Is it possible to have a panel within a panel in one method in Java?
Like If I created a JPanel within a method called, CreatePanel, could I add another one below it? I'm trying to add two or possibly three panels within one method but have not succeeded thus far.
If this is not possible, how would you create a JPanel, say LeftPanel, and add another JPanel within LeftPanel?
Any help with sources and clear explanation would be terrific because I'm a beginner at Java and sometimes when something you say might be obvious to you and all the CS-jocks but not to me.
What you ask is possible but i think you will learn more by reading the tutorial on layout managers than being given the answer. Please read up on layout managers and laying out components :)
http://docs.oracle.com/javase/tutorial/uiswing/layout/index.html
The basic premise would follow the same work flow for adding any other component to a panel...
You could do something like...
public JPanel createMasterPane() {
JPanel master = new JPanel(new BorderLayout());
JPanel leftPane = new JPanel();
leftPane.add(new JLabel("Left"));
master.add(leftPane, BorderLayout.WEST);
JPanel rightPanel = new JPanel();
rightPanel.add(new JLabel("Right"));
master.add(rightPanel, BorderLayout.EAST);
return master;
}
A better solution (IMHO) would be to separate the individual areas of responsibility and do something more like this...
public JPanel createLeftPane() {
JPanel leftPane = new JPanel();
leftPane.add(new JLabel("Left"));
return leftPane;
}
public JPanel createRightPane() {
JPanel rightPanel = new JPanel();
rightPanel.add(new JLabel("Right"));
return rightPanel;
}
public JPanel createMasterPane() {
JPanel master = new JPanel(new BorderLayout());
master.add(createLeftPane(), BorderLayout.WEST);
master.add(createRightPane(), BorderLayout.EAST);
return master;
}
You might like to spend some time looking through How to create a UI with Swing for more details...
Related
I'm using the NetBeans GUI builder to handle my layout (I'm terrible with LayoutManagers) and am trying to place a simple JLabel so that it is always centered (horizontally) inside its parent JPanel. Ideally, this would maintain true even if the JPanel was resized, but if that's a crazy amount of coding than it is sufficient to just be centered when the JPanel is first created.
I'm bad enough trying to handle layouts myself, but since the NetBeans GUI Builder autogenerates immutable code, it's been impossible for me to figure out how to do this centering, and I haven't been able to find anything online to help me.
Thanks to anybody who can steer me in the right direction!
Here are four ways to center a component:
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
class CenterComponent {
public static JLabel getLabel(String text) {
return getLabel(text, SwingConstants.LEFT);
}
public static JLabel getLabel(String text, int alignment) {
JLabel l = new JLabel(text, alignment);
l.setBorder(new LineBorder(Color.RED, 2));
return l;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JPanel p = new JPanel(new GridLayout(2,2,4,4));
p.setBackground(Color.black);
p.setBorder(new EmptyBorder(4,4,4,4));
JPanel border = new JPanel(new BorderLayout());
border.add(getLabel(
"Border", SwingConstants.CENTER), BorderLayout.CENTER);
p.add(border);
JPanel gridbag = new JPanel(new GridBagLayout());
gridbag.add(getLabel("GridBag"));
p.add(gridbag);
JPanel grid = new JPanel(new GridLayout());
grid.add(getLabel("Grid", SwingConstants.CENTER));
p.add(grid);
// from #0verbose
JPanel box = new JPanel();
box.setLayout(new BoxLayout(box, BoxLayout.X_AXIS ));
box.add(Box.createHorizontalGlue());
box.add(getLabel("Box"));
box.add(Box.createHorizontalGlue());
p.add(box);
JFrame f = new JFrame("Streeeetch me..");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setContentPane(p);
f.pack();
f.setLocationByPlatform(true);
f.setVisible(true);
}
});
}
}
By using Borderlayout, you can put any of JComponents to the CENTER area. For an example, see an answer to Stack Overflow question Get rid of the gap between JPanels. This should work.
Even with BoxLayout you can achieve that:
JPanel listPane = new JPanel();
listPane.setLayout(new BoxLayout(listPane, BoxLayout.X_AXIS ));
JLabel label = new JLabel();
listPane.add(Box.createHorizontalGlue());
listPane.add(label);
listPane.add(Box.createHorizontalGlue());
mKorbel's solution is perfect for your goal. Anyway I always like to suggest BoxLayout because it's very flexible.
Mara: "thanks for your response, however the NetBeans GUI Build uses GroupLayout and this is not overridable."
