how to set new text in JTextField after creation?

I have a jTextField , and I set it's value to a certain sum when I create the frame.

Here is the initiation code:

totalTextField.setText(
            itemsPriceText开发者_运维百科Field.getText() +           
                    Float.toString(orderDetails.delivery)
);

This textfield should show a sum of items selected by the user.

The selection is done on a different frame, and both frames are visible / invisible at a time.

The user can go back and forth and add / remove items.

Now, every time i set this frame visible again, I need to reload the value set to that field

(maybe no changes were made, but if so, I need to set the new correct sum) .

I'm quite desperate with it.

Can anyone please give me a clue?

Thanks in advance! :)

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Before setting the frame visible again, one should update the fields with the new values / states.
something like:

jTextField.setText("put your text here");  
jRadioButton.setSelected(!isSelected());  
.  
/* update all you need */
.  
jFrame.setVisible(true);

The frame will come up with the new values / states.

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Add a WindowListener to the frame. Then you can handle the windowActivated event and reset the text of the text field.

See How to Write Window Listeners.

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Use a DocumentListener triggering the JTextField public void setText(String t)

Here an example with DocumentListener:

public class SetTextInJTextField extends JFrame implements DocumentListener {

JTextField entry;
JTextField entryToSet = new JTextField();

public SetTextInJTextField() {
    createWindow();
    entry.getDocument().addDocumentListener(this);
}

private void createWindow() {
    JFrame frame = new JFrame("Swing Tester");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    createUI(frame);
    frame.setSize(560, 200);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
}

private void createUI(final JFrame frame) {
    JPanel panel = new JPanel();
    entry = new JTextField();
    entryToSet = new JTextField();

    LayoutManager layout = new BoxLayout(panel, BoxLayout.PAGE_AXIS);
    panel.setLayout(layout);

    panel.add(this.entry);
    panel.add(entryToSet);
    frame.getContentPane().add(panel, BorderLayout.CENTER);
}

public void setTextInTargetTxtField() {
    String s = entry.getText();
    entryToSet.setText(s);
}

// DocumentListener methods
public void insertUpdate(DocumentEvent ev) {
    setTextInTargetTxtField();
}

public void removeUpdate(DocumentEvent ev) {
    setTextInTargetTxtField();
}

public void changedUpdate(DocumentEvent ev) {
}

public static void main(String args[]) {
    //Schedule a job for the event dispatch thread:
    //creating and showing this application's GUI.
    SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            new SetTextInJTextField().setVisible(true);
        }
    });
  }
}

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inspired from: https://docs.oracle.com/javase/tutorial/displayCode.html?code=https://docs.oracle.com/javase/tutorial/uiswing/examples/components/TextFieldDemoProject/src/components/TextFieldDemo.java

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related lesson: https://docs.oracle.com/javase/tutorial/uiswing/components/textfield.html