Usage depends on whether the component’s parent has a layout manager or not. setSize() — use when a parent layout manager does not exist; setPreferredSize() (also its related setMinimumSize and setMaximumSize) — use when a parent layout manager exists. The setSize() method probably won’t do anything if the component’s parent is using a layout manager; … Read more
It’s not clear why you’re passing around byte[], but it looks like you want to update a component’s Icon with a gray thumbnail. The example below creates grayscale icons from existing sample icons and uses setIcon() to do the update. A similar approach works with any Image. See also this example that suggests ColorConvertOp, and … Read more
If you want the GUI to behave as if you clicked the X close button then you need to dispatch a window closing event to the Window. The ExitAction from Closing An Application allows you to add this functionality to a menu item or any component that uses Actions easily. frame.dispatchEvent(new WindowEvent(frame, WindowEvent.WINDOW_CLOSING));
The problem with your very nice example may be platform dependent, but I can offer a few observations: You’re not adding or removing components, so you don’t need revalidate(). Because the background color is a bound property of the buttons, you don’t need the subsequent calls to repaint(). You do need repaint() in your custom … Read more
Here first watch this small example, do let me know if you understood what is going on in here. Then only we will go a step further, slowly slowly. Try to go through this example, in which I am showing you how to draw on a JPanel import java.awt.*; import java.awt.image.BufferedImage; import java.io.IOException; import java.net.URL; … Read more
ComponentImageCapture.java import java.awt.BorderLayout; import java.awt.Component; import java.awt.Image; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.awt.event.ActionListener; import java.awt.event.ActionEvent; import java.awt.event.KeyEvent; import java.awt.event.InputEvent; import javax.swing.*; import javax.swing.border.TitledBorder; import javax.imageio.ImageIO; import java.io.File; /** Create a screenshot of a component. @author Andrew Thompson */ class ComponentImageCapture { static final String HELP = “Type Ctrl-0 to get a screenshot of the current … Read more
I’m just wondering whether it is good practice to use multiple JFrames? Bad (bad, bad) practice. User unfriendly: The user sees multiple icons in their task bar when expecting to see only one. Plus the side effects of the coding problems.. A nightmare to code and maintain: A modal dialog offers the easy opportunity to … Read more
Don’t put your code in the main method. Instead I’d put it into the class constructor for the class the holds the main method, in your case Kalkulator. Then instantiate Kalkulator in the main method. Kalkulator won’t be static, so you won’t recieve this message. If you want to know why you’re getting this error, … Read more
Get a map of the United States Draw it on a JPanel Add a click handler to the JPanel In the click handler, retrieve information where the user clicked from the event Have a set of polygons of all the state boundaries Iterate through all the poloygons to check if the user clicked inside one … Read more
In CreateNewJTextField: this.getContentPane().setLayout(new FlowLayout()); This create a Pane and sets a default layout. Pane is like a piece of paper on which you draw. JTextField field3 = new JTextField(10); add(field3); This creates a text field and adds it to that pane. In createAndShowGUI, you are adding this pane to a JFrame(the frame with minimize, close … Read more