Not true! Right click anywhere inside JFrame (or any other GUI container) in NetBeans GUI builder and select "Set Layout". By default is selected "Free Design", which is Group layout, but you can select any other layout including Border layout as advised by mKorbel.
There's many ways to do this, depending on the layout manager(s) you use. I suggest you read the Laying Out Components Within a Container tutorial.
I believe the following will work, regardless of layout manager:
JLabel.setHorizontalAlignment(SwingConstants.CENTER)
I am working on a GUI in Java and I have the following code:
public class MainWindow extends JFrame {
public MainWindow () {
setUpWindow();
JPanel upperPanel = new JPanel();
JPanel lowerPanel = new JPanel();
upperPanel.setBorder(new LineBorder(Color.GRAY, 1));
lowerPanel.setBorder(new LineBorder(Color.GRAY, 1));
getContentPane().add(upperPanel, BorderLayout.NORTH);
getContentPane().add(lowerPanel, BorderLayout.SOUTH);
}
private void setUpWindow () {
setSize(600, 450);
setTitle("Subjects");
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
setLayout(new BorderLayout());
getRootPane().setBorder(BorderFactory.createMatteBorder(4,4,4,4,Color.LIGHT_GRAY));
setVisible(true);
}
}
If I compile this, the output I get is:
As you can see, I have one JPanel at NORHT and another one at SOUTH.
I want to add text in the border of a JPanel so I can get as an output something similar as this:
I have tried multiple things but I don't know how. Is there a JPanel method that does this? Should I create a JLabel and place it there somehow?
Thanks in advance.
What you're looking for is the BorderFactory. It can be applied like so:
upperPanel.setBorder(BorderFactory.createTitledBorder("Favorite subjects"));
For a detailed explanation of JPanels, Borders and what's possible (with examples), see the Oracle article How to Use Borders.
I currently have a Jframe that I want to add to a tab instead.
(I used a frame just for testing purposes, to make sure the look and feel is correct, but when trying to add it to a JTabbedPane, the frame starts to look blue (weird top aswell).
I tried copying my settings from my original frame to the new frame but that did not help.
JTabbedPane tabs = new JTabbedPane();
tabs.addTab("1", frame.getContentPane());
JFrame FinalFrame = new JFrame();
FinalFrame.setDefaultLookAndFeelDecorated(true);
FinalFrame.setSize(WIDTH, HEIGTH);
FinalFrame.setLocation(100, 150);
FinalFrame.setTitle("Primal-Pvm Notification center");
FinalFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
FinalFrame.add(tabs);
Side by side view of the problem and the frame before adding it to the tab:
Edit: Answer by George Z. helped me out a lot.
Like he said to solve the problem:
Don't add things to your main frame but add them to a Jpanel and add that to a JTabbedPane.
If you have a Jpanel that you are adding to a tab that contains an override in the paintComponent, you have to create that class as the Jpanel so:
JPanel panel = new LineDrawer([Enter parameters]);
panel.setLayout([Enter Layout]);
The way you are approaching this seems to be pretty complex hence this weird behavior. (Looks like a look and feel problem? - show the part of the code that sets it)
However, I suggest you to create only one JFrame (this question explains why you should do that), set the layout of its content pane to BorderLayout and keep it like this. Its a rare situation to mess up with content panes. After that create independent JPanels representing the tab(s) you would like to have. Finally create a JTabbedPane with these panels and add it to the content frame of the JFrame.
A small example would be:
public class TabbedPanelExample extends JFrame {
public TabbedPanelExample() {
super("test");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLayout(new BorderLayout());
JTabbedPane pane = new JTabbedPane();
pane.addTab("FirstTab", createFirstTab());
pane.addTab("SecondTab", createSecondTab());
add(pane);
setSize(400, 400);
setLocationRelativeTo(null);
}
private Component createFirstTab() {
JPanel panel = new JPanel(new FlowLayout());
panel.add(new JLabel("Some Component"));
panel.add(new JTextField("Some Other Component"));
return panel;
}
private Component createSecondTab() {
JPanel panel = new JPanel(new FlowLayout());
panel.add(new JLabel("Some Component"));
panel.add(new JButton("Some Other Component"));
return panel;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
new TabbedPanelExample().setVisible(true);
});
}
}
Post edit based on this comment:
Well I do have a Jframe with a lot of elements added to it so it kinda
is a hassle to switch it all to panels;
A JFrame cannot have a lot of elements. You take a look on how to use root panes. The container that "has a lot of elements" of a JFrame is its rootpane which is mostly completed by its contentpane. When you frame.add(component), you add the component to its content pane. Guess what? A JFrame's content pane is a JPanel. So are a already to panels.
