Develop Reference

call JFrame from active running or background JFrame without calling new JFrame

I am having problem with JFrames.
Currently I have 2 JFrames running,
MainFrame with a button to call Frame2.
And from Frame2 with JButton, I wan to call the current running/background MainFrame without calling another new MainFrame.
Actually I am making a search function on Frame2 and when click button search, wanna display the results in the Main Frame.

If Frame2 inherits MainFrame then do this:
Frame2.getParent().getBackground();

There are a multitude of solutions for such problems. It really depends on what best suits your use case.
In the example below I use an interface to issue callbacks to MainFrame from Frame2. I assume the latter is a member of MainFrame. This sort of solution makes it easy for you to use the same Frame2 implementation in multiple implementations of MainFrame (a common search for more than one frame).
Note that code below is just skeleton code to demonstrate the pattern being used.
public class Frame2 extends JFrame {
private final Controller controller;
private JButton button;
public Frame2(Controller controller) {
this.controller = controller;
button = new JButton("Search");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// do search and create result object
Object results = new Object();
Frame2.this.controller.displaySearchResults(results);
}
});
}
public interface Controller {
// users implement this
public void displaySearchResults(Object results);
}
}
public class MainFrame extends JFrame {
private Frame2 search;
private JButton button;
public MainFrame() {
search = new Frame2(new ControllerImplementation());
button = new JButton("Show search");
button.addActionListener(new ShowSearch());
}
private class ShowSearch implements ActionListener {
public void actionPerformed(ActionEvent e) {
search.setVisible(true);
}
}
private class ControllerImplementation implements Frame2.Controller {
public void displaySearchResults(Object results) {
// display results by accessing members of MainFrame
}
}
}
This may help you achieve what you want.

Linking two frames in java

I am creating a java application which consists of two frames(JFrame1 and JFrame2)
JFrame1 has a grid 6x6 button; and JFrame2 has 6 radio buttons representing colours. How can I link the two frames so that when a button in JFrame1 is clicked, JFrame2 pops up and when a colour is chosen from that the JFrame2 closes and the clicked button gets the respective colour?

It is better to have one JFrame for every application. Use one for the 6x6 JButtons and create a modal JDialog for your color JRadioButtons.
The color selection JDialog should have a public getSelectedColor() method in order to return the selected color to the caller class.
Instantiate the ColorDialog in main and do not set it visible.
The ActionListener of each JButton should make the modal JDialog visible.
The RadioButton ActionPerformed should set the selected color and make the JDialog invisible.
Call getSelectedColor() and apply the returned color to your JButton.

In your frame1's button action listner, you can do something like this
public void actionPerformed(ActionEvent e) {
Frame2 frame = new Frame2(this);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
where "this" refers to the frame1 object. This is you can access its jTEXTFIELD and jBUTTONs from the second frame. So naturally you have store it in Frame1 object declared in your second class.
Suppose you have a clickable color field in frame2 object, once you click on it, you should trigger a function that get the input field from frame1 (using your locale object reference) and store it in it. something like this:
public void actionPerformed(ActionEvent e) {
frame1.getMyTextField().setText(WHAT_THE_CLICKED_ON);
this.close();
}
Sorry if I made any syntax errors, it's been a long time I didnt work with java :)

Just create another class, let us say FrameMananger, then use the singleton pattern to manage them.
Then in any class, you can use FrameManager.getFrame1() to get the frame1, same as the frame2. You can add logic judgement inside, like dynamically dispose some frame or only create them when needed.
This issue is fairly common concept when you create a game and try to navigate between your every view(like the show score panel from everywhere).
public class FrameManager
{
Frame1 frame1;
Frame1 frame2;
public static Frame1 getFrame1()
{
if(frame1 == null)
frame1 = new Frame1();
return frame1;
}
public static Frame1 getFrame2()
{
if(frame2 == null)
frame2 = new Frame1();
return frame2;
}
public class Frame1 extends JFrame
{
}
public class Frame2 extends JFrame
{
}
}

