Swing/AWT/SWT :: Using Doubles For Positioning Objects And Testing Equality
Aug 15, 2014
I've been noticing some of my programs have been a little buggy recently, and think it's down to confusion over doubles and positioning. Lets say I have a label called banner that I want to scroll across the screen. Now I need to know the label's width in order to position it, but the width depends on the amount of text, so i use this code:
double bannerWidth = banner.getWidth();
Which forces me into using a double if I want to be accurate.
But the problem is that I'm trying to use a condition that compares the label's horizontal position (currentX) to the left edge of the screen (LEFT_EDGE), minus the width of the label (bannerWidth). In other words when the label is off the screen, it should go back to its starting position.
I assume that means that any variables I use to track the label's position (in this case currentX), or constants that I use to check equality (LEFT_EDGE), have to be doubles as well?
My difficulty is that I iterate currentX. But currentX--; won't work because doubles don't iterate as I'd expect.
So casting becomes an option..... but if I cast to an integer I effectively lose width on the label. And that is magnified each loop, resulting in the label's starting position moving further and further to the left.
Also, the e.getX()/Y() methods in my mouse listeners always spit out the position of the mouse relative to window instead of the entire screen. Is there a way to flip that or at least a way to track the movement of my window on my screen? Another acceptable fix for me would be to have my Robot object's mouseMouse(x,y) method move my mouse to a position (x,y) relative to the window instead of the entire screen.
I have written a drum machine using Java. Into said drum machine I list all 47 available MIDI drums. The instrument list is placed into a JPanel, along with a gridArray of checkboxes. The JPanel is then in turn added to a scrollpane. I have listed the MIDI drums in order of 'ground-up'. For example, the bass drum is generally at the bottom of most drum kits, so it is at the bottom of my MIDI drums list. Next up would be the snare, followed by the cymbals, and then by all the specialty percussives. Since most beats are started from the 'ground-up', laying to foundation, so to speak, I want the scroll bar of the scrollpane which houses the JPanel, which in turn houses the instrument list and the beat checkboxes, to be positioned, upon opening, at the bottom of the scroll pane. Nothing I have tried works. It always positions the slider somewhere in the middle of the scroll track. Below is a listing of just the buildGUI portion of the code, all the MIDI functionality has been removed to keep the size of the post to this forum down.
I need to find out if two dates are equal or not. I have two dates coming from UI and from DB. From UI I am getting as Sun Jun 15 00:00:00 CDT 2014 from DB I am getting as 2014-06-15 00:00:00.0. Data type for both fields are java.util.Date but when I do uiDate.equals(dbDate) it return false. So how can I test these dates to fins out they are equal or not?
So I have a player an enemy and enemy bounds the enemy can go. I need to have the enemy track my position and when I go into the position (I am using a collision method for this) the enemy comes over at a speed of 1. My problem is the enemy jumps to me and then follows at speed of 2 (2 is the player speed). The code is wrong this is why it is jumping and I have my other problems. so my question is what is a good solution for this? I am trying to make a method to track playerposition() so what I am thinking I could do is find x, y of player then store those into an array and return the array to Enemy so he tracks.
player.java public class Player{ int x = 100; // Location of player int y = 200; // location of player int xa = 0; // Representation of where the player goes int ya = 0; // Representation of where the player goes private int speed = 2;
[Code] .....
Please note this is not the entire code I have cut some things out that did not need to be there. Also, the code is just to get an idea of what I was thinking of doing. The ideas that are came up with are not meant to be a reflection of what I already have but, what I could add or replace.
import java.awt.GridLayout; import javax.swing.*; public class Screen { JButton start; JButton reset; JButton box[][] = new JButton[20][20]; Screen()
[Code] ....
I am trying to place the buttons on the bottom. I tried a few different things but the grid layout keeps grabbing it and making them a part of the grid at the button.
