Create Instance Of Class Used To Populate DefaultListModel When JList Item Selected
Jan 28, 2015
New to Java Swing. What I am trying to achieve here is to create an instance of the class used to populate the DefaultListModel when a JList item is selected. All examples I have seen show how to return the text displayed in the JList which really is of no practical use.
I have achieved what I want to achieve in that I am successfuly creating the selected object within my ListCellRenderer class.
For the purpose of testing I am using a call to the JOptionPane.showMessageDialog method to display the id of the selected object.
So, I launch the JFrame, the JList is populated, I select an item from the JList and the id value is displayed in the prompt. All this works fine except for one thing.
When I click OK on the JOptionPane.showMessageDialog prompt, the prompt disappears and reappears. The system seems to be in a loop. It is behaving as if the change or click event handler on the JList keeps firing.
This happens even without the creation of the object:
BookEntry be = (BookEntry)list.getModel().getElementAt(list.getSelectedIndex());
I have scoured the code and object properties to see if I can figure out where this behaviour is coming from without success.
All there is in the JFrame design view is a single JList with a variable name of "list". Everything else is in code as below:
Here is the .java code. Its not that complex
import java.awt.Color;
import java.awt.Component;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.ListCellRenderer;
import javax.swing.DefaultListModel;
public class NewJFrame3 extends javax.swing.JFrame {
I would like to create a sub menu for every list item in a Jlist. I need the UI like avast interface. If we hover over an list item, its sub menu should be shown. I attempted to put an sub menu but didn't work. Is this possible in Swing?
So in the code below I create an instance of my own triangle class and use one of its methods. The thing is I use one of my triangle classes methods in a method other the main method of my main program so I'm thinking it can't access it?
Any way here's the code for my triangle class
import java.util.Scanner; public class QudratullahMommandi_Triangle_06 { Scanner keyboard = new Scanner(System.in); private double side1; private double side2; private double side3;
[Code] ....
and here's the error message
QudratullahMommandi_S_06.java:46: error: cannot find symbol { triangle1.outPut(); ^ symbol: variable triangle1 location: class QudratullahMommandi_S_06 1 error
is there a good way to change the color of a JList item that isn't selected? I'm throwing my hand at building a client/server chat app and on the client side, I need to highlight the name of the person (which is in a JList) who has sent a message to the client GUI.
Create a class called Employee that includes three pieces of information as instance variables:
-Employee ID (string type) -first name (string type) (default value 'John') -last name (string type) (default value 'Smith') and -monthly salary (type double). -No argument constructor that initializes the three instance variables. The employee id should be generated using the following process:
The employee id should be a combination of first initial, last initial and a number starting from 10001 for the first employee and increasing by one for each employee. e.g. if John Smith is the first employee then its id will be JS10001 and if George Brown is the second employee then its id will be GB10002
-Provide get and set methods for each instance variable. The set method for monthly salary should ensure that its value remains positive - if an attempt is made to assign a negative value, leave the original value.
I was wanting to select an item in a comboBox and display it in a text field but all it's doing at the minute is retrieving the first item in the comboBox and placing that in the txt field
String value = (String) comboBoxEnv.getSelectedItem().toString(); if(comboBoxEnv.getSelectedItem()!= null){ txtTo.setText(value);
I have to use the company's login resource, which returns a login page for authentication after a browser/user page request; after successfully authenticated, the session attributes are set in a (remote) valued object (VO) invoked via servlet; then, such values are set in my (local) POJO.
I want to display the current user session attribute (see xChave below) and save it in database. How can I persist http User session attributes through the structure below?
Abstract Controller (just the main code):
public abstract class AbstractController<T> { @Inject private AbstractFacade<T> ejbFacade; private Class<T> itemClass; private T selected; private Collection<T> items; //GETTERS AND SETTERS OMMITED public AbstractController(Class<T> itemClass) { this.itemClass = itemClass; }
select 3 elements from the list: you'll see the log of the ChangeListener that tell you every time all items selected remove 1 element from previous selection: you will not receive the notification!!! remove the other two elements: only when the selection is empty you will see a new notification from changeListener...
I have a combobox with this PopupMenuListener. All works fine, except that the popupMenuWillBecomeInvisible method does not capture the selection made and neither does it show the selection.
PopupMenuListener pmlMqMessagePurged = new PopupMenuListener() { @SuppressWarnings("unchecked") public void popupMenuWillBecomeVisible(PopupMenuEvent arg0) { try { JdbcSqlServerDataSource ds = new JdbcSqlServerDataSource( DbConnectionURL.UToolDbHostName, 0,
[Code] .....
The popupMenuWillBecomeInvisible does fire but the System.out.println() returns 'nul'l as answer to the value i have selected from the combobox.
I'm working on my Android project where I created Expandablelistview with men's and women's sports. Now I have to populate each sport with my text data which contains events. I'm stack at this point, already tried few thing but that did not work. Here is my data how it looks like:
I have here my Main method where I have to pass data to each of my sports(activities). I tried to create a for loop and then pass result to my sport(activity) but I'm doing something wrong and can not get that work. Here is my code:
GroupedFeed findFeed(String locateSport){ //here I tried to create a loop which gonna search for certain sport in array list //and then pass it to gfResult. } public boolean onChildClick(ExpandableListView parent, android.view.View v, int groupPosition, int childPosition, long id) { switch (groupPosition)
.I was reading head first java book and saw a barbell question on page no. 280,question-"what if you want to write a class in such a way that only one instance of it can be created,and anyone who wants to use an instance of the class will always use that one,single instance?"
