I am having some issues with my GUI. I have a UserList GUI (not finished) that, on button click, will check for an open chat window and open a new window if none exists or add a tab if one does (this is working fine). My issue is that the listeners I added to my chat window only work for the last tab added. If I switch back to a previous tab, I can no longer use my input textField and send button to write to my textArea. I add listeners when I initially create the window and first tab. I thought about adding ChangeState listener, but couldn't work out how it would be any different than what I am doing now. Do I not fully understand how listeners are added to a particular object?
I will post my code for the whole class so you can get the full picture.
I am making an MVC program and I am not allowed to put the action listeners in the view class. I was able to get one button working fine but since I am unable to reference them I cannot give them both individual responses.
import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class Controller { HobbyList model; ListView view;
So I'm doing a basic MVC layout for a pretty basic game that I am making in order to understand the whole MVC layout. The game requires the user to move up/down/left/right via JButtons on the GUI. Since I'm using an MVC layout and my buttons are in a different class than the ActionListeners, I was wondering what the best way to add the action listeners are?
Method 1:
View Class ActionListener method: Java Code: public void addMovementListeners(ActionListener u, ActionListener d, ActionListener l, ActionListener r){ moveUp.addActionListener(u); moveDown.addActionListener(d); moveLeft.addActionListener(l); moveRight.addActionListener(r);
[Code] ....
Which method is better? Is there another method that is even better than these two? Trying to get this MVC thing down.
My output is all over the place. I cancelled out the borderlayouts beneath each panel I created and it completely changed the output, and I'm not sure why. The first photo below, shows what it looked like with the layouts and the second shows the output without. I still don't understand why I don't see the digits 1-9.
Java Code:
import javax.swing.*; import java.awt.*; import java.awt.event.ActionListener; public class Atm extends JFrame { Atm(){ super("ATM"); //Create Panels For ATM JPanel buttonPanel1 = new JPanel(); //To Contain Digits 1-9
[Code] ....
Why would setting the layout beneath each object change the layout so much? I stayed consistent in my use of BLayout and GLayout in the program.
How the event Listeners work in java,To get the data based on the event occurs in outside the application. I have this method in one of my API class I am not understanding how this methods are going to work.
public interface SBXPCXMLEventListener { public void OnReceiveEventXML(String eventXML); } private static List<SBXPCXMLEventListener> listenerList = new ArrayList<SBXPCXMLEventListener>(); protected static void fireXMLEvent(String xml) {
[Code] ....
I have done like this.This is used to capture the events from the fingerprint machine when run this class I am not getting any data from the machine when i did thumb impression in the machine.
public class EventListnere implements SBXPCXMLEventListener { public static void main(String[] args) { boolean flag = SBXPCProxy.ConnectTcpip(1, "10.0.0.8", 5005, 1234); System.out.println("flag = " + flag); // SBXPCProxy.st
So I'm doing a basic MVC layout for a pretty basic game that I am making in order to understand the whole MVC layout. The game requires the user to move up/down/left/right via JButtons on the GUI. Since I'm using an MVC layout and my buttons are in a different class than the ActionListeners, I was wondering what the best way to add the action listeners are?
So im making a calculator just basic 4 function with a clear button. as i am working into this project i am running into an issue of assigning which click sets what. For instance i click the two button how do i tell it to assign it to firstNum, versus secondNum?
private class theHandler implements ActionListener{ public void actionPerformed(ActionEvent event){ if(event.getSource()==one){ firstNum=1; } if(event.getSource()==two){ secondNum =2; } if(event.getSource()==three){ secondNum =3; }
So this for instance allows me to set one to the firstNum and then add it to two or three but im not sure what to do next. I have in my mind i want to do something like make three listener classes, that operate in sequential order like you pick the first numbers, click an operation, and then select the second numbers then hit the operation(equal) button to display answer. Am i on the right track or what?
I am having trouble with a jTable that I am using. I have set the listeners of the cells to save the information of the entire table every time they are modified, but run into the problem that the last modified cell does will not reflect its most recent value. The value will display visually, but not show up when I try to read from the cell. I have tried wrapping the saveProcGuide() call in swing's invokelater, but to no avail. I have marked the area where the problem becomes evident (values returned do not match those present in the visible table object). Below is the offending code:
// This is where I set up the listeners private void addProcGuideWithValues() { procTableModel.addRow(new Object[]{"", ""}); // document listener to be fed into editor/renderers for cells... DocumentListener docuListener = new DocumentListener() { public void changedUpdate(DocumentEvent e) { saveProcGuide();
Create an equals method that takes an object reference and returns true if the given object equals this object.
Hint: You'll need 'instanceof' and cast to a (Geocache)
So far I have:
public boolean equals(Object O){ if(O instanceof Geocache){ Geocache j=(Geocache) O; if (this.equals(j)) //I know this is wrong... but I can't figure it out return true; }
else return false; }
I think I have it correct up to the casting but I don't understand what I'm suppose to do with the this.equals(). Also I'm getting an error that I'm not returning a boolean... I get this all the time in other problems. I don't get why since I have to instances of returning booleans in this. "returns true if the given object equals this object" makes no sense to me. I assume the given object, in my case, is 'O'. What is 'this' object referring to?
