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 created a instance of a class AddItemView, inside StartUpMenuController. I then passed it into the class, the main method is below showing that as well. However when I do this:
else if(e.getSource()==menu.addBtn) { new addItem(); }
I get an error, little red line on the bottom of the text. I am testing the frame at the moment to make sure it is what I want before I move on to the Controller side of it. I just want to display it and go from there.
package mainMenu.Home.DataBase; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import addItemBtn.Home.DataBase.AddItemView; public class StartUpMenuController { StartUpMenu menu; AddItemView addItem;
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Not sure if this is the issue but the class I am making a new instance of is in a different package. I imported the package though.
<%@ page language="java" isErrorPage="true" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Error</title> </head>
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I have put error.jsp and badpage.jsp file in public access folder that is web content in eclipsewhen I am running the code I am status code of 500 and not the errorpage.jsp message .
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 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 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?