How do i fix java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 in android? I am trying to learn ArrayList

Question

What the hell is this thing

public class MainActivity extends AppCompatActivity {
ArrayList<String> celebrityURL = new ArrayList<>();
int chosenCeleb = 0;
ImageView celebrityImage;
int locationAnswer = 0;
//random answers

ArrayList<String> answers = new ArrayList<>();
//random buttons reference
Button button01;
Button button02;
Button button03;
Button button04;


ArrayList<String> names = new ArrayList<>();

public void selectCeleb(View view) {

    if (view.getTag().toString().equals(Integer.toString(locationAnswer))) {
        Toast.makeText(getApplicationContext(), "CORRECT ", Toast.LENGTH_LONG).show();



    } else {
        Toast.makeText(getApplicationContext(), "WRONG, IT WAS: " + names.get(chosenCeleb), Toast.LENGTH_SHORT).show();



    }

    randomCelebrity();
}

public class imagesGet extends AsyncTask<String, Void, Bitmap> {

    @Override
    protected Bitmap doInBackground(String... params) {

        try {
            URL imagesURL = new URL(params[0]);
            HttpURLConnection connection = (HttpURLConnection)   imagesURL.openConnection();
            connection.connect();
            InputStream inputStream = connection.getInputStream();
            Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
            return bitmap;

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }
}


public class getData extends AsyncTask<String, Void, String> {

    @Override
    protected String doInBackground(String... urls) {

        String result = "";
        URL url;
        HttpURLConnection connection = null;
        try {
            url = new URL(urls[0]);
            connection = (HttpURLConnection) url.openConnection();
            InputStream inputStream = connection.getInputStream();
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
            int data = inputStreamReader.read();
            while (data != -1) {
                char current = (char) data;
                result += current;
                data = inputStreamReader.read();
            }
            return result;
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }


        return null;
    }
}


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    celebrityImage = (ImageView) findViewById(R.id.celebrityID);
    button01 = (Button) findViewById(R.id.celebrity01);
    button02 = (Button) findViewById(R.id.celebrity02);
    button03 = (Button) findViewById(R.id.celebrity03);
    button04 = (Button) findViewById(R.id.celebrity04);

    getData task = new getData();
    String resultData = null;
    try {
        try {
            resultData = task.execute("http://www.posh24.se/kandisar").get();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        String[] spResult = resultData.split("<div class\"sidebarContainer\">");

        //images
        Pattern pattern = Pattern.compile("img src=\"(.*?)\"");
        Matcher matcher = pattern.matcher(spResult[0]);
        while (matcher.find()) {
            celebrityURL.add(matcher.group(1));
        }

        //names of the celebrities
        pattern = Pattern.compile("alt=\"(.*?)\"");
        matcher = pattern.matcher(spResult[0]);
        while (matcher.find()) {
            names.add(matcher.group(1));
        }


    }  catch (ExecutionException e) {
        e.printStackTrace();
    }
    randomCelebrity();
}

public void randomCelebrity() {
    //random  celebrity
    Random random = new Random();
    chosenCeleb = random.nextInt
            //between zero and the size of celebURL
                    (celebrityURL.size());

    //update imageView with new celebrity image
    imagesGet imagesGet = new imagesGet();
    Bitmap celebBitmap;
    try {
        celebBitmap = imagesGet.execute(celebrityURL.get(chosenCeleb)).get();
        celebrityImage.setImageBitmap(celebBitmap);
        int incorrectLocation;
        locationAnswer = random.nextInt(4);

        for (int i = 0; i < answers.size(); i++) {
            if (i == locationAnswer) {
                //update answers
                answers.get(chosenCeleb);

            } else {
                //create random celebrity from celebs urls
                incorrectLocation = random.nextInt(celebrityURL.size());

                //avoid getting the correct and wrong answer in same location
                //generate random answer if this condition is met
                while (incorrectLocation == chosenCeleb) {
                    incorrectLocation = random.nextInt(celebrityURL.size());
                }

                //assign wrong location answer in answers array
                answers.get(names.indexOf(incorrectLocation));
            }
        }

        button01.setText(answers.get(0));
        button02.setText(answers.get(1));
        button03.setText(answers.get(2));
        button04.setText(answers.get(3));
    } catch (ExecutionException e) {
        e.printStackTrace();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

  }
  }

I divide the code so you can see it better. I am not idea how to fix this, but i know it is something with the ArrayList answers thing. I am trying to make an app that will random take html data and display it in android app. I am making an app to ques the celebrity name.