getContentPane and linking GUIs together

I'm having trouble with getContentPane() in my GUI.
public class CryptoMainMenu extends JPanel implements ActionListener {
public CryptoMainMenu()
{
Templates template = new Templates();
//setting up the primary panel
primaryPanel = new JPanel();
primaryPanel.setLayout(new BorderLayout());
//setting up algorithm button
algorithm = new JButton("Algorithm");
algorithm.addActionListener(this);
add(primaryPanel);
setSize(730, 400);
}
}
public class CryptoCategoriesMenu extends JFrame implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
if (event.getSource() == back)
{
CryptoMainMenu main = new CryptoMainMenu();
main.setVisible(true);
this.setVisible(false);
}
}
}
In CryptoMainMenu if I'm extending JPanel I can't use getContentPane().add(primaryPanel), but if I just have add(primaryPanel), then my program isn't working because I linked all of my GUI classes together, so that when it gets to CryptoCategoriesMenu, and if I try pressing the JButton back, CryptoMainMenu shows as blank window. Is there something similar to getContentPane() that I can use with JPanel?
Edit:
This is suppose to a menu type GUI. In CryptoMainMenu, it displays a GUI where the user can press a button and it leads to another GUI which is CryptoCategoriesMenu. In CryptoCategoriesMenu, it shows another set of buttons and one of them is back. When I just have add() and I press back, CryptoMainMenu doesn't show up and that's the problem I'm having.

Passing values between JFrames

I have two Jframes where frame1 has some text fields and when a button on frame1 is clicked, I open another JFrame which contains a search box and a JTable containing search results.
When I click on a result row on JTable, I want that particular values to be reflected in the frame1 text fields.
I tried passing the JFrame1's object as a parameter but I have no clear idea on how to achieve this.
Any help would be highly appreciated.
Thanks

First of all, your program design seems a bit off, as if you are using a JFrame for one of your windows where you should in fact be using a JDialog since it sounds as if one window should be dependent upon the other.
But regardless, you pass references of GUI objects the same as you would standard non-GUI Java code. If one window opens the other (the second often being the dialog), then the first window usually already holds a reference to the second window and can call methods off of it. The key often is when to have the first window call the second's methods to get its state. If the second is a modal dialog, then the when is easy -- immediately after the dialog returns which will be in the code immediately after you set the second dialog visible. If it is not a modal dialog, then you probably want to use a listener of some sort to know when to extract the information.
Having said this, the details will all depend on your program structure, and you'll need to tell us more about this if you want more specific help.
For a simple example that has one window open another, allows the user to enter text into the dialog windows JTextField, and then places the text in the first window's JTextField, please have a look at this:
import java.awt.Window;
import java.awt.Dialog.ModalityType;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class WindowCommunication {
private static void createAndShowUI() {
JFrame frame = new JFrame("WindowCommunication");
frame.getContentPane().add(new MyFramePanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
// let's be sure to start Swing on the Swing event thread
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
class MyFramePanel extends JPanel {
private JTextField field = new JTextField(10);
private JButton openDialogeBtn = new JButton("Open Dialog");
// here my main gui has a reference to the JDialog and to the
// MyDialogPanel which is displayed in the JDialog
private MyDialogPanel dialogPanel = new MyDialogPanel();
private JDialog dialog;
public MyFramePanel() {
openDialogeBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
openTableAction();
}
});
field.setEditable(false);
field.setFocusable(false);
add(field);
add(openDialogeBtn);
}
private void openTableAction() {
// lazy creation of the JDialog
if (dialog == null) {
Window win = SwingUtilities.getWindowAncestor(this);
if (win != null) {
dialog = new JDialog(win, "My Dialog",
ModalityType.APPLICATION_MODAL);
dialog.getContentPane().add(dialogPanel);
dialog.pack();
dialog.setLocationRelativeTo(null);
}
}
dialog.setVisible(true); // here the modal dialog takes over
// this line starts *after* the modal dialog has been disposed
// **** here's the key where I get the String from JTextField in the GUI held
// by the JDialog and put it into this GUI's JTextField.
field.setText(dialogPanel.getFieldText());
}
}
class MyDialogPanel extends JPanel {
private JTextField field = new JTextField(10);
private JButton okButton = new JButton("OK");
public MyDialogPanel() {
okButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
okButtonAction();
}
});
add(field);
add(okButton);
}
// to allow outside classes to get the text held by the JTextField
public String getFieldText() {
return field.getText();
}
// This button's action is simply to dispose of the JDialog.
private void okButtonAction() {
// win is here the JDialog that holds this JPanel, but it could be a JFrame or
// any other top-level container that is holding this JPanel
Window win = SwingUtilities.getWindowAncestor(this);
if (win != null) {
win.dispose();
}
}
}
You'd do a very similar technique to get information out of a JTable.
And again, if this information doesn't help you, then please tell us more about your program including showing us some of your code. The best code to show is a small compilable example, an SSCCE similar to what I've posted above.

