Develop Reference

JPanel, problems with resizing

I'm a newbie.
Trying to make auto resize border. I made border on my frame with 2 panels. I added panels with border into first panel.
I want border which retreated from all edges. In this border panel I also added text panel and button.
When I expand the window, or resize it panel with border is resizing too. But there is not indents from edges when I am using BorderLayout.
public class App {
private JFrame frame;
private JPanel panel;
private JPanel panel_1;
private JTextField textField;
private JButton addBtn;
public static void main(String args[]) {
App app = new App();
app.initialize();
app.frame.pack();
app.frame.setVisible(true);
}
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 800, 600);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel = new JPanel();
frame.getContentPane().add(panel, BorderLayout.NORTH);
panel.setLayout(new BorderLayout(0, 0));
panel_1 = new JPanel();
panel_1.setPreferredSize(new Dimension(784, 40));
panel_1.setBorder(new LineBorder(new Color(0, 0, 0)));
panel.add(panel_1, BorderLayout.CENTER);
textField = new JTextField();
textField.setPreferredSize(new Dimension(6, 24));
panel_1.add(textField);
textField.setColumns(50);
addBtn = new JButton("Add");
addBtn.setPreferredSize(new Dimension(70, 24));
panel_1.add(addBtn);
}
}
This is with BorderLayout - http://snag.gy/S43C2.jpg.
Also I tried with FlowLayout in panel - http://snag.gy/ndjDG.jpg
Can you help me please?

The problem is that because you set the border on a panel that you add into BorderLayout.NORTH. When you resize the window, BorderLayout.NORTH section will only resize horizontally, that's why the border will not be resized correctly.
public static void main(String args[]) {
JavaApplication11 app = new JavaApplication11();
app.initialize();
app.frame.pack();
app.frame.setVisible(true);
}
private JFrame frame;
private JPanel panel;
private JTextField textField;
private JButton addBtn;
private void initialize() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel = new JPanel();
frame.add(panel);
Border border = new CompoundBorder(new EmptyBorder(5, 10, 15, 20), new LineBorder(Color.BLACK));
panel.setBorder(border);
textField = new JTextField(50);
panel.add(textField);
addBtn = new JButton("Add");
panel.add(addBtn);
}

I'm assuming that this is the GUI you're trying to create.
To create this GUI, you need to use multiple JPanels with more than one Swing layout manager.
Here's the hierarchy of Swing components I would use.
JFrame - border layout
JPanel - main panel, border layout
JPanel - text, button panel, border layout, border north
JTextField - border center
JButton - border east
JScrollPane - border center
JTable
JPanel - button panel, flow layout, border south
JButton (3)
You get the spacing by setting an empty border on the JPanels and JScrollPane. The empty border can be as wide as you wish.

How to resize a JPanel

I am trying to resize the JPanels but there is a space under it . Here is a link to show :
And this is the code :
import java.awt.*;
import javax.swing.*;
public class Ex1 extends JFrame{
private JTextArea textarea = new JTextArea ();
private JTextField field = new JTextField ();``
private JButton buton = new JButton ("Trimite");
public Ex1(){
JPanel panel = new JPanel (new BorderLayout(2,2));
JPanel panel1 = new JPanel (new BorderLayout(2,2));
JPanel panel2 = new JPanel (new BorderLayout(2,2));
JLabel label1 = new JLabel ("Mesaje");
JLabel label2 = new JLabel ("Scrieti un mesaj");
panel1.setPreferredSize(new Dimension(350,100));
panel2.setPreferredSize(new Dimension(350,25));
panel1.add(label1, BorderLayout.NORTH);
panel1.add(textarea, BorderLayout.CENTER);
panel2.add(label2, BorderLayout.WEST);
panel2.add(field, BorderLayout.CENTER);
panel2.add(buton, BorderLayout.EAST);
setLayout(new GridLayout(2,1,1,1));
panel.add(panel1, BorderLayout.NORTH);
panel.add(panel2, BorderLayout.CENTER);
add(panel);
}
public static void main(String[] args) {
JFrame frame = new Ex1();
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}

