This is my coin object that I use in an arraylist in my driver code.
public class Coin
{
private int side;
private double value;
private String name;
public Coin()
{
side = 1;
value = 0.25;
name = "Quarter";
}
public Coin(String iname, double ivalue)
{
name = iname;
value = ivalue;
flip();
}
public String getName()
{
return name;
}
public double getValue()
{
return value;
}
public void setName(String iname)
{
name = iname;
}
public void setValue(double ivalue)
{
value = ivalue;
}
public String flip()
{
side = (int)(Math.random()* 2);
if (side == 0)
return "Heads";
else
return "Tails";
}
public String toString()
{ String outside = "";
if (side == 0)
outside = "Heads";
else
outside = "Tails";
return "Coin name " + name + "Coin value: " + value + " " + outside;
}
}
This is my coindriver class This is where I have the problem in which Im unable to return the value of the updated wallet arraylist.
import java.util.List;
import java.util.Scanner;
import java.util.ArrayList;
public class CoinDriver
{
private List<Coin> Wallet;
public CoinDriver()
{
Wallet = new ArrayList<>();
}
public static void main(String[] args)
{
int choice = 0;
CoinDriver Wallet = new CoinDriver();
Scanner scanner = new Scanner(System.in);
while (choice != 2)
{
System.out.println("1 Purchase an item 2 Calculate money in wallet and end program");
choice = scanner.nextInt();
Wallet.InputCoin();
if (choice == 1)
Wallet.PurchaseItem();
System.out.println("Net amount in your wallet is " + Wallet.WalletValue());
}
}
void InputCoin()
{
Coin Penny = new Coin ("Penny",0.01);
Coin Dime = new Coin ("Dime", 0.10);
Coin Dollar = new Coin ("Dollar",1.00);
Coin Twenty = new Coin ("Twenty", 20.00);
Wallet.add(Penny);
Wallet.add(Dime);
Wallet.add(Dollar);
Wallet.add(Twenty);
Wallet.add(Penny);
Wallet.add(Dime);
Wallet.add(Dollar);
Wallet.add(Twenty);
Wallet.add(Penny);
Wallet.add(Dime);
Wallet.add(Dollar);
Wallet.add(Twenty);
Wallet.add(Penny);
Wallet.add(Dime);
Wallet.add(Dollar);
Wallet.add(Twenty);
Wallet.add(Penny);
Wallet.add(Dime);
Wallet.add(Dollar);
Wallet.add(Twenty);
Wallet.add(Penny);
Wallet.add(Dime);
Wallet.add(Dollar);
Wallet.add(Penny);
Wallet.add(Dime);
Wallet.add(Dollar);
Wallet.add(Penny);
Wallet.add(Dime);
Wallet.add(Dollar);
Wallet.add(Penny);
Wallet.add(Dime);
Wallet.add(Dollar);
}
double WalletValue()
{
double sum = 0;
for(int x = 1; x < Wallet.size(); x++)
{
sum += Wallet.get(x).getValue();
}
return sum;
}
void PurchaseItem()
{
Coin Penny = new Coin ("Penny",0.01);
Coin Dime = new Coin ("Dime", 0.10);
Coin Dollar = new Coin ("Dollar",1.00);
Coin Twenty = new Coin ("Twenty", 20.00);
Scanner scanner = new Scanner(System.in);
System.out.println("Enter the cost of item you want to purchase: ");
double price = scanner.nextDouble();
double total = WalletValue();
int round = (int) Math.round(price);
int calctwenty = round/20;
int calcdollar = round - calctwenty*20;
double calcdime = price%1;
double rounddime = (Math.round(calcdime))/10;
double calcpenny = (price*10)%1;
double roundpenny = (Math.round(calcpenny));
if (price > total)
{
System.out.println("Insufficient money, cannot purchase");
return;
}
if (calctwenty > 0)
{
for (int i = 0; i < calctwenty; i++)
{
Wallet.remove(Twenty);
}
}
if (calcdollar > 0)
{
for (int j = 0; j < calcdollar; j++)
{
Wallet.remove(Dollar);
}
}
if (rounddime > 0)
{
for( int y = 0; y < rounddime; y++)
{
Wallet.remove(Dime);
}
}
if (rounddime > 0)
{
for ( int p = 0; p < roundpenny; p++)
{
Wallet.remove(Penny);
}
}
WalletValue();
}
}
I wish for the code to return the updated values after making a purchase and removing the objects. However in practice the code still returns the initial wallet value. Please help thanks
Related
Suppose two Items 8 and 4 are there in the list. So the Sum I should get is 12. But I am getting result as 84 and not 12. I am a beginner So I don't have an idea what wrong I am doing here.