I am trying to implement the following example to override the equality and hashCode method if the class has reference type member. I do get the expected result "true" for equal and "false" for non-equal objects. But the print statement in the Circle's equal method is not executed when the objects values are not equal. I don't know what i am missing, though i get the equality result "false" as expected for non equal objects.
class Point{ private int x, y; Point (int x, int y) { this.x =x; this.y = y;
import java.awt.GridLayout; import javax.swing.*; public class Screen { JButton start; JButton reset; JButton box[][] = new JButton[20][20];
[Code] ....
I am trying to place the buttons on the bottom. I tried a few different things but the grid layout keeps grabbing it and making them a part of the grid at the button.
1: 3D space. How do i define the space where i will make my world? Is there a certain point that i will define as 0,0,0 or is there some other way.
2: Camera positioning. When i have the 3D space, how to i make it so that the camera will show that what i want it to show. Lets say il define its lokatios 30,50,100 and direction is NW, then how to i make it so that is see the SW direction from the point 30,50,100?
I'm allowing the user to choose certain items to buy that is moved to an array.Now I'm trying to add those thing in the array use a different class. how I can call the array from my driver class to my checkout class that adds them together.
I have a problem with my program. My aim is to display in a JPanel, 2 rectangles from an arraylist, and resize them by clicking. I want to give the user the ability to change the height of the rectangles (independently) by moving the top and/or bottom edges. There is errors in my code but where ? Netbeans underlines 2 lines (in bold).
I have to do an assigment using Swing, where I have to make a Board(extends JPanel) and add multiple instances of moving elements to it, with following requirements:
By adding a new object to the Board, the others must not slow down. Also the user interface must not be blocked by the moving objects. So, the movement of the objects must be handled in a separate thread.
and
The application must support adding lots of objects, so it is not okay if every object has its own thread, as this would take too many resources. Design the application in such a way that it uses a constant number of threads, meaning that the number of threads does not grow when adding more objects.
The question is:
How to do this thing with constant number of threads?
I had to use scanner to receive input from the user for a formula and everything compiled and worked correctly except when I entered a double into the Scanner, it only accepts ints and gives me this error every time I enter a double:
java.util.InputMismatchException at java.util.Scanner.throwFor(Unknown Source) at java.util.Scanner.next(Unknown Source) at java.util.Scanner.nextDouble(Unknown Source) at TestA1Q2.main(TestA1Q2.java:36) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:272)
I know that you usually get that error when the Scanner expects something else that is different from what you type and I have looked over my code time and time again and cannot find anything. I created a test program to see if it was just that problem and not something else in the code and I still got the same error but when I tried compiling and running it here browxy.com everything worked and I got the right answer for the formula. Here's the test I used:
import java.util.Scanner; public class TestA1Q2 { public static void main(String[] args) { Scanner keyboard = new Scanner(System.in); System.out.println("Enter a double"); double velocity = keyboard.nextDouble(); } }
At this point I'm thinking it might be a problem with my install of DrJava and I've tried re-installing but nothing changed.
while(fileScan.hasNextLine()) { String currentLine = fileScan.nextLine(); String[]dataSet = currentLine.split(" "); String zip = dataSet[7]; String phone = dataSet[8]; String donation = dataSet[9]; int ZIP = Integer.parseInt(zip); Double Donation = Double.parseDouble(donation);
As you can see I made the donation read as a double, my question is how do I get the donation total? I need to write the code to add up and get the total donations but cannot figure it out.
Just done a quick test to try and figure out the difference between floats and doubles.I made a quick program which outputs the result of 3.3 * 2 as both a float and a double.
I assumed since a float is the larger and more precise of the two data types that there would be more numbers after the decimal point, however this was not the case, it was in fact the double which had more numbers after the decimal point. Result was as follows:
Float: 29.699999 Double: 29.7
BTW for the above code I simply had a few text fields and a button with the following code:
Also, as these are limited to a certain amount of numbers im thinking there must be a more precise way for currency, if so what would I use for that? I suppose what im trying to figure out is what data type to use in different scenarios? When to use integer, float, double and long.
I currently have the code set up to iterate through objects and keep track of them but how do I do the same and draw the objects on the panel window? I'm confused on what to do and how to start it.
