多项选择题
多项选择题
注意：请勿改动main( )主方法和其他已有语句内容，仅在下划线处填入适当的语句。
import java.awt.*;
import java.awt.event.*;
public class ex1_2 extends Frame implements ActionListener, ItemListener{
private Label l;
private String str="label";
private Choice choice1_2;
public static void main(String[] arg) {
new ex1_2();
}
ex1_2() {
setLayout( );
choice1_2 = new Choice();
choice1_2.addItem("item1");
choice1_2.addItem("item2");choice1_2. ;
add(choice1_2);
l=new Label(str);
add(l);
Button exit1_2 = new Button("exit");
exit1_2.addActionListener(this);
add(exit1_2);
for(int i=0; i<3; i++)
add(new Button("button" + i));
setSize(300,300);
pack();
show();
}public void actionPerformed(ActionEvent event) {
if(event.getActionCommand().equals("exit")) {
System.exit(0);
}
}
public void itemStateChanged(ItemEvent event){
str=choice1_2. getSelectedItem();
l.setText(str);
}
}