Question

我想在标签中使用当前可用的值并使用数字添加（计算）并显示在文本字段上但有错误

private void ch13ActionPerformed(java.awt.event.ActionEvent evt)     

    r1=Integer.parseInt(tLabel.getText());  //r2 and r1 are integers               

    // error .. It says "Void type not allowed here"
    r2 = Integer.parseInt(tLabel.setText(String.valueOf("3")));    


    result=r1+r2; 
    creaditTxt.setText(result+"");
}

然后我该如何解决这个问题？

Answer 1

setText()返回void。所以通过这样做

r2 = Integer.parseInt(tLabel.setText(String.valueOf("3")));

你说r2 =无效。那是不可能的。

您可能希望改为使用2个文本字段，并使用标签显示结果

public class AddFrame extends JFrame {
    private JLabel result = new JLabel();
    private JTextField number1 = new JTextField(10);
    private JTextField number2 = new JTextField(10);
    private JButton addBut = new JButton("Add");

    public AddFrame(){
        setLayout(new GridLayout(4, 1));
        add(result);
        add(number1);
        add(number2);
        add(addBut);

        addBut.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                int num1 = Integer.parseInt(number1.getText());
                int num2 = Integer.parseInt(number2.gettext());
                int total = num1 + num2;
                result.setText(String.valueOf(total));
            }
        });
    }

    public static void main(String[] args){
        SwingUtilities.invokeLater(new Runnable(){
            public void run(){
                AddFrame frame = new AddFrame();
                frame.pack();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });

    }

}

在java中标记与textField的连接

1 个答案: