 0; 
private static Double chkBal = 0.00; 
private static Double savBal = 0.00; 


public static void main(String[] args){ 
    new GUI(); 
} 


public GUI() { 

    //default location and size 
    this.setSize(300,182); 
    this.setLocationRelativeTo(null); 
    this.setResizable(false); 
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    this.setTitle("ATM Machine"); 

    //add buttons 
    wdBtn = new JButton("Withdraw"); 
    dpBtn = new JButton("Deposit"); 
    xferBtn = new JButton("Transfer"); 
    balBtn = new JButton("Show Balance"); 
    chkRadio = new JRadioButton("Checking"); 
    chkRadio.setSelected(false); 
    savRadio = new JRadioButton("Savings"); 
    savRadio.setSelected(false); 
    textField = new JTextField("", 20); 
    final JLabel textLabel = new JLabel("Enter amount: "); 
    textField.setToolTipText("Enter amount"); 

    //Listener class to pass button listeners 
    ListenForButton lForButton = new ListenForButton(); 
    wdBtn.addActionListener(lForButton); 
    dpBtn.addActionListener(lForButton); 
    xferBtn.addActionListener(lForButton); 
    balBtn.addActionListener(lForButton); 
    chkRadio.addActionListener(lForButton); 
    savRadio.addActionListener(lForButton); 

    ListenForText textFieldListener = new ListenForText(); 
    textField.addKeyListener(textFieldListener); 

    //Configure layouts 
    JPanel PANEL = new JPanel(); 
    PANEL.setLayout(new FlowLayout(FlowLayout.CENTER)); 
    JPanel panel1 = new JPanel(); 
    panel1.setLayout(new GridLayout(2,2, 5, 10)); 
    JPanel panel2 = new JPanel(); 
    panel2.setLayout(new GridLayout(1,2,10,10)); 
    panel2.setLayout(new FlowLayout(FlowLayout.CENTER)); 
    JPanel panel3 = new JPanel(); 
    panel3.setLayout(new GridLayout(2,1)); 

    //add buttons to their panels 
    panel1.add(wdBtn); 
    panel1.add(dpBtn); 
    panel1.add(xferBtn); 
    panel1.add(balBtn); 
    panel2.add(chkRadio); 
    panel2.add(savRadio); 
    panel3.add(textLabel); 
    panel3.add(textField); 

    PANEL.add(panel1); 
    PANEL.add(panel2); 
    PANEL.add(panel3); 

    this.add(PANEL); 
    //this.setAlwaysOnTop(true); 
    this.setVisible(true); 
} 
//implement listeners 
private class ListenForText implements KeyListener { 

    @Override 
    public void keyTyped(KeyEvent e) { 
     txtFldAmnt = (e.toString()); 
     fldAmnt = Integer.parseInt(txtFldAmnt); 

    } 

    @Override 
    public void keyPressed(KeyEvent e) { 
     // TODO Auto-generated method stub 

    } 

    @Override 
    public void keyReleased(KeyEvent e) { 
     // TODO Auto-generated method stub 

    } 

} 
private class ListenForButton implements ActionListener { 

    public void actionPerformed(ActionEvent e){ 

     //maybe do case/switch statements 
     if (e.getSource() == wdBtn) { 
      JFrame newFrame = new JFrame("Withdraw Title"); 
      newFrame.setResizable(false); 
      newFrame.setLocationRelativeTo(null); 
      newFrame.setSize(300, 91); 

      JPanel panel = new JPanel(); 
      JLabel newLbl = new JLabel("Withdraw Frame", JLabel.CENTER); 

      panel.add(newLbl); 
      newFrame.add(panel); 
      newFrame.setVisible(true); 
     } 
     if (e.getSource() == dpBtn) { 
      JFrame newFrame = new JFrame("Deposit Title"); 
      /* 
      * Set the newFrame.setSize(300,182); to this comment in the if statement to place 
      * the window directly over current window 
      */ 
      newFrame.setResizable(false); 
      newFrame.setLocationRelativeTo(null); 
      newFrame.setSize(300, 91); 

      JPanel panel = new JPanel(); 
      JLabel newLbl = new JLabel("Deposit Frame", JLabel.CENTER); 

      panel.add(newLbl); 
      newFrame.add(panel); 
      newFrame.setVisible(true); 
     } 
     if (e.getSource() == xferBtn) { 
      JFrame newFrame = new JFrame("Transfer Title"); 

      newFrame.setResizable(false); 
      newFrame.setLocationRelativeTo(null); 
      newFrame.setSize(300, 91); 

