如何使一個關鍵事件使用單個文本字段

Question

好的，我有一個任務，我們要創建一個通用對類，然後測試它，看它是否工作。配對班有一定的必須遵守的要求，但我們可以自由地做我們想要的測試班。我承認自己有點過分了，但只是因爲玩弄想法可以幫助我學習其他我們在課堂上沒有涉及到的東西。現在，我無法顯示泛型類的東西，因爲那部分是作業的重要部分，但對於我的測試類，我將展示所有這些。我試圖使我的第五個文本字段（tf5）能夠接收用戶信息，並在點擊回車鍵之後，將該信息（其設置爲ArrayList）發送到我的JSrollPanel， （myScrollPane）。現在，我有我的鍵盤記錄器設置的方式，它將我輸入的任何內容添加到文本字段中，當我輸入它時，將它添加到JScrollPanel中。所以，如果我輸入1,2,3,4，我會在面板上打印出4個數組列表（每個列表有1個數字）。我希望能夠在文本字段中輸入任何我想要的內容，並且只有在我進入後才能將其傳遞到JScrollPanel，但對於我而言，我無法理清如何做到這一點。任何人都可以幫我解決這個問題嗎？這裏是我的代碼：

package lab10; 

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.*; 
import java.lang.Integer.*; 
import java.util.ArrayList; 


public class Lab10 extends JFrame { 

private Container content; 
private JTextField tf1, tf2, tf3, tf4, tf5, tf6; 
private JLabel lbl1, lbl2, lbl3, lbl4, lbl5, lbl6, lbl7, lbl8, lbl9, lbl10; 
private Font myFont; 
private JButton myBtn, myBtn2, tstb; 
private JTextArea myTextArea; 
private JScrollPane myScrollPane; 
private KeyEvent x; 
Integer I1, I2; 
String S1, S2; 
Double D1, D2; 
ArrayList A1, A2; 
Pair<Integer, Integer> myPairInt = new Pair<>(I1, I2); 
Pair<String, Double> myPairStrDbl = new Pair<>(S1, D2); 
Pair<ArrayList, String> myPairAryStr = new Pair<>(A1, S2); 

public Lab10() { 
    this(640, 540, "Testing a Generic Pair"); 
} 

public Lab10(int width, int height, String title) { 
    this.setVisible(true); 
    this.setTitle(title); 
    this.setSize(width, height); 
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    guiComponent(); 

} 

private void guiComponent() { 
    SpringLayout layout = new SpringLayout(); 
    content = this.getContentPane(); 
    content.setLayout(layout); 
    myFont = new Font("Magneto", Font.BOLD, 12); 
    myBtn = new JButton("Do It!"); 
    myBtn2 = new JButton(); 
    myBtn2.setLayout(new BorderLayout()); 
    JLabel label1 = new JLabel("Click here to add elements to Array List"); 
    JLabel label2 = new JLabel("(Before you click the bottom button!)"); 
    myBtn2.add(BorderLayout.NORTH, label1); 
    myBtn2.add(BorderLayout.SOUTH, label2); 
    myBtn.addActionListener(new ButtonClick()); 
    myBtn2.addActionListener(new ArrayListClickAdd()); 
    lbl1 = new JLabel("Enter a string of numbers for me to count"); 
    lbl2 = new JLabel("Now enter another string of numbers for me to count"); 
    lbl3 = new JLabel("This is where I show you what you typed "); 
    lbl4 = new JLabel("Now type a String and I'll count the Ascii sum "); 
    lbl5 = new JLabel("Now type in a double, i.e. 2.4 or 2.3 or 5.6 "); 
    lbl6 = new JLabel("This is where I show you what you typed "); 
    lbl7 = new JLabel("Now Enter an Array List, (just a standard string of numbers) "); 
    lbl8 = new JLabel("Now Enter a String and I will convert it all to uppercase"); 
    lbl9 = new JLabel("This is where I will show you what you've typed "); 
    lbl10 = new JLabel(); 
    tf1 = new JTextField(8); 
    tf2 = new JTextField(8); 
    tf3 = new JTextField(8); 
    tf4 = new JTextField(8); 
    tf5 = new JTextField(8); 
    tf6 = new JTextField(8); 

