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Java game lag, too many if statement?

I'm working on a game in java, based on the Atari game adventure. I got the basic KeyListener part working fine, but then I added another if statement, using another class, to test if if the player was going to hit a wall, and stopping movement if that was the case. The method I used also used if statements, and when I ran the code, it had MAJOR lag. I tried a while loop first, but that made it lag even worse. Anyway to make this not lag so much? It doesn't seem that complex a program to run, and I still have to add yet another if statement to make be able to move into another room, so I have to do something to massively cut down on the lag.
Here is the class:
class Player extends JPanel implements KeyListener{
private char c = 'e';
int x = 400;
int y = 400;
int mapX = 0;
int mapY = 0;
public Player() {
this.setPreferredSize(new Dimension(800, 500));
addKeyListener(this);
}
public void addNotify() {
super.addNotify();
requestFocus();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Environment Layout = new Environment();
Layout.drawRoom(mapX,mapY,g);
g.fillRect(x , y , 20, 20);
}
public void keyPressed(KeyEvent e) { }
public void keyReleased(KeyEvent e) { }
public void keyTyped(KeyEvent e) {
c = e.getKeyChar();
repaint();
Environment Layout = new Environment();
if(Layout.isWall(x,y,c)){}
else{
if (c == 'a'){
x = x - 3;
}
else if (c == 'w'){
y = y - 3;
}
else if (c == 's'){
y = y + 3;
}
else if (c == 'd'){
x = x + 3;
}
}
}
public static void main(String[] s) throws IOException{
JFrame f = new JFrame();
f.getContentPane().add(new Player());
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.pack();
f.setVisible(true);
}
}
The draw room method I used in this was just to put the background of the room into place.
Here is the isWall method from the Environment class:
public boolean isWall(int moveX, int moveY, char let){
BufferedImage room = null;
try {
room = ImageIO.read(new File(xNum + "," + yNum + ".png"));
}
catch (IOException e) {
}
int[][] walls = convertImage(room);
boolean blocked = false;
if(let == 'w') {
if(walls[moveY-8][moveX] == -3584){blocked = true;}
}
else if(let == 's') {
if(walls[moveY+20][moveX] == -3584){blocked = true;}
}
else if(let == 'a') {
if(walls[moveY][moveX-5] == -3584){blocked = true;}
}
else if(let == 'd') {
if(walls[moveY][moveX+20] == -3584){blocked = true;}
}
return blocked;
}
the convertImage method just converts the image of the room into an int array, for the value of the colors. -3584 is the color of the walls. It's possible this is what's lagging it, but this seemed like the best way for each room to have the walls done automatically.
I also tried a timer, but either I did that wrong, or it just didn't help.
I can give more of my code if that's needed, but help with this would be much appreciated. I'm relatively new to this kind of stuff, so it's likely I'm missing something big. Thanks.

The lag here is almost certainly not from the if statements. Those are really fast. I think the bigger issue is in isWall. Notice that any time you want to check for whether a wall is present, you
Open a file,
read the file contents,
convert the file contents from an image to a grid of pixels, and
read exactly one pixel.
Reading files from disk is extremely slow compared to looking at values in memory. For example, a regular magnetic hard drive works at around 7200 RPM, so the seek time is measured in milliseconds. On the other hand, your processor can do about a billion operations per second, so other operations take nanoseconds. That means that a disk read is roughly a million times slower than other operations, which is almost certainly where you're getting the lag from!
To fix this, consider rewriting your isWall code so that you only read the file and do the conversion once and, having done that, then just look up the part of the image you need. This converts doing tons of (glacially slow) file reads to one single (slow but inevitable) file read followed by tons of fast memory reads.

You appear to be moving your walls further than you are moving your player.
Is it possible that your player object is getting stuck in a wall there by producing "blocked = true" continuously?
Your character gets +- 3 in every direction, however your walls seem inconsistent and range from 8 up to 20 down to 5 left to 20 right.

This is an extension to #templatetypedef's answer.
Instead of loading the image files upon calling the isWall method, you might want to consider caching all of the walls on game start.
So I am thinking;
have a HashMap data structure keyed by <String, Integer>. Where String is your coordinates. E.g. coordinate string = "100,238"
parse all the .png image files in the directories and store the coordinates as key and the value can just be any dummy value like 1 or 2.
Then when isWall() is invoked. Given the X and Y coordinate, build the coordinate string as mentioned in point 1 and check if the key exists. If it does then we know it is a piece of wall else not.
This should drastically reduce the I/O disk contention.
In future, if you would like to extend the solution to incorporate APIs like isTreasureChest() or isMonster(). It can be extended by building a immutable class call "Room" or "Tile" to represent the object. Then modify the HashMap to take in <String, Room>.