Performing action when closing JFrame

In my program I have a main JFrame that holds a button. When this button is clicked a new JFrame appears in which I can change some information. Whenever I finish editing I press a save button on the new JFrame which saves the changes and disposes the JFrame. Now when this is done, I'd like to perform an action in the main JFrame as well, but only if something changed. If I open the new JFrame and just close it again without using the save button, I don't want to do anything in the main frame.
I've tried searching the web for a solution, but just don't seem to be anything useful out there..
An example of the code I've got so far:
Main Frame...
public class MainFrame extends JFrame
{
public MainFrame()
{
super("Main Frame");
JButton details = new JButton("Add Detail");
add(details);
details.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
new DetailFrame().setVisible(true);
}
});
}
}
Detail Frame...
public class DetailFrame extends JFrame
{
public DetailFrame()
{
super("Detail Frame");
JButton save = new JButton("Save");
add(save);
save.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
// Save whatever content
dispose();
}
});
}
}
So when I click the "Save" button on the Detail Frame, I want to do something in the Main Frame, whereas when the "x" is clicked on the Detail Frame, I don't want to do anything..
Hope someone is able to help me, and sorry for my english..

You can pass a MainFrame handle to the DetailFrame constructor. Then, on clicking the Save button, the DetailFrame would call a function in MainFrame and pass the changes to it.
Another way is to create a public boolean variable in DetailFrame and set it to true when the Save button is clicked. This way MainFrame will know whether the DetailFrame was closed or Save'd.
EDIT: Some more ideas:
Use JDialog instead of JFrame. JDialog.setVisible is modal, i.e. it will block the calling function until the dialog is closed; this way you can process the results of the dialog in the same "Details" button listener.
To access the dialog after it is called, store the dialog in a separate variable. First construct the dialog, then show it, and then process the result by analyzing its variables.
Store the results of editing in other public variables of DetailFrame (or let's call it DetailDialog). This should happen only when the "Save" button is clicked. This may even allow to go without the boolean variable (depends on the types of values you are editing).
DetailDialog dlg = new DetailDialog();
dlg.setVisible(true);
if(dlg.approvedResult != null) {
// process the result...
}
EDIT: Sorry, JDialog is not modal by default. Need to call a special super constructor to make it modal.
Also, here you will have to pass the reference to MainFrame to the dialog constructor, but you still can declare it as a simple JFrame and avoid unnecessary dependencies.
To get the reference to the enclosing MainFrame from within the anonymous ActionListener, use MainFrame.this.
To be able to change the button text after it was created, you will have to store the button in a member variable.
Main Frame...
public class MainFrame extends JFrame
{
private JButton details = new JButton("Add Detail");
public MainFrame()
{
super("Main Frame");
getContentPane().add(details);
details.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
DetailDialog dlg = new DetailDialog(MainFrame.this);
dlg.setVisible(true);
if(dlg.approved){
details.setText("Edit Detail");
}
}
});
}
}
Detail Dialog... (not Frame)
public class DetailDialog extends JDialog
{
public boolean approved = false;
public DetailDialog(JFrame parent)
{
super(parent,"Detail Dialog",true); // modal dialog parented to the calling frame
JButton save = new JButton("Save");
getContentPane().add(save);
save.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
// Save whatever content
approved = true;
dispose();
}
});
}
}

Create the detail frame in the main frame, and add a windowlistener to it, using the windowadapter class. Implement the windowclosing event by checking for changes, handle those, and then dispose the detail frame. This is all done in the mainframe.
The detail frame should have do nothing on close set to prevent the detail frame being disposed before you recorded the changes.
You may wish to implement checking for changes in the detailframe as a method returning a class holding the interesting data. That way your windowlistener can be small an to the point.

Forget the 2nd JFrame. use a modal dialog instead. It will block input until dismissed. Once dismissed, the only thing to do is decide whether to update the original data. JOptionPane has some inbuilt functionality that makes that easy. If the user presses Cancel or the esc key, the showInputDialog() method will return null as the result.
import java.awt.BorderLayout;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
class EditInfo {
public static void main(String[] args) {
Runnable r = new Runnable() {
public void run() {
final JFrame f = new JFrame("Uneditable");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel p = new JPanel(new BorderLayout(10,10));
final JTextField tf = new JTextField("Hello World!", 20);
tf.setEnabled(false);
p.add(tf, BorderLayout.CENTER);
JButton edit = new JButton("Edit");
edit.addActionListener( new ActionListener(){
public void actionPerformed(ActionEvent ae) {
String result = JOptionPane.showInputDialog(
f,
"Edit text",
tf.getText());
if (result!=null) {
tf.setText(result);
}
}
} );
p.add(edit, BorderLayout.EAST);
p.setBorder(new EmptyBorder(10,10,10,10));
f.setContentPane(p);
f.pack();
f.setLocationByPlatform(true);
f.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
}
If it is necessary to edit a number of fields all at once in the JOptionPane, use a JPanel to contain them all, and put them in a showMessageDialog() call. Check the integer based return result to determine if the user OK'd the changes.