Now in order to make this work, try to do as i said and frame.setLayout(new BorderLayout(); //changes layout to contentpane. Assuming you have a bunch of components (lets say comp1,comp2) and you are adding them like:
frame.add(comp1);
frame.add(comp2);
You must do the following in order to make it clear. Create a JPanel and instead of frame.add(comp1), do panel.add(comp1). So this JPanel has all the components you added in JFrame. After that create your JTabbedPane:
JTabbedPane pane = new JTabbedPane();
pane.addTab("tab", panel);
and finally add this pane to the content pane of your JFrame:
frame.add(pane);
In conclusion, you will move all the components you have added to your frame into a JPanel, add this JPanel to a JTabbedPane, and finally add this JTabbedPane to the frame (contentpane). Frame has only one component.
I am trying to make my first GUI-program and sofar everything went well, but now I have a problem:
First my Window had a minimum size and everything worek well, but now I dont want a minimum size, therefore I want a ScrollBar (vertical and horizonal) to be able to to see everything. I am trying to make this with a JScrollPane. The Problem is, that I have my program structured with a BorderLayout and I am not able to connect my JScrollPane with my BorderLayout. "JScrollPane Constructor is undefinied for BorderLayout". So I
initialized a JPanel and set the layout to my BorderLayout.
windowContainer = new JPanel(new BorderLayout(10, 10));
Then I can connect the "windowContainer"(JPanel) with my JscrollPane
windowScrollPane = new JScrollPane(windowContainer);
After changing the rest of the code (changed "getContentPane.add..." to "windowContainer.add...") I didnt become errors but the JScrollPane didnt work. In my BorderLayout (LINE_START) is a JPanel with a minimim width of "300", so at least if the window is thinner than 300px the ScrollBar should appaer.
I spend a lot of research on the iinternet but everything what i found was "How to create a JScrollPane in a BorderLayout" and not "How to create a JScrollPane around the BorderLayout".
To clarify it i will uploat a picture (the red things are the JScrollBars).
Sorry I wasnt allowed to upload pictures, so please look here: http://www.fotos-hochladen.net/view/jscrollpanepu20315v9x.png
And i dont know how much code i have to give you, because everything would be to much, so just say something if you need more.
Here is again the important code about it:
...
windowContainer = new JPanel(new BorderLayout(10, 10));
windowScrollPane = new JScrollPane(windowContainer);
frame.add(windowContainer);
...
PS: This is my first post, so please correct me if I did something wrong (about the post). And sorry for my english.
Try this code. Method initComponent() use in contructor, or in place where you build view. Below I put example of JFrame with BorderLaylout as you want:
public class TestWindow extends JFrame{
int containerHeigh=300;
int containerWitdh=400;
private JPanel container;
private JPanel westPanel;
private JPanel eastPanel;
private JPanel northPanel;
private JPanel southPanel;
private JPanel centerPanel;
private JScrollPane scroll;
public TestWindow(){
super("test");
initComponents();
}
private void initComponents(){
container=new JPanel();
westPanel=new JPanel();
eastPanel=new JPanel();
northPanel=new JPanel();
southPanel=new JPanel();
centerPanel=new JPanel();
//...fill panels of container
westPanel.setBackground(new Color(95,183,70));
eastPanel.setBackground(new Color(0,164,232));
northPanel.setBackground(new Color(255,255,185));
southPanel.setBackground(new Color(34,177,76));
centerPanel.setBackground(new Color(152,114,203));
scroll=new JScrollPane();
scroll.setViewportView(container);
BorderLayout containerLayout=new BorderLayout(containerHeigh, containerWitdh);
container.setLayout(containerLayout);
container.add(westPanel, BorderLayout.WEST);
container.add(eastPanel, BorderLayout.EAST);
container.add(northPanel, BorderLayout.NORTH);
container.add(southPanel, BorderLayout.SOUTH);
container.add(centerPanel, BorderLayout.CENTER);
add(scroll);
setVisible(true);
}
public static void main(String...args){
new TestWindow();
}
}
If you want you can use NetBeans for create Panels and other element of desctop applications. I generally build in NetBeans simple Panels, Dialog and then combine together dynamically in application. This provide me get user interface exactly what I want and prepare really fast.
I'm having some troubles with Java Swing.
I'm trying to make a frame with a control panel at the top with some buttons in it.
and below that i want a JTable to show
I've been trying but the table is not showing.
If I remove the controlPanel at the top, it sometimes shows and sometimes not.
