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Retrieving status of JCheckbox inside a JTable

For some reason, i cannot find out what is wrong with my code. Basically
I have a counter (total) initialized to 2 in this case
Increment to a max of 6, each time a JCheckbox is checked (in this case 4 )and throws a message when too much is clicked.
At first, it throws null pointer when exactly a total of 6 is checked; but works fine if more than 6 checkboxes are selected, then reduced to 6 with more than one button click.
Can anyone guide me to where it is messing with my head? Thank you very much.
public void panelThree(JTable user, JButton save, JButton logout, JButton exit, int j) {
System.out.println("J in external main is: " + j);
save.addActionListener(new ActionListener() {
boolean arr[] = new boolean[user.getRowCount()];
public void actionPerformed(ActionEvent e) {
int total = j;
System.out.println("Total in listener is: "+total);
System.out.println("No of rows: " + user.getRowCount());
for (int z = 0; z < arr.length; z++) {
arr[z] = false;
}
for (int i = 0; i < user.getRowCount(); i++) {
if (Boolean.valueOf(user.getModel().getValueAt(i, 3).toString()) == true) {
if (arr[i] == false) {
arr[i] = true;
total++;
}
} else {
if (arr[i] == true) {
arr[i] = false;
total--;
}
}
}
System.out.println("Total is: " + total);
if (total > 6) {
JOptionPane.showMessageDialog(null, "Please choose up to a maximum of " + (6 - j) + " modules");
} else {
int reply = JOptionPane.showConfirmDialog(null, "Are you sure to enroll in these modules?", "Yes", JOptionPane.YES_NO_OPTION);
if (reply == JOptionPane.YES_OPTION) {
JOptionPane.showMessageDialog(null, "Enrollment Successful");
}
}
}
});
}
The line if (Boolean.valueOf(user.getModel().getValueAt(i, 3).toString()) == true) seems to be responsible for all the error all the edit i am making console says null pointer at that line

Your table seems to contain null values. So you need to consider it in your check. Something like this:
if (user.getModel().getValueAt(i, 3) == Boolean.TRUE)
If my suggestion don't work please provide a SSCCE so we can also reproduce your problem.

Why is my arrayList selecting items that have been removed?

I have an arrayList, with about 80 objects, I am trying to randomly select one of the objects, assign it to another object, remove it from the array list then return the selected object. Instead I am returning objects that have already been removed.
here is my code:
while (!ballStorage.isEmpty()) {
SecureRandom rnd = new SecureRandom();
int arraySize = ballStorage.size();//this is 80
for (int j = 80; j >= 0; j--) {
while (arraySize > 0) {
int i = rnd.nextInt(arraySize);
ballSelected = ballStorage.get(i);
ballStorage.remove(i);
ballStorage.trimToSize();
arraySize--;
//debugging println's
System.out.print(ballStorage);
System.out.println("random number generated is: " + i);
System.out.println("ball selected is: " +ballSelected);
System.out.println("Array size is: " + arraySize);
return ballSelected;
}
}
}
return ballSelected;
//output:45W,[62Bl,, 74Bl,]random number generated is: 2
ball selected is: 16W,
Array size is: 2
16W,[62Bl,]random number generated is: 1
ball selected is: 74Bl,
Array size is: 1
74Bl,[]random number generated is: 0
ball selected is: 62Bl,
Array size is: 0

while (!ballStorage.isEmpty()) {
SecureRandom rnd = new SecureRandom();
int i = rnd.nextInt(ballStorage.size());
ballSelected = ballStorage.get(i);
ballStorage.remove(i);
ballStorage.trimToSize();
System.out.print(ballStorage);
System.out.println("random number generated is: " + i);
System.out.println("ball selected is: " +ballSelected);
System.out.println("Array size is: " + arraySize);
}
return ballSelected;
I can't understand why you return inside a loop. This is the reason why your
loop executing 1 time.
But i suppose you want to return the BallSelected every time so:
class BallStorage implements Iterator<Ball>, Iterable<Ball> {
private int size;
private Random random;
private ArrayList<Ball> balls;
public BallStorage() {
this.size = 0;
this.balls = new ArrayList<>();
this.random = new Random();
}
public void add(Ball ball) {
this.size++;
balls.add(ball);
}
Ball next() {
Ball b = balls.get(random.nextInt(size));
balls.remove(b);
this.size--;
return b;
}
boolean hasNext() {
return size > 0;
}
Iterator<Ball> iterator() {
return this;
}
public static void main(String[] args) {
//Create Balls and add them in ballStorage object
for(Ball ball: ballStorage)
System.out.println("ball selected is: " +ball);
}
}

