I'm a total newbie to Java, and until now all I've done was draw some shapes and flags. I'm struggling to understand the code I've been given. I need to access values stored in an ArrayList within another class. Here are the two classes Seat and Mandate:
package wtf2; import java.util.*; public class Seat { public int index; public String place; public int electorate;
[Code] ....
The main class contains code that feeds data from 2 text files into Seat and Mandate. From there I managed to access the date in Seat (at the end):
package wtf2; import java.io.*; import java.util.*; public class CW2 { public static void main(String[] args)throws Exception {
[Code] ....
Now,instead of getting just the mp for Edinburgh South I need to get the vote values, compare them to each other, take the second biggest and display the associate party value. How to access data from that Array to get started at least.
I am trying to create a method in BlueJ which needs the values from a Map to be copied into a List so I can use the List methods min() and max(). Here is the method I have created so far:
public String findNamesInPageRange() { int minOfRange = Integer.parseInt(OUDialog.request("Input number for start of range")); int maxOfRange = Integer.parseInt(OUDialog.request("Input number for end of range")); String foundIt = null; for(String eachKey : bookIndex.keySet()) { List<Integer> pageList = new ArrayList<>(); //Cannot access values from a map using this List if((minOfRange >= Collections.min(pageList)) && (maxOfRange <= Collections.max(pageList))) { foundIt = eachKey; } } return foundIt; }
As can be seen there is a comment showing where my problem lies.
The Map is coded as Map<String, Set<Integer>> bookIndex = new TreeMap<>();
Ive tried using bookIndex.values() as the argument of the List but I get an incompatible type error
I am trying code a method where each key in a Map is iterated through keySet in a for-each loop but while each key is being accessed I need to also access its values where the values are of the type Set<Integer>. The Map is named bookIndex and I have tried using bookIndex.values() but this accesses all the values of the Map and not just the values of the key being presently accessed. Ive tried using a List to do this but was advised that this was not needed in another thread (Accessing Map values through a List). Ive tried creating a Set to contain these values but bookIndex.values() does not do it.
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");
What I want to do is this, this is my first class:
public class Footballer { int goals; String surname= ""; String team=""; private static int counter=0; private int dres; }
(this is just the header of the class... And this is my second class, which contains an ArrayList of the first class:
public class FootballTeam{ String teamname=""; String league=""; ArrayList<Footballer> f; }
And this is my third class which contains an ArrayList of the second class:
public class FootballLeague{ String leaguename=""; ArrayList<FootballTeam> ft; }
What I want to do is, know how many of footballers are there in the league? Meaning how many of "f"s are in the "ft"... I remember from C++ it was easy, you just did it something like this: ft.f[i]; (where i is a position), then you'd go through each of them, if you wanted to do something with them, or just ask for it's length, if you needed to know how much footballers are there.
I'm trying this method to get the size of the array in the 2nd class, from the 3rd class (containing an ArrayList of classes of 2nd class, but no luck:
int counter=0; for(int i=0;i<this.ft.size();i++) { counter+=this.ft[i].f.size(); }
I'm getting this: Array required, but ArrayList<FootballTeam> found ---
I have an admin class that needs to access a method of another class and I'm unsure how to do it.
One of the methods in the admin class (DancerAdmin) accesses a .txt file with information in and each line is to be extracted and is to be created as an object of the Dancer class. The information in each line is to then be used to set the variables in the Dancer class.
To set the values the Dancer class has setter methods which I need to access each time a new object is created while cycling through the .txt file. I'm struggling to access these methods from the DancerAdmin class when I run the relevant method.
The snippet of code I have from the method in DancerAdmin is
while (bufferedScanner.hasNextLine()) { currentLine = bufferedScanner.nextLine(); lineScanner = new Scanner(currentLine); lineScanner.useDelimiter(","); dancer.add(new Dancer()); Dancer.setName(lineScanner.next()); mh_sh_highlight_all('java');
I get an error saying non static method setName cannot be referenced from a static content?
What I want to do is this, this is my first class:
Java Code:
public class Footballer { int goals; String surname= ""; String team=""; private static int counter=0; private int dres; } mh_sh_highlight_all('java');
(this is just the header of the class, just how it looks)...
And this is my second class, which contains an ArrayList of the first class:
Java Code:
public class FootballTeam{ String teamname=""; String league=""; ArrayList<Footballer> f; } mh_sh_highlight_all('java'); And this is my third class which contains an ArrayList of the second clas: Java Code: public class FootballLeague{ String leaguename=""; ArrayList<FootballTeam> ft; } mh_sh_highlight_all('java');
What I want to do is, know how many of footballers are there in the league? Meaning how many of "f"s are in the "ft"... I remember from C++ it was easy, you just did it something like this: ft.f[i]; (where i is a position), then you'd go through each of them, if you wanted to do something with them, or just ask for it's length, if you needed to know how much footballers are there.
Suppose I have private static void name() { ... } that has a two dimensional string array named array[. Now suppose I have private static void different() {...} and I want to write a condition where if (item == array) { ... }, how can I access my array from name() when I am in different()? I get a compile error saying cannot find symbol. My code is similar to:
I am getting an error trying to access a static method of another class...theyre both in the same package, I've tried importing the class.
I've tried to do A b=new A() and then b.evaluate();
Everything that I try I get the following error:
Exception in thread "main" java.lang.NoClassDefFoundError: B$A Caused by: java.lang.ClassNotFoundException: B$A at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Code :
public class A{ public static String evaluate(String op) { } } public class B{ String output=A.evaluate(input); }
I have a situation where I have 2 classes and an array of objects which are causing me trouble.