      JPanel panel = new JPanel(); 
      JLabel newLbl = new JLabel("Transfer Frame", JLabel.CENTER); 

      panel.add(newLbl); 
      newFrame.add(panel); 
      newFrame.setVisible(true); 
     } 
     if (e.getSource() == balBtn){ 
      JFrame newFrame = new JFrame("Balance Title"); 

      newFrame.setResizable(false); 
      newFrame.setLocationRelativeTo(null); 
      newFrame.setSize(300, 91); 

      JPanel panel = new JPanel(); 
      JTextField newLbl = new JTextField(Integer.toString(fldAmnt)); 

      panel.add(newLbl); 
      newFrame.add(panel); 
      newFrame.setVisible(true); 

     } 
    } 
} 
} 

-cheers

EDITED低於

謝謝你的回答，我對這個可怕的描述感到抱歉...但是我找到了一個解決辦法，我不確定它是否合適。 與上面的例子：

fldAmnt = Integer.pareseInt(txtFldAmnt) 

我只是增加了一個.getText（）//雖然我重寫了整個源代碼

fldAmnt = Integer.pareseInt(txtFldAmnt.getText()) 

這對我的工作我的整個程序。

我希望我不必在下面發佈我的整個代碼，但我還沒有決定存儲我的所有代碼的好地方。 （建議，歡迎：d）

但在這裏它是： 進口的javax.swing。 ; import java.awt.GridLayout; import java.awt.event。; import javax.swing.border。*;

public class ATM extends JFrame{ 
//buttons needed 
JButton wBtn; 
JButton dBtn; 
JButton xBtn; 
JButton bBtn; 
//radios needed 
JRadioButton cRadio; 
JRadioButton sRadio; 
//Text field needed 
JTextField txt; 
JLabel txtLabel; 
static int withdraw = 0; 
Double amount = 0.00; 
Double cBal = 100.00; 
Double sBal = 100.00; 


double number1, number2, totalCalc; 

public static void main(String[] args){ 

    new Lesson22(); 

} 
public ATM(){ 
    this.setSize(400, 200); 
    this.setLocationRelativeTo(null); 
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    this.setTitle("My Third Frame"); 

    wBtn = new JButton("Withdraw"); 

    dBtn = new JButton("Deposit"); 
    xBtn = new JButton("Transfer"); 
    bBtn = new JButton("Show Balance"); 
    cRadio = new JRadioButton("Checking"); 
    sRadio = new JRadioButton("Savings"); 
    txtLabel = new JLabel("Amount: $"); 
    txt = new JTextField("", 10); 

    JPanel thePanel = new JPanel(); 

    // Create an instance of ListenForEvents to handle events 

    ListenForButton lForButton = new ListenForButton(); 

    wBtn.addActionListener(lForButton); 
    dBtn.addActionListener(lForButton); 
    xBtn.addActionListener(lForButton); 
    bBtn.addActionListener(lForButton); 


    // How to add a label -------------------------- 

    // Creates a group that will contain radio buttons 
    // You do this so that when 1 is selected the others 
    // are deselected 

    ButtonGroup operation = new ButtonGroup(); 

    // Add radio buttons to the group 

    operation.add(cRadio); 
    operation.add(sRadio); 

    // Create a new panel to hold radio buttons 

    JPanel operPanel = new JPanel(); 
    JPanel btnPanel1 = new JPanel(); 
    JPanel btnPanel2 = new JPanel(); 
    btnPanel1.setLayout(new GridLayout(1,2)); 
    btnPanel2.setLayout(new GridLayout(1,2)); 

    Border btnBorder = BorderFactory.createEmptyBorder(); 
    btnPanel1.setBorder(btnBorder); 
    btnPanel1.add(wBtn); 
    btnPanel1.add(dBtn); 
    btnPanel2.setBorder(btnBorder); 
    btnPanel2.add(xBtn); 
    btnPanel2.add(bBtn); 


    Border operBorder = BorderFactory.createBevelBorder(1); 

    // Set the border for the panel 

    operPanel.setBorder(operBorder); 

    // Add the radio buttons to the panel 

    operPanel.add(cRadio); 
    operPanel.add(sRadio); 


    // Selects the add radio button by default 
    cRadio.setSelected(true); 
    JPanel txtPanel = new JPanel(); 
    txtPanel.add(txtLabel); 
    txtPanel.add(txt); 


    thePanel.add(btnPanel1); 
    thePanel.add(btnPanel2); 
    thePanel.add(operPanel); 
    thePanel.add(txtPanel); 
    thePanel.setLayout(new GridLayout(4,2)); 
    this.add(thePanel); 

    this.setVisible(true); 

    txt.requestFocus(); 