private void getCreditEntries() {
final String shift = kvName.getText().toString();
final String leaveType = selectLeaveType.getSelectedItem().toString();
final String employeeCode = empCode.getText().toString();
final String calendarYear = selectYear.getText().toString();
DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("LeaveDetails").child(shift)
.child("Credit").child(employeeCode).child(calendarYear);
DatabaseReference dbRef = reference.child(leaveType);
dbRef.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
list = new ArrayList<>();
if (!dataSnapshot.exists()) {
creditEntryLayout.setVisibility(View.GONE);
} else {
creditEntryLayout.setVisibility(View.VISIBLE);
for (DataSnapshot snapshot: dataSnapshot.getChildren()) {
LeaveCreditData data = snapshot.getValue(LeaveCreditData.class);
list.add(data);
}
rvCreditEntry.setHasFixedSize(true);
rvCreditEntry.setLayoutManager(new LinearLayoutManager(LeaveDetails.this));
rvCreditEntry.setItemAnimator(new DefaultItemAnimator());
leaveCreditAdapter = new LeaveCreditAdapter(list, LeaveDetails.this);
rvCreditEntry.setAdapter(leaveCreditAdapter);
int total = 0;
for(int i = 0; i < list.size(); i++){
total = Integer.parseInt(total + list.get(i).getTotalLeaveCredit());
creditSum.setText(String.valueOf( total));
//Suppose two Items 8 and 4 are there in the list
// So the Sum I should get is 12.
// But I am getting result as 84 and not 12
}
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Toast.makeText(LeaveDetails.this, databaseError.getMessage(), Toast.LENGTH_LONG).show();
}
});
}
I simply edited the code as below and achieved what I wanted.
int total = 0;
for(int i = 0; i < list.size(); i++){
total += Integer.parseInt(list.get(i).getTotalLeaveCredit());
creditSum.setText(String.valueOf( total));
}
Not working Query :
select lookup(city, state, tax,'addresslookup')
from (select distinct city, state, tax
from open_glory.addylookup) a
Working Query (without distinct):
select lookup(city, state, tax,'addresslookup')
from (select city, state, tax
from open_glory.addylookup) a
Any help would be appreciated.
UDF code:
Not working Query :
select lookup(city, state, tax,'addresslookup')
from (select distinct city, state, tax
from open_glory.addylookup) a
Working Query (without distinct):
select lookup(city, state, tax,'addresslookup')
from (select city, state, tax
from open_glory.addylookup) a
Any help would be appreciated.
UDF code:
public class Lookup extends GenericUDF {
private static String delimiter = "|";
private ConcurrentHashMap < String, HashMap < String, String >> fileMap = new ConcurrentHashMap < String, HashMap < String, String >> ();
protected String loggedInUser;
protected String loggedInApplication;
private transient GenericUDFUtils.StringHelper returnHelper;
private transient StringConverter[] stringConverter;
private static final Logger LOG = LoggerFactory.getLogger(Lookup.class.getName());
#Override
public ObjectInspector initialize(ObjectInspector[] arguments)
throws UDFArgumentException {
if (arguments.length < 2) {
throw new UDFArgumentLengthException(
"lookup takes 2 or more arguments");
}
stringConverter = new StringConverter[arguments.length];
for (int i = 0; i < arguments.length; i++) {
if (arguments[0].getCategory() != Category.PRIMITIVE) {
throw new UDFArgumentException(
"lookup only takes primitive types");
}
stringConverter[i] = new PrimitiveObjectInspectorConverter.StringConverter(
(PrimitiveObjectInspector) arguments[i]);
}
setLoggedInUser();
returnHelper = new GenericUDFUtils.StringHelper(
PrimitiveCategory.STRING);
LOG.info("initialize successful");
return PrimitiveObjectInspectorFactory.writableStringObjectInspector;
}
private void setLoggedInUser() {
if (loggedInUser == null) {
loggedInUser = SessionState.get().getUserName();
if (loggedInUser != null) {
int idx = loggedInUser.indexOf('.');
loggedInApplication = idx > -1 ? loggedInUser.substring(0, idx) : null;
}
}
}
private void initMap(String f) {
LOG.info("initMap involked");
if (loggedInApplication == null)
throw new NullPointerException(
"Unable to retrieve application name from user.");
String filePath = "/basepath/" + loggedInApplication.toLowerCase() + "/" + f +
".txt";
String line = null;
try {
LOG.info("filePath =" + filePath);
FileSystem fs = FileSystem.get(new Configuration());