You are setting a layout for a frame to GridLayout in which all components are given equal size. You have two rows, add(panel) adds the panel to the first row of the grid. The second row is left empty. See How to Use GridLayout.
Comment out setLayout(new GridLayout(2,1,1,1)); and the extra space should go away. When you comment this line the layout of frame's content pane will be BorderLayout. The default layout of the JFrame is BorderLayout. So add(panel); will add the panel to the center of the frame's content pane. As a result the panel should occupy all the available space.
As a side note, avoid setPreferredSize(), usually it is not necessary, see Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing for details.
You can specify the number of rows and columns for a text area and wrap it in the scroll pane, ie:
textArea = new JTextArea(5, 20);
JScrollPane scrollPane = new JScrollPane(textArea);
For more details see How to Use Text Areas
EDIT: example of getPreferredSize()
import java.awt.BorderLayout;
import java.awt.Dimension;
import javax.swing.*;
public class Ex1 extends JPanel{
private JTextArea textarea = new JTextArea ();
private JTextField field = new JTextField ();
private JButton buton = new JButton ("Trimite");
public Ex1() {
setLayout(new BorderLayout());
JPanel panel1 = new JPanel (new BorderLayout(2,2));
JPanel panel2 = new JPanel (new BorderLayout(2,2));
JLabel label1 = new JLabel ("Mesaje");
JLabel label2 = new JLabel ("Scrieti un mesaj");
panel1.add(label1, BorderLayout.NORTH);
panel1.add(new JScrollPane(textarea), BorderLayout.CENTER);
panel2.add(label2, BorderLayout.WEST);
panel2.add(field, BorderLayout.CENTER);
panel2.add(buton, BorderLayout.EAST);
add(panel1, BorderLayout.CENTER);
add(panel2, BorderLayout.SOUTH);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(350, 300);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationByPlatform(true);
Ex1 panel = new Ex1();
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
});
}
}

You need to resize the JFrame not the JPanel. Try:
this.setPreferredSize(new Dimension(350, 25);// in Ex1
Or in your main method:
frame.setPreferredSize(new Dimension(350, 25);

JPanels: One with a JTextArea and another with a JLabel

I've been at this for a good while now, but I cannot seem to get a hand of it. I'm trying to produce a JPanel that has a JTextArea above and two JLabels below, but my JLabel ends up on the left side of my JTextArea and I cannot make the other appear.
Here's my code (sorry for the display stuff- just filler really):
public JPanel contentPane() {
JPanel something = new JPanel();
String information = "Please";
info = new JTextArea(information, 4, 30);
info.setEditable(false);
info.setLineWrap(true);
info.setWrapStyleWord(true);
JPanel one = new JPanel(new BorderLayout());
one.setBackground(Color.WHITE);
one.setLocation(10, 10);
one.setSize(50, 50);
one.add(info, BorderLayout.CENTER);
something.add(one, BorderLayout.NORTH);
JPanel two = new JPanel(new BorderLayout());
two.setBackground(null);
two.setLocation(220, 10);
two.setSize(50, 50);
two.add(new JLabel("Please work"), BorderLayout.EAST);
two.add(new JLabel("Oh gosh, please"), BorderLayout.WEST);
something.add(two, BorderLayout.SOUTH);
something.setOpaque(true);
return something;
}
public static void GUI() {
JFrame frame = new JFrame("You Guessed It!");
DisplayStudent panel = new DisplayStudent();
frame.setContentPane(panel.contentPane());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 150);
frame.setVisible(true);
}
Please and thank you to anyone who takes the time to help.

When you create you something, you don't specify any layout manager, but later on you attempt to add one to something using BorderLayout constants -- which will not work, since the default layout manager for a JPanel is FlowLayout.
Try this instead;
JPanel something = new JPanel(new BorderLayout());

drag and drop of jcomponents in java in rum time

I can do this:
I have a JFrame with 2 JPanel objects. In the panel on the left, I want to put the components of Java Swing useful for the construction of an user interface. The panel on the right is empty.
On run-time, my user should to be able to copy with drag and drop drag from one panel to another the selected component. But the copied component on the right panel, can be moved or deleted.
I have created the panel, but I don't know if is better inserire the component as image, label or true component.. and how to make this possible..
This is my panel for the customization.. I have to insert the component in the JTabbedPane in the PanelSx..
public class Customize extends JFrame {
private JPanel panelSx, panelCx, panelMobile;
private JButton buttonSave;
private TabbedPaneComponents tpc;
public Customize(){
Container c = getContentPane();
c.setLayout(new BorderLayout());
setResizable(true);
setTitle("Design Preview");
setSize(800, 650);
setLocation(250,50);
panelSx = new JPanel();
panelSx.setPreferredSize(new Dimension(300, 200));
panelSx.setOpaque(true);
panelSx.setBackground(Color.RED.darker());
panelCx = new JPanel();
panelCx.setPreferredSize(new Dimension(200, 200));
panelCx.setOpaque(true);
panelCx.setBackground(Color.BLUE);
// display panel
panelMobile = new JPanel();
panelMobile.setPreferredSize(new Dimension(300,500));
panelMobile.setOpaque(true);
panelMobile.setBackground(Color.PINK.darker());
panelMobile.setFocusable(false);
buttonSave = new JButton("Save");
panelCx.add(panelMobile);
c.add(panelSx, BorderLayout.WEST);
c.add(panelCx, BorderLayout.CENTER);
tpc = new TabbedPaneComponents();
panelSx.add(tpc);
}
}
public class TabbedPaneComponents extends JTabbedPane{
private JPanel panel1,panel2,panel3;
public TabbedPaneComponents(){
panel1 = new JPanel();
panel1.setPreferredSize(new Dimension(200,300));
addTab("Form Widgets", panel1);
panel1 = new JPanel();
panel1.setPreferredSize(new Dimension(200,300));
addTab("Text Field", panel2);
panel1 = new JPanel();
panel1.setPreferredSize(new Dimension(200,300));
addTab("Other", panel3);
}
}