} 

private class ListenForButton implements ActionListener{ 

    // This method is called when an event occurs 

    public void actionPerformed(ActionEvent e){ 
     /****************************************************** 
     * THIS IS FOR CHECKING 
     *****************************************************/ 
     // Check if the source of the event was the button 
     if(cRadio.isSelected()){ 
      if(e.getSource() == wBtn){ 
       try { 
        amount = Double.parseDouble(txt.getText()); 
        cBal -= amount; 
       } 
       catch(NumberFormatException excep){ 
        JOptionPane.showMessageDialog(ATM.this, 
          "Please enter a valid number in multiples of 20", 
          "ERROR", JOptionPane.ERROR_MESSAGE); 
       } 
      } 
      if(e.getSource() == bBtn){ 
       JFrame bFrame = new JFrame(); 
       bFrame.setSize(300, 182); 
       bFrame.setLocationRelativeTo(null); 
       JPanel panel = new JPanel(); 
       JLabel cLabel = new JLabel(Double.toString(cBal)); 
       JLabel CLBL = new JLabel("Checking: "); 
       panel.add(CLBL); 
       panel.add(cLabel); 
       bFrame.add(panel); 
       bFrame.setVisible(true); 
      } 

      if(e.getSource() == dBtn){ 
       amount = Double.parseDouble(txt.getText()); 
       cBal += amount; 
      } 
      if(e.getSource() == xBtn){ 
       amount = Double.parseDouble(txt.getText()); 
       if (sBal >= 0 && sBal >= amount){ 
        cBal += amount; 
        sBal -= amount; 
       } 
       else if (sBal < amount) { 
        JOptionPane.showMessageDialog(ATM.this, 
          "INSUFFICENT FUNDS", "ERROR", 
          JOptionPane.ERROR_MESSAGE); 
       } 
      } 
     } 
     /****************************************************** 
     * THIS IS FOR SAVINGS 
     *****************************************************/ 
     if(sRadio.isSelected()){ 
      if(e.getSource() == wBtn){ 
       try { 
        amount = Double.parseDouble(txt.getText()); 
        if(sBal >= 0 && sBal >= amount){ 
         sBal -= amount; 
        } 
        else if (sBal < amount) { 
         JOptionPane.showMessageDialog(ATM.this, 
           "INSUFFICENT FUNDS", "ERROR", 
           JOptionPane.ERROR_MESSAGE); 
        } 
       } 
       catch(NumberFormatException excep){ 
        JOptionPane.showMessageDialog(ATM.this, 
          "Please enter a valid number in multiples of 20", 
          "ERROR", JOptionPane.ERROR_MESSAGE); 
       } 
      } 
      if(e.getSource() == bBtn){ 
       JFrame bFrame = new JFrame(); 
       bFrame.setSize(300, 182); 
       bFrame.setLocationRelativeTo(null); 
       JPanel panel = new JPanel(); 
       JLabel sLabel = new JLabel(Double.toString(sBal)); 
       JLabel SLBL = new JLabel("Savings: "); 
       panel.add(SLBL); 
       panel.add(sLabel); 

       bFrame.add(panel); 
       bFrame.setVisible(true); 
      } 

      if(e.getSource() == dBtn){ 
       try{ 
        amount = Double.parseDouble(txt.getText()); 
        sBal += amount; 
       } 
       catch(NumberFormatException excep){ 
        JOptionPane.showMessageDialog(ATM.this, 
          "Please enter a valid number!", 
          "ERROR", JOptionPane.ERROR_MESSAGE); 
       } 
      } 
      if(e.getSource() == xBtn){ 
       amount = Double.parseDouble(txt.getText()); 
       if (cBal >= 0 && cBal >= amount){ 
        sBal += amount; 
        cBal -= amount; 
       } 
       else if (cBal < amount) { 
        JOptionPane.showMessageDialog(ATM.this, 
          "INSUFFICENT FUNDS", "ERROR", 
          JOptionPane.ERROR_MESSAGE); 
       } 
      } 
     } 
    } 
} 
} 

...順便說任何人都可以解釋此警告消息： 的序列化類ATM沒有聲明型長

如果不是簡單地穿上」的靜態最後的serialVersionUID領域麻煩了。我有空的時候會繼續研究它。

這仍然不完整，但謝謝大家的幫助！

Answer 1

KeyListener在任何JTextComponent是一個壞主意。

要監視更改文本組件，使用DocumentListener，該文本組件可以處理，使用DocumentFilter內容過濾器。有關更多詳細信息，請參閱Listening for Changes on a Document，Implementing a Document Filter和DocumentFilter Examples。

在你的情況下，很可能最好使用一個JSpinner或JFormattedTextField，因爲它們是設計來處理（除其他事項外）的數字

見How to Use Spinners和How to Use Formatted Text Fields更多細節