     tf5.addKeyListener(new MyKeyEvent()); 

    myTextArea = new JTextArea(); 
    myTextArea.setColumns(12); 
    myTextArea.setRows(8); 
    myTextArea.setFont(myFont); 


    content.add(lbl1); 
    layout.putConstraint(SpringLayout.WEST, lbl1, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, lbl1, 10, SpringLayout.NORTH, content); 

    content.add(tf1); 
    layout.putConstraint(SpringLayout.WEST, tf1, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, tf1, 10, SpringLayout.SOUTH, lbl1); 

    content.add(lbl2); 
    layout.putConstraint(SpringLayout.WEST, lbl2, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, lbl2, 10, SpringLayout.SOUTH, tf1); 

    content.add(tf2); 
    layout.putConstraint(SpringLayout.WEST, tf2, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, tf2, 10, SpringLayout.SOUTH, lbl2); 

    content.add(lbl3); 
    layout.putConstraint(SpringLayout.WEST, lbl3, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, lbl3, 10, SpringLayout.SOUTH, tf2); 

    content.add(lbl4); 
    layout.putConstraint(SpringLayout.WEST, lbl4, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, lbl4, 10, SpringLayout.SOUTH, lbl3); 

    content.add(tf3); 
    layout.putConstraint(SpringLayout.WEST, tf3, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, tf3, 10, SpringLayout.SOUTH, lbl4); 

    content.add(lbl5); 
    layout.putConstraint(SpringLayout.WEST, lbl5, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, lbl5, 10, SpringLayout.SOUTH, tf3); 

    content.add(tf4); 
    layout.putConstraint(SpringLayout.WEST, tf4, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, tf4, 10, SpringLayout.SOUTH, lbl5); 

    content.add(lbl6); 
    layout.putConstraint(SpringLayout.WEST, lbl6, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, lbl6, 10, SpringLayout.SOUTH, tf4); 

    content.add(lbl7); 
    layout.putConstraint(SpringLayout.WEST, lbl7, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, lbl7, 10, SpringLayout.SOUTH, lbl6); 

    content.add(tf5); 
    layout.putConstraint(SpringLayout.WEST, tf5, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, tf5, 10, SpringLayout.SOUTH, lbl7); 

    content.add(lbl8); 
    layout.putConstraint(SpringLayout.WEST, lbl8, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, lbl8, 10, SpringLayout.SOUTH, tf5); 

    content.add(tf6); 
    layout.putConstraint(SpringLayout.WEST, tf6, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, tf6, 10, SpringLayout.SOUTH, lbl8); 

    content.add(lbl9); 
    layout.putConstraint(SpringLayout.WEST, lbl9, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, lbl9, 10, SpringLayout.SOUTH, tf6); 

    content.add(lbl10); 
    layout.putConstraint(SpringLayout.WEST, lbl10, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, lbl10, 2, SpringLayout.SOUTH, lbl9); 

    myScrollPane = new JScrollPane(myTextArea); 
    content.add(myScrollPane); 
    layout.putConstraint(SpringLayout.WEST, myScrollPane, 250, SpringLayout.EAST, tf4); 
    layout.putConstraint(SpringLayout.NORTH, myScrollPane, 1, SpringLayout.SOUTH, myBtn2); 

    content.add(myBtn2); 
    layout.putConstraint(SpringLayout.WEST, myBtn2, 3, SpringLayout.EAST, lbl7); 
    layout.putConstraint(SpringLayout.NORTH, myBtn2, 8, SpringLayout.SOUTH, lbl6); 

    content.add(myBtn); 
    layout.putConstraint(SpringLayout.WEST, myBtn, 10, SpringLayout.WEST, content); 
    layout.putConstraint(SpringLayout.NORTH, myBtn, 10, SpringLayout.SOUTH, lbl10); 
} 

private String upper(String y) { 
    return y.toUpperCase(); 
} 

private String getAsciiSum(String z) { 
    int addSum = 0; 
    for (int i = 0; i < z.length(); i++) { 
     char x = z.charAt(i); 
     int j = (int) x; 
     addSum += x; 
    } 
    z = Integer.toString(addSum); 
    return z; 
} 