FSDataInputStream in = fs.open(new Path(filePath));
BufferedReader br = new BufferedReader(new InputStreamReader( in ));
HashMap < String, String > map = new HashMap < String, String > ();
while ((line = br.readLine()) != null) {
// ignore comment lines
if (line.startsWith("#")) {
continue;
}
String[] strs = line.split("\t");
if (strs.length == 2) {
map.put(strs[0].toUpperCase().trim(), strs[1].trim());
} else if (strs.length > 2) {
map.put(getKey(strs), strs[strs.length - 1].trim());
}
}
fileMap.put(f, map);
br.close();
} catch (Exception e) {
LOG.error(e.getMessage(), e);
}
}
public Text getValue(String s, String f) {
initMap(f);
HashMap < String, String > map = fileMap.get(f);
LOG.info("getValue() fileMap =" + fileMap);
String v = map.get(s);
return v == null ? null : new Text(v);
}
#Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
String val = buildVal(arguments);
String lookupFile = (String) stringConverter[arguments.length - 1].convert(arguments[arguments.length - 1].get());
Text returnVal = getValue(val.toUpperCase(), lookupFile.toLowerCase());
return returnVal == null ? null : returnHelper.setReturnValue(returnVal.toString());
}
#Override
public String getDisplayString(String[] arg0) {
return "lookup()";
}
private String buildVal(DeferredObject[] arguments) throws HiveException {
StringBuilder builder = new StringBuilder();
int cnt = arguments.length - 1;
for (int i = 0; i < cnt; i++) {
builder.append((String) stringConverter[i].convert(arguments[i].get()));
if (i < cnt - 1) {
builder.append(delimiter);
}
}
return builder.toString();
}
private String getKey(String[] strs) {
StringBuilder builder = new StringBuilder();
int cnt = strs.length - 1;
for (int i = 0; i < cnt; i++) {
builder.append(strs[i].toUpperCase().trim());
if (i < cnt - 1) {
builder.append(delimiter);
}
}
return builder.toString();
}
}
I've setup 2 different array lists that coincide and I have code to find the biggest age and smallest age, However my youngest age isn't outputting. I am getting the biggest age as outputted
import java.util.Scanner;
import java.util.ArrayList;
public class Database1{
public static void main(String[] args){
Scanner in = new Scanner(System.in);
ArrayList<Integer> age = new ArrayList<>();
ArrayList<String> name = new ArrayList<>();
int count = 0;
while (count < 10) {
System.out.println("Please enter a first name");
String inputName = in.nextLine();
if(inputName.contains("done")){
break;
}
name.add(inputName);
System.out.println("Please enter an age");
age.add(in.nextInt());
in.nextLine();
count++;
}
int smallest = age.get(0);
int biggest = age.get(0);
String youngestName = "" ;
String oldestName = "";
for (int i = 0; i < age.size(); i++) {
if(age.get(i) > biggest){
biggest = age.get(i);
oldestName = name.get(i);
}if (age.get(i) < smallest){
smallest = age.get(i);
youngestName = name.get(i);
}
}
System.out.println("The oldest person was " + oldestName);
System.out.println("The youngest person was " + youngestName);
System.out.println(name);
System.out.println(age);
}
}
I am receiving this as an output
The oldest person was john
The youngest person was
[Luke, Chris, Neal, john]
[18, 19, 44, 66]
Modify to the following:
public static void main(String[] args){
Scanner in = new Scanner(System.in);
ArrayList<Integer> age = new ArrayList<>();
ArrayList<String> name = new ArrayList<>();
int count = 0;
while (count < 10) {
System.out.println("Please enter a first name");
String inputName = in.nextLine();
if(inputName.contains("done")){
break;
}
name.add(inputName);
System.out.println("Please enter an age");
age.add(in.nextInt());
in.nextLine();
count++;
}
int smallest = age.get(0);
int biggest = age.get(0);
String youngestName = name.get(0); ;
String oldestName = name.get(0);
for (int i = 0; i < age.size(); i++) {
if(age.get(i) > biggest){
biggest = age.get(i);
oldestName = name.get(i);
} else if (age.get(i) < smallest){
smallest = age.get(i);
youngestName = name.get(i);
}
}
System.out.println("The oldest person was " + oldestName);
System.out.println("The youngest person was " + youngestName);
System.out.println(name);
System.out.println(age);
}
Item class:
public class Item {
public float x, y, speedx, speedy;
public Rectangle container;
public Texture texture;
static Timer timer = new Timer();
static int amount;
static int spawned;
public int itemtype;