I am trying to create a GUI interface in swing which consists of four classes: a GUI class, which creates a main JPanel, a label, and a JList, which it takes from the second class, a MovesList class that contains a JList and the stuff needed to interface with it. It also has a main class, which basically just creates an object of the GUI class for the main window, and an Other class from which I would like to be able to add an item to the JList. I created methods in the MovesList class to get each component (like getMoveslist, or getMovesListScrollPane), which I then used to create the JList in the GUI class. I also created an addMove method so that I can add an item to the JList from any class through a MovesList object. However, this addMove method only works when called from the GUI or MovesList classes -- it does nothing when I collect from the Other class.
Here is my code:
//Main class public class TestProject { public static void main(String[] args) { GUI mainWindow = new GUI(); mainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
[Code] ....
When I run this code, I get a window with a JLabel that says "Moves," and a JList that contains five elements -- test 1-test 5, but not a sixth "test from other class." ( using the add move method ) However, when I click on the window, the addMove method is also called, and successfully adds "test 6" to the list.
I can't figure out where to create the StringHandler object. My code should take a string as input, then create StringHandler object ord with the string input. This should repeat until cancel is pressed, then ord should be sent to the Utskrift-method (a print method).
If I do like this, null is also sent to Utskrift. I dont want that to happen. If I put StringHandler last in the loop ord can not be resolved.
String text = ""; while (text != null){ text = showInputDialog(null, "Enter text:"); StringHandler ord = new StringHandler(text); if (text == null){ [Utskrift(ord.getNumber(), ord.getString(), ord.getWords()); break; } }
I have to make a cash register class that can be used with a RetailItem class that I did in another assignment. It should simulate the sale of an item. It should have a constructor that accepts a RetailItem object as an argument, and the constructor should also accept an integer that represents the quantity of the items being purchased.
I have no errors but here is the output I am getting:
How many candy bars are you buying? 5 Subtotal : $0.00 Sales tax : $0.06 Total : $0.06 BUILD SUCCESSFUL (total time: 3 seconds)
The code I have so far below:
CashRegister Class package cashregisterdemo; public class CashRegister { private RetailItem retailItem; private int quantityItems; private final double SALES_TAX = .06; private int Subtotal; public CashRegister()
public void randomCreate(ParentObject obj){ int x = random(0-4); //pseudo int y = random(0-4); //pseudo create new ParentObj(x,y); }
ParentObject is actually abstract, so you would only ever pass one of its children objects to it, and a child object of that type would be created. It seems like there should be a way to pass a type, rather than an object, and then create an instance later down, but I don't know if that is actually possible, or if it is poor programming style.
what have I done wrong n the following code? I'm trying to create a new instance carte of object Carti using the constructor and then to insert a row into a table created with SQL.The error I'm getting is:
Exception in thread "main" java.lang.NullPointerException at Carti.Carti.InsertCarti(Carti.java:103) at Main.main(Main.java:37) Java Result: 1 BUILD SUCCESSFUL (total time: 28 seconds)
The line Main.main(Main.java:37) is when I try to insert the row. The line Carti.Carti.InsertCarti(Carti.java:103) is when I do the PreparedStatement st = conn.prepareStatement("insert into Carti (Id,titlu" + ", descriere, autor, editie, anPublicare) values (?,?,?,?,?,?)");
I have to make two classes. The first one crates an instance of an array of several integers and prints data (average, greatest, lowest, et cetera) based on the second class, which contains the methods. I'm having a problem with the syntax for the first class required to use the methods.
Here's a shortened version of what I have right now just based on processing the number of integers in the array (because if I can get just one method properly connected, I could figure out everything else).
Driver
import java.util.Arrays; public class ArrayMethodsDriver { //Creates the ArrayMethods object public static void main(String[] args) { int[] a = {7,8,8,3,4,9,8,7};
[Code] ....
When I try to compile this, I currently get the "class expected" error on the count part.
package Threads; // THIS PROGRAM WILL HAVE TWO THREADS i.e. "main" AND ANOTHER THREAD (SYSTEM WILL NAME IT "Thread-0" //THE STORY IS THAT WE WILL START Thread-0 FROM main AND LET IT EXECUTE. //main WILL WAIT AND LET IT EXECUTE FOR 5 MINUTES. //IF IT FINISHES ITS EXECUTION BEFORE 5 MINUTES, WELL AND GOOD; //BUT IF IT DOESN'T, WE WILL INTERRUPT IT. //AFTER INTERRUPTION, WE WILL DECIDE TO WAIT INDEFINITELY.
public class SimpleThreadsCopy { public static void threadMessage(String s){ String sThreadName= Thread.currentThread().getName(); System.out.format("%s: %s%n", sThreadName, s);
[Code] ....
The statement against which I have written many *'s gives the following error.
No enclosing instance of type SimpleThreadsCopy is accessible. Must qualify the allocation with an enclosing instance of type SimpleThreadsCopy (e.g. x.new A() where x is an instance of SimpleThreadsCopy).
Now that a similar "error-free" code is given here, what's wrong with this piece of code and what should I do about it?
Trying to understand the error statement, I replaced the erroneous statement with
Java Code : Thread t= new Thread(new SimpleThreadsCopy().new MessageLoop()); mh_sh_highlight_all('java');
And the error got fixed. From that I understand that the inner class is just kinda a nonstatic member of the outer class and it will be accessed by the objects of the outer class only.
But then why doesn't the code in the tutorial give an error?
