My program compiles and runs ok how ever when i open my Jinternal frame and click on one of the JLabels i get a error on the Cmd ther error reads as follows
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at JLabelAssignment.mouseClicked(JLabelAssignment.jav a:429) at java.awt.Component.processMouseEvent(Component.jav a:6508) at javax.swing.JComponent.processMouseEvent(JComponen t.java:3320)
My program has a MainFrame(extends JFrame)class and BasePanel(extends JPanel) class,and many other panels.I had used Images with JLabel in BasePanel.My current panel in MainFrame is BasePanel.I had used MouseListener so that when I click on any of the label it should show Other panel in same MainFrame and hide the BasePanel.But I am getting some problem with that.When I click on the Label,It hides the BasePanel but do not show the new Panel(Dictionary Panel in my code). In short when label is clicked I want to make DictionaryPanel visible and BasePanel invisible,both in MainFrame. I am using the following code on Label:
//constructor of BasePanel class public BasePanel() { dict=new Dictionary(); mf=new MainFrame(); dictLabel.addMouseListener(new MouseListener() { public void mouseReleased(MouseEvent arg0) {
I am trying to make movingLabel move to a different JPanel each time the JButton is clicked. I can see that the random integer is changing each time the button is clicked, but the movingLabel wasn't doing anything. I noticed that if I click the button and then resize the JFrame with my mouse, it shows in the correct panel. Is there something I am missing, or is there a way to make it automatically display in the correct panel without having to manually resize the JFrame each time? I was thinking that I could add something that resizes the window slightly each time the button is clicked to show it, but I don't think that is probably the "right" way to do it.
import javax.swing.*; import java.awt.*; import java.awt.event.*; import java.util.Random; public class JMovingFrame extends JFrame implements ActionListener
I am adding JLabels to my JPanel, and the last one always does not show up. For example if I add 3 JLabels, the 3rd will not show up. If i change it to add 4, the 4th will not show up, but the 3rd will now. Here is a snipit of what my code looks like:
A workaround that I DO NOT want to keep doing is to put an extra fake JLabel at the end of the for loop, that way everything I want to show up does, but the fake one does not.
I'm having some problems with the graphics of my hangman game. The graphic that's supposed to show up on the first guess (the hangman pole) doesn't show up until guess number 2. And on the eighth guess, no graphics show up (I just get a blank frame).
import java.awt.*; import javax.swing.*; public class HangmanFigure extends JPanel { private int guesses; private Image background; public HangmanFigure() { super();
class A { List<StringBuilder> list; public void output(List<StringBuilder> objectToOutput){ try(BufferedWriter bw = new BufferedWriter(new FileWriter("temp.txt"))){ for(StringBuilder row:objectToOutput) bw.write(row.toString()); }catch(IOException e){}
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Why don't the a's show up on the console? I put them in as part of the debugging process and now I don't understand why they don't show up in both places.
How do i make the 'date' column show only the date and 'timeIn' and 'timeOut' column only show the time. In my database table my 'date' column is a date type and 'timeIn' and 'timeOut' column is time.
I am trying to Make A GUI which has a Jcombo box i also want it to have a jlabel that up dates depending on which option the user selects from the JcomboBox
for exampl if i select lion i want it to say you chose lion on the Jlabel and if i choose ostrich i want it to say ostrich and so on
I'm having problems getting my program to display a JLabel. The program draws shapes of random size and color across a panel. I have this part working. (There is more code for the drawing of shapes, I left it out for easier reading). When I try to add a JLabel in the main method, it does not display.
import javax.swing.JFrame; import javax.swing.*; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class TestDraw {
I am trying to move a JLabel in a JPanel, but can't seem to make it work. I can't provide a compiling code, but a few fragments. I have a JLabel [] array. i want to move with the mouse elements of this array. Let's say i want to move JLabel[i]. I implemented this:
Java Code:
static int labelY; static Point labelX; static Boolean flag = false; jLabel[i].addMouseListener(new MouseAdapter(){ public void mousePressed(MouseEvent evt){ labelY=evt.getY();
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I used the bool flag because i can't make changes to the label when it is inside an anonymous class. I also tried using setLocation but that did not work also. I don't get any errors when compiling. But when i run it and try to drag the JLabel[i] i get a long list of errors:
Java Code:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at puzzle.hw$1$2.mouseDragged(hw.java:276) at java.awt.Component.processMouseMotionEvent(Unknown Source) at javax.swing.JComponent.processMouseMotionEvent(Unknown Source) at java.awt.Component.processEvent(Unknown Source) at java.awt.Container.processEvent(Unknown Source)
I read many posts online and watched tutorials on YouTube. I can't seem to get this work. Notice I am not using any drawing/graphics capabilities - I'd like to keep it this way as we have not gotten that far yet in my studies.The image is in a source folder titled Images under/in my project.