// float delay = 1; // seconds
public void move() {
x += speedx;
y += speedy;
container.x = x;
container.y = y;
}
public void setTexture(int itemtype){
switch(itemtype){
case 1:
texture = new Texture("items/item1.png");
break;
case 2:
texture = new Texture("items/item2.png");
break;
case 3:
texture = new Texture("items/item3.png");
break;
case 4:
texture = new Texture("items/item4.png");
break;
case 5:
texture = new Texture("items/item5.png");
break;
case 6:
texture = new Texture("items/item6.png");
break;
case 7:
texture = new Texture("items/item7.png");
break;
case 8:
texture = new Texture("items/item8.png");
break;
case 9:
texture = new Texture("items/item9.png");
break;
case 10:
texture = new Texture("items/item10.png");
break;
default:
texture = new Texture("items/error.png");
break;
}
}
public static void spawnItem(int amount){
Item.amount = amount;
mainscreen.items.clear();
// for(int spawned = 0; spawned <= amount; spawned++){
timer.schedule(new Timer.Task() {
#Override
public void run() {
if (mainscreen.canclick == false) {
Item item = new Item();
item.x = 600;
item.y = -42;
item.speedx = -20;
item.speedy = 0;
Rectangle itemcontainer = new Rectangle();
itemcontainer.x = item.x;
itemcontainer.y = item.y;
itemcontainer.width = mainscreen.container.getWidth() / 4f;
itemcontainer.height = mainscreen.container.getHeight() - 15f;
item.container = itemcontainer;
item.itemtype = MathUtils.random(1, 10);
item.setTexture(item.itemtype);
mainscreen.items.add(item);
spawned++;
}
for (Item item : mainscreen.items) {
if (item.x <= -4000) {
if (spawned >= Item.amount) {
mainscreen.canclick = true;
timer.stop();
spawned = 0;
}
} else {
}
}
}
}, 0, 0.325f);
}
public void dispose(){
texture.dispose();
}
}
Mainscreen class:
public class mainscreen implements Screen, GestureDetector.GestureListener,InputProcessor {
#Override
public void render(float delta) {
this.delta = delta;
Gdx.gl.glClearColor(115 / 255F, 115 / 255F, 115 / 255F, 1 / 255F);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batch.setProjectionMatrix(camera.combined);
if(Gdx.input.justTouched()) {
Vector3 touch1 = new Vector3(Gdx.input.getX(), Gdx.input.getY(), 0);
camera.unproject(touch1);
if (debug.contains(touch1.x, touch1.y)) {
items.clear();
}
if (start.contains(touch1.x, touch1.y)) {
if (canclick == true) {
canclick = false;
Item.spawnItem(20);
}
}
}
}
LOG:
On first click start:
(After the Timer has finished)
canclick: true
items list: [com.abc.luckyllama.Item#37237aa0, com.abc.luckyllama.Item#2de938e3, com.abc.luckyllama.Item#3cb912d5, com.abc.luckyllama.Item#2bae592c, com.abc.luckyllama.Item#774c083, com.abc.luckyllama.Item#633edeae, com.abc.luckyllama.Item#176557a6, com.abc.luckyllama.Item#4edb1b5f, com.abc.luckyllama.Item#6f8abadf, com.abc.luckyllama.Item#7a54d22e, com.abc.luckyllama.Item#473162a5, com.abc.luckyllama.Item#51a698ff, com.abc.luckyllama.Item#6bc08c56, com.abc.luckyllama.Item#37d9e6a2, com.abc.luckyllama.Item#7bb19eb6, com.abc.luckyllama.Item#1eb5805f, com.abc.luckyllama.Item#71780de3, com.abc.luckyllama.Item#9ec0998, com.abc.luckyllama.Item#7edf723d, com.abc.luckyllama.Item#4c5aa2c1]
After clicking the debug button(clears arraylist):
canclick: true
items list: []
After clicking the start button again:
(After the Timer has finished)
canclick: true
items list: [com.abc.luckyllama.Item#7d7cb9bc, com.abc.luckyllama.Item#1435cf42, com.abc.luckyllama.Item#117e1963, com.abc.luckyllama.Item#82bfd27, com.abc.luckyllama.Item#108214c7, com.abc.luckyllama.Item#2a77864a, com.abc.luckyllama.Item#4b232766, com.abc.luckyllama.Item#1cb629e0, com.abc.luckyllama.Item#1c92229d, com.abc.luckyllama.Item#ac1b293, com.abc.luckyllama.Item#588bbcba, com.abc.luckyllama.Item#75df6762, com.abc.luckyllama.Item#78d4358e, com.abc.luckyllama.Item#7f86452d, com.abc.luckyllama.Item#7aed480b, com.abc.luckyllama.Item#7407d443, com.abc.luckyllama.Item#2da6e708, com.abc.luckyllama.Item#604470bc, com.abc.luckyllama.Item#70f9d1af, com.abc.luckyllama.Item#3a16a63f, com.abc.luckyllama.Item#201288d2, com.abc.luckyllama.Item#6310ddfc, com.abc.luckyllama.Item#5d5a1c98, com.abc.luckyllama.Item#52727e52, com.abc.luckyllama.Item#669228d6]
You see that the Items inside the ArrayList didn't get cleared. It increased. I think that's because the instances of Item created in spawnItem() are still there. How do I fix this?