I would have to suggest using a JToolBar because of it's built in drag'n'drop features. I would put the component inside of the toolbar.

Adding components into JPanel inside a JFrame

Since im a beginner and i don't want to get involved with the layout managers, i was simply adding a JPanel into my main JFrame and giving spesific location to each component in the panel. But somehow the output appears way too wrong..
frame = new JFrame(email + " (Offline)");
frame.setSize(400, 400);
frame.setLocation(0, 0);
frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
frame.setLayout(new FlowLayout());
frame.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
// out.println("BYE");
// out.flush();
frame.dispose();
thread.stop();
}
});
panel = new JPanel();
frame.add(panel);
chat = new JTextArea();
chat.setSize(400, 200);
chat.setLocation(0, 0);
chat.setEditable(false);
panel.add(chat);
panel.validate();
JLabel you = new JLabel("You:");
you.setSize(you.getPreferredSize());
you.setLocation(0, 210);
panel.add(you);
panel.validate();
input = new JTextArea();
input.setSize(200, 200);
input.setLocation(0, 220 + chat.getSize().height);
panel.add(input);
panel.validate();
send = new JButton("Send");
send.setSize(send.getPreferredSize());
send.setLocation(210, 220 + chat.getSize().height);
panel.add(send);
panel.validate();
frame.setVisible(true);
The outcome of this frame is that text areas are invisible, a You: label in the middle and next to the right of it the button.. What am i missing here?

Again, don't use null layout since it makes updating and maintaining your GUI much more difficult than it should be, and can lead to ugly GUI's if you plan on having them run on multiple platforms. Instead
Use several JPanels, each one holding a core group of components and each using its best layout manager
Nest these JPanels in other JPanels that use the best layout manager to display them
and that will allow your GUI to be resizeable without need of extra code.
Put your JTextAreas in JScrollPanes so that you can see all text even if it goes beyond the text area.
Never set the size of the JTextArea as that will not allow it to scroll. Instead set its columns and rows.
As a very simple example, run this to see what I mean:
import java.awt.*;
import javax.swing.*;
public class FooSwing2 {
public static void main(String[] args) {
JTextArea chatArea = new JTextArea(8, 40);
chatArea.setEditable(false);
chatArea.setFocusable(false);
JScrollPane chatScroll = new JScrollPane(chatArea);
JPanel chatPanel = new JPanel(new BorderLayout());
chatPanel.add(new JLabel("Chat:", SwingConstants.LEFT), BorderLayout.PAGE_START);
chatPanel.add(chatScroll);
JTextField inputField = new JTextField(40);
JButton sendBtn = new JButton("Send");
JPanel inputPanel = new JPanel();
inputPanel.setLayout(new BoxLayout(inputPanel, BoxLayout.LINE_AXIS));
inputPanel.add(inputField);
inputPanel.add(sendBtn);
JPanel youLabelPanel = new JPanel(new FlowLayout(FlowLayout.LEFT, 0, 0));
youLabelPanel.add(new JLabel("You:"));
JPanel mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.PAGE_AXIS));
mainPanel.add(chatPanel);
mainPanel.add(Box.createVerticalStrut(10));
mainPanel.add(youLabelPanel);
mainPanel.add(inputPanel);
JFrame frame = new JFrame("Foo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
This would result in a simple (non-functioning) GUI that looked like this:
Now say you want to change this and add another button, an "exit" JButton to the right of the send JButton. If you used null layout, you'd have to resize your GUI, you'd have to move the send button over to the left and make sure that your math was without error, etc. If you used layout managers, you'd need just two new lines of code (to change the display, not the functionality of course):
JTextField inputField = new JTextField(40);
JButton sendBtn = new JButton("Send");
JButton exitBtn = new JButton("Exit"); // ***** added
JPanel inputPanel = new JPanel();
inputPanel.setLayout(new BoxLayout(inputPanel, BoxLayout.LINE_AXIS));
inputPanel.add(inputField);
inputPanel.add(sendBtn);
inputPanel.add(exitBtn); // ***** added
That's it, and this would display: