CODEWITHSUNDEEP
javaandroidarraylistwhile-loopout-of-memory
F3RN1
F3RN1

Reputation: 179

OutOfMemoryError with ArrayList in Android Application

In a activy I have written code that works correctly.

But now I have added a method to this activity with the following code:

    private void obtenerDatosReuniones(){

    try {

        int j=0;

        String aux = jsonReuniones.getString("nombres");

        String aux2 = null;

        aux2 = aux.replace("[", "");

        aux2= aux2.replace("]", "");

        String [] campos = aux2.split(",");

        while(j<campos.length){

            nombres_reuniones.add(campos[j]);

        }

the type of nombres_reunones is ArrayList

When I run the application appears out the following error on line nombres_reuniones.add (campos [j]):

What am I doing wrong?

Thanks!

Upvotes: 2

Views: 1464

Answers (3)

&#211;scar L&#243;pez
&#211;scar L&#243;pez

Reputation: 236004

You're not advancing the loop:

while (j < campos.length) {
    nombres_reuniones.add(campos[j]);
    j++; // without this, you'll loop forever!
}

What's happening is that you're adding an infinite amount of "campos" to the ArrayList, exhausting all the memory available to your program in the process.

Remember: a loop's condition must be false at some point for the loop to end. If you forget to advance the loop (in this case, by incrementing the j variable) the condition will always be true and the loop will never exit, therefore creating an infinite loop.

Upvotes: 3

OscarRyz
OscarRyz

Reputation: 199215

You are not updating the value of j hence j is always 0 and always smaller than campos.length

Upvotes: 0

Jon Skeet
Jon Skeet

Reputation: 1500405

Look at your loop:

while(j<campos.length){
    nombres_reuniones.add(campos[j]);
}

How do you anticipate that ever finishing? You don't modify j. Given that you don't make any change to j after declaring it and assigning it a value of 0 right at the start, it would be much clearer as:

for (int j = 0; j < campos.length; j++) {
    nombres_reuniones.add(campos[j]);
}

Or better:

for (String item : campos) {
    nombres_reuniones.add(item);
}

Or even simpler:

nombres_reunions.addAll(Arrays.asList(campos));

Additionally, your earlier code can be simpler. Look at this:

String aux2 = null;
aux2 = aux.replace("[", "");
aux2= aux2.replace("]", "");

Why bother assigning aux2 an initial value of null which you then immediately overwrite? Additionally, you can easily chain the method calls. It would be neater as:

String aux2 = aux.replace("[", "").replace("]", "");

And in fact, you can just chain the whole of the string manipulation together from start to finish:

String[] campos = jsonReuniones.getString("nombres")
                               .replace("[", "")
                               .replace("]", "")
                               .split(",");
nombres_reunions.addAll(Arrays.asList(campos));

(I'd stop there, rather than inlining even that expression...)

Upvotes: 3

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