error when test duplication in the database
<p>my app will load data from server and save it to database sqlite on device android.My problem is when i want test duplication of data in the database -> my app error. Can you help me!error on postion "<em>*</em>" at code
CLASS DB_Adapter query on database</p>

<pre><code>public class DB_Adapter {
public static final String INVOICEID = "invoiceid";
public static final String NUMBERPHONE = "numberphone";
public static final String ADDRESS = "address";
public static final String NUMBER = "number";
public static final String SNAME = "name";
public static final String URL = "url";
public static final String STATUS = "status";

public static final String DB_NAME = "CSDL";
public static final String DB_TABLE = "Saigonfleamarket";
public static final int DB_VERSION = 2;

private final Context mContext;
private SQLiteDatabase mDB;
private DBHelper mDBHelper;

public DB_Adapter(Context c) {
    mContext = c;
}

private static class DBHelper extends SQLiteOpenHelper
{

    public DBHelper(Context context, String name, CursorFactory factory,
            int version) {
        super(context, name, factory, version);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        try
        {
            db.execSQL("CREATE TABLE Saigonfleamarket (number integer PRIMARY KEY autoincrement, invoiceid text,name text, numberphone text, address text,url text, status text);");
        } catch (SQLException ex)
        {
            ex.printStackTrace();
        }
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        Log.i("DBAdapter", "Updating database...");
        db.execSQL("DROP TABLE IF EXISTS Saigonfleamarket");
        onCreate(db);
    }
}

public DB_Adapter openDB()
{
    mDBHelper = new DBHelper(mContext, DB_NAME, null, DB_VERSION);
    mDB = mDBHelper.getWritableDatabase();
    return this;
}

public void closeDB()
{
    mDBHelper.close();
}

public long insert(String _invoiceid, String _name, String _numberphone, String _address,
        String _url, String _status)
{
    ContentValues cv = new ContentValues();
    cv.put(INVOICEID, _invoiceid);
    cv.put(SNAME, _name);
    cv.put(NUMBERPHONE, _numberphone);
    cv.put(ADDRESS, _address);
    cv.put(URL, _url);
    cv.put(STATUS, _status);
    return mDB.insert(DB_TABLE, null, cv);
}

public boolean remove(int _number)
{
    return mDB.delete(DB_TABLE, INVOICEID + "=" + _number, null) &gt; 0;
}

public Cursor getAllStudent()
{
    return mDB.query(DB_TABLE, new String[] {
            NUMBER, INVOICEID, SNAME, NUMBERPHONE, ADDRESS, URL, STATUS
    }, null, null, null, null, null);
}

public Cursor getStudentById(int _number)
{
    Cursor mCursor = mDB.query(true, DB_TABLE, new String[] {
            NUMBER, INVOICEID, SNAME, NUMBERPHONE, ADDRESS, URL, STATUS
    }, NUMBER + "=" + _number, null, null, null, null, null);
    if (mCursor != null)
    {
        mCursor.moveToFirst();
    }

    return mCursor;
}

***public Boolean test (String mahoadon)***
{
    Boolean flag=true;
    Cursor mCursor = mDB.query(true, DB_TABLE, new String[] {
            NUMBER, INVOICEID, SNAME, NUMBERPHONE, ADDRESS, URL, STATUS
    }, INVOICEID + "=" + mahoadon, null, null, null, null, null);
    if (mCursor != null)
    {
        flag=false;
    }
    else
    {
        flag=true;
    }

    return flag;
}
</code></pre>

<p>}</p>

<p>CLASS LOAD DATA AND SAVE TO DATABASE</p>

<pre><code>private DB_Adapter mDb = new DB_Adapter(this); 
// class load data từ server về thiết bị
private class LoadData extends AsyncTask&lt;Void, Void, Void&gt; {
    private ProgressDialog progressDialog;
    private Boolean flag = false;
    String phonenumber;
    String name;
    String address;
    String url;
    String code;
    private JSONArray jArray;
    private String result = null;
    private InputStream is = null;
    private StringBuilder sb = null;
    private ArrayList&lt;String&gt; phonenumberArray = new ArrayList&lt;String&gt;();
    private ArrayList&lt;String&gt; codeInvoiceArray = new ArrayList&lt;String&gt;();
    private ArrayList&lt;String&gt; nameArray = new ArrayList&lt;String&gt;();
    private ArrayList&lt;String&gt; addressArray = new ArrayList&lt;String&gt;();
    private ArrayList&lt;String&gt; urlArray = new ArrayList&lt;String&gt;();
    private ListView listview;


