NullPointerException not in my code but in onResume() for LibGDX AndroidInput - android-studio

Question

This the stack trace:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.epl.game, PID: 18789
java.lang.RuntimeException: Unable to resume activity {com.epl.game/com.epl.game.AndroidLauncher}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.badlogic.gdx.backends.android.AndroidInput.onResume()' on a null object reference
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:4205)
at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:4237)
at android.app.servertransaction.ResumeActivityItem.execute(ResumeActivityItem.java:52)
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:176)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.badlogic.gdx.backends.android.AndroidInput.onResume()' on a null object reference
at com.badlogic.gdx.backends.android.AndroidApplication.onResume(AndroidApplication.java:300)
at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1453)
at android.app.Activity.performResume(Activity.java:7962)
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:4195)
at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:4237) 
at android.app.servertransaction.ResumeActivityItem.execute(ResumeActivityItem.java:52) 
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:176) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
at android.os.Handler.dispatchMessage(Handler.java:107) 
at android.os.Looper.loop(Looper.java:214) 
at android.app.ActivityThread.main(ActivityThread.java:7356) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:49 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 
This is my main project
package com.epl.game;
import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Input;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.BitmapFont;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.math.Intersector;
import com.badlogic.gdx.math.Rectangle;
import org.omg.PortableServer.POAManagerPackage.State;
import java.util.ArrayList;
import java.util.Random;
public class epl extends ApplicationAdapter {
MyTextInputListener listener = new MyTextInputListener();
SpriteBatch batch;
Texture background;
Texture[] man;
State[] gsm;
int batsmanState = 0;
int pause = 0;
float gravity = 0.2f;
float velocity = 0;
int manY = 0;
Rectangle manRectangle;
BitmapFont font1;
BitmapFont font2;
BitmapFont font3;
Texture dizzy;
int score = 0;
int gameState = 0;
int i1 = 0;
int i2 = 0;
State state0;
State state1;
State state2;
State state3;
State state4;
State state5;
Random random;
String humanName;
ArrayList<Integer> coinXs = new ArrayList<>();
ArrayList<Integer> coinYs = new ArrayList<>();
ArrayList<Rectangle> coinRectangles = new ArrayList<>();
Texture coin;
int coinCount;
ArrayList<Integer> bombXs = new ArrayList<>();
ArrayList<Integer> bombYs = new ArrayList<>();
ArrayList<Rectangle> bombRectangles = new ArrayList<>();
Texture bomb;
int bombCount;
PlayServices ply;
#Override
public void create() {
batch = new SpriteBatch();
background = new Texture("bg.png");
man = new Texture[4];
man[0] = new Texture("batsman.jpg");
man[1] = new Texture("batsman.jpg");
man[2] = new Texture("batsman.jpg");
man[3] = new Texture("batsman.jpg");
gsm = new State[6];
gsm[0] = (state0);
gsm[1] = (state1);
gsm[2] = (state2);
gsm[3] = (state3);
gsm[4] = (state4);
gsm[5] = (state5);
manY = Gdx.graphics.getHeight() / 2;
coin = new Texture("ball.png");
bomb = new Texture("stump.jpeg");
random = new Random();
dizzy = new Texture("out.jpeg");
font1 = new BitmapFont();
font1.setColor(Color.RED);
font1.getData().setScale(10);
font2 = new BitmapFont();
font2.setColor(Color.RED);
font2.getData().setScale(10);
font3 = new BitmapFont();
font3.setColor(Color.RED);
font3.getData().setScale(10);
}
public void makeCoin() {
float height = random.nextFloat() * Gdx.graphics.getHeight();
coinYs.add((int) height);
coinXs.add(Gdx.graphics.getWidth());
}
public void makeBomb() {
float height = random.nextFloat() * Gdx.graphics.getHeight();
bombYs.add((int)height);
bombXs.add(Gdx.graphics.getWidth());
}
private String myText;
public class MyTextInputListener implements Input.TextInputListener {
#Override
public void input(String text) {
}
#Override
public void canceled() {
whatIsYourName();
}
public String getText() {
return myText;
}
public void whatIsYourName() {
Gdx.input.getTextInput(listener, "Name : ", "", "eg:Jonathan");
humanName = listener.getText();
gameState = 1;
}
}
public epl(PlayServices ply){
this.ply = ply;
}
#Override
public void render () {
batch.begin();
batch.draw(background, 0, 0, Gdx.graphics.getWidth(),
Gdx.graphics.getHeight());
if (gameState == 1 && state1 == null) {
// GAME IS LIVE
// BOMB
if (bombCount < 250) {
bombCount++;
} else {
bombCount = 0;
makeBomb();
}
bombRectangles.clear();
for (int i = 0; i < bombXs.size(); i++) {
batch.draw(bomb, bombXs.get(i), bombYs.get(i));
bombXs.set(i, bombXs.get(i) - 8);
bombRectangles.add(new Rectangle(bombXs.get(i),
bombYs.get(i),
bomb.getWidth(), bomb.getHeight()));
}
// COINS
if (coinCount < 100) {
coinCount++;
} else {
coinCount = 0;
makeCoin();
}
coinRectangles.clear();
for (int i = 0; i < coinXs.size(); i++) {
batch.draw(coin, coinXs.get(i), coinYs.get(i));
coinXs.set(i, coinXs.get(i) - 4);
