Come risolvere NullPointerException

Salve, sto cercando di fare un app in cui c'è una casella di ricerca, ho scritto il codice, ma quando provo a digitare la prima lettera nell' AutoCompleteTextView, mi da un errore (java.lang.NullPointerException) senza specificare che tipo di errore l'ha causato.

public class Search extends Activity{<br /> AutoCompleteTextView acTV;<br /> ListView lview;<br /> <br /> String[] first = { "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten"};<br /> <br /> String[] second = { "Uno", "Due", "Tre", "Quattro", "Cinque", "Sei", "Sette", "Otto", "Nove", "Dieci"};<br /> int textlength = 0;<br /> ArrayList<String> first_sort = new ArrayList<String>();<br /> ArrayList<String> second_sort = new ArrayList<String>();<br /> <br /> public void onCreate(Bundle savedInstanceState){<br /> super.onCreate(savedInstanceState);<br /> setContentView(R.layout.mains);<br /> <br /> acTV = (AutoCompleteTextView) findViewById(R.id.acTV);<br /> lview = (ListView) findViewById(R.id.list);<br /> lview.setAdapter(new MyCustomAdapter(first, second));<br /> <br /> lview.setClickable(true);<br /> lview.setOnItemClickListener(new OnItemClickListener() { <br /> public void onItemClick(AdapterView<?> adapter, View view, int position, long id){ <br /> <br /> Intent intent = new Intent(Search.this,Details.class);<br /> startActivity(intent);<br /> }<br /> {<br /> }});<br /> <br /> lview.setTextFilterEnabled(true);<br /> acTV.addTextChangedListener(new TextWatcher(){<br /> <br /> public void afterTextChanged(Editable s){<br /> }<br /> <br /> public void beforeTextChanged(CharSequence s, int start, int count, int after)<br /> {<br /> }<br /> <br /> public void onTextChanged(CharSequence s, int start,<br /> int before, int count)<br /> {<br /> <br /> textlength = acTV.getText().length();<br /> first_sort.clear();<br /> second_sort.clear();<br /> for (int i = 0; i < first.length; i++)<br /> {<br /> if (textlength <= first[i].length())<br /> {<br /> if (acTV.getText().toString().equalsIgnoreCase((String) first[i].subSequence(0, textlength)))<br /> {<br /> first_sort.add(first[i]);<br /> second_sort.add(first[i]);<br /> }<br /> }<br /> }<br /> <br /> lview.setAdapter(new MyCustomAdapter (first_sort, second_sort));<br /> <br /> }<br /> });<br /> }<br /> <br /> class MyCustomAdapter extends BaseAdapter{<br /> <br /> String[] data_first;<br /> String[] data_second;<br /> <br /> {<br /> <br /> }<br /> <br /> MyCustomAdapter(String[] first, String[] second){<br /> data_first = first;<br /> data_second = second;<br /> }<br /> <br /> MyCustomAdapter(ArrayList<String> first, ArrayList<String> second)<br /> {<br /> for(int i=0;i<first.size();i++)<br /> {<br /> data_first[i] = first.get(i);<br /> data_second[i] = second.get(i);<br /> }<br /> <br /> }<br /> <br /> public int getCount()<br /> {<br /> return data_first.length;<br /> }<br /> <br /> public String getItem(int position)<br /> {<br /> return null;<br /> }<br /> <br /> public long getItemId(int position)<br /> {<br /> return position;<br /> }<br /> <br /> public View getView(int position, View convertView, ViewGroup parent)<br /> {<br /> <br /> LayoutInflater inflater = getLayoutInflater();<br /> View row;<br /> <br /> row = inflater.inflate(R.layout.listitem_row, parent, false);<br /> <br /> TextView textview = (TextView) row.findViewById(R.id.textView1);<br /> TextView textview1 = (TextView) row.findViewById(R.id.textView2);<br /> <br /> textview.setText(data_first[position]);<br /> textview1.setText(data_second[position]);<br /> <br /> return (row);<br /> <br /> }<br /> }<br /> }


Questo è l'errore che mi da:

12-24 02:51:28.761: E/AndroidRuntime(15427): FATAL EXCEPTION: main<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): java.lang.NullPointerException<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at it.gogle.com.Search$MyCustomAdapter.<init>(Search. java:111)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at it.gogle.com.Search$2.onTextChanged(Search.java:85 )<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.widget.TextView.sendOnTextChanged(TextView .java:6240)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.widget.TextView.handleTextChanged(TextView .java:6281)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.widget.TextView$ChangeWatcher.onTextChange d(TextView.java:6456)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.text.SpannableStringBuilder.sendTextChange (SpannableStringBuilder.java:889)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.text.SpannableStringBuilder.change(Spannab leStringBuilder.java:352)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.text.SpannableStringBuilder.change(Spannab leStringBuilder.java:269)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.text.SpannableStringBuilder.replace(Spanna bleStringBuilder.java:432)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.text.SpannableStringBuilder.replace(Spanna bleStringBuilder.java:409)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.text.SpannableStringBuilder.replace(Spanna bleStringBuilder.java:28)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.view.inputmethod.BaseInputConnection.repla ceText(BaseInputConnection.java:583)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.view.inputmethod.BaseInputConnection.commi tText(BaseInputConnection.java:174)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at com.android.internal.widget.EditableInputConnectio n.commitText(EditableInputConnection.java:120)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at com.android.internal.view.IInputConnectionWrapper. executeMessage(IInputConnectionWrapper.java:247)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at com.android.internal.view.IInputConnectionWrapper$ MyHandler.handleMessage(IInputConnectionWrapper.ja va:73)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.os.Handler.dispatchMessage(Handler.java:99 )<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.os.Looper.loop(Looper.java:123)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at android.app.ActivityThread.main(ActivityThread.jav a:4627)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at java.lang.reflect.Method.invokeNative(Native Method)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at java.lang.reflect.Method.invoke(Method.java:521)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at com.android.internal.os.ZygoteInit$MethodAndArgsCa ller.run(ZygoteInit.java:858)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at com.android.internal.os.ZygoteInit.main(ZygoteInit .java:616)<br /> 12-24 02:51:28.761: E/AndroidRuntime(15427): at dalvik.system.NativeStart.main(Native Method)


La riga incriminata è questa:
lview.setAdapter(new MyCustomAdapter (first_sort, second_sort));

Come faccio a risolvere questo errore? Qualcuno saprebbe gentilmente aiutarmi? Grazie mille.