I am working with a program where I am required to use a JFrame in a child class. The only way that I know how to access a JFrame is to do, example (public class Example extends JFrame), but since it is already extending the parent class, I am kind of stuck. I do not think that you can extend two separate classes, so..... I am stuck.
View RepliesCan an interface extend a class?When I am running the following code it's showing some errors..I have commented them.
class A {
public void methodA() {
System.out.println("Class A methodA");
}
}
interface B extends A //interface expected here {
public void methodA();
[code]....
how to 'implement' an interface and 'extend' a class. Now I want to try and recall the information by memory without using any reference material.
Implementing an interface...
Java Code: //This interface will hold information for cell phones//Like saying... you can't BE a cell phone unless you have this information, at the very least
public interface CellInfo {
public void model();
public void make();
public void androidVer();
}
//Now I implement the interface for a class called Galaxy, which is a class about a specific phone
public class Galaxy implements CellInfo
public void model() {
System.out.println("I'm a Galaxy S5.");
}
public void make() {
System.out.println("I'm made by Samsung.");
[code]....
I want to extend hashCode method in my class. As we know that hashCode is generating with 32 bit. Now I wanna generate 64-bit hashCode for user given Input.. Input may be string or Integer.
Please let me know.. take me out from this problem..
MY code follows like this...
package hash_table;
public class Hash_table
{
private int num;
private String data;
public boolean equals(Object obj)
{
if(this == obj)
[Code]...
In the following program i have called the anonymous class of dev class.
interface emp {
void desig();
}
public class dev implements emp {
dev e = new dev() //this line is throwing error ...works fine if i use emp instead of dev {
[Code] .....
i am getting stack over flow error as :
Exception in thread "main" java.lang.StackOverflowError
at dev$1.<init>(dev.java:17)
at dev.<init>(dev.java:16)
at dev$1.<init>(dev.java:17)
[Code] .....
Is it because the jvm is not able to decide which of the 2 desigs() it has to load in the memory when its object is created in the main..??
Does child class gets a copy of the methods and variables of parent class?
public class test1 {
public static void main(String a[]) {
Child c = new Child();
c.print();
[Code] ....
why is the output 1?
Regarding the lifecycle of servlet , in headfirst servlet i can find :
You normally will NOT override the service() method, so the one from HttpServlet will run. The service() method figures out which HTTP method (GET, POST, etc.) is in the request, and invokes the matching doGet() or doPost() method. The doGet() and doPost() inside HttpServlet don’t do anything, so you have to override one or both. This thread dies (or is put back in a Container-managed pool) when service() completes.
How can I call the doGet method of the subclass from the superclass. i am not getting this .
I want to know is there any way we can call parent class method using child class object without using super keyword in class B in the following program like we can do in c++ by using scoop resolution operator
class A{
public void hello(){
System.out.println("hello");
}
}
class B extends A{
public void hello(){
//super.hello();
System.out.println("hello1");
[code]....
I've a parent class with a argument constructor like below(a sample code)
public class Parent {
Parent(String name) {
System.out.println(name);
}
public static void main(String[] args) {
}
}
Also I've child.class which extends Parent.class as shown below,
public class child extends Parent {
child(String name) {
super(name);
}
}
Now, I want create/modify the constructor which is in child, by taking "int i" as an input instead of "String name". How can I do that? Run time I want to execute child constructor not a parent constructor.
Condition is: Without making any changes to the Parent class
1. I want to use a scanner in my child class so that I may populate my parent class. It won't allow me something about scanner constructor. I posted this issue second which is my child's method Tests
2. I can't call my addTestsAnswers method from main to my child class but can call my child's display method from main.
import java.util.Scanner;
public class Tests extends Assessment{
private String q;
private String a;
private int userInput;
Scanner scan = new Scanner();
Scanner scn = new Scanner();
Scanner u = new Scanner();
public void addTestsAnswers(){
[code]....
