ClassCastException: java.lang.Object[] cannot be cast to java.lang.String[] android

Question

In my application I need to convert my arraylist to a string of an array. However, I am getting an error:

ClassCastException: java.lang.Object[] cannot be cast to java.lang.String[] android

At the line with listofurls I am getting the error: listofurls = (String[])image_urls.toArray();

This is the full code:

public class Test2 extends AsyncTask<Void, Void, Void> 
{
  String[] listofurls ;
  private static final String url = "http://www.tts.com/album_pro/array_to_encode";
  JSONParser jParser = new JSONParser();
  ArrayList<String> image_urls = new ArrayList<String>();

  protected void onPreExecute() {
    //Log.e(LOG_CLASS, "in side assyntask");
  }

  protected Void doInBackground(Void... voids) {
    Log.v("Async","Async");
    JSONObject json = jParser.getJSONFromUrl(url);

    try {
      JSONObject seo = json.getJSONObject("SEO");
      JSONArray folio = seo.getJSONArray("Folio");

      // JSONArray image_urls1 = new JSONArray();
      //String s1=seo.getString("Folio");

      for(int i=0;i<folio.length();++i) {
        String m = folio.getString(i);
        Log.v("M"+i,m);
        image_urls.add(m);
        Log("test-url"+image_urls);
      }
    } catch(Exception e) {
      e.printStackTrace();
    }

    listofurls = (String[])image_urls.toArray();  //ERROR OCCURS HERE

    return null;
  }

  private void Log(String string) {
    Log.v("Test",string);
  }

  protected void onProgressUpdate(Integer... progress) { }

  protected void onPostExecute(Void result) {
    mAdapter = new ImagePagerAdapter(getSupportFragmentManager(),listofurls.length );
    mAdapter.setImageurls(listofurls);
    mPager.setAdapter(mAdapter);
  }

@MiserableVariable Better wording, yes .. – Mar 07 '13 at 06:09 — , Mar 07 '13 at 06:09
actually opposite meaning, but you get the point :) – Miserable Variable Mar 07 '13 at 06:21 — Miserable Variable, Mar 07 '13 at 06:21

score 126 · Accepted Answer · answered Mar 07 '13 at 06:03

126

try

listofurls = image_urls.toArray(new String[image_urls.size()]);

Note: I suggest to rename listofurls to arrayOfURLs

answered Mar 07 '13 at 06:03

Evgeniy Dorofeev

133,369
30
199
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1

still getting the error.it says, Caused by: java.lang.ClassCastException: java.lang.Object[] cannot be cast to java.lang.String[] – Shweta Mar 07 '13 at 06:05
you mean to say : String[] listofurls ; listofurls = image_urls.toArray(new String[image_urls.size()]); , instead of "listofurls" i should use "arrayOFURLs"?? but how does it make a difference – Shweta Mar 07 '13 at 06:06
i suggest to try and localize the problem, try this: List image_urls = new ArrayList(); String[] listofurls = image_urls.toArray(new String[image_urls.size()]); – Evgeniy Dorofeev Mar 07 '13 at 06:09
1

@Shweta Naming conventions. If you're calling your array a list, it's confusing. – Kevin Coppock Mar 07 '13 at 06:09

score 30 · Answer 2 · answered Mar 07 '13 at 06:09

30

You should use toArray as mentioned above, but not in that way.

Either initialize the array first and fill it:

String[] urlArray = new String[image_urls.size()];
image_urls.toArray(urlArray);

After which, urlArray will contain all the Strings from image_urls, or pass in a zero-length String array:

listofurls = (String[]) image_urls.toArray(new String[0]);

See the documentation for toArray().

answered Mar 07 '13 at 06:09

Kevin Coppock

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Other solutions didn't work for me. Passing 0 length array worked. – mythicalcoder Jul 04 '16 at 19:35
This is right solution, Just no need for casting to `(String[])` – Sergey Stasishin Dec 02 '19 at 15:57

score 3 · Answer 3 · answered Mar 07 '13 at 06:21

You just need to get the contents of arraylist in an array, right??

Can't u do like this?

       for(int i=0;i<folio.length();++i)
        {
            String m = folio.getString(i);
            Log.v("M"+i,m);
            image_urls.add(m);
            Log("test-url"+image_urls);


            listofurls[i] = m ;
        }

score 3 · Answer 4 · answered Jul 25 '16 at 11:35

3

listofurls = image_urls.toArray(new String[0]);

that should do the trick for all cases, even if you don't know the size of the resulting array.

answered Jul 25 '16 at 11:35

Samarth S

313
4
5

score 2 · Answer 5 · edited May 23 '17 at 12:10

2

Try this:

ArrayList<String> stock_list = new ArrayList<String>();
stock_list.add("stock1");
stock_list.add("stock2");
String[] stockArr = new String[stock_list.size()];
stockArr = stock_list.toArray(stockArr);
for(String s : stockArr)
    System.out.println(s);

Taken directly from here: link

edited May 23 '17 at 12:10

Community

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answered Mar 07 '13 at 06:08

crazylpfan

1,038
7
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ClassCastException: java.lang.Object[] cannot be cast to java.lang.String[] android

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