how to use variable size array in android?

Question

I'm using string array which I'm passing to ArrayAdapter for spinner item. my array size(usually less than 10) and values are variable (I'm taking it from asset file)

if I'm using this :

String[] arr = new String[10];
protected void onCreate(Bundle savedInstanceState) {
        breader = new BufferedReader(new InputStreamReader(getAssets().open(path)));
        int length = Integer.parseInt(breader.readLine());
        for(int i=0; i<length; i++){
            arr[i]=breader.readLine();

        initialize();
....
}

initialize(){    
    spinner1 = (Spinner) findViewById(R.id.spinner1);
    ArrayAdapter<String> array = new ArrayAdapter<String>(Activity.this, android.R.layout.simple_spinner_item, arr);
    spinner1.setAdapter(array);
}

it shows NullPointerException at spinner1.setAdapter(array); line. can I reassign array length. I think its not possible.

instead of Activity.this use YourActivity.this like MainActivity.this and its better to use ArrayLis<String> instead String[], because you don't know exactly what is the size of your list — Shayan Pourvatan
– Shayan Pourvatan, Commented Jul 29, 2014 at 12:30

Jayesh Khasatiya · Accepted Answer · 2014-07-29 12:36:20Z

2

because of you add null when no data in last portion of array. I mean there are 7 data in assest file and you move for loop 10 times so after 7 data Add there are null represent. so breader.readLine(); read null and add it to your string array and when you parse StringArray to Array Adapter there are null get on 8th position of array and nullpointer Exception fire.

So just check breader.readLine() != Null then add it to String of Array otherwise add some Temp text.

Or

You Also Use ArrayList instead of String[] Array. ArrayList is dynamically Arraylist you can add data to list useing array.add(yourdata).

Thats it...

answered Jul 29, 2014 at 12:36

Jayesh Khasatiya

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4 Comments

akshay bhange Over a year ago

will ArratAdapter Accept ArrayList?

akshay bhange Over a year ago

sorry it is not accepting ArrayList<String>. same error occurred.

Jayesh Khasatiya Over a year ago

have you change Activity.this to yourActivityname.this? in arrayAdapter.

akshay bhange Over a year ago

sorry it was my mistake of initializing before the setContentView. Thanks for help. Thank you again

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