So I have this line of code...
ioexception11.addChoosableFileFilter(new Jframe());
And when I compile it gives me...
error: constructor Jframe in class Jframe cannot be applied to given types;
ioexception11.addChoosableFileFilter(new Jframe());
This is my main.java:
import javax.swing.UnsupportedLookAndFeelException;
public class Main
{
public static void main(String[] args)
throws ClassNotFoundException, InstantiationException, IllegalAccessException, UnsupportedLookAndFeelException
{
Core window = new Core("GAME1", 0, 0, true, true);
}
}
And this is my Core.java:
import java.awt.GraphicsEnvironment;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
[Code] ....
In Core.Java at line 80 how can I access window (
JFrame window = new JFrame(Game_Title); // <- this window
) ?
Also should I use throws or try and catch ?
I would like to pass a variable I have in my main to my JFrame. In my main I calculate which pictures I should show in my JFrame. Is it possible to make objects of these pictures in my main class and use them in my JFrame? something like my code below.
public class JFrameTesting {
public static void main(String[] args) {
Image ImageVariable = Toolkit.getDefaultToolkit().getImage("C:1.jpg");
MyJFrame f = new MyJFrame();
f.setTitle("Drawing Graphics in Frames");
[code]....
I have one question that suppose I am designing a Swing applications and I am using JFrame as Top level container.
So what is best
1)first Extends that class like
public class A Extends JFrame
{
//Do all stuff with Top Level container with gui
}
2)Or design like this from this source
[URL] ....
package components;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/* TopLevelDemo.java requires no other files. */
public class TopLevelDemo {
/**
* Create the GUI and show it. For thread safety, this method should be invoked from the event-dispatching thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
[Code] .....
I have a jFrame and a Java Class. Now i have a path of image in my jFrame which I want to display in java class(Crop2). I created an object in jFrame
Crop2 d=new Crop2();
and then I'm trying to send the data to the class file but it is not working.
I'll start off by showing my full code:
Main class
import javax.swing.JFrame;
public class groupingTest {
public static void main (String[] args) {
groupWindow test = new groupWindow();
[Code]....
At the start of the groupWindow it turns yellow and it says "The serializable class groupWindow does not declare a static final serialVersionUID field of type long".
Right so I have my ItemsPage Jframe Class and I'm trying to pass my TotalPrice variable to my CashPay so I can calculate the change. CashPrice runs and works but when I try run ItemsPage it does nothing I don't even get errors. I tried to remove that small section of trying to pass the variable to CashPay and it worked perfectly so I 100% know that's the problem. This section "public ItemsPage() { Pounds = ""; //super();
Scanner sc = new Scanner(System.in);
CashPay sendTotalPrice = new CashPay();
//System.out.println("Enter your amount");
TotalPrice = sc.nextDouble();
sendTotalPrice.printTotalPrice(TotalPrice);
"
Here is complete code for both classes, I'm using GUI builder.
import java.awt.BorderLayout;
import java.awt.Checkbox;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
[code].....
I am making a simple battleship program, you have the menu and click Start to get the board with the bombs (4 buttons as of now) Each button has either a bomb or a defualtbutton. I created my button so it can't be unselected. The problem is I have the button in a Class.java and I want that to close in a period of time. What do you recommend using?
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package battleship;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
[code]....
I can call the clas in my main jFrame but I want to close the class after a certain time.
What is the difference between extending JFrame in one class and simply constructing a new JFrame object in that same class? What benefits do I have with each solution, providing I want to use that class to create the GUI. Is it the same or are there differences rather than not having to reference to a new JFrame to be able to use its functions?
View Replies View Related1) when you create a class and compile it and open and see the class using javap command .. that class file contains that it extends java.lang.object and a default constructor is created automatically..... But when you extends another class the java.lang.Object class is not appeared as extended why?
Code example:
1St Case ----- Java code:
public class temp(){
}
Javap Code:
public class temp() extends java.lang.Object {
public temp(){
}
}
2nd case --- Java Code:
public class temp() extends dummy{
}
javap Code:
public class temp() extends dummy{
public temp(){
}
}
why for the above scenario it doesn't extends object class .. if it does implicitly then why it did not do in the first case instead why did the compiler extends Object class ?
