Design consideration

Hi guys,

im currently creating an application(Alarm Clock) which can be comprise of several frame interacting with each other. I will have one main frame with a menu calling the other frames. But im also considering the use of JPanel and just past it on the contentpane of the main frame.

Another thing is how would i maintain the communication between frames. Here is an example, lets say Frame1 was displayed and has a button to display a second frame. The second frame has a textfield on it.

If i will close frame2 i want that text on its textfield to be displayed on frame1.

thanks

make frame2 a modal dialog
then, in your actionListener that displays the dialog
String text = new MyDialog().getTextFieldValue();
//check text for null
frame1.setText(text)

the method getTextFieldValue() won't return until the dialog closes (if modal = yes)

@michael

are you referring to a dialog object? or a Frame object.. thanks

a dialog object

new MyDialog() would be your current frame2

@michael

what if i wanted to use a Frame object instead of a dialog. i still wanted the user to input some information. the new window will display several textfields.. How can my first frame communicate or get the values of the previous frame.

thanks

you just need to pass references between the objects.

here's a simple demo of one way.

click the button, enter some text into the textfield, click OK

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Frame1
{
  JLabel lbl = new JLabel("Hello World");
  public void buildGUI()
  {
    JButton btn = new JButton("Show Frame2");
    JFrame f = new JFrame();
    f.getContentPane().add(lbl,BorderLayout.NORTH);
    f.getContentPane().add(btn,BorderLayout.SOUTH);
    f.pack();
    f.setLocation(100,300);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setVisible(true);
    btn.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent ae){
        new Frame2().buildGUI(Frame1.this);
      }
    });
  }
  public static void main(String[] args)
  {
    SwingUtilities.invokeLater(new Runnable(){
      public void run(){
        new Frame1().buildGUI();
      }
    });
  }
}
class Frame2
{
  public void buildGUI(final Frame1 f1)
  {
    final JTextField tf = new JTextField(5);
    JButton btn = new JButton("OK");
    final JFrame f = new JFrame();
    f.getContentPane().add(tf,BorderLayout.NORTH);
    f.getContentPane().add(btn,BorderLayout.SOUTH);
    f.pack();
    f.setLocation(400,300);
    f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    f.setVisible(true);
    btn.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent ae){
        f1.lbl.setText(tf.getText());
        f.dispose();
      }
    });
  }
}

@mike

thanks. really a big help.

[ November 06, 2006: Message edited by: Cyrus Serrano ]

@mike,

you said this is just one solution, can you tell me another way to do this.

thanks again

because Frame2 is a JFrame, it needs a reference to Frame1 to pass the data to.
the reference in the example is the Frame1 instance.
the reference could be just the label.
in an actual program, it would generally be the Frame1 that is passed, and the
object (label) in Frame1 changed via a setter method (the label being private)

here's the same code, but using Frame2 as a JDialog.

no need to pass a reference, the method getData() does not return until the dialog closes,
due to setModal(true). This is not the same when Frame2 is a JFrame

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Frame1
{
  JLabel lbl = new JLabel("Hello World");
  public void buildGUI()
  {
    JButton btn = new JButton("Show Frame2");
    JFrame f = new JFrame();
    f.getContentPane().add(lbl,BorderLayout.NORTH);
    f.getContentPane().add(btn,BorderLayout.SOUTH);
    f.pack();
    f.setLocation(100,300);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setVisible(true);
    btn.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent ae){
        //new Frame2().buildGUI(Frame1.this);
        Frame2 f2 = new Frame2();
        f2.buildGUI();
        lbl.setText(f2.getData());
      }
    });
  }
  public static void main(String[] args)
  {
    SwingUtilities.invokeLater(new Runnable(){
      public void run(){
        new Frame1().buildGUI();
      }
    });
  }
}
class Frame2
{
  JTextField tf = new JTextField(5);
  //public void buildGUI(final Frame1 f1)
  public void buildGUI()
  {
    //final JTextField tf = new JTextField(5);
    JButton btn = new JButton("OK");
    //final JFrame f = new JFrame();
    final JDialog f = new JDialog();
    f.setModal(true);
    f.getContentPane().add(tf,BorderLayout.NORTH);
    f.getContentPane().add(btn,BorderLayout.SOUTH);
    f.pack();
    f.setLocation(400,300);
    //f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    f.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
    //f.setVisible(true);//<--------------moved, otherwise listener won't work
    btn.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent ae){
        //f1.lbl.setText(tf.getText());
        f.dispose();
      }
    });
    f.setVisible(true);
  }
  public String getData(){return tf.getText();}//<----returns data here
}

many thanks mike