java - 如何在单击另一个 Jbutton 时更改 Jbutton 的功能？

Question

我正在编写一个程序，它将以磅为单位的重量转换为公斤，并将以公斤为单位的重量转换为磅。输出窗口如下:

当我想将公斤转换为磅时，我单击切换按钮，输出更改如下:

但问题是，当我单击“转换”时，它仍然将重量转换为千克而不是磅。

我希望在单击“切换”按钮时更改“转换”按钮的功能，以便将重量(公斤)转换为磅。请帮忙。

我的源代码如下:

public class convertApp extends JFrame implements ActionListener {
private JLabel poundlbl = new JLabel("Weight in Pounds");
private JLabel kglbl = new JLabel("Weight in Kilograms");

private JTextField poundbx= new JTextField(12);
private JTextField kgbx= new JTextField(12);

private JButton conbtn=new JButton("Convert");
private JButton switchbtn=new JButton("Switch");
private JButton newconbtn=new JButton("Convert");
private JPanel bxPanel = new JPanel();

public convertApp(){
    super("Weight Converter");
    bxPanel.setLayout(new GridLayout(5,29,5,5));
    bxPanel.add(poundlbl);
    bxPanel.add(poundbx);
    bxPanel.add(kglbl);
    bxPanel.add(kgbx);
    bxPanel.add(conbtn);
    bxPanel.add(switchbtn);

    //bxPanel.setBackground(Color.gray);



    this.setLayout(new GridLayout(1,1,0,0));
    this.add(bxPanel);



    this.setVisible(true);
    //what to do if i close
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    //put window in the center
    this.setLocationRelativeTo(null);
    //disable resize
    this.setResizable(false);
    //pack all the components within the window
    this.pack();

    conbtn.addActionListener(this);
    switchbtn.addActionListener(this);


}

public void actionPerformed(ActionEvent evnt){
   if(evnt.getSource()==conbtn){
        String poundtext = poundbx.getText();
        int pound = Integer.parseInt(poundtext);

        double kilo = pound * 0.453592;

        kgbx.setText(""+kilo);
    }

   else if(evnt.getSource()==switchbtn)
    {
        poundlbl.setText("Weight in Kilograms:");
        kglbl.setText("Weight in Pounds:");

        if(evnt.getSource()==conbtn){
        String kilotext = poundbx.getText();
        int kilo = Integer.parseInt(kilotext);

        double pound = kilo * 2.20462;

        kgbx.setText(""+pound);
        }

    }


}

}

Answer 1

创建 boolean 变量

boolean switch=true;

void kiloGramToPound{
//Convert Codes Here
}

void PoundToKiloGram{
//Convert Codes Here
}

转换按钮操作已执行

if(switch==true){
     kiloGramToPound();
}else{
     PoundToKiloGram();
}

切换按钮操作已执行

if(switch==true){
    switch=false;
}else{
  switch=true;
}