NullPointerException at com.badlogic.gdx.graphics.g2d.TextureRegion.setRegion LIBGDX - button

Question

I am getting null pointer exception when I try spawning an item(Mushroom) when the player collides with a particular coin(As in MARIO game). I have been following this tutorial but I want the inputs to be buttons and not the keys. I have created 4 buttons and added to the stage . The inputs are working perfectly . But I am getting exception when,
I simply add the buttons to the stage and the input is still using keys
I am not getting exception when,
I remove all the buttons from the code and the input is using keys.
Here is my code for adding buttons to the stage ,
public class PlayScreen implements Screen, InputProcessor
{
.......
private Array<Item> items;
private LinkedBlockingQueue<ItemDef> itemsToSpawn;
private TextureAtlas atlas = new TextureAtlas("move_sprites.pack"); //contains the mushroom as well as the player packed together
public PlayScreen(MyGame game) {
.............
stage = new Stage();
atlas = new TextureAtlas("ui/button_pack.pack");
skin = new Skin(atlas);
white = new BitmapFont(Gdx.files.internal("fonts/white.fnt"), false);
black = new BitmapFont(Gdx.files.internal("fonts/black.fnt"), false);
TextButton.TextButtonStyle textButtonStyle = new TextButton.TextButtonStyle();
textButtonStyle.up = skin.getDrawable("buttonin");
textButtonStyle.down = skin.getDrawable("buttonout");
textButtonStyle.pressedOffsetX = 1;
textButtonStyle.font = black;
buttonright = new TextButton("Right", textButtonStyle);
buttonleft = new TextButton("Left", textButtonStyle);
//table.setBounds(500, 5, 250, 150);
buttonleft.setPosition(350, 5);
buttonleft.setHeight(100);
buttonleft.setWidth(100);
buttonright.setPosition(100, 5);
buttonright.setHeight(100);
buttonright.setWidth(100);
buttonup = new TextButton("up", textButtonStyle);
buttonup.setPosition(600, 5);
buttonup.setHeight(100);
buttonup.setWidth(100);
stage.addActor(buttonup);
stage.addActor(buttonright);
stage.addActor(buttonleft);
Gdx.input.setInputProcessor(stage);
......
}
//create a new method
public void spawnItem(ItemDef idef)
{
itemsToSpawn.add(idef);
}
public void handleSpawingItems()
{
if (!itemsToSpawn.isEmpty()) {
ItemDef idef = itemsToSpawn.poll(); //poll is pop
if (idef.type == Mushroom.class) {
items.add(new Mushroom(this, idef.position.x, idef.position.y));
}
}
}
public void update(float dt) {
handleInput(dt);
handleSpawingItems();
........
}
//Giving inputs using buttons
public void handleInput(float dt)
{
if (gamehero.currentState != Hero.State.DEAD) {
buttonup.addListener(new InputListener() {
#Override
public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
gamehero.heroBody.setLinearVelocity(0, 4f);
}
return true;
}
}
);
}
}
public void render(float delta)
{
......
update(delta);
stage.act();
stage.draw();
}
}
}
Mushroom Class..
public class Mushroom extends Item {
public Mushroom(PlayScreen screen, float x, float y) {
super(screen, x, y);
//mush is one of the sprite packed together using texture packer. Exception is thrown in the below line
setRegion(screen.getAtlas().findRegion("mush"), 0, 0, 16, 16);
velocity = new Vector2(0.7f, 0); //velocity of mushroom
}
I am triggering this mushroom when mario head collides with coin like below,
public class Coins extends InteractiveTileObject {
....
public void onHeadHit(Hero hero) {
if (object.getProperties().containsKey("mushroom")) {
Gdx.app.log("coins", "collision");
//Exception occurs in the below line too. When the collision occurs, spawnItem method is called in the main class
screen.spawnItem(new ItemDef(new Vector2(body.getPosition().x, body.getPosition().y + 16 / MyGame.PPM), Mushroom.class));
}
ItemDef Class,
public class ItemDef {
public Vector2 position;
public Class<?> type;
public ItemDef(Vector2 position, Class<?> type)
{
this.position = position;
this.type = type;
}
}
Exception occurs if I just add a button to my code and gave the input using keys. Problem lies in spawning the mushroom if I just add a button to my code. Its weird. Please help. I am a beginner . Thanks in advance

Answer 1

I found the cause for this Exception.
I have given the same name for 2 TextureAtlas while declaring,
private TextureAtlas atlas = new TextureAtlas("move_sprites.pack");
and the other,
atlas = new TextureAtlas("ui/button_pack.pack");
But I am referring the first TextureAtlas in other class. Since I have declared the TextureAtlas only once but used for two different packs, It threw null pointer exception as there was name conflict. Thanks for all your answers.