ComponentListener接口
ComponentEvent類必須實現這個接口。類的對象組件注冊。使用addComponentListener()方法,該對象可以被注冊。組件事件提出僅供參考。
接口聲明
以下是聲明的java.awt.event.ComponentListener接口:
public interface ComponentListener extends EventListener
接口中的方法
S.N. | 方法&說明 |
---|---|
1 |
void componentHidden(ComponentEvent e) Invoked when the component has been made invisible. |
2 |
void componentMoved(ComponentEvent e) Invoked when the component's position changes. |
3 |
void componentResized(ComponentEvent e) Invoked when the component's size changes. |
4 |
void componentShown(ComponentEvent e) Invoked when the component has been made visible. |
繼承的方法
這個接口繼承的方法從下麵的接口:
-
java.awt.EventListener
ComponentListener示例
選擇使用任何編輯器創建以下java程序 D:/ > AWT > com > yiibai > gui >
AwtListenerDemopackage com.yiibai.gui; import java.awt.*; import java.awt.event.*; public class AwtListenerDemo { private Frame mainFrame; private Label headerLabel; private Label statusLabel; private Panel controlPanel; public AwtListenerDemo(){ prepareGUI(); } public static void main(String[] args){ AwtListenerDemo awtListenerDemo = new AwtListenerDemo(); awtListenerDemo.showComponentListenerDemo(); } 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 showComponentListenerDemo(){ headerLabel.setText("Listener in action: ComponentListener"); ScrollPane panel = new ScrollPane(); panel.setBackground(Color.magenta); Label msglabel = new Label(); msglabel.setAlignment(Label.CENTER); msglabel.setText("Welcome to TutorialsPoint AWT Tutorial."); panel.add(msglabel); msglabel.addComponentListener(new CustomComponentListener()); controlPanel.add(panel); mainFrame.setVisible(true); } class CustomComponentListener implements ComponentListener { public void componentResized(ComponentEvent e) { statusLabel.setText(statusLabel.getText() + e.getComponent().getClass().getSimpleName() + " resized. "); } public void componentMoved(ComponentEvent e) { statusLabel.setText(statusLabel.getText() + e.getComponent().getClass().getSimpleName() + " moved. "); } public void componentShown(ComponentEvent e) { statusLabel.setText(statusLabel.getText() + e.getComponent().getClass().getSimpleName() + " shown. "); } public void componentHidden(ComponentEvent e) { statusLabel.setText(statusLabel.getText() + e.getComponent().getClass().getSimpleName() + " hidden. "); } } }
編譯程序,使用命令提示符。到 D:/ > AWT 然後鍵入以下命令。
D:AWT>javac comyiibaiguiAwtListenerDemo.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:AWT>java com.yiibai.gui.AwtListenerDemo
驗證下麵的輸出