事件监听：当某个事件发生的时候，运行程序在干什么。如：点击按钮，输出hello；通过上下左右键控制方向等…
如：按下按钮，输出框输出hello
package 狂神说__Listener; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; public class TestActionEvent { public static void main(String[] args) { Frame frame = new Frame(); Button button = new Button(); MyActionListener myActeionListener=new MyActionListener(); button.addActionListener(myActeionListener);//需要一个接口 frame.add(button,BorderLayout.CENTER); frame.setBackground(Color.blue); frame.setBounds(200,200,600,400); frame.setVisible(true); windowsClose(frame); } //关闭窗口 private static void windowsClose(Frame frame){ frame.addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent e) { System.exit(0); } }); } } class MyActionListener implements ActionListener{ @Override public void actionPerformed(ActionEvent actionEvent) { System.out.println("hello word!"); } }
如：输入框的文字被监听，在输入框中输入文字，按下Enter键就会在输入区内输出文本框内容
package 狂神说__Listener; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; public class TestAction { public static void main(String[] args) { Myframe myframe = new Myframe(); windowsClose(myframe); } private static void windowsClose(Myframe frame){ frame.addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent e) { System.exit(0); } }); } static class Myframe extends Frame{ public Myframe(){ TextField textField = new TextField(); this.add(textField); //监听文本框输入的汉字 MyActionListener1 myActionListener1 = new MyActionListener1(); //按下enter，就会触发输入框事件 textField.addActionListener(myActionListener1); setVisible(true); setBounds(300,300,200,200); } } } class MyActionListener1 implements ActionListener{ @Override public void actionPerformed(ActionEvent actionEvent) { //获得资源，返回对象 TextField field=(TextField)actionEvent.getSource(); System.out.println(field.getText()); field.setText("");//Enter键触发后，文本框的内容会被清空 } }
