awt

问题 I'm a beginner when it comes to Java and I'm following the instructions from a book. I am going to create a FigurePanel with the following code: import java.awt.*; import javax.swing.*; public class TestFigurePanel extends JFrame{ public TestFigurePanel() { setLayout(new GridLayout(2, 3, 5, 5)); add(new FigurePanel(FigurePanel.LINE)); } } But at the "add(new FigurePanel(FigurePanel.LINE));" I get the following error: "Cannot find symbol: Symbol: class FigurePanel class: TestFigurePanel" I

问题 First of all: sorry, if this question was asked before, but I cannot seem to find an answer anywhere, so here we go: I am trying to get a canvas element to show while it being added to a panel with a titled border around the panel. Here is my code. public class TestClass extends JFrame{ private TestClass() { GuiCanvas canvas = new GuiCanvas(); setTitle("TestClass"); setDefaultCloseOperation(EXIT_ON_CLOSE); setSize(1300, 800); Border menuBorder = BorderFactory.createTitledBorder( BorderFactory

问题 I have a panel on which I want to draw stuff. Painting on it when it is beeing created is no problem. canvas = new Panel() { public void paint(Graphics g) { g.setColor(Color.WHITE); g.drawLine(0, 0, 10, 10); } }; But then I want to draw on it during runtime. By instinct, I've created something like this: Graphics g = canvas.getGraphics(); g.setColor(Color.GREEN); g.drawLine(10, 10, 20, 20); canvas.paint(g); Sadly, this doesn't work. This is probably a simple question but I cannot find a

问题 I am developing a virtual keyboard application. Everything works fine except that what ever i write is written into the present application only not the one that is running behind. I fell this is because ROBOT class in java only works for the application context that creates it. Is there a work around for this? Here is the code, i am trying to write ls in the terminal that is behind my java application: Robot robot = new Robot(); robot.keyPress(KeyEvent.VK_ALT); robot.keyPress(KeyEvent.VK_TAB

问题 This question already has answers here : Extending Swing's UndoManager to provide repeat and multiple undo/redo (2 answers) Closed 5 years ago . I am trying to create a little drawing pad in one of my programs. This is the class: class DrawPad extends JComponent { Image image; Graphics2D graphics; int currentX, currentY, oldX, oldY; public DrawPad() { setDoubleBuffered(false); addMouseListener(new MouseAdapter() { @Override public void mousePressed(MouseEvent e) { oldX = e.getX(); oldY = e

问题 I'm writing a simply chat client and am moving it over to a nice GUI. The constructor for the server side (client side is android) contains a list that's in the JFrame, and the first part of the server runs, but then the entire frame locks up. Does anyone see the issue? Sorry for the relatively disorganized, not cleanly commented code... Server: import java.awt.List; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintWriter; import

问题 I've looked around for ways to rotate BufferedImage s in Java and all I have found is AffineTransform . That's fine, but it seems like a bit of overkill if all I want to do is rotate 90 degrees. Would it be more efficient to just do it pixel-by-pixel? Is there some other method I could use? 回答1: From the Javadoc of the class you mention: Handling 90-Degree Rotations In some variations of the rotate methods in the AffineTransform class, a double-precision argument specifies the angle of

问题 I have Code where I can move image. Everything works well. here I have only one ImagePanel (children of JPanel) on the frame. Questions: I need to drag and drop image from one JPanel to another JPanel. Then I need to move dragged image to current panel . Can you give me an example code, please? class ImagePanel extends JPanel { int x, y; BufferedImage image; ImagePanel() { setBackground(Color.white); setSize(450, 400); addMouseMotionListener(new MouseMotionHandler()); Image img = getToolkit()

问题 I'm trying to make a gridbaglayout, to simply have the label atop the textbox atop the textview in a vertical window, but I'm getting the exception Exception in thread "main" java.lang.IllegalArgumentException: cannot add to layout: constraints must be a GridBagConstraint at java.awt.GridBagLayout.addLayoutComponent(GridBagLayout.java:685) at java.awt.Container.addImpl(Container.java:1072) at java.awt.Container.add(Container.java:957) at javax.swing.JFrame.addImpl(JFrame.java:540) at java.awt

问题 I have a JAR file generated by an ANT script with the following code in it: <manifest> <attribute name="Main-Class" value="org.epistasis.exstracs.Main"/> <attribute name="Class-Path" value="."/> <attribute name="SplashScreen-Image" value="logo_anim.gif"/> </manifest> <!--Some code--> <zipfileset dir="." includes="logo.png"/> <zipfileset dir="." includes="logo_anim.gif"/> <zipfileset dir="." includes="icon.png"/> When I run the JAR file, no splash screen is generated. I verified that the GIF