I noticed that every time I click the button there aren't more items. The items are spawned faster. But how to stop this?
I fixed it! The problem was that I needed to create a Timer.Task seperately and the use task.cancel(); to stop the Timer.Task:
import com.badlogic.gdx.utils.Timer;
public class Item {
public static Timer.Task task;
public static void spawnItem(int amount){
Item.amount = amount;
task = new Timer.Task() {
#Override
public void run() {
if (mainscreen.canclick == false) {
item = new Item();
item.x = 600;
item.y = -42;
item.speedx = -20;
item.speedy = 0;
Rectangle itemcontainer = new Rectangle();
itemcontainer.x = item.x;
itemcontainer.y = item.y;
itemcontainer.width = mainscreen.container.getWidth() / 3f;
itemcontainer.height = mainscreen.container.getHeight() - 15f;
item.container = itemcontainer;
item.itemtype = MathUtils.random(1, 10);
item.setTexture(item.itemtype);
mainscreen.items.add(item);
mainscreen.itemsspawned += 1;
// mainscreen.items.remove(item);
spawned++;
}
for (Item item : mainscreen.items) {
if (item.x <= -4000) {
if (spawned >= Item.amount) {
mainscreen.canclick = true;
timer.clear();
timer.stop();
task.cancel();
spawned = 0;
}
}
}
}
};
timer.schedule(task, 0, 0.4f);
}
}
new guy to stack and to java.
to start off, here's my code,
AsteroidsGame.java
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.net.*;
import java.util.*;
public class AsteroidsGame extends JApplet implements Runnable, KeyListener {
Thread thread;
Dimension dim;
Image img;
Graphics g;
long endTime, startTime, framePeriod;
Ship ship;
boolean paused;
// True if the game is paused. Enter is the pause key
Shot[] shots;
int numShots;
boolean shooting;
Asteroid[] asteroids;
int numAsteroids;
double astRadius;
double minAstVel;
double maxAstVel;
int astNumHits;
int astNumSplit;
int level;
private AudioClip audioClip;
public void init() {
resize(500, 500);
shots = new Shot[41];
numAsteroids = 0;
level = 0;
astRadius = 60;
minAstVel = .5;
maxAstVel = 5;
astNumHits = 3;
astNumSplit = 2;
endTime = 0;
startTime = 0;
framePeriod = 25;
addKeyListener(this);
setFocusable(true);
requestFocusInWindow();
dim = getSize();
img = createImage(dim.width, dim.height);
g = img.getGraphics();
thread = new Thread(this);
thread.start();
URL urlAudioClip = getClass().getResource("audio/minorcircuit.wav");
audioClip = Applet.newAudioClip(urlAudioClip);
audioClip.loop();
}
public void start() {
audioClip.loop();
}
public void stop() {
audioClip.stop();
}
public void setUpNextLevel() {
level++;
ship = new Ship(250, 250, 0, .35, .98, .1, 12);
numShots = 0;
paused = false;
shooting = false;
asteroids = new Asteroid[level * (int)Math.pow(astNumSplit, astNumHits - 1) + 1];
numAsteroids = level;
for(int i = 0; i < numAsteroids; i++) {
asteroids[i] = new Asteroid(Math.random() * dim.width, Math.random() * dim.height, astRadius, minAstVel, maxAstVel, astNumHits, astNumSplit);
}
}
public void paint(Graphics gfx) {
g.setColor(Color.black);
g.fillRect(0, 0, 500, 500);
for(int i = 0; i < numShots; i++) {
shots[i].draw(g);
}
for(int i = 0; i < numAsteroids; i++) {
asteroids[i].draw(g);
}
ship.draw(g);
//draw the ship
g.setColor(Color.cyan);
g.drawString("Level " + level, 20, 20);
gfx.drawImage(img, 0, 0, this);
}
public void update(Graphics gfx) {
paint(gfx);
}
public void run() {
for(;;) {
startTime = System.currentTimeMillis();
//start next level when all asteroids are destroyed
if(numAsteroids <= 0) {
setUpNextLevel();
}
if(!paused) {
