Develop Reference

JSplitPane ignoring alignment

Hello StackExchange community,
I'm at my wits end about this JSplitPane I'm trying to put into my frame, it is sitting on the right side of my frame instead of filling it up or atleast sitting on the left.
If anyone could help me with this issue I'd be very thankful.
See below an image of my problem and the code
The problem area is the pane with "tab1" and "tab2", the divider and the pane on the right side of that divider:
I've tried setting setAlignmentX(Component.LEFT_ALIGNMENT) on all the individual parts of the JSplitPane. I've also tried making a JPanel to hold it and aligning that. All to no avail.
Furthermore, existing information I've been able to find hasn't been relevant, mostly people discussing how to align the contents of the JSplitPane.
The code below is all that is needed to make this frame, if any of you need it to help me out feel free.
package test;
import java.awt.Color;
import java.awt.Component;
import java.util.ArrayList;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextField;
import javax.swing.ListSelectionModel;
public class FrameMaker {
public int x = 0;
private ArrayList<String> mpLabels;
private JFrame theFrame;
public void MakeFrame() {
theFrame = new JFrame("title");
theFrame.getContentPane().setLayout(new BoxLayout(theFrame.getContentPane(), BoxLayout.Y_AXIS));
mpLabels = new ArrayList<String>();
//label1
JPanel bgSwitches = new JPanel();
JLabel calcsLabel = new JLabel("top label, broadened with lines to exaggerate problem-------------------------------------------");
bgSwitches.add(calcsLabel);
//label2
JPanel topLevel = new JPanel();
JLabel textinfo = new JLabel("label below that");
topLevel.add(textinfo);
//splitpane tabs
mpLabels.add("tab1");
mpLabels.add("tab2");
String[] mpLabelsAr = new String[mpLabels.size()];
JList<String> posL = new JList<String>(mpLabels.toArray(mpLabels.toArray(mpLabelsAr)));
posL.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
//panel inside the right splitpane pane, this is needed for something later.
JPanel RPanel = new JPanel();
RPanel.setLayout(new BoxLayout(RPanel, BoxLayout.Y_AXIS));
JScrollPane scrollPos = new JScrollPane(posL);
JScrollPane scrollROI = new JScrollPane(RPanel);
JSplitPane posPanel = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,scrollPos,scrollROI);
posPanel.setOneTouchExpandable(false);
posPanel.setDividerLocation(75);
//label and textfield
JLabel msLabel = new JLabel("another label");
JTextField msField = new JTextField("textfield");
JPanel buttonPanel = new JPanel();
buttonPanel.add(msLabel);
buttonPanel.add(msField);
bgSwitches.setBackground(new Color(0,0,255));
theFrame.add(bgSwitches);
topLevel.setBackground(new Color(0,255,0));
theFrame.add(topLevel);
posPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
posPanel.setBackground(new Color(0,255,255));
theFrame.add(posPanel);
buttonPanel.setBackground(new Color(255,0,0));
theFrame.add(buttonPanel);
theFrame.pack();
theFrame.setVisible(true);
}
}

You need to align all of your other elements to the left as well.
bgSwitches.setAlignmentX(Component.LEFT_ALIGNMENT);
topLevel.setAlignmentX(Component.LEFT_ALIGNMENT);
buttonPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
You can also add posPanel.setResizeWeight(VALUE BETWEEN 0 AND 1); to specify what percent of the space the JSplitPane should occupy and it will resize with your window.

How to see the components inside a layered pane

I placed two components inside a JLayeredPane but I can't make them visible. Here is a fairly MCV code. How do I see my JTextField and JLabel inside the layeredPane?
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EtchedBorder;
public class GUI extends JFrame {
JFrame mainframe = new JFrame();
JPanel centrejPanel = new JPanel();
JTextField keyText;
JLabel jLabel;
public GUI() {
mainframe.setLayout(new BorderLayout());
mainframe.setSize(1200, 700);
mainframe.getContentPane().add(centrejPanel, BorderLayout.CENTER);
keyText = new JTextField("hello");
keyText.setOpaque(false);
keyText.setCaretColor(Color.BLACK);
keyText.setBorder(BorderFactory.createEtchedBorder(EtchedBorder.LOWERED));
jLabel = new JLabel("hello");
jLabel.setFont(new Font("Palatino", Font.BOLD, 18));
jLabel.setVerticalAlignment(JLabel.TOP);
jLabel.setForeground(Color.GRAY);
JLayeredPane layeredPane = new JLayeredPane();
layeredPane.add(keyText, 1);
layeredPane.add(jLabel, 0);
centrejPanel.getRootPane().add(layeredPane);
mainframe.setVisible(true);
}
}
public class Main {
public static void main(String[] args) {
GUI gui = new GUI();
}
}

