介绍
TextField组件允许用户编辑单行文本。当用户在文本字段中键入一个关键的事件被发送到TextField。键盘事件,可能是按下键盘,重点发布或关键的类型。键盘事件被传递到注册keyListener。它也有可能为一个ActionEvent ActionEvent 启用ActionEvent文本框,然后按回车键可能被触发。
类的声明
以下是声明java.awt.TextField类:
public class TextField extends TextComponent
类的构造函数
| S.N. | 构造函数与说明 | 
|---|---|
| 1 | TextField() Constructs a new text field. | 
| 2 | TextField(int columns) Constructs a new empty text field with the specified number of columns. | 
| 3 | TextField(String text) Constructs a new text field initialized with the specified text. | 
| 4 | TextField(String text, int columns) Constructs a new text field initialized with the specified text to be displayed, and wide enough to hold the specified number of columns. | 
类方法
| S.N. | 方法和说明 | 
|---|---|
| 1 | void addActionListener(ActionListener l) Adds the specified action listener to receive action events from this text field. | 
| 2 | void addNotify() Creates the TextField's peer. | 
| 3 | boolean echoCharIsSet() Indicates whether or not this text field has a character set for echoing. | 
| 4 | AccessibleContext getAccessibleContext() Gets the AccessibleContext associated with this TextField. | 
| 5 | ActionListener[] getActionListeners() Returns an array of all the action listeners registered on this textfield. | 
| 6 | int getColumns() Gets the number of columns in this text field. | 
| 7 | char getEchoChar() Gets the character that is to be used for echoing. | 
| 8 | <T extends EventListener> T[] getListeners(Class<T> listenerType) Returns an array of all the objects currently registered as FooListeners upon this TextField. | 
| 9 | Dimension getMinimumSize() Gets the minumum dimensions for this text field. | 
| 10 | Dimension getMinimumSize(int columns) Gets the minumum dimensions for a text field with the specified number of columns. | 
| 11 | Dimension getPreferredSize() Gets the preferred size of this text field. | 
| 12 | Dimension getPreferredSize(int columns) Gets the preferred size of this text field with the specified number of columns. | 
| 13 | Dimension minimumSize() Deprecated. As of JDK version 1.1, replaced by getMinimumSize(). | 
| 14 | Dimension minimumSize(int columns) Deprecated. As of JDK version 1.1, replaced by getMinimumSize(int). | 
| 15 | protected String paramString() Returns a string representing the state of this TextField. | 
| 16 | Dimension preferredSize() Deprecated. As of JDK version 1.1, replaced by getPreferredSize(). | 
| 17 | Dimension preferredSize(int columns) Deprecated. As of JDK version 1.1, replaced by getPreferredSize(int). | 
| 18 | protected void processActionEvent(ActionEvent e) Processes action events occurring on this text field by dispatching them to any registered ActionListener objects. | 
| 19 | protected void processEvent(AWTEvent e) Processes events on this text field. | 
| 20 | void removeActionListener(ActionListener l) Removes the specified action listener so that it no longer receives action events from this text field. | 
| 21 | void setColumns(int columns) Sets the number of columns in this text field. | 
| 22 | void setEchoChar(char c) Sets the echo character for this text field. | 
| 23 | void setEchoCharacter(char c) Deprecated. As of JDK version 1.1, replaced by setEchoChar(char). | 
| 24 | void setText(String t) Sets the text that is presented by this text component to be the specified text. | 
继承的方法
这个类继承的方法从以下类:
- 
		java.awt.TextComponent 
- 
		java.awt.Component 
- 
		java.lang.Object 
TextField 实例
选择使用任何编辑器创建以下java程序 D:/ > AWT > com > zaixian > gui >
AwtControlDemopackage com.zaixian.gui; import java.awt.*; import java.awt.event.*; public class AwtControlDemo { private Frame mainFrame; private Label headerLabel; private Label statusLabel; private Panel controlPanel; public AwtControlDemo(){ prepareGUI(); } public static void main(String[] args){ AwtControlDemo awtControlDemo = new AwtControlDemo(); awtControlDemo.showTextFieldDemo(); } private void prepareGUI(){ mainFrame = new Frame("Java AWT 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 Label(); headerLabel.setAlignment(Label.CENTER); statusLabel = new Label(); statusLabel.setAlignment(Label.CENTER); statusLabel.setSize(350,100); controlPanel = new Panel(); controlPanel.setLayout(new FlowLayout()); mainFrame.add(headerLabel); mainFrame.add(controlPanel); mainFrame.add(statusLabel); mainFrame.setVisible(true); } private void showTextFieldDemo(){ headerLabel.setText("Control in action: TextField"); Label namelabel= new Label("User ID: ", Label.RIGHT); Label passwordLabel = new Label("Password: ", Label.CENTER); final TextField userText = new TextField(6); final TextField passwordText = new TextField(6); passwordText.setEchoChar('*'); Button loginButton = new Button("Login"); loginButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { String data = "Username: " + userText.getText(); data += ", Password: " + passwordText.getText(); 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:/ > AWT 然后键入以下命令。
D:AWT>javac comzaixianguiAwtControlDemo.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:AWT>java com.zaixian.gui.AwtControlDemo
验证下面的输出
 
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