Edit: Sorry i forgot to include the error

FATAL EXCEPTION: main
Process: com.stringmanipulation.stringmanipulation, PID: 24397
                                                 java.lang.IllegalStateException: Could not execute method for android:onClick
                                                   at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
                                                   at android.view.View.performClick(View.java:5610)
                                                   at android.view.View$PerformClick.run(View.java:22265)
                                                   at android.os.Handler.handleCallback(Handler.java:751)
                                                   at android.os.Handler.dispatchMessage(Handler.java:95)
                                                   at android.os.Looper.loop(Looper.java:154)
                                                   at android.app.ActivityThread.main(ActivityThread.java:6077)
                                                   at java.lang.reflect.Method.invoke(Native Method)
                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
                                                Caused by: java.lang.reflect.InvocationTargetException
                                                   at java.lang.reflect.Method.invoke(Native Method)
                                                   at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
                                                   at android.view.View.performClick(View.java:5610) 
                                                   at android.view.View$PerformClick.run(View.java:22265) 
                                                   at android.os.Handler.handleCallback(Handler.java:751) 
                                                   at android.os.Handler.dispatchMessage(Handler.java:95) 
                                                   at android.os.Looper.loop(Looper.java:154) 
                                                   at android.app.ActivityThread.main(ActivityThread.java:6077) 
                                                   at java.lang.reflect.Method.invoke(Native Method) 
                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) 
                                                Caused by: java.lang.IndexOutOfBoundsException: Index: 103, Size: 100
                                                   at java.util.ArrayList.get(ArrayList.java:411)
                                                   at com.stringmanipulation.stringmanipulation.MainActivity.randomCelebrity(MainActivity.java:183)
                                                   at com.stringmanipulation.stringmanipulation.MainActivity.selectCeleb(MainActivity.java:53)
                                                   at java.lang.reflect.Method.invoke(Native Method) 
                                                   at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
                                                   at android.view.View.performClick(View.java:5610) 
                                                   at android.view.View$PerformClick.run(View.java:22265) 
                                                   at android.os.Handler.handleCallback(Handler.java:751) 
                                                   at android.os.Handler.dispatchMessage(Handler.java:95) 
                                                   at android.os.Looper.loop(Looper.java:154)

Possible duplicate of [Array index out of bound in C](http://stackoverflow.com/questions/671703/array-index-out-of-bound-in-c) — Farid, Mar 05 '17 at 11:49
Can you please share the stack trace and mark the lines it's corresponding to? In general, you have an empty ArrayList (Size: 0) and you are trying to access the first element, which doesn't exist. — Larce, Mar 05 '17 at 11:49

score 1 · Answer 1 · edited May 23 '17 at 12:09

Until you highlight what line causes the problem, I will not be able to help you solve it accurately

IndexOutOfBoundsException is an exception thrown when you try to access an array and request an index that is too high. Example:(this goes for ArrayList and other types of array)

ArrayList<Integer> ex = new ArrayList<>();
int exceptionThrownHere = ex.get(0);

The exception is thrown when you try to get an object from the list whose index is out of bounds. Another example:

int[] ex = new int[10];
//initialize for this example to be valid
int exceptionThrownHere = ex[10];

The max index in this case is 9(0-9) and in the event you try to get 10 or more, you get the exception.

The solution:(need the line where the exception is thrown for accurate answer)

Make sure you don't try to get an object whose index is bigger than the amount of objects in the list. Another solution is to check how many objects are in the ArrayList(using .size()) and make sure you aren't trying to access an index that is bigger than the amount of objects in the list.

From analyzing your code, I see(assuming all the code is in the question) that you never add anything to the array "answers" - thus there are no objects in the list and it causes the exception. Make sure to add objects to the list by:

answers.add("whatever string you need here");

Also see

Java Documentation - IndexOutOfBoundsException

Java Arraylist got java.lang.IndexOutOfBoundsException?

How do i fix java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 in android? I am trying to learn ArrayList

1 Answers1