//mainframe.setLayout(new BorderLayout());
Not needed. The default layout manager of the content pane of the frame is a BorderLayout.
//mainframe.getContentPane().add(centrejPanel, BorderLayout.CENTER);
Don't add an empty panel to the content pane of the frame. Just add the LayeredPane directly to the content pane.
keyText.setBounds(0, 50, 100, 20);
...
jLabel.setBounds(0, 150, 100, 20);
A JLayeredPane uses a null layout so it is your responsibility to set the size and location of each component added to the layered pane.
//centrejPanel.getRootPane().add(layeredPane);
Don't add the layered pane to the root pane. Don't even know if this will work but in any case the content pane will just cover the layered pane.
Read the section from the Swing tutorial on Using Top Level Containers to see how all the frame layers are structured.
mainframe.add(layeredPane);
Just add the layered pane directly to the content pane of the frame. Read the Swing tutorial on How to Use LayeredPane for more information and working examples.
Always start with examples from the tutorial when learning a new concept or component.

JLabel alignment in JPanel

I'm trying to align a JLabel to the right in a JPanel. I'm adding a JTabbedPane, a JPanel which contains my JLabel and JTextArea to a main JPanel.
I have searched SO and tried some methods like setAlignmentX, setHorizontalAlignment(SwingConstants.LEFT) and nested containers to no avail.
Here's my code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class LabelProblem
{
public static void main(String[] args)
{
JFrame frame = new JFrame("Label Problem");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel Main = new JPanel();
Main.setLayout(new BoxLayout(Main, BoxLayout.Y_AXIS));
JPanel ComponentPanel = new JPanel();
JLabel label = new JLabel("Sample Text");
label.setHorizontalAlignment(SwingConstants.LEFT);
label.setBorder(BorderFactory.createLineBorder(Color.BLACK));
label.setAlignmentX(Component.RIGHT_ALIGNMENT);
ComponentPanel.add(label);
JTabbedPane Tab = new JTabbedPane();
Tab.add("Document 1", new JPanel());
Main.add(Tab);
Main.add(ComponentPanel);
JTextArea Area = new JTextArea(10,10);
JScrollPane Scroll = new JScrollPane(Area);
frame.add(Main);
frame.add(Scroll, BorderLayout.SOUTH);
frame.setSize(450,450);
frame.setVisible(true);
}
}
How can I align my JLabel to the right?
Thanks!

So, the place of that label is determined by the layout of ComponentPanel. Since you didn't specify any layout it is using the default FlowLayout with a CENTER alignment. Assuming that you are ok with a FlowLayout it is a mere question of setting the alignment of the LEFT since this is possible with this layout.
Here's the code with the fix, however I suspect that as you put more elements to the ComponentPanel you will want to use another layout since FlowLayout is more adequate for menus and the like and not for displaying the main content.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.FlowLayout;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
class LabelProblem
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
initGUI();
}
});
}
public static void initGUI()
{
JFrame frame = new JFrame("Label Problem");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel main = new JPanel();
main.setLayout(new BoxLayout(main, BoxLayout.Y_AXIS));
JPanel componentPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
JLabel label = new JLabel("Sample Text");
label.setBorder(BorderFactory.createLineBorder(Color.BLACK));
componentPanel.add(label);
JTabbedPane Tab = new JTabbedPane();
Tab.add("Document 1", new JPanel());
main.add(Tab);
main.add(componentPanel);
JTextArea area = new JTextArea(10, 10);
JScrollPane scroll = new JScrollPane(area);
frame.add(main);
frame.add(scroll, BorderLayout.SOUTH);
frame.setSize(450, 450);
frame.setVisible(true);
}
}
Result:
Note: I also changed the variable names to follow the java style convention: variable names should start with lower case to differenciate them from clases names, starting in upper case.

One simple approach is to set the label's horizontalAlignment to JLabel.RIGHT in the constructor.
import java.awt.*;
import javax.swing.*;
class LabelProblem {
public static void main(String[] args) {
JFrame frame = new JFrame("Label Problem");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridLayout(0, 1));
JTabbedPane tab = new JTabbedPane();
tab.add("Document 1", new JPanel());
frame.add(tab);
JLabel label = new JLabel("Sample Text", JLabel.RIGHT);
frame.add(label);
JTextArea area = new JTextArea(10, 10);
JScrollPane scroll = new JScrollPane(area);
frame.add(scroll);
frame.pack();
frame.setSize(450, 450);
frame.setVisible(true);
}
}

I think it may be a matter of you not actually setting layouts where you imagine you're setting layouts.
You have a JPanel with a vertically oriented BoxLayout (Main) enclosing another JPanel with default layout (ComponentPanel), finally enclosing your label. The reason why your label can't be pushed to the right is because is already is pushed to the right within it's enclosing container. If you set a colored border around ComponentPanel, you'll see what I mean -- it only occupies the same amount of space as the JLabel, giving the JLabel nowhere to move.
You need to set a layout and constraints for your intermediate ComponentPanel, allowing it to horizontally fill its parent container so that the label has someplace to go.
You haven't really specified how your layout is supposed to look, but if you change the layout on Main to X_AXIS, your label will pop over to the left (as will its parent container). Without knowing what you're really trying to do, I can't say much more.
I would however, suggest you throw your BoxLayout away entirely and look into using GridBagLayout, which gives you a high level control over your UI. GridBagLayout isn't the most concise construct, but that's the price of control.