How to Search ArrayList For Integer and Remove It If It Exists In Java

In my program I have to to be able to remove items from an arrayList. The user inputs a number and then if it exists in the arrayList it is removed. When I press the remove button the program would crash if it weren't for my try and catch statements, does anyone know what I should change for the removal to work properly?
public class SumElements extends javax.swing.JFrame {
ArrayList <Integer> values = new ArrayList();
...
private void removeButtonActionPerformed(java.awt.event.ActionEvent evt) {
try {
//declare variables
int searchVal = Integer.parseInt(valueInput.getText());
//search array for inputed value
int index = Collections.binarySearch(values, searchVal);
if (index >= 0){
//clear outputArea
outputArea.setText(null);
outputLabel.setText(null);
//remove from array
values.remove(valueInput.getText());
//display updated values
Collections.sort(values);
for (int i = 0; i < values.size(); i++)
{
outputArea.setText(outputArea.getText() + values.get(i) + "\n");
}
//clear input
valueInput.setText(null);
}
else {
outputLabel.setText("Data not found. Please try again.");
}
}
//set default
catch (NumberFormatException a)
{
outputLabel.setText("Please input a valid number.");
}
}

scroll view in relation to tts android

how can i scroll a view (recyclerview) in relation to my tts,
ive looked at onUtterance but it seems to only have a start and stop listener, so i need to think outside the box, i give my tts a string from an Arraylist like this
ArrayList<String> list = new ArrayList<>();
for (int i = 0; i < SpeakRecyclerGrid.recyclerView.getChildCount(); i++)
{
list.add(((EditText) SpeakRecyclerGrid.recyclerView.getChildAt(i)).getText().toString());
}
speakWords(words);
I was thinking about cutting the string up into sections and giving it to the TTS one string at a time and move the view as I go. I already give my gridlayout manager an int for the amount of columns (called columns).
The array list adds a comma after every word, so I was thinking something like
find the nth/(column) comma
split the string
check if tts is speaking and listen for onUtterance onDone to pass new string
read the string
move the view
and keep doing this until theres no words left and coding for the remainder % im not sure how to do all of that so if anyone wants to help feel free, (I think Im looking at StringUtils and creating each smaller string with a for loop and passing them to the tts in onUtteranceListener onDone, but im still a little new to android), but mainly does anyone have a better way

