简单问题,请各位解答
fzymr 2002-04-14 03:56:29 import java.awt.*;
import java.awt.event.*;
public class myException extends Frame implements ActionListener,WindowListener
{
private TextArea ta;
public static void main(String args[])
{
myException test = new myException();
Button b1 = new Button("安全");
Button b2 = new Button("危险");
test.addWindowListener(test); **********
b1.addActionListener(test);
b2.addActionListener(test);
test.setLayout(new GridLayout(3,1));
test.add(b1);
test.add(b2);
test.ta = new TextArea(null,10,20,TextArea.SCROLLBARS_VERTICAL_ONLY);
test.add(test.ta); *******
test.setSize(300,300);
test.setVisible(true);
}
private void CheckButton(String label) throws exaException
{
ta.append("safe"); *******
...
}
...
}
请问一下,两个问题:
1,test.addWindowListener(test); 换成 test.addWindowListener(this),
我认为this就是指向test的
2, test.add(test.ta); 为什么不能改为test.add(ta)而在下面就可以直接调用