coinRectangles.add(new Rectangle(coinXs.get(i),
coinYs.get(i),
coin.getWidth(), coin.getHeight()));
}
if (Gdx.input.justTouched()) {
velocity = -10;
}
if (pause < 8) {
pause++;
} else {
pause = 0;
if (batsmanState < 3) {
batsmanState++;
} else {
batsmanState = 0;
}
}
velocity += gravity;
manY -= velocity;
if (manY <= 0) {
manY = 0;
}
} else if (gameState == 5 && state5 == null) {
//leaderboard
if (Gdx.input.justTouched()){
ply.submitScore(humanName,score);
ply.showScore(humanName);
gameState = 1;
}
}else if (gameState == 3 && state3 == null) {
//name
listener.whatIsYourName();
gameState = 1;
} else if (gameState == 0 && state0 == null) {
// Waiting to start
if (humanName == null){
gameState = 3;
}else{
gameState = 1;
}
} else if (gameState == 4 && state4 == null) {
//final score display
font3.draw(batch, "Score = " + score,100,1400);
if (Gdx.input.justTouched()){
score = 0;
gameState = 1;
}
}else if (gameState == 2 && state2 == null) {
// GAME OVER
if (Gdx.input.justTouched()) {
manY = Gdx.graphics.getHeight() / 2;
velocity = 0;
coinXs.clear();
coinYs.clear();
coinRectangles.clear();
coinCount = 0;
bombXs.clear();
bombYs.clear();
bombRectangles.clear();
bombCount = 0;
i1 = 0;
i2 = 0;
}
}
if (gameState == 2) {
batch.draw(dizzy, Gdx.graphics.getWidth() / 2 -
man[batsmanState].getWidth() / 2, manY);
if (Gdx.input.justTouched()){
gameState = 4;
}
} else {
batch.draw(man[batsmanState], Gdx.graphics.getWidth() / 2 -
man[batsmanState].getWidth() / 2, manY);
}
manRectangle = new Rectangle(Gdx.graphics.getWidth() / 2 -
man[batsmanState].getWidth() / 2, manY,
man[batsmanState].getWidth(), man[batsmanState].getHeight());
for (int i=0; i < coinRectangles.size();i++) {
if (Intersector.overlaps(manRectangle, coinRectangles.get(i))) {
score++;
i1 = random.nextInt((4 -1) + 1);
score = score + i1;
i2 = i1 + 1;
coinRectangles.remove(i);
coinXs.remove(i);
coinYs.remove(i);
break;
}
}
for (int i=0; i < bombRectangles.size();i++) {
if (Intersector.overlaps(manRectangle, bombRectangles.get(i))) {
gameState = 2;
}
}
font1.draw(batch, String.valueOf(score),100,200);
font2.draw(batch, String.valueOf(i2),900,200);
batch.end();
}
#Override
public void dispose () {
batch.dispose();
}
}
This is my android launcher
package com.epl.game;
import android.content.Intent;
import android.os.Bundle;
import com.badlogic.gdx.backends.android.AndroidApplication;
import com.google.android.gms.games.Games;
import com.google.example.games.basegameutils.GameHelper;
public class AndroidLauncher extends AndroidApplication implements PlayServices {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
gameHelper = new GameHelper(this, GameHelper.CLIENT_GAMES);
gameHelper.enableDebugLog(true);
GameHelper.GameHelperListener gameHelperListener = new GameHelper.GameHelperListener() {
#Override
public void onSignInFailed() {
}
#Override
public void onSignInSucceeded() {
}
};
gameHelper.setup(gameHelperListener);
}
String leaderboard = "CgkI7PuNlqsVEAIQAA";
private GameHelper gameHelper;
#Override
protected void onStart() {
super.onStart();
gameHelper.onStart(this); // You will be logged in to google play services as soon as you open app , i,e on start
}
#Override
protected void onStop() {
super.onStop();
gameHelper.onStop();
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
gameHelper.onActivityResult(requestCode, resultCode, data);
}
#Override
public boolean signIn() {
try {
runOnUiThread(new Runnable() {
#Override
public void run() {
gameHelper.beginUserInitiatedSignIn();
}
});
} catch (Exception e) {
}
return true;
}
#Override
public void submitScore(String LeaderBoard, int highScore) {
if (isSignedIn()) {
Games.Leaderboards.submitScore(gameHelper.getApiClient(), LeaderBoard, highScore);
} else {
System.out.println(" Not signin Yet ");
}
}
#Override
public void showScore(String leaderboard) {
if (isSignedIn()) {
startActivityForResult(Games.Leaderboards.getLeaderboardIntent(gameHelper.getApiClient(), leaderboard), 1);
} else {
signIn();
}
}
#Override
public boolean isSignedIn() {
return false;
}
And this is my play services interface
package com.epl.game;
public interface PlayServices
{
boolean signIn();
void submitScore(String LeaderBoard, int highScore);
void showScore(String LeaderBoard);
boolean isSignedIn();
}
I am new to libgdx and I am trying to create a game with a leaderboard .
I created this by importing the BaseGameUtils .
Else if you have another way i could create a global leaderboard in my
game please let me know.

Answer 1

It is critical that you call the initialize method in onCreate of your AndroidLauncher class. This is what sets up LibGDX's backends for graphics, sound, and input. Since you did not call initialize, the input class (along with graphics, sound, files, etc.) was not set up and assigned, and so is still null when the resume part of the lifecycle is reached. This leads to the NullPointerException.
In your case, your onCreate method should look something like:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
AndroidApplicationConfiguration config = new AndroidApplicationConfiguration();
// customize the configuration here
initialize(new epl(), config);
// Your other setup code...
}
Note, class names in Java should always start with a capital letter. It will make it easier to read and understand your code.