如何将值从JTextField存储到局部变量？

Question

I want to store the value from TextField to a local variable so I can get the value by reference it from other package

I have tried a few way to solve this myself, but I found the value null.

private JButton execute = new JButton("Execute");
public JTextField radius = new JTextField(5);


    // Find the result.
    gc.gridx = 2;
    gc.gridy = 3;
    gc.weightx = 1;
    gc.weighty = 1;
    add(execute, gc);

    List<MainController> listeners = new ArrayList<MainController>();
    execute.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            for (MainController listener : listeners) {
                listener.notify(radius.getText());
            }
        }
    });
    add(execute, gc);

and the one below is the class I want to get the value

public class MainController extends JFrame {

private int radius;
private static final long serialVersionUID = 1L;

public void notify(String rad) {
    radius = Integer.parseInt(rad);
    System.out.println(radius);
}

}

What should I do to store the value to a local variable so that I can get the value from other package

Answer 1

From the code you have, I understand that when you press the button you want to save the text inside radius oa local variable, strRad, so later on you can access it from another class. If that is the case then you can maybe create a listener pattern yourself and then have something like:

private List<YourListener> listeners = new ArrayList<>(); 
.
.
.
execute.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        for (YourListener listener : listeners) {
           listener.notify(radius.getText());
        }
    }
});

You have to create the YourListener interface other class that wants to access the JTextField value would implement it.