I have a checksum function that is suppose to read IPV4 packet and return a short integer value. The IPV4 packets are stored in a byte array. I am having trouble storing the first 8 bits and second 8 bits of the short integer into the byte arrays especially when they have leading 1s. For example, if my checksum returns 5571 (binary = 0001 0101 1100 0011) The first 8 bits is suppose to represent 195 but when I try to assign a larger integer type to a btye the information gets sign extended. The 195 turns into -61. I tried using bit addition like array[10] = array[10] & 0xff, but the result remains the same.
public static short checksum(byte [] a, int length) {
short sum = 0;
long data;
int i = 0;
while(length > 1) {
data = (((a[i] << 8) & 0xff00) | ((a[i + 1]) & 0xff));
sum += data;
[code]....
I have a GUI that I've been working on for a while now. What I am trying to figure out, is a way to have the user push a button, and when they do have the GUI extend out to the right with another table to use for Filter Data. Once They are done, I want them to push that button again, and the panel with the query data retracts and is hidden again, all without changing the size of the current GUI in question. I've tried a bunch of different things with setting preferred and Minimal values to my GUI, and I've played around with different Layouts (Border Layout.East, etc), but I can't seem to find a good working solution.
Ideally it would be slick if I could make my panel SLIDE out and SLIDE back in, which would look really cool, but I'd settle for something that just worked.
I'm working on a program using GUI. My problem is that I'm reaching **1000 Line** and this is stressful because all my code are in one file. I'm not liking this. So I research the internet about Inheritance. However, what I know about Inheritance that Inherit everything in the parent class. However, when I try to use a variables in the child class to override it in the parent class I can't for example let say that I have in the parent class something like this:
JButton getButton = new JButton("Enter");
Now when I go to the child class. I want to Inherit and use this variable so I can use the ActionListener on the getButton and override for the parent class, but it's not working.
This is my code:
public class H_Store extends JFrame {
private String s ="Kinds: ";
private JButton calculateButton;
private JPanel mainPane;
private JPanel getProfitPanel;
private JTextField ground_M_QTextField;
[Code] ....
What I want to do exactly is to take the last code into another class or do something with it so I can use it in the Parent class, in other word any math calculation method or class I want them outside the Parent class. I mean this code :
private class CalcButtonListener implements ActionListener{
// vairbles for the ground Meat check box
private double total_GM;
private double weightPrice_1;
private String stringQ;
private String stringW;
private String stringP;
[Code] ....
I got stuck with the error "Unknown class" with the code that I copied from the book ...
import javax.swing.*;
class SwingDemo
{
// create a new JFrame container
JFrame MAIN_FRAME = new JFrame ("A Simple Swing Application");
// give the frame an initial size
MAIN_FRAME.setSize(275, 100);
// terminate the program when the user closes the application
MAIN_FRAME.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
[code]...
The error comes from lines 21 and 27.
21 MAIN_FRAME.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
27 MAIN_FRAME.add(FIELD_LABEL);
I have tried to rewrite from scratch and still gets the same error.
I've been trying to pull data from another class file "Calculations.java" and have it be displayed in a TextField in "DataAnalyzerGUI.java". Here is how the hierarchy is broken down for my assignment:
DataAnalyzerGUI.java extends JFrame
ReadFiles.java extends DataAnalyzerGUI.java
Calculations.java extends ReadFiles.java
Everything displays and functions correctly in a command prompt if I use a line like this:
System.out.println ("Lowest opening " + dateArray[lowestOpenIndex] + ": " + dataArray[lowestOpenIndex][2]);
But trying to get it to display in a GUI has been quite troubling.
I know the code is supposed to look something like this:
dataOutput.setText(DESIRED CODE HERE);
But I am unable to find anything of value to work out.
I have attached my complete project....
Attached File(s)
Assignment 4.pdf (247.05K)
Assignment 4.zip (235.81K)
I have a swing jFrame set up with a control group which contains 3 radio buttons.
When one is clicked it sends its label to a jtextfield in a different class i have code parsing text by a term
Java Code:
Scanner s = null;
try {
s = new Scanner(new BufferedReader(new FileReader("/Stage_One.txt")));
s.useDelimiter("*");
String total = (s.next());
Pattern p = Pattern.compile("[]+");
[Code] ....
I just need to know how to access the jframe variables (textfields, panels and such) so i can use their inputs in code to filter a text file.