Add Multiple JPanels to JFrame

Been having a hard time adding JPanels to JFrame. Am pretty much new on java, always used C++
I need to do 4 Panels inside one Frame.
Here is my Code, just started today..
package project2;
import javax.swing.JOptionPane;
import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.BorderLayout;
import javax.swing.*;
import java.awt.Container;
import java.awt.Dimension;
public class GUI extends JFrame
{
private JPanel Checks; //Panel to Hold Checks
private JPanel Transactions;
private JPanel History;
private JPanel Graphics;
private JLabel CLabel;
public GUI()
{
super ( "UTB Check-In");
JPanel Checks = new JPanel(); //set up panel
CLabel = new JLabel("Label with text");
Checks.setBackground(Color.red);
Checks.setLayout( new BoxLayout(Checks,BoxLayout.LINE_AXIS));
add(Checks);
// JPanel Transactions = new JPanel();
// Transactions.setToolTipText("Electronic Transactions");
//Transactions.setBackground(Color.blue);
// add(Transactions);
}
}
I was trying to put Transaction and Checks one side from the other with different colors,in this case blue and red it doesnt stay in the middle it those one or the other.
One of my Colleagues told me that the BoxLayout(or any layout) needed to be implemented with the size..something to that extend. am not really sure I been reading
http://docs.oracle.com/javase/tutorial/uiswing/layout/box.html
But I still do not get it completely. If somebody can help me out
thanks!

Your code fail cause you are adding directly to the JFrame which have by default BorderLayout. You are setting BoxLayout to the wrong panel.
You have to setLayout() to the top component(jframe) that you are adding or as i prefer adding to a jpanel rather than directly to the jframe to acomplish what you want to do.
Example:
public GUI()
{
super ( "UTB Check-In");
JPanel parent = new JPanel();
parent.setLayout(new BoxLayout(parent,BoxLayout.LINE_AXIS));
add(parent);
JPanel Checks = new JPanel(); //set up panel
CLabel = new JLabel("Label with text");
Checks.setBackground(Color.red);
parent.add(Checks);
JPanel Transactions = new JPanel();
Transactions.setToolTipText("Electronic Transactions");
Transactions.setBackground(Color.blue);
parent.add(Transactions);
}
By the way, in Java variables starts with lowerCase as a code convention.

Image display in JFrame

I'm just wondering why this 100x100 px .gif image isn't showing up on the screen. The image is in the same directory, so the program should have no problem finding it. Does anybody know how to solve this problem?
import java.awt.*;
import java.awt.image.ImageObserver;
import java.io.File;
import javax.imageio.*;
import javax.swing.*;
public class Window extends JFrame{
//the pictures
ImageIcon guy = new ImageIcon("tester.gif");
JLabel pn = new JLabel(guy);
JPanel panel = new JPanel();
Window(){
super("Photuris Lucicrescens");
//Important
setSize(700,600);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(panel);
setVisible(true);
//Decoration
Image customIcon = Toolkit.getDefaultToolkit().getImage("iconImage.gif");
setIconImage(customIcon);
//Adding the image
add(pn);
}
}

The problem is that you add two components to the JFrame. When you add a Component to a JFrame, it actually adds it to its content pane. By default, the content pane uses the BorderLayout as its LayoutManager. If you don't set a constraint, the component is considered to be in the center. Therefore, here you have two components that are in the center and receives the same bounds from the LayoutManager, resulting in only one component to be shown, the other being hidden. This is why you see the JPanel and not the JLabel.
If you want to see the JLabel, then don't add that panel to the frame.
Other remarks:
setVisible() should be invoked after you have created your component hierarchy.

I try it on my computer and image is showing up on icon. If you want show the image on background try this :
import java.awt.Image;
import java.awt.Toolkit;
import javax.swing.*;
public class Caine extends JFrame{
//the pictures
ImageIcon guy = new ImageIcon("tester.gif");
JLabel pn = new JLabel(guy);
JPanel panel = new JPanel();
Caine(){
super("Photuris Lucicrescens");
//Important
setSize(700,600);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(panel);
setVisible(true);
JLabel im = new JLabel(new ImageIcon("iconImage.gif"));
setIconImage(customIcon);
panel.add(im);
add(pn);
}
}