ship.move(dim.width, dim.height);
//move the ship
for(int i = 0; i < numShots; i++) {
shots[i].move(dim.width, dim.height);
if(shots[i].getLifeLeft() <= 0) {
deleteShot(i);
i--;
}
}
updateAsteroids();
if(shooting && ship.canShoot()) {
//add a shot on to the array
shots[numShots] = ship.shoot();
numShots++;
}
}
repaint();
try {
endTime = System.currentTimeMillis();
if(framePeriod - (endTime - startTime) > 0) {
Thread.sleep(framePeriod - (endTime - startTime));
}
}
catch(InterruptedException e) {
}
}
}
private void deleteShot(int index) {
//delete shot and move all shots after it up in the array
numShots--;
for(int i = index; i < numShots; i++) {
shots[i] = shots[i + 1];
shots[numShots] = null;
}
}
private void deleteAsteroid(int index) {
//delete asteroid and shift ones after it up in the array
numAsteroids--;
for(int i = index; i < numAsteroids; i++) {
asteroids[i] = asteroids[i + 1];
asteroids[numAsteroids] = null;
}
}
private void addAsteroid(Asteroid ast) {
//adds asteroid in at end of array
asteroids[numAsteroids] = ast;
numAsteroids++;
}
private void updateAsteroids() {
for(int i = 0; i < numAsteroids; i++) {
// move each asteroid
asteroids[i].move(dim.width, dim.height);
//check for collisions with the ship
if(asteroids[i].shipCollision(ship)) {
level--;
//restart this level
numAsteroids = 1;
return;
}
//check for collisions with any of the shots
for(int j = 0; j < numShots; j++) {
if(asteroids[i].shotCollision(shots[j])) {
//if the shot hit an asteroid, delete the shot
deleteShot(j);
//split the asteroid up if needed
if(asteroids[i].getHitsLeft() > 1) {
for(int k = 0; k < asteroids[i].getNumSplit(); k++) {
addAsteroid(
asteroids[i].createSplitAsteroid(
minAstVel, maxAstVel));
}
}
//delete the original asteroid
deleteAsteroid(i);
j=numShots;
i--;
}
}
}
}
public void keyPressed(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_ENTER) {
if(!ship.isActive() && !paused) {
ship.setActive(true);
}
else {
paused = !paused;
//enter is the pause button
if(paused) {
//grays out the ship if paused
ship.setActive(false);
}
else {
ship.setActive(true);
}
}
}
else if(paused || !ship.isActive()) {
return;
}
else if(e.getKeyCode() == KeyEvent.VK_SPACE) {
ship.setAccelerating(true);
}
else if(e.getKeyCode() == KeyEvent.VK_LEFT) {
ship.setTurningLeft(true);
}
else if(e.getKeyCode() == KeyEvent.VK_RIGHT) {
ship.setTurningRight(true);
}
else if(e.getKeyCode() == KeyEvent.VK_CONTROL) {
shooting=true;
}
else if(e.getKeyCode() == KeyEvent.VK_M) {
audioClip.stop();
}
else if(e.getKeyCode() == KeyEvent.VK_S) {
audioClip.loop();
}
}
public void keyReleased(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_UP) {
ship.setAccelerating(false);
}
else if(e.getKeyCode() == KeyEvent.VK_LEFT) {
ship.setTurningLeft(false);
}
else if(e.getKeyCode() == KeyEvent.VK_RIGHT) {
ship.setTurningRight(false);
}
else if(e.getKeyCode() == KeyEvent.VK_CONTROL) {
shooting=false;
}
}
public void keyTyped(KeyEvent e) {
}
}
this is a "clone" of Asteroids. Some of you who have been around maybe a little longer than myself have probably played it in an arcade. Anyways, I wrote this for a final project in my Java course, but could never get to work completely. It starts up just fine, you can turn and shoot, but not move forward. I'm not worried about moving right now though. What happens after applet starts is music plays and an "asteroid" travels across the screen. If you shoot the asteroid or shoot 3 times in any direction, a thread exception occurs.
