Swing JTextField

JTextField类是一个组件，它允许编辑一个单行文本。

类声明

以下是声明的 javax.swing.JTextField 类：

public class JTextField
   extends JTextComponent
      implements SwingConstants

字段域

以下是javax.swing.JList类字段域：

static String notifyAction -- 动作名称的字段已被接受的内容发送通知。

类构造函数

S.N.	构造函数 & 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.

类方法

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.

方法继承

这个类从以下类继承的方法：

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

JTextField 例子

选择使用任何编辑器创建以下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);  
   }
}

编译程序，使用命令提示符。到 D:/ > SWING 然后输出以下命令。

D:SWING>javac comyiibaiguiSwingControlDemo.java

如果没有错误出现，这意味着编译成功。使用下面的命令来运行程序。

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

验证下面的输出