okay this is what i have so far but it could probably use some work im still an amateur, I've split the string into blocks based on the size of the screen, and the handler that scrolls the screen relies on the amount of letters in each broken up string, also the smoothscrolltoposition is scrolling a custom layout manager that scrolls pretty slowly im having an issue though where on some devices the array list counting the words will only reach 20 not sure why but ill ask and hopefully update this when ive fixed it so here is my speak and move method
public void speakAndMove(){
final ArrayList<String> list = new ArrayList<>();
SpeakGrid.recyclerView.getLayoutManager().scrollToPosition(0);
for (int i = 0; i < SpeakRecyclerGrid.recyclerView.getChildCount(); i++) {
list.add(((EditText) SpeakRecyclerGrid.recyclerView.getChildAt(i)).getText().toString());
}
Integer numOfWords = list.size();
words = list.toString();
Integer count = 0;
Integer startPoint = 0;
scrollPos = 0;
final Integer speed = words.length() * 15;
Integer leftOver = 0;
final int columns = getResources().getInteger(R.integer.grid_columns);
System.out.println(numOfWords);
ArrayList<String> arrayList = new ArrayList<>();
if (list.size() <= columns) {
if (words.contains("[]")) {
speakWords("");
} else if (words.contains(", 's")) {
formatString = words.replaceFirst(", 's", "'s");
speakWords(formatString);
} else if (words.contains(", ing")) {
formatString = words.replaceFirst(", ing", "ing");
speakWords(formatString);
} else {
speakWords(words);
}
}
if (list.size()>=columns) {
for (int i = 0; i < words.length(); i++) {
if (words.charAt(i) == ',') {
count++;
if (count == columns) {
String ab = words.substring(startPoint, i + 1);
//speakWords(ab);
if (ab.contains(", 's")) {
formatString = ab.replaceFirst(", 's", "'s");
speakWords(formatString);
} else if (ab.contains(", ing")) {
formatString = ab.replaceFirst(", ing", "ing");
speakWords(formatString);
} else {
speakWords(ab);
}
startPoint = i + 1;
count = 0;
leftOver = words.length() - startPoint;
}
//SpeakGrid.recyclerView.getLayoutManager().scrollToPosition(scrollPos);
System.out.println("main string"+" scroll " + scrollPos + " startpoint " + startPoint +" speed " + speed);
}
}
if (leftOver > 0) {
String ab2 = words.substring(startPoint, words.length());
//speakWords(ab2);
if (ab2.contains(", 's")) {
formatString = ab2.replaceFirst(", 's", "'s");
speakWords(formatString);
} else if (ab2.contains(", ing")) {
formatString = ab2.replaceFirst(", ing", "ing");
speakWords(formatString);
} else {
speakWords(ab2);
}
//SpeakGrid.recyclerView.getLayoutManager().scrollToPosition(scrollPos);
System.out.println("leftovers "+ leftOver + " scroll " + scrollPos + " startpoint " + startPoint +" count " + scrollPos);
count = 0;
//scrollPos = 0;
}
}
final Handler h = new Handler();
h.postDelayed(new Runnable() {
public void run() {
// This method will be executed once the timer is over
// Start your app main activity
scrollPos = scrollPos + columns;
SpeakGrid.recyclerView.getLayoutManager().smoothScrollToPosition(SpeakGrid.recyclerView, null ,scrollPos);
System.out.println("position "+ scrollPos + " speed " + speed + " list size " + list.size());
if (scrollPos < list.size())
h.postDelayed(this,speed);
// close this activity
}
}, speed);
}

Why do object arrays in my ArrayList fail to retain their values?