Exception in thread "Thread-3" java.lang.NullPointerException
at AsteroidsGame.updateAsteroids(AseroidsGame.java:161)
at AsteroidsGame.run(AsteroidsGame.java:115)
at java.lang.Thread.run(Thread.java:722)
Having looked around online has benefited me very little. Most of what I have learned was self taught and not as easy to wrap my head around. I'm not exactly sure what to do here to resolve this exception. In another thread on stack, it was mentioned to use an ArrayList because the array was not formerly declared with a size. Tinkered with that; never got it to work.
I need ideas/suggestions/criticism. I want to get this to work just so I can say I finished it.
other classes,
Asteroid.java
import java.awt.*;
public class Asteroid {
double x, y, xVelocity, yVelocity, radius;
int hitsLeft, numSplit;
public Asteroid(double x,double y,double radius,double minVelocity, double maxVelocity,int hitsLeft,int numSplit) {
this.x = x;
this.y = y;
this.radius = radius;
this.hitsLeft = hitsLeft;
this.numSplit = numSplit;
double vel = minVelocity + Math.random() * (maxVelocity - minVelocity);
double dir = 2 * Math.PI * Math.random();
xVelocity = vel * Math.cos(dir);
yVelocity = vel * Math.sin(dir);
}
public void move(int scrnWidth, int scrnHeight) {
x += xVelocity;
y += yVelocity;
if(x < 0 - radius) {
x += scrnWidth + 2 * radius;
}
else if(x > scrnWidth + radius) {
x -= scrnWidth + 2 * radius;
}
if(y < 0 - radius) {
y += scrnHeight + 2 * radius;
}
else if(y > scrnHeight + radius) {
y -= scrnHeight + 2 * radius;
}
}
public void draw(Graphics g) {
g.setColor(Color.gray);
g.fillOval((int)(x - radius + .5), (int)(y - radius + .5), (int)(2 * radius), (int)(2 * radius));
}
public Asteroid createSplitAsteroid(double minVelocity,double maxVelocity) {
return new Asteroid(x, y, radius / Math.sqrt(numSplit), minVelocity, maxVelocity, hitsLeft - 1, numSplit);
}
public boolean shipCollision(Ship ship) {
if(Math.pow(radius + ship.getRadius(), 2) > Math.pow(ship.getX() - x, 2) + Math.pow(ship.getY() - y, 2) && ship.isActive()) {
return true;
}
return false;
}
public boolean shotCollision(Shot shot) {
if(Math.pow(radius, 2) > Math.pow(shot.getX() - x, 2) + Math.pow(shot.getY() - y, 2)) {
return true;
}
return false;
}
public int getHitsLeft() {
return hitsLeft;
}
public int getNumSplit() {
return numSplit;
}
}
Ship.java
import java.awt.*;
public class Ship {
final double[] origXPts = {14,-10,-6,-10}, origYPts = {0,-8,0,8}, origFlameXPts = {-6,-23,-6}, origFlameYPts = {-3,0,3};
final int radius = 6;
double x, y, angle, xVelocity, yVelocity, acceleration, velocityDecay, rotationalSpeed;
//used for movement
boolean turningLeft, turningRight, accelerating, active;
int [] xPts, yPts, flameXPts, flameYPts;
//current location of ship
int shotDelay, shotDelayLeft;
//rate of fire
public Ship(double x, double y, double angle, double acceleration, double velocityDecay, double rotationalSpeed, int shotDelay) {
this.x = x;
this.y = y;
this.angle = angle;
this.acceleration = acceleration;
this.velocityDecay = velocityDecay;
this.rotationalSpeed = rotationalSpeed;
xVelocity = 0;
yVelocity = 0;
turningLeft = false;
turningRight = false;
accelerating = false;
active = false;
xPts = new int[4];
yPts = new int[4];
flameXPts = new int[3];
flameYPts = new int[3];
this.shotDelay = shotDelay;
shotDelayLeft = 0;
}
public void draw(Graphics g) {
if(accelerating && active) {
for(int i = 0; i < 3; i++) {
flameXPts[i] = (int)(origFlameXPts[i] * Math.cos(angle) - origFlameYPts[i] * Math.sin(angle) + x + .5);
