为什么我这个java程序中i和j的值传不出去？

Question

double i,j;
jia1 = new JTextField();
jia1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
String s1=jia1.getText();
Double i = Double.parseDouble(s1);
}
});
jia1.setBounds(210, 184, 66, 21);
frame.getContentPane().add(jia1);
jia1.setColumns(10);

JLabel jia = new JLabel("+");
jia.setBounds(286, 187, 12, 15);
frame.getContentPane().add(jia);

jia2 = new JTextField();
jia2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String s2=jia1.getText();
Double j = Double.parseDouble(s2);
}
});
jia2.setBounds(300, 184, 66, 21);
frame.getContentPane().add(jia2);
jia2.setColumns(10);

JLabel dengyu = new JLabel("=");
dengyu.setBounds(376, 187, 12, 15);
frame.getContentPane().add(dengyu);

txtJiajieguo = new JTextField();
txtJiajieguo.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
double sum=i+j;
String s = String.valueOf(sum);
txtJiajieguo.setText(s);
}
});
txtJiajieguo.setBounds(398, 184, 66, 21);
frame.getContentPane().add(txtJiajieguo);
txtJiajieguo.setColumns(10);

Answer 1

去掉actionPerformed方法 i 和 j 前面的Double，你相当于初始化了一个内部变量