JTextArea中整数的增量值

Question

I have created a JTextField as follows:

  int val = 0;

 JTextArea area = new JTextArea(20,15);
 add(new JScrollPane(area), BorderLayout.CENTER);

I have added the value of val to the JTextArea:

 area.setText(String.valueOf(val));

I have created a button called"Inc" which increments the value of val by 1 and displays it in the JTextArea BUT IT IS NOT WORKING. The action listener is as follows:

  JMenuItem inc = new JMenuItem("Inc");
  menu.add(inc);


 JMenuItem
 inc.addActionListener(this);

 @Override
 public void actionPerformed(ActionEvent e) {
  // TODO Auto-generated method stub
    if(e.getActionCommand().equals("Inc")) 
      {
          int result= val + 1;
          area.setText(String.valueOf(result));
      }

Answer 1

You'll need to post a Minimal, Complete, and Verifiable example

In the meantime, it looks like val is an instance variable so will remain at 0 unless you change the value itself

val = val + 1;
area.setText(String.valueOf(val));

Answer 2

I think what you want in your action listener is:

public void actionPerformed(ActionEvent e) {
  if(e.getActionCommand().equals("Inc")) 
  {
      int result= Integer.parseInt(area.getText()) + 1;
      area.setText(String.valueOf(result));
  }