flameYPts[i] = (int)(origFlameXPts[i] * Math.sin(angle) + origFlameYPts[i] * Math.cos(angle) + y + .5);
}
g.setColor(Color.red);
//color of flame
g.fillPolygon(flameXPts, flameYPts, 3);
}
for(int i = 0; i < 4; i++) {
xPts[i] = (int)(origXPts[i] * Math.cos(angle) - origYPts[i] * Math.sin(angle) + x + .5);
yPts[i] = (int)(origXPts[i] * Math.sin(angle) + origYPts[i] * Math.cos(angle) + y + .5);
}
if(active) {
g.setColor(Color.white);
}
else {
g.setColor(Color.darkGray);
}
g.fillPolygon(xPts, yPts, 4);
}
public void move(int scrnWidth, int scrnHeight) {
if(shotDelayLeft > 0) {
shotDelayLeft--;
}
if(turningLeft) {
angle -= rotationalSpeed;
}
if(turningRight) {
angle += rotationalSpeed;
}
if(angle > (2 * Math.PI)) {
angle -= (2 * Math.PI);
}
else if(angle < 0) {
angle += (2 * Math.PI);
}
if(accelerating) {
xVelocity += acceleration * Math.cos(angle);
yVelocity += acceleration * Math.sin(angle);
}
x += xVelocity;
y += yVelocity;
xVelocity *= velocityDecay;
yVelocity *= velocityDecay;
if(x<0) {
x += scrnWidth;
}
else if(x > scrnWidth) {
x -= scrnWidth;
}
if(y < 0) {
y += scrnHeight;
}
else if(y > scrnHeight) {
y -= scrnHeight;
}
}
public void setAccelerating(boolean accelerating) {
this.accelerating = accelerating;
//start or stop accelerating the ship
}
public void setTurningLeft(boolean turningLeft) {
this.turningLeft = turningLeft;
//start or stop turning the ship
}
public void setTurningRight(boolean turningRight) {
this.turningRight = turningRight;
}
public double getX() {
return x;
//returns the ship’s x location
}
public double getY() {
return y;
//returns the ship's y location
}
public double getRadius() {
return radius;
//returns radius of circle that approximates the ship
}
public void setActive(boolean active) {
this.active = active;
//used when the game is paused or unpaused
}
public boolean isActive() {
return active;
}
public boolean canShoot() {
if(shotDelayLeft > 0) {
return false;
}
else {
return true;
}
}
public Shot shoot() {
shotDelayLeft=shotDelay;
//set delay till next shot can be fired
//a life of 40 makes the shot travel about the width of the
//screen before disappearing
return new Shot(x, y, angle, xVelocity, yVelocity, 40);
}
}
Shot.java
import java.awt.*;
public class Shot {
final double shotSpeed = 12;
double x, y, xVelocity, yVelocity;
int lifeLeft;
public Shot(double x, double y, double angle, double shipXVel, double shipYVel, int lifeLeft) {
this.x = x;
this.y = y;
xVelocity = shotSpeed * Math.cos(angle) + shipXVel;
yVelocity = shotSpeed * Math.sin(angle) + shipYVel;
this.lifeLeft = lifeLeft;
}
public void move(int scrnWidth, int scrnHeight) {
lifeLeft--;
x += xVelocity;
y += yVelocity;
if(x < 0) {
x += scrnWidth;
}
else if(x > scrnWidth) {
x -= scrnWidth;
}
if(y < 0) {
y += scrnHeight;
}
else if(y > scrnHeight) {
y -= scrnHeight;
}
}
public void draw(Graphics g) {
g.setColor(Color.yellow);
g.fillOval((int)(x - .5), (int)(y - .5), 3, 3);
}
public double getX() {
return x;
}
public double getY() {
return y;
}
public int getLifeLeft() {
return lifeLeft;
}
}
thanks for looking.
---------------------Edit 12/9/2012------------------------
Tried debugging with NetBeans IDE 7.2.1. It improperly depicts the turning of ship and gives a completely different error:
Exception in thread "Thread-3" java.lang.NullPointerException
at AsteroidsGame.run(AsteroidsGame.java:122)
at java.lang.Thread.run(Thread.java:722)
It is directing attention to the Shot[] shots array inside the run method.
This could be expected as the array for Asteroid[] and Shot[] are set up the same.