string index out of bound exception while carrying search operation

string index out of bound exception while carrying search operation

when I am carrying out a search operation after fetching the contacts,it
shows this exception when I type the letters very fast in the search bar
and the application crashes.Could you please help me out to resolve this
issue.I am including the portion of the code also along
@Override
public boolean onQueryTextChange(String newtext) {
String searchString = newtext;
int textLength = searchString.length();
ArrayList<Masterlistmodel> type_name_filter = new
ArrayList<Masterlistmodel>();
/* String text = edtField.getText().toString(); */
for (int i = 0; i <masterarr.size(); i++) {
String Name = masterarr.get(i).getName();
if (searchString.equalsIgnoreCase(Name.substring(0,
textLength))) {
type_name_filter.add(masterarr.get(i));
}
}
type_name_copy = type_name_filter;
listUpdate(type_name_copy);
return true;
}
@Override
public boolean onQueryTextSubmit(String arg0) {
// TODO Auto-generated method stub
return false;
}