The code that I use inside my constructor of my JTable is provided in the same application,
so it's no network error
public ServerMainFrame(GuiController gc){
this.gc = gc;
initGUI();
}
private void initGUI() {
System.out.println("initiating GUI");
createFrame();
addContentPanel();
addControls();
//openPopUpServerSettings();
addSongTable();
}
private void createFrame()
{
this.setTitle("AudioBuddy 0.1");
this.setVisible(true);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setSize(800, 600);
this.setResizable(false);
this.setLocationRelativeTo(null);
}
private void addContentPanel()
{
JPanel p = new JPanel();
p.setLayout(new FlowLayout());
p.setSize(new Dimension(800, 600));
this.setContentPane(p);
}
private void addControls()
{
JPanel controlPanel = new JPanel();
controlPanel.setLayout(new FlowLayout());
controlPanel.setBorder(BorderFactory.createLineBorder(Color.black));
controlPanel.setSize(700,100);
// Buttons
JButton play = new JButton("Play");
JButton pause = new JButton("Pause");
JButton stop = new JButton ("Stop");
JButton next = new JButton("Next");
JButton prev = new JButton("Previous");
controlPanel.add(play);
controlPanel.add(pause);
controlPanel.add(stop);
controlPanel.add(next);
controlPanel.add(prev);
// Currently playing
JLabel playing = new JLabel("Currently playing:");
controlPanel.add(playing);
JLabel current = new JLabel("Johnny Cash - Mean as Hell");
controlPanel.add(current);
this.getContentPane().add(controlPanel);
}
private void addSongTable()
{
JTable songTable = new JTable(Server.getSongTableModel());
songTable.setVisible(true);
JPanel tablePanel = new JPanel();
tablePanel.setVisible(true);
tablePanel.add(songTable);
songTable.repaint();
this.getContentPane().add(tablePanel);
JButton btnMulticastList = new JButton("send list to clients");
btnMulticastList.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
Server.MulticastPlaylist();
}
});
getContentPane().add(btnMulticastList);
}
if I remove the controlPanel at the top, it sometimes shows and
sometimes not.
everything is hidden in Server.getSongTableModel(), nobody knows without posting an SSCCE with hardcoded value returns from
GUI has issue with Concurency in Swing
XxxModel loading data continiously with building GUi, then exception caused described problems
The code that I use inside my constructor of my JTable is provided in
the same application, so it's no network error
no idea what you talking about
have to create an empty GUI, see InitialTread
showing GUI, then to start loading data to JTable
then starting Workers Thread (Backgroung Task) from SwingWorker or (descr. Network issue) better Runnable#Thread (confortable for catching an exceptions and processing separate threads)
output from Runnable to the Swing GUI must be wrapped into invokeLater()
If you want controls at the top of your window, and the table filling the majority of the window, then I'd suggest you try using BorderLayout instead of FlowLayout. Create it like this...
private void addContentPanel()
{
JPanel p = new JPanel();
p.setLayout(new BorderLayout());
p.setSize(new Dimension(800, 600));
this.setContentPane(p);
}
And add the components by specifying the location in the BorderLayout. In this case, the controls should be added to the top in their minimal size...
this.getContentPane().add(controlPanel,BorderLayout.NORTH);
And the table should be in the center, filling the remaining window space...
this.getContentPane().add(tablePanel,BorderLayout.CENTER);
In your case, you also have a button at the bottom...
getContentPane().add(btnMulticastList,BorderLayout.SOUTH);
For the layout you're after, BorderLayout is much more appropriate. The benefit of using BorderLayout here is that the components should be automatically resized to the size of the window, and you're explicitly stating where each component resides, so panels shouldn't not appear.
It would also be my recommendation that you find an alternative to calling getContentPane() in all your methods. Maybe consider keeping a global variable for the main panel, like this...
private mainPanel;
private void addContentPanel()
{
mainPanel = new JPanel(new BorderLayout());
mainPanel.setSize(new Dimension(800, 600));
this.setContentPane(mainPanel);
}
Then you can reference the panel directly when you want to add() components to it.
Finally, I'd also suggest using GridLayout for your controls, as it will allow you to place all your buttons in it, and they'll be the same size for consistency. Define it like this to allow 5 buttons in a horizontal alignment...
JPanel controlPanel = new JPanel(new GridLayout(5,1));
then you just add the buttons normally using controlPanel.add(button) and they'll be added to the next slot in the grid.
For more information, read about GridLayout or BorderLayout, or just see the Java Tutorial for a Visual Guide to Layout Managers to see what alternatives you have and the best one for your situation. In general, I try to avoid FlowLayout, as I find that there are other LayoutManagers that are more suitable in the majority of instances.