Java Code:
private JPanel jpImage = new JPanel(); private JLabel lblImage; private ImageIcon image; private Image img; // All those above defined prior to method // Within method (relevant to code above) ...
I have tried to set a background Image to a calculator usinf JLabel. However I've ended up with my image to the left of my calculator , my calculator textfield becoming the size of the background image and then all my buttons below it. Like so(if you can view the image)..Calculator.jpg
How can I fix this so the background is behind my buttons and my text area is a normal size again.
I am currently trying to make a method that will enable a jLabel to be dragged across the screen. I want to be able to drag the object pretty much anywhere on the screen(I hope to eventually make a destination for it where it can be dropped but I will get to that later). I have looked on various places on the internet on how to achieve this and the most simple solution does something like this:
Java Code:
jLabel6.setText("jLabel6"); jLabel6.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() { public void mouseDragged(java.awt.event.MouseEvent evt) { jLabel6MouseMoved(evt); } }); private void jLabel6MouseDragged(java.awt.event.MouseEvent evt) { x = evt.getX();
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This actually works somewhat but it is very faulty. For example the jLabel keeps appearing and reappearing as I drag it. Furthermore when I drag it I can see a duplicate Jlabel being dragged as well in the top left hand screen. So how might I fix this?
I have a JFrame with four JPanels, SensorLL, SensorLC, SensorCR and SensorRR. They are instances of the class SensorUI. Each has a JLabel called Sensor.
The class SensorUI has a method writeSensor that writes to the JLabel "Sensor". I will have four temperature sensors. I have not started the code to read the temperature sensors yet. I will have a timer that will run once a second. When it fires I will read the sensors and display the result in the
JLabel "Sensor" in each jPanel.
I use MyMain to call FrameDemo and create the JFrame and a method
in FrameDemo to add the JPanels using addObject.
I can use SensorLL.writeSensor will write text to JLabel Sensor while in Mymain.
Then I start the timer ReadSensor.
When it times out it calls SampleSensors
For an experiment, while in SampleSensors I try to write to the JLabel in the instance SensorLL with
SensorLL.writeSensor("xx_");
I can't because it says it can't find the symbol variable SensorLL in SampleSensors class.
How can I "get to" that JLabel text when ever I need to?
Java Code:
public class MyMain { /** * @param args the command line arguments */ public static void main(String[] args) { // TODO code application logic here //SensorUI SensorLL = null; System.out.println("Start of main"); //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. FrameDemo.createAndShowGUI();
messageLabel = new JLabel("Top buttons change the panel color and bottom radio buttons change the text color."); messageLabel.setHorizontalTextPosition(SwingConstants.CENTER); messageLabel.setVerticalAlignment(SwingConstants.CENTER);
The text always displays in top-center part of the center panel. i want to align it as center-center horizontally and vertically. The problem could be, bcoz the jlabel text is inside a constructor but im not sure. The whole code is
import javax.swing.*; import java.awt.*; import java.awt.event.*; public class ColorSample extends JFrame { private JPanel TopPanel;
I've tried to add a background image to my calculator , however I have ended up with this ...Calculator.jpg
How do I fix it so the image is behind my buttons etc (as a background) And how do I fix my textarea so it is back to the normal size and not the height of the image? My code is below, please be specific.
import javax.swing.*; import java.awt.*; import java.awt.event.*; /** * Program using SWING components to create a Christmas themed Calculator. */
public class GridBag1 extends JFrame implements ActionListener { private JFrame window= new JFrame("Christmas Calculator");
I have four buttons with different names and depending on which button is pressed I want to change the label to be displayed. Center is the name of the label the other directions are buttons. The label should change if a different button is pressed. The error I get is that it cannot be converted to String.
public void actionPerformed(ActionEvent event){ Object source = event.getSource(); if (source == east){ center.setText(east); } if (source == west){ center.setText(west);
I'm trying to make a JLabel with an image fade in from transparent to fully visible.Is this possible with the JLabel itself or would I have to change the Image? If I'd have to change the Image's opacity how would I do this?