Swing JTextField

JTextField類是一個組件，它允許編輯一個單行文本。

類聲明

以下是聲明的 javax.swing.JTextField 類：

public class JTextField
   extends JTextComponent
      implements SwingConstants

字段域

以下是javax.swing.JList類字段域：

static String notifyAction -- 動作名稱的字段已被接受的內容發送通知。

類構造函數

S.N.	構造函數 & 描述
1	JTextField() Constructs a new TextField.
2	JTextField(Document doc, String text, int columns) Constructs a new JTextField that uses the given text storage model and the given number of columns.
3	JTextField(int columns) Constructs a new empty TextField with the specified number of columns.
4	JTextField(String text) Constructs a new TextField initialized with the specified text.
5	JTextField(String text, int columns) Constructs a new TextField initialized with the specified text and columns.

類方法

S.N.	方法 & 描述
1	protected void actionPropertyChanged(Action action, String propertyName) Updates the textfield's state in response to property changes in associated action.
2	void addActionListener(ActionListener l) Adds the specified action listener to receive action events from this textfield.
3	protected void configurePropertiesFromAction(Action a) Sets the properties on this textfield to match those in the specified Action.
4	protected PropertyChangeListener createActionPropertyChangeListener(Action a) Creates and returns a PropertyChangeListener that is responsible for listening for changes from the specified Action and updating the appropriate properties.
5	protected Document createDefaultModel() Creates the default implementation of the model to be used at construction if one isn't explicitly given.
6	protected void fireActionPerformed() Notifies all listeners that have registered interest for notification on this event type.
7	AccessibleContext getAccessibleContext() Gets the AccessibleContext associated with this JTextField.
8	Action getAction() Returns the currently set Action for this ActionEvent source, or null if no Action is set.
9	ActionListener[] getActionListeners() Returns an array of all the ActionListeners added to this JTextField with addActionListener().
10	Action[] getActions() Fetches the command list for the editor.
11	int getColumns() Returns the number of columns in this TextField.
12	protected int getColumnWidth() Returns the column width.
13	int getHorizontalAlignment() Returns the horizontal alignment of the text.
14	BoundedRangeModel getHorizontalVisibility() Gets the visibility of the text field.
15	Dimension getPreferredSize() Returns the preferred size Dimensions needed for this TextField.
16	int getScrollOffset() Gets the scroll offset, in pixels.
17	String getUIClassID() Gets the class ID for a UI.
18	boolean isValidateRoot() Calls to revalidate that come from within the textfield itself will be handled by validating the textfield, unless the textfield is contained within a JViewport, in which case this returns false.
19	protected String paramString() Returns a string representation of this JTextField.
20	void postActionEvent() Processes action events occurring on this textfield by dispatching them to any registered ActionListener objects.
21	void removeActionListener(ActionListener l) Removes the specified action listener so that it no longer receives action events from this textfield.
22	void scrollRectToVisible(Rectangle r) Scrolls the field left or right.
23	void setAction(Action a) Sets the Action for the ActionEvent source.
24	void setActionCommand(String command) Sets the command string used for action events.
25	void setColumns(int columns) Sets the number of columns in this TextField, and then invalidate the layout.
26	void setDocument(Document doc) Associates the editor with a text document.
27	void setFont(Font f) Sets the current font.
28	void setHorizontalAlignment(int alignment) Sets the horizontal alignment of the text.
29	void setScrollOffset(int scrollOffset) Sets the scroll offset, in pixels.

方法繼承

這個類從以下類繼承的方法：

javax.swing.text.JTextComponent
javax.swing.JComponent
java.awt.Container
java.awt.Component
java.lang.Object

JTextField 例子

選擇使用任何編輯器創建以下java程序在 D:/ > SWING > com > yiibai > gui >

SwingControlDemo.java

package com.yiibai.gui;
 
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class SwingControlDemo {
    
   private JFrame mainFrame;
   private JLabel headerLabel;
   private JLabel statusLabel;
   private JPanel controlPanel;

   public SwingControlDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      SwingControlDemo  swingControlDemo = new SwingControlDemo();      
      swingControlDemo.showTextFieldDemo();
   }

   private void prepareGUI(){
      mainFrame = new JFrame("Java Swing Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new JLabel("", JLabel.CENTER);        
      statusLabel = new JLabel("",JLabel.CENTER);    

      statusLabel.setSize(350,100);

      controlPanel = new JPanel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showTextFieldDemo(){
      headerLabel.setText("Control in action: JTextField"); 

      JLabel  namelabel= new JLabel("User ID: ", JLabel.RIGHT);
      JLabel  passwordLabel = new JLabel("Password: ", JLabel.CENTER);
      final JTextField userText = new JTextField(6);
      final JPasswordField passwordText = new JPasswordField(6);      

      JButton loginButton = new JButton("Login");
      loginButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {     
            String data = "Username " + userText.getText();
            data += ", Password: " 
            + new String(passwordText.getPassword()); 
            statusLabel.setText(data);        
         }
      }); 

      controlPanel.add(namelabel);
      controlPanel.add(userText);
      controlPanel.add(passwordLabel);       
      controlPanel.add(passwordText);
      controlPanel.add(loginButton);
      mainFrame.setVisible(true);  
   }
}

編譯程序，使用命令提示符。到 D:/ > SWING 然後輸出以下命令。

D:SWING>javac comyiibaiguiSwingControlDemo.java

如果冇有錯誤出現，這意味著編譯成功。使用下麵的命令來運行程序。

D:SWING>java com.yiibai.gui.SwingControlDemo

驗證下麵的輸出