The object type is one I have created - it is made from a class which is neither of the 2 classes I previously mentioned.
The array is created and occupied in Class1 and the problem arises when I try to reference one of the element from Class2.
At first I forgot the the array would be local to Class1.main so I made the array a global variable using:
Java Code: public MyObjectType[] myArray; mh_sh_highlight_all('java'); Then I tried accessing an element (2) from Class2 using:
Java Code: Class1.myArray[2] mh_sh_highlight_all('java'); However I get errors saying that I can't access the static variable from a non-static context.
I understand a little bit about static and non-static objects/methods but don't know how to fix this. Do I need to include "static" in the array declaration?
1) When a variables are declared "Private" How should it be accessed from the driver class ? Sometimes i get an error in driver class saying "your variable is declared Private" why am I getting this error ...
The document says "Private" declared variables should be accessed only through methods. What does that mean.
I am having some problem accessing variables from an array instance of a class. Heres what i have done;
In the main class:
Example obj[]= new Example[4];
In the main class constructor:
obj[0] = new Example(0); obj[1] = new Example(1); obj[2] = new Example(2); obj[3] = new Example(3);
In the main update() method:
if(condition) //update
In the Example class constructor:
private boolean change = false;
In the Example class update() method:
if(x >20) change= true;
Now, i want to access the variable change from the main class, how do i do it? The 'condition' in the if statement is the condition of wether the change variable ia true or false. How do i access it?
I have several different PopupWindows that i want to access from the same fragment. I would like for each PopupWindow to be it's own java file. Here is trimmed down code from an example showPopup.java file,
showPopup.java public class showPopup { //public class showPopup extends Activity implements View.OnClickListener{ //public class showPopup extends Window { public static Context appContext; PopupWindow popupWindow; SQLiteDatabase db; EditText edSpeciesLookup,edSpeciesLookupRowid;
[code]...
How do I configure inheritance to allow showPopup() class to reside in it's own Java file and be called from another class (file)? I've reviewed several hours of online resources as well as my reference books with no productive illumination. I've tried a number of possible implementations and extensions such as "public class showPopup extends Activity implements View.OnClickListener{...", and "public class showPopup extends Window.
i am trying to write a class method which will take in a string and returns a string which is the reversed version of that string. it compiles fine but when i try to run it it states Main method not found in class StringReverse,please define the main method as public static void main(String[]args). I am new to java and cannot figure out
import javax.swing.JOptionPane; public class StringReverse { public String reverseString(String str){ JOptionPane.showInputDialog(null,"Please enter word"); char c = str.charAt(str.length()-1); if(str.length() == 1) return Character.toString(c); return c + reverseString(str.substring(0,str.length()-1));}}
Suppose i have a string which has certain file names, S = "a.png, b.gif, c.xlsx, d.docx, e.xlsx, f.gif";I need to check if the string has more than one .xlsx file names,
I am trying some exercises on codingbat.com, and am stuck at the following program.
"Given a string, return true if it ends in "ly"."
With the following lines, if I type a print command instead of return, I get "ly". Yet if I aks to compare the result (which is "ly" as I can see with a print command) with == "ly", I get false?
What I also don't get, is that if I tye the programs in javascript, in that language the program works.
I'm looking to get two values from this string. I have tried re formatting and with little success. I read this in from a text file and then tried the below code to extract it. I have also tried
{Deposit=100.00, Fees Paid=5.00}
I am just looking to get the 100.00 and the 5.00. I tried using this code below but it separated it into Comma and put it in an array which is probably what im not looking for.
[code] final Pattern pattern = Pattern.compile("[=st]"); final String[] result = pattern.split(st2); System.out.println(Arrays.toString(result)) [code]
I want to write an app that declares a class Person(String name, int age), and an Account class, Account(int code, double balance).But, additionally, every Person has at most 3 accounts, and each account has a Peron associated with it.
my code so far...
public class Person { private String name; private int age; private Account[] accounts; private int numOfAccounts; public Person(String name,int age){ this.name=name;
[code]....
My problem is:When I make data input for a person, and additionally I want to read data for the account(s) that this rerson has, what code should I write to create a new Account object as account[numOfAccounts].And, what is the code to assign an owner to a new created Account object?
There exists a relationship between the two classes, but I cannot find the way to implement this relation....
I am trying to get the username and password for one class and send them to another. However I cannot send them in the constructor because a database class is getting them and I need that constructor blank. However if I do not pass the class in the constructor I get a NULL error, even better when I do pass it in I seem to get a thread lock. I do try to do my own housekeeping and close the one frame before I open a new one but it doesn't work. I will do my best to show the design of the program.
program starts Java Code: public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { // connects to database and generates a GUI new UserPromptScreen();
[code]....
I have to pass in UserPromptScreen in for it to work. This will cause me issues later with my design.
I'm having an issues with adding integer values to a string list. The question is asking me "the method should iterate over runners, and for each runner generate a random number between 90 and 180 (inclusive) which should be used to set the time (in minutes) for that runner."
I have been able to get the random number and iterating over the runner arraylist but I haven't been able to figure out how to add the values generated into the runners list. I am also using BlueJ.
Here's the whole code I have at the moment:
import java.util.*; import java.io.*; import ou.*; import java.util.Random; /** * Write a description of class MarathonAdmin here. */ public class MarathonAdmin { // instance variables - replace the example below with your own