I am new to Java and have read books, the Java docs, and searched the Internet for my problem to no avail. I have an Array of objects that contains strings. How can I get the object's strings to print in a list so that the user can select that object to manipulate its attributes? For example, the user can select "Guitar 1" from a list and manipulate its attributes like tuning it, playing it, etc. I have a class called Instruments and created 10 guitar objects.Here is the code:
Instrument [] guitar = new Instrument[10]; for (int i = 0; i < 10; i++) { guitar[0] = new Instrument("Guitar 1"); guitar[1] = new Instrument("Guitar 2"); guitar[2] = new Instrument("Guitar 3"); guitar[3] = new Instrument("Guitar 4"); guitar[4] = new Instrument("Guitar 5"); guitar[5] = new Instrument("Guitar 6");
Now lets say that I want to access a method 'addInterest()' that is in the 'SavingsAccount' class I would have to do: '((SavingsAccount)s).addInterest();'
The question I have is why do I have to cast 'b' to SavingsAccount? Isn't the actual object reference of 'b' already an instance of 'SavingsAccount' class? How does the 'BankAccount' affect the object itself? I'm really confused as to what class is truly getting instantiated and how BankAccount and SavingsAccount are both functioning to make the object 'b'.
I don't understand why the object reference variable 'a' cannot be recast from a thisA object reference to a thisB object reference.Is it the case that once a reference variable is linked to a particular object type then it cannot switch object types later on.I am facing the Java Associate Developer exam soon and I am just clearing up some issues in my head around object reference variable assignment,
class thisA {} class thisB extends thisA { String testString = "test";} public class CastQuestion2 { public static void main(String[] args) { thisA a = new thisA(); thisB b = new thisB();
I am trying to get this to where I can type in a name and it will search through each object and print back the corresponding object info.
Java Code:
import java.util.Scanner; public class MyPeople { public static void main(String[] args) { Person[] p = new Person[] { new Person("Chris", 26, "Male", "NJ", "Single"), new Person("JoAnna", 23, "Female", "NJ", "Single"), new Person("Dana", 24, "Female", "NJ", "Single"), new Person("Dan", 25, "Male", "NJ", "Single"), new Person("Mike", 31, "Male", "NJ", "Married") };
Task:The main method of the class Things below creates an object called printer deriving from the class PrintingClass and uses that object to print text. Your task is to write the PrintingClass class.
Program to complete: import java.util.Scanner; public class Things { public static void main(String args[]) { String characterString; Scanner reader = new Scanner(System.in); PrintingClass printer = new PrintingClass(); System.out.print("Type in the character string for printing: "); characterString = reader.nextLine(); printer.Print(characterString); } }
// Write the missing class here
Note: In this exercise the solution is part of a conversion unit where many classes have been declared. Because of this the classes are not declared as public using the public attribute.
Example output
Type in the character string for printing: John Doe
John Doe
My Class: class PrintingClass { public void print(){ System.out.println(characterString); } }
I have just started working with linked lists. I have a linked list of Objects and I want to be able to search for a specific object. But currently my code continues to return false. Also how would I go about removing the first index of the linked list.
public static void main(String[] args) { LinkedList<Cookies> ml = new LinkedList<>(); int choice = 0; while (choice >= 0) { choice = menu();
I am reading Head First: Java and got to Object References. In the book I got a little bit confused on what happens when two object reference's point at the same object so I wrote a small crude test, the below code. This of course clarified what happens but what I am interested in knowing is in what circumstances would you want to have two separate references for the same object when you could just use the original? Eg. v1
class ObjectValue{ int objVal = 1; } class ObjectValueTestDrive{ public static void main(String [] args){ // "Value of v# should be" refers to if it copied the given object values, instead of referencing the same object ObjectValue v1 = new ObjectValue(); System.out.println("Value of v1 should be 1:" + " "+ v1.objVal);
Explain anonymous objects with example clearly...i read some where anonymous objects advantage is saving memory...it is benificiable when there is only one time object usage in our program..i can't understand one time usage of object ....i know anonymous objects but i don't know in which context we use them in our programs...i did the anonymous object program with my own example but i can't differentiate this one with normal object..i'm providing my own example below
//anonymous object public class anonymous { int x=10; int y=25; void display() { System.out.println("anomymous");
What I want to do is have a label that is updated whenever an object gets some new, relevant data.The way you do it in Java looks different from the way we do it in Objective-C. In Objective-C, we have what's known as a protocol. An Objective-C protocol is almost exactly like a Java "implementation." In Obj-C, if I want the user to see the address of where he is, I can have an object that gets the information and invokes a view controller's method; at that point, the view controller would then take the data passed to it and display the data in a label. However, the view controller is an instance of a subclass of the bundled view controller class.
I am trying to find either some references to point me on the right track with passing an object with all of it's properties still in tact after it's been created. Currently I am trying to do this through an interface but it seems to just create a new object everytime without the properties. Example below :
import java.util.ArrayList; import java.util.List; public interface TPerson{ //public Person p = null; } class Thrower { Person p;
[code]....
When I implement the interface on the other objects as soon as I call the setP method shown above it seems to just create a new one even though I pass the object to the method I want to use.
I've been trying to learn Java for the last 36 hours or so (after applying for a HTML/CSS job saying "Java knowledge preferred"), and decided to experiment a bit making a graphical tic-tac-toe game. I eventually managed to get that done and it's working. Working code below:
[Java] tic tac toe 1 - Pastebin
So, it works to an extent, however, the way I am capturing which cell is selected seems very sloppy, and would not work if the cells weren't squares or rectangles. So I made a copy of the project and restructured it adding the mouse event to the cells, but now I can't get JComponent to repaint. New code below:
tic tac toe 2 - Pastebin
Curiously, clicking triggers the action for all 9 cells, but I presume it's because I haven't bounded them making it think I've clicked all 9 simultaneously.
What I've tried:
Make the Cell class extend the game class and call this.repaint()- causes stack overflow.
Calling Game.GameState() within the cell clicking event and making that function static - compiler doesn't like calling repaint() inside a static function.
Making another class to make a clone of the Game object and then refresh- was never going to work....
