How to minimize a JFrame window from Java?
minimize with frame.setState(Frame.ICONIFIED) restore with frame.setState(Frame.NORMAL)
jframe
What is the relation between ContentPane and JPanel?
It’s not two competing mechanisms – a JPanel is a Container (just look at the class hierarchy at the top of the JPanel javadocs). JFrame.getContentPane() just returns a Container to place the Components that you want to display in the JFrame. Internally, it’s using a JPanel (by default – you can change this by calling … Read more
How to switch JPanels in a JFrame from within the panel?
Like so : import java.awt.BorderLayout; import java.awt.CardLayout; import java.awt.Color; import java.awt.Dimension; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; public class CardLayoutDemo extends JFrame { public final String YELLOW_PAGE = “yellow page”; public final String RED_PAGE = “red page”; private final CardLayout cLayout; private final JPanel mainPane; boolean isRedPaneVisible; public CardLayoutDemo(){ setTitle(“Card Layout Demo”); setDefaultCloseOperation(EXIT_ON_CLOSE); setLocationRelativeTo(null); mainPane … Read more
How to add an image to a JFrame title bar?
Since JPanel doesn’t have a title bar, I’m assuming that you’re referring to JFrame. That being said, use setIconImage(…). Here is an example of using setIconImages(). import java.awt.Image; import javax.swing.*; import javax.imageio.ImageIO; import java.net.URL; import java.util.*; class FrameIcons { public static void main(String[] args) throws Exception { URL url16 = new URL(“http://i.stack.imgur.com/m0KKu.png”); URL url32 = … Read more
How to add JCheckBox in JTable?
Start with How to use tables. Your table model needs several things. It needs to return Boolean.class from the getColumnClass method for the appropriate column. You will need to override this method. The method isCellEditable will need to return true for the table column you want to make editable (so the user can change the … Read more
Why do we need to extend JFrame in a swing application?
You don’t need to extend JFrame and in fact many of us who do a lot of Swing programming make it a point not to extend this class. Myself, I try to extend classes where I plan on altering the innate behavior of the class — i.e., override one of the non-static methods of the … Read more
Drag and Resize undecorated JFrame
You can check out mr Rob Camick’s ComponentResizer class. Pretty simple and straight forward to use. Just instantiate the ComponentResizer and register the frame with something like: JFrame frame = new JFrame(); ComponentResizer cr = new ComponentResizer(); cr.registerComponent(frame); cr.setSnapSize(new Dimension(10, 10)); cr.setMaximumSize(new Dimension(…)); cr.setMinimumSize(new Dimension(…)); Here’s a complete example of using the class import java.awt.*; … Read more
How to use KeyListener with JFrame?
The rectangle is not moving because you are not using JFrame correctly. You have to assign frame to new mainFrame() instead of ignoring the instantiated mainFrame object. There are several other issues as @MadProgrammer points out. Here is the code that fixes some of the issues: mainFrame.java import java.awt.*; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import javax.swing.JFrame; … Read more
Center JDialog over parent
On the JDialog you’ve created you should call pack() first, then setLocationRelativeTo(parentFrame), and then setVisible(true). With that order the JDialog should appear centered on the parent frame. If you don’t call pack() first, then setting the location relative to the parent doesn’t work properly because the JDialog doesn’t know what size it is at that … Read more
Why are my items not showing up in JFrame?
but when i run it i get this: You get an empty screen because you add the components to the frame after the frame is visible. As has already been suggested you need to use an appropriate layout manager. FlowLayout is the easiest to start with. invoke setVisible(true) AFTER adding the components to the frame. … Read more