How do i create a grid map on a png image with java?

The thing is that i'm helping a friend with a java project for the universty, and we have to create a remake of MSX's Knightmare. The game is pretty developed already but we don't know how to create the collision with the scenary's stuff, like the columns and the bridge over the river. In order to do this i thought that we could just create a logical "grid-mapping" over the png (the whole level is this image, invoked on the game like a plain image) and do the logic on it, just a boolean logic.
So the basic way, that i suggest to do, is a 2D array with this grid calculated on our minds. Is there some tool that we could use in order to do this easier or automated somehow?
Knightmare original version video
And this is the image that we are using on the game

I am going to try answering the title question, which seemed like the important one.
I wrote a little platform game in Java some time ago, and there I wrote a method called comprobarColisiones() (check collisions) which I call everytime
// Check collisions
comprobarColisiones();
h.mover(pasadas); //Move hero
// Moving enemies
if (h.x > en.getX()){
en.mover(h.getdx(), h.getIzq(),pasadas);
}
if (h.x> en2.getX()){
en2.mover(h.getdx(), h.getIzq(),pasadas);
}
// Moving static objects (rocks)
roca1.mover(h.getdx(),h.getIzq());
roca2.mover(h.getdx(),h.getIzq());
roca3.mover(h.getdx(),h.getIzq());
// REPAINTING
repaint();
// A time calculation that I use to control the game speed somewhere
tiempoAnteriorTipito = System.currentTimeMillis();
When I mean "static objects" it's just to differentiate objects with self-movement with those that just scroll as long as the hero moves, in your game (as in mine's) there probably will not be any static object (well, probably the scores and stuff), even rocks will scroll.
public void comprobarColisiones(){
// Getting bounds
Rectangle r1 = en.getBounds();
Rectangle r2 = en2.getBounds();
Rectangle rec_roca1 = roca1.getBounds();
Rectangle rec_roca2 = roca2.getBounds();
Rectangle rec_roca3 = roca3.getBounds();
// Getting bounds and resolving collisions with shooting objects
ArrayList martillos = Heroe.getMartillos();
for (int i = 0; i < martillos.size(); i++) {
Martillo m = (Martillo) martillos.get(i);
Rectangle m1 = m.getBounds();
if (r1.intersects(m1) && en.vive())
{
en.setVive(false);
m.visible = false;
}
else if (r2.intersects(m1)&& en2.vive())
{
en2.setVive(false);
m.visible = false;
}
}
// Checking if hero touches enemies
Rectangle heroecuad = h.getBounds();
if (heroecuad.intersects(r1)&&en.vive()){
perdio = true;
System.out.println("PERDIO CON EL ENEMIGO 1");
}
if (heroecuad.intersects(r2)&&en2.vive()){
perdio = true;
System.out.println("PERDIO CON EL ENEMIGO 2");
}
// Checking if hero touches static objects
if(heroecuad.intersects(rec_roca1)){
System.out.println("CHOCO ROCA 1");
}
if(heroecuad.intersects(rec_roca2)){
System.out.println("CHOCO ROCA 2");
}
if(heroecuad.intersects(rec_roca3)){
System.out.println("CHOCO ROCA 3");
}
}
I created enemies and static stuff and placed them when I load the escenario, just like this:
en = new Enemigo(800, ALTURA_PISO+8);
en2 = new Enemigo(900, ALTURA_PISO+8);
roca1 = new Roca(1650, ALTURA_PISO+17);
roca2 = new Roca(2200, ALTURA_PISO+17);
roca3 = new Roca(3400, ALTURA_PISO+17);
// Being the first number the initial X-Pos and the second the initial Y-Pos, this will change everytime the hero moves, of course
Probably in your game, you'll define any area of the map as explorable, and add some ghost objects to check intersection with the hero and stop his movement. For what I could see, water and columns should NOT be explorable by your hero.
Hope this would give you some ideas.

