title: Problem with android single choice dialog using arrayAdapter
body: <p>I tried to do a custom single choice dialog using an ArrayAdapter. First i created a Array Adapter with anonymous class.</p>
  
  <pre><code>private final Dialog createListFile(final String[] fileList) {
  AlertDialog.Builder builder = new AlertDialog.Builder(this);
  builder.setTitle(R.string.compare);
  ArrayAdapter&lt;String&gt; dialogArrayAdapter = new ArrayAdapter&lt;String&gt;(this, R.layout.dialog_row, fileList) {
  
          @Override
          public View getView(int position, View convertView, ViewGroup parent) {
              ViewHolderDialog holder = null;
              if (convertView == null) {are
                  LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                  convertView = inflater.inflate(R.layout.dialog_row, null);
                  holder = new ViewHolderDialog();
                  holder.date = (TextView) convertView.findViewById(R.id.dialogDate);
                  holder.days = (TextView) convertView.findViewById(R.id.dialogDays);
                  convertView.setTag(holder);
              } else {
                  holder = (ViewHolderDialog) convertView.getTag();
              }
              String item = getItem(position);
              holder.date.setText(item);
              holder.days.setText("giorni");
              return convertView;
          }
      };
  </code></pre>
  
  <p>Then i called the setSingleChoiceItems method of the builder to create a list of items with a check mark displayed; passing as the first parameter arrayAdapter created earlier.</p>
  
  <pre><code>builder.setSingleChoiceItems(dialogArrayAdapter, -1, new DialogInterface.OnClickListener() {
  public void onClick(DialogInterface dialog, int whichButton) {
      n = whichButton;
          }
      });
  </code></pre>
  
  <p>The problem is that when I run the code shows the check mark. Where am I doing wrong?</p>