I am creating a program in Java to simulate evolution. The way I have it set up, each generation is composed of an array of Organism objects. Each of these arrays is an element in the ArrayList orgGenerations. Each generation, of which there could be any amount before all animals die, can have any amount of Organism objects.
For some reason, in my main loop when the generations are going by, I can have this code without errors, where allOrgs is the Organism array of the current generation and generationNumber is the number generations since the first.
orgGenerations.add(allOrgs);
printOrgs(orgGenerations.get(generationNumber));
printOrgs is a method to display an Organism array, where speed and strength are Organism Field variables:
public void printOrgs(Organism[] list)
{
for (int x=0; x<list.length; x++)
{
System.out.println ("For organism number: " + x + ", speed is: " + list[x].speed + ", and strength is " + list[x].strength + ".");
}
}
Later on, after this loop, when I am trying to retrieve the data to display, I call this very similar code:
printOrgs(orgGenerations.get(0));
This, and every other array in orgGenerations, return a null pointer exception on the print line of the for loop. Why are the Organism objects loosing their values?
Alright, here is all of the code from my main Simulation class. I admit, it might be sort of a mess. The parts that matter are the start and simulator methods. The battle ones are not really applicable to this problem. I think.
import java.awt.FlowLayout;
import java.util.*;
import javax.swing.JFrame;
public class Simulator {
//variables for general keeping track
static Organism[] allOrgs;
static ArrayList<Organism[]> orgGenerations = new ArrayList <Organism[]>();
ArrayList<Integer> battleList = new ArrayList<Integer>();
int deathCount;
boolean done;
boolean runOnce;
//setup
Simulator()
{
done = false;
Scanner asker = new Scanner(System.in);
System.out.println("Input number of organisms for the simulation: ");
int numOfOrgs = asker.nextInt();
asker.close();
Organism[] orgArray = new Organism[numOfOrgs];
for (int i=0; i<numOfOrgs; i++)
{
orgArray[i] = new Organism();
}
allOrgs = orgArray;
}
//graphsOrgs
public void graphOrgs() throws InterruptedException
{
JFrame f = new JFrame("Evolution");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(1000,500);
f.setVisible(true);
Drawer bars = new Drawer();
//System.out.println(orgGenerations.size());
for (int iterator=0;iterator<(orgGenerations.size()-1); iterator++)
{
printOrgs(orgGenerations.get(0));
//The 0 can be any number, no matter what I do it wont work
//System.out.println("first");
f.repaint();
bars.data = orgGenerations.get(iterator);
f.add(bars);
//System.out.println("before");
Thread.sleep(1000);
//System.out.println("end");
}
}
//prints all Orgs and their statistics
public void printOrgs(Organism[] list)
{
System.out.println("Number Of Organisms: " + list.length);
for (int x=0; x<list.length; x++)
{
System.out.println ("For organism number: " + x + ", speed is: " + list[x].speed + ", and strength is " + list[x].strength + ".");
}
System.out.println();
}
//general loop for the organisms lives
public void start(int reproductionTime) throws InterruptedException
{
int generationNumber = 0;
orgGenerations.add(allOrgs);
printOrgs(orgGenerations.get(0));
generationNumber++;
while(true)
{
deathCount = 0;
for(int j=0; j<reproductionTime; j++)
{
battleList.clear();
for(int m=0; m<allOrgs.length; m++)
{
if (allOrgs[m].alive == true)
oneYearBattleCheck(m);
}
battle();
}
reproduction();
if (done == true)
break;
orgGenerations.add(allOrgs);
printOrgs(orgGenerations.get(generationNumber));
generationNumber++;
}
printOrgs(orgGenerations.get(2));
}
//Checks if they have to fight this year
private void oneYearBattleCheck(int m)
{
Random chaos = new Random();
int speedMod = chaos.nextInt(((int)Math.ceil(allOrgs[m].speed/5.0))+1);
int speedSign = chaos.nextInt(2);
if (speedSign == 0)
speedSign--;
speedMod *= speedSign;
int speed = speedMod + allOrgs[m].speed;
if (speed <= 0)
speed=1;
Random encounter = new Random();
boolean battle = false;
int try1 =(encounter.nextInt(speed));
int try2 =(encounter.nextInt(speed));
int try3 =(encounter.nextInt(speed));
int try4 =(encounter.nextInt(speed));
if (try1 == 0 || try2 == 0 || try3 == 0 || try4 == 0 )
{
battle = true;
}
if(battle == true)
{
battleList.add(m);
}
}
//Creates the matches and runs the battle
private void battle()
{
Random rand = new Random();
if (battleList.size()%2 == 1)
{
int luckyDuck = rand.nextInt(battleList.size());
battleList.remove(luckyDuck);
}
for(int k=0; k<(battleList.size()-1);)
{
int competitor1 = rand.nextInt(battleList.size());