Here's the code I have so far, the 'Car' which I want to draw extends to another class which extends to GameObject. I currently have a 'draw()' method under the 'Car' class but nothing in the 'draw()' method yet. From what I understand i'm suppose to have a 'draw()' method under 'GameObjects' class also?
public class MapView extends JPanel implements IObserver, ActionListener{ JPanel myPanel; private Timer timer = new Timer(5, this); int x = 0; int moveX = 2; public MapView(){ super.setBorder(BorderFactory.createTitledBorder("Map:"));
[code]....
Mostly I don't understand how to go through the iterator again to paint the objects. Wouldn't I need to put another iterator under 'paintComponent()' or can it be done under 'update()' ?
how to get some shapes from the GameObjects onto my panel.
* A pop-up menu generates an array of rectangle objects; each rectangle having random x.y coords and colour. * The number of rectangles in the array is user selected from the popup list. * The APopUp class has a 'getter' method that returns the array. * The pop-up object is instantiated in an object of the AFrame class. * The AFrame object needs to get the array each time the popup changes its state.
The problem: . * As I see it, the AFrame object needs to informed of the pop-up's state of change event or does the problem lie in how I have decided which responsibilities each class is to have? I've tried to be as logical as possible during planning.
In the days of FORTRAN or BASIC we would hammer a solution through with brute force, but I would like to keep to Java's philosophy of encapsulation and clean interfaces and that it seems to has generated a impasse of brain warping proportions.
import java.awt.Frame; import java.awt.Label; import java.awt.event.ItemEvent; import java.awt.event.ItemListener; public class AFrame extends Frame implements ItemListener {
I am attempting to test a TCP Client and Server for an assignment I am doing in class. The goal here is to "test your client and Server applications by transferring (i) a file having 10,000+ lines (see supplied big-file1.txt having 12000+ lines), (ii) a file having 20,000+ lines (you may create one of your own from big-file1.txt, or obtain a large size file from the Google website at [URL] ...). Then, compute and display the total transfer time of the files at both of the sides separately (your choice in millisecond/second)."
I have created the TCPClient and TCPServer java classes, ran the server first and then the client, and using mathematical formulas to calculate the transfer time. Trouble is, I'm having trouble testing the client and server in the file area and not the area where I had to input a line, let the server print it, and then have the client eliminate the articles from the line. I need testing the file. Here is my code so far:
TCPClient:
package tcpclient; import java.io.*; import java.net.*; public class TCPClient { public static void main(String[] args) throws IOException{ // TODO Auto-generated method stub String sentence;
[code] ....
How to fix the code so that the time in seconds does not output as 60 for both files and that the files go through the exchange?
I wrote a class for encapsulating coins and I was to do a boolean statement but when I test the statement the results are not showing.Here is the code for my coin class coins.java
package project_3; /** * * @author user a */ public class Coins { private double pennies; private double nickles ; private double dimes ; private double quarters ; private int dollars ;
how to execute a particular class. I've created a Kinematics class that will execute and calculate all the functions pertaining to kinematic equations. In the main class, I will have the user provide the data in JTextField. Now I need to test which JTextfields (variables) were left empty. I plan to use a number of if/else statements :
if(distanceI != null && distanceF != null)
The problem with this is that these variables are double and therefore cannot be tested as null. I read a few things about Double but I really don't see how I'm supposed convert each double variable to Double, is that even possible?
public class Kinematics { double distanceI, distanceF, velocityI, velocityF, velocityAverage, acceleration; public Kinematics(){ //v2 = v1 + a*dt if(distanceI != null && distanceF != null){
I have been designing a music collection application that runs from a database. I now need to develop a junit test to test the application but I am not sure if Junit has anything to work with testing databases. I have been googling on the internet but most of the search results do not really give any good examples that I can easily follow and adapt to my application. I am using only one table and I would like to test INSERT, UPDATE and DELETE actions and I would also like to test a successful connection.
I once found one tutorial which I cannot find any more that had something that retrieves all the data in the database and stores it in a CSV file and the loops through the CSV file to check or update information.