int sumNums(int x) { 
    String myNum = Integer.toString(x); 
    int addSum = 0; 
    for (int i = 0; i < myNum.length(); i++) { 
     addSum += Character.digit(myNum.charAt(i), 10); 
    } 
    return addSum; 
} 

int[] getArray(int num) { 
    String counter = "" + num; 
    int digits = counter.length(); 
    int[] nums = new int[digits]; 
    for (int i = digits - 1; i >= 0; i--) { 
     nums[i] = num % 10; 
     num /= 10; 
    } 
    return nums; 
} 

private class MyKeyEvent implements KeyListener { 

    public MyKeyEvent() { 
    } 

    @Override 
    public void keyTyped(KeyEvent ke) { 

     ke.setKeyCode(KeyEvent.VK_RIGHT); 
     if (ke.getKeyCode() == KeyEvent.VK_RIGHT) { 

      String arrNum = tf5.getText(); 
      ArrayList arList = new ArrayList(); 
      arList.add(arrNum); 
      myPairAryStr.setFirst(arList); 
      myTextArea.append(myPairAryStr.getFirst() + "\n"); 
      tf5.setText(""); 
     } 
    } 

    @Override 
    public void keyPressed(KeyEvent ke) { 
    } 

    @Override 
    public void keyReleased(KeyEvent ke) { 
    } 
} 

private class ArrayListClickAdd implements ActionListener { 

    public ArrayListClickAdd() { 
    } 

    @Override 
    public void actionPerformed(ActionEvent ae) { 

     String arrNum = tf5.getText(); 
     ArrayList arList = new ArrayList(); 
     arList.add(arrNum); 
     myPairAryStr.setFirst(arList); 
     myTextArea.append(myPairAryStr.getFirst() + "\n"); 
     tf5.setText(""); 
    } 
} 

private class ButtonClick implements ActionListener { 

    public ButtonClick() { 
    } 

    @Override 
    public void actionPerformed(ActionEvent ae) { 


     int num = Integer.parseInt(tf1.getText()); 
     int num2 = Integer.parseInt(tf2.getText()); 
     String num3 = tf3.getText(); 
     double num4 = Double.parseDouble(tf4.getText()); 
     String arrLst = tf5.getText(); 
     String num6 = tf6.getText(); 

     int count1 = sumNums(num); 
     int count2 = sumNums(num2); 
     String strSum = getAsciiSum(num3); 
     String goBig = upper(num6); 


     Integer int1 = new Integer(count1); 
     Integer int2 = new Integer(count2); 
     String str1 = strSum; 
     Double dbl2 = new Double(num4); 
     ArrayList arList = new ArrayList(); 
     arList.add(arrLst); 
     String str2 = goBig; 

     myPairInt.setFirst(int1); 
     myPairInt.setSecond(int2); 
     myPairStrDbl.setFirst(str1); 
     myPairStrDbl.setSecond(dbl2); 
     myPairAryStr.setFirst(arList); 
     myPairAryStr.setSecond(str2); 

     lbl3.setText("Your numbers fromthe first field add up to : " + myPairInt.getFirst() + " and your numbers from the second field add up to : " + myPairInt.getSecond()); 
     lbl6.setText("The Ascii sum of the first Field is : " + myPairStrDbl.getFirst() + " and you typed : " + myPairStrDbl.getSecond() + " In the Second Field"); 
     lbl9.setText("You typed : " + myPairAryStr.getFirst() + " In the first Field,"); 
     lbl10.setText("and : " + myPairAryStr.getSecond() + " In the Second"); 
     myTextArea.append(myPairAryStr.getFirst() + "\n"); 

    } 
} 

public static void main(String[] args) { 
    Lab10 test = new Lab10(); 
} 

}

Answer 1

首先看看How to use textfields。

基本上，你要註冊上的文本框的ActionListener，當過用戶按下回車關鍵

看看How to write Action Listeners有關詳細信息，這將會收到通知。

您應該避免使用KeyListener s，使用DocumentListener來監視底層文檔的更改，或者如果要過濾輸入的內容，請使用DocumentFilter。有關更多詳細信息，請參閱Using Text Components

Answer 2

不要重新每個在的keyTyped ArrayList。爲ArrayList創建類的字段，併爲列表中的類型添加值。

當按下ENTER時，將ArrayList的內容發送到文本區域並重新創建。