Java - Water Tile Animation

I am trying to get animated water tile and I cannot figure it out..
Here, I try to use the modulus to get the remainder and switch it from there, I set it up like I would in my player walking animation. Here is the code I try to use to get it to fluctuate.
public void update() {
if (anim < 1000000) anim++;
else anim = 0;
if(anim % 30 > 20) {
sprite = Sprite.water_;
} else {
sprite = Sprite.water;
}
}
Then within my Main class I put in private WaterTile water; and called it, and put it in my update() method but it decides to not work.
If you would like to look at my overall code, here are my classes involved..:
Game.java http://pastebin.com/6sTePyx0
Tile.java http://pastebin.com/ZtGwdcmt
Sprite.java http://pastebin.com/e7yt9gek
WaterTile.java http://pastebin.com/EMezX4QQ

LibGdx - Tile Game Collision Detection

I'm working on a tile 2d-side platformer game. I have done some stuff so far.
I'm working on a basic collision detection using rectangles of libgdx so considering
I have only grass block for now I made a single block world in Java (file reader is not ready)
the problem is my detection only works the first time in other words if I spawn my colliding
to a block it detects collision and do so. Although if i spawn my player top of the block
with out colliding player falls forever.
Here is the code world.update(); =>
public void update() {
Iterator<block> cb = Blocks.iterator();
while (cb.hasNext()) {
block b = cb.next();
if (b.getBounds().overlaps(player.getBounds())) {
if (player.getPosition().x >= b.getPosition().x + 32) {
//RIGHT
player.getVelocity().x = 0;
} else if (player.getPosition().x + 32 <= b.getPosition().x) {
//Left
player.getVelocity().x = 0;
}
//All Y
player.getVelocity().y = 0;
}
if (!b.getBounds().overlaps(player.getBounds())) {
player.getVelocity().y = -gravity;
}
}
}

Your while loop is applying gravity for every block your player does not intersect with. So if you have 10 blocks, and the player intersects just 1, you'll still apply gravity 9 times. You should only apply the gravity change to the player once.
Set a flag (boolean hitSomething = false) before your loop, then set it to true (hitSomething = true) if the player hits any block. Then, after the loop, if hitSomething is false, apply gravity to the player.
Stepping through the update method with a debugger is a good way to figure out what your code is doing in cases like this. It should be quicker than waiting for Stack Overflow to debug your code, too.

How do I go about making this Conways Life program in java

I am making a Conway's Game of Life program in java, and am trying to change it from the command line version to a GUI. From the command line I just printed an array which showed the generations (the objects such as blocks and blinkers are shown as a series of 1's and 0's where it is blank, and in the GUI I'm showing it as squares (white squares as blank and blue squares where it isn't). But where I'm getting stuck is when I make another method (which replaces the method which prints the array) which checks the grid array, if there is a zero then the square changes from white to blue, and vice-versa. The Conway's Life rules are dealt with in a separate class which is independent, and all this method does is after the rules have changed the array this method checks it.
The rules are done in methods in one class and the GUI components are done in another. But since I need instance of both how would I go about doing it?, merge the two classes (all the GUI classes into the Life one, embed them some how, I am completely stuck on what to do
public void runGUI() {
int x = getX(), y = getY();
x /= squareSize;
y /= squareSize;
for (int i = 0; i < LifeData.grid.length; i++) {
for (int j = 0; j < LifeData.grid[i].length; j++) {
if (LifeData.grid[i][j] == 0)
l.setCell(x, y, l.getCell(x, y) + 1);
else
l.setCell(x, y, l.getCell(x, y) - 1);
this.repaint();
}
}
}
That is what I have changed it to now but when compiling it is saying "non-static variable grid cannot be referenced from a static context" and "non-static method runGUI() cannot be referenced from a static context". When trying to run the method.

Make a separate thread that will execute the game of life and update the GUI.
Something like this
public class GameExecutor implements Runnable {
private static final int DELAY = 1000;
private GameOfLife game;
private boolean stop = false;
private Gui gui;
public GameExecutor(Gui gui, GameOfLife game) {
this.gui = gui;
this.game = game;
};
public void run(){
game.start();
while (!stop) {
game.step(); //execute a step
gui.update(game.getState());
try {
Thread.sleep(DELAY);
} catch (InterruptedException e) {}
}
}
}
Launch this in a thread at startup and pass it your gui. Don't forget to update the gui in the correct Swing thread.
Obviously you'll need to add some code to stop it, too :)