battleList.remove(competitor1);
int competitor2 = rand.nextInt(battleList.size());
battleList.remove(competitor2);
//Competitor 1 strength
int strengthMod = rand.nextInt(((int)Math.ceil(allOrgs[competitor1].strength/5.0))+1);
int strengthSign = rand.nextInt(2);
if (strengthSign == 0)
strengthSign--;
strengthMod *= strengthSign;
int comp1Strength = strengthMod + allOrgs[competitor1].strength;
//Competitor 2 strength
strengthMod = rand.nextInt(((int)Math.ceil(allOrgs[competitor2].strength/5.0))+1);
strengthSign = rand.nextInt(2);
if (strengthSign == 0)
strengthSign--;
strengthMod *= strengthSign;
int comp2Strength = strengthMod + allOrgs[competitor2].strength;
//Fight!
if (comp1Strength>comp2Strength)
{
allOrgs[competitor1].life ++;
allOrgs[competitor2].life --;
}
else if (comp2Strength>comp1Strength)
{
allOrgs[competitor2].life ++;
allOrgs[competitor1].life --;
}
if (allOrgs[competitor1].life == 0)
{
allOrgs[competitor1].alive = false;
deathCount++;
}
if (allOrgs[competitor2].life == 0)
{
allOrgs[competitor2].alive = false;
deathCount ++ ;
}
}
}
//New organisms
private void reproduction()
{
//System.out.println("Number of deaths: " + deathCount + "\n");
if (deathCount>=(allOrgs.length-2))
{
done = true;
return;
}
ArrayList<Organism> tempOrgs = new ArrayList<Organism>();
Random chooser = new Random();
int count = 0;
while(true)
{
int partner1 = 0;
int partner2 = 0;
boolean partnerIsAlive = false;
boolean unluckyDuck = false;
//choose partner1
while (partnerIsAlive == false)
{
partner1 = chooser.nextInt(allOrgs.length);
if (allOrgs[partner1] != null)
{
if (allOrgs[partner1].alive == true)
{
partnerIsAlive = true;
}
}
}
count++;
//System.out.println("Count 2: " + count);
partnerIsAlive = false;
//choose partner2
while (partnerIsAlive == false)
{
if (count+deathCount == (allOrgs.length))
{
unluckyDuck=true;
break;
}
partner2 = chooser.nextInt(allOrgs.length);
if (allOrgs[partner2] != null)
{
if (allOrgs[partner2].alive == true)
{
partnerIsAlive = true;
}
}
}
if (unluckyDuck == false)
count++;
//System.out.println("count 2: " + count);
if (unluckyDuck == false)
{
int numOfChildren = (chooser.nextInt(4)+1);
for (int d=0; d<numOfChildren; d++)
{
tempOrgs.add(new Organism(allOrgs[partner1].speed, allOrgs[partner2].speed, allOrgs[partner1].strength, allOrgs[partner2].strength ));
}
allOrgs[partner1] = null;
allOrgs[partner2] = null;
}
if (count+deathCount == (allOrgs.length))
{
Arrays.fill(allOrgs, null);
allOrgs = tempOrgs.toArray(new Organism[tempOrgs.size()-1]);
break;
}
//System.out.println(count);
}
}
}
Main method:
public class Runner {
public static void main(String[] args) throws InterruptedException {
Simulator sim = new Simulator();
int lifeSpan = 20;
sim.start(lifeSpan);
sim.graphOrgs();
}
}
Organism class:
import java.util.Random;
public class Organism {
static Random traitGenerator = new Random();
int life;
int speed;
int strength;
boolean alive;
Organism()
{
speed = (traitGenerator.nextInt(49)+1);
strength = (50-speed);
life = 5;
alive = true;
}
Organism(int strength1, int strength2, int speed1, int speed2)
{
Random gen = new Random();
int speedMod = gen.nextInt(((int)Math.ceil((speed1+speed2)/10.0))+1);
int speedSign = gen.nextInt(2);
if (speedSign == 0)
speedSign--;
speedMod *= speedSign;
//System.out.println(speedMod);
int strengthMod = gen.nextInt(((int)Math.ceil((strength1+strength2)/10.0))+1);
int strengthSign = gen.nextInt(2);
if (strengthSign == 0)
strengthSign--;
strengthMod *= strengthSign;
//System.out.println(strengthMod);
strength = (((int)((strength1+strength2)/2.0))+ strengthMod);
speed = (((int)((speed1+speed2)/2.0))+ speedMod);
alive = true;
life = 5;
}
}
The problem lies in the graphOrgs class when I try to print to check if it is working in preparation for graphing the results. This is when it returns the error. When I try placing the print code in other places in the Simulator class the same thing occurs, a null pointer error. This happens even if it is just after the for loop where the element has been established.

You have code that sets to null elements in your allOrgs array.
allOrgs[partner1] = null;
allOrgs[partner2] = null;
Your orgGenerations list contains the same allOrgs instance multiple times.
Therefore, when you write allOrgs[partner1] = null, the partner1'th element becomes null in all the list elements of orgGenerations, which is why the print method fails.
You should create a copy of the array (you can use Arrays.copy) each time you add a new generation to the list (and consider also creating copies of the Organism instances, if you want each generation to record the past state of the Organisms and not their final state).