java awt 事件監聽器

//TestActionEvent.javaimport java.awt.*;import java.awt.event.*;public class TestActionEvent{public static void main(String[] args){Frame f=new Frame("TestActionEvent");Button b=new Button("Press Me !");Monitor bh=new Monitor();b.addActionListener(bh);f.add(b,BorderLayout.CENTER);f.pack();

//TestTextField.javaimport java.awt.*;import java.awt.event.*;class TestTextField{public static void main(String[] args){new TFFrame();}}class TFFrame extends Frame{TFFrame(){TextField tf=new TextField();add(tf);tf.addActionListener(new TFActionListener());pack();setVisible(true);}}class TFActionListener implements ActionListener{public void actionPerformed(ActionEvent e){TextField tf=(TextField)e.getSource();System.out.println(tf.getText());tf.setText("");}}

//TestTextField.java 更改回顯字元import java.awt.*;import java.awt.event.*;class TestTextField{public static void main(String[] args){new TFFrame();}}class TFFrame extends Frame{TFFrame(){TextField tf=new TextField();add(tf);tf.addActionListener(new TFActionListener());tf.setEchoChar('*');pack();setVisible(true);}}class TFActionListener implements ActionListener{public void actionPerformed(ActionEvent e){TextField tf=(TextField)e.getSource();System.out.println(tf.getText());tf.setText("");}}

//加法計算機import java.awt.*;import java.awt.event.*;class TestTFMath{public static void main(String[] args){new TFMath();}}class TFMath extends Frame{TextField a=null;TextField b=null;TextField c=null;TFMath(){a=new TextField();b=new TextField();c=new TextField();Button plus=new Button("計算");Label lbPlus=new Label("+");Label lbIs=new Label("=");plus.addActionListener(new ActionListener_plus(this));setLayout(new FlowLayout());add(a);add(lbPlus);add(b);add(lbIs);add(c);add(plus);pack();setVisible(true);}}class ActionListener_plus implements ActionListener{/*TextField a,b,c;ActionListener_plus(TextField a,TextField b,TextField c){this.a=a;this.b=b;this.c=c;}*/TFMath tm=null;ActionListener_plus(TFMath tm){this.tm=tm;}public void actionPerformed(ActionEvent e){int i_a=Integer.parseInt(tm.a.getText());int i_b=Integer.parseInt(tm.b.getText());tm.c.setText(""+(i_a+i_b));}}

//匿名內部類事件監聽器import java.awt.*;import java.awt.event.*;class TestTFMath{public static void main(String[] args){new TFMath();}}class TFMath extends Frame{TFMath(){final TextField a=new TextField();final TextField b=new TextField();final TextField c=new TextField();Button plus=new Button("計算");Label lbPlus=new Label("+");Label lbIs=new Label("=");plus.addActionListener(new ActionListener(){public void actionPerformed(ActionEvent e){c.setText(""+(Integer.parseInt(a.getText())+Integer.parseInt(b.getText())));}});setLayout(new FlowLayout());add(a);add(lbPlus);add(b);add(lbIs);add(c);add(plus);pack();setVisible(true);}}

//TestActionEvent2.javaimport java.awt.*;import java.awt.event.*;public class TestActionEvent2{public static void main(String[] args){Frame f=new Frame("TestActionEvent");Button btn_start=new Button("Start");Button btn_stop=new Button("Stop");Monitor bh=new Monitor();btn_start.addActionListener(bh);btn_stop.addActionListener(bh);f.add(btn_start,BorderLayout.WEST);f.add(btn_stop,BorderLayout.EAST);f.pack();f.setVisible(true);}}class Monitor implements ActionListener{public void actionPerformed(ActionEvent e){System.out.println("Button " + e.getActionCommand() + " Pressed!");}}