Swing FocusAdapter類
FocusAdapter類接收鍵盤焦點事件是一個抽象類（適配器）。這個類的所有方法都是空的。這個類是方便的類創建監聽器對象。
類聲明
以下是聲明 java.awt.event.FocusAdapter類：
public abstract class FocusAdapter extends Object implements FocusListener
類構造函數
S.N.
構造函數 & 描述
1
FocusAdapter()
類方法
S.N.
方法 & 描述
1
void focusGained(FocusEvent e)
Invoked when a component gains the keyboard focus.
2
focusLost(FocusEvent e)
Invoked when a component loses the keyboard focus.
方法繼承
這個類從以下類繼承的方法：
- java.lang.Object
FocusAdapter 例子
選擇使用任何編輯器創建以下java程序在 D:/ > SWING > com > yiibai > gui >
SwingAdapterDemo.java
package com.yiibai.gui; import java.awt.*; import java.awt.event.*; import javax.swing.*; public class SwingAdapterDemo { private JFrame mainFrame; private JLabel headerLabel; private JLabel statusLabel; private JPanel controlPanel; public SwingAdapterDemo(){ prepareGUI(); } public static void main(String[] args){ SwingAdapterDemo swingAdapterDemo = new SwingAdapterDemo(); swingAdapterDemo.showFocusAdapterDemo(); } private void prepareGUI(){ mainFrame = new JFrame("Java SWING Examples"); mainFrame.setSize(400,400); mainFrame.setLayout(new GridLayout(3, 1)); headerLabel = new JLabel("",JLabel.CENTER ); statusLabel = new JLabel("",JLabel.CENTER); statusLabel.setSize(350,100); mainFrame.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent windowEvent){ System.exit(0); } }); controlPanel = new JPanel(); controlPanel.setLayout(new FlowLayout()); mainFrame.add(headerLabel); mainFrame.add(controlPanel); mainFrame.add(statusLabel); mainFrame.setVisible(true); } private void showFocusAdapterDemo(){ headerLabel.setText("Listener in action: FocusAdapter"); JButton okButton = new JButton("OK"); JButton cancelButton = new JButton("Cancel"); okButton.addFocusListener(new FocusAdapter(){ public void focusGained(FocusEvent e) { statusLabel.setText(statusLabel.getText() + e.getComponent().getClass().getSimpleName() + " gained focus. "); } }); cancelButton.addFocusListener(new FocusAdapter(){ public void focusLost(FocusEvent e) { statusLabel.setText(statusLabel.getText() + e.getComponent().getClass().getSimpleName() + " lost focus. "); } }); controlPanel.add(okButton); controlPanel.add(cancelButton); 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 comyiibaiguiSwingAdapterDemo.java
如果沒有錯誤出現，這意味着編譯成功。使用下面的命令來運行程序。
D:SWING>java com.yiibai.gui.SwingAdapterDemo
驗證下面的輸出