    @Override
    // can use UI thread here
    protected void onPreExecute() {
        this.progressDialog = ProgressDialog.show(Hoadon.this, "",
                " Đang tải thông tin...");
    }

    // hiển thị thông tin lên listview của Activity
    @Override
    protected void onPostExecute(final Void unused) {
        this.progressDialog.dismiss();
        if (flag == true)
        {

            thongbao("Tải dữ liệu thành công");
        }
        else
        {
            thongbao("Hôm nay không có gì để giao!");
        }
        try {
            listview = (ListView) findViewById(R.id.listView1);
            this.progressDialog.dismiss();
            listview.setAdapter(new DataAdapter(Hoadon.this, codeInvoiceArray
                    .toArray(new String[codeInvoiceArray.size()]), nameArray
                    .toArray(new String[nameArray.size()]),phonenumberArray
                    .toArray(new String[phonenumberArray.size()]), addressArray
                    .toArray(new String[addressArray.size()])));
            listview.setOnItemClickListener(new OnItemClickListener() {

                //xử lý sự kiện khi chọn item trên listview
                @Override
                public void onItemClick(AdapterView&lt;?&gt; parent, View view,
                        int position, long id) {
                    Intent j=new Intent(Hoadon.this,Menu_Main.class);

                    //lấy thông tin thông qua vị trí của item được chọn
                    String url = urlArray.get(position);
                    String address = addressArray.get(position);
                    String mahoadon = codeInvoiceArray.get(position);
                    String phone=phonenumberArray.get(position);

                    //chuyển thông tin này qua bên phần ký tên
                    j.putExtra("url", url);
                    j.putExtra("address", address);
                    j.putExtra("mahoadon", mahoadon);
                    j.putExtra("phone",phone);
                    j.putExtra("ID", IDinvoice);
                    startActivity(j);
                }
            });
        } catch (Exception e) {

            Toast.makeText(getApplicationContext(), e.toString(),
                    Toast.LENGTH_LONG).show();
        }
    }

    // lấy thông tin từ server về dưới dạng json, được chuyển thành chuỗi và
    // lưu vào các mảng
    @Override
    protected Void doInBackground(Void... params) {
        try {
            /*Calendar cal = Calendar.getInstance();
            int date1 = cal.get(Calendar.DAY_OF_MONTH);
            int month = cal.get(Calendar.MONTH) + 1;
            int year = cal.get(Calendar.YEAR);
            String str1 = date1 + "/" + month + "/" + year;*/

            //Gửi thông tin id người giao hàng lên server để lấy danh sách hóa đơn về
            ArrayList&lt;NameValuePair&gt; nameValuePairs = new ArrayList&lt;NameValuePair&gt;();
            HttpClient httpclient = new DefaultHttpClient();
            HttpPost httppost = new HttpPost(
                    "http://longvansolution.tk/monthlytarget.php");
            nameValuePairs = new ArrayList&lt;NameValuePair&gt;(1);
            nameValuePairs.add(new BasicNameValuePair("user", IDinvoice));
            /*nameValuePairs.add(new BasicNameValuePair("mydate", str1));*/
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
            HttpResponse response = httpclient.execute(httppost);
            HttpEntity entity = response.getEntity();
            is = entity.getContent();

            //chuyển thông tin nhận được về dạng chuỗi
            BufferedReader reader = new BufferedReader(
                    new InputStreamReader(is, "iso-8859-1"), 80);
            sb = new StringBuilder();
            sb.append(reader.readLine() + "\n");
            String line = "0";
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();
            result = sb.toString();
        } catch (Exception e) {
            Toast.makeText(getApplicationContext(), e.toString(),
                    Toast.LENGTH_LONG).show();
        }

        //kiểm tra thông tin nhận được từ server 
        if (result.equalsIgnoreCase("null\n\n \n"))
        {
            flag = false;

            //làm sạch mảng trước khi muốn thêm các thành phần để tránh tình trạng trùng lặp
            phonenumberArray.clear();
            codeInvoiceArray.clear();
            nameArray.clear();
            addressArray.clear();
            urlArray.clear();
        } else
        {
            flag = true;
            try {
                jArray = new JSONArray(result);
                JSONObject json_data = null;
                phonenumberArray.clear();
                codeInvoiceArray.clear();
                nameArray.clear();
                addressArray.clear();
                urlArray.clear();
                mDb.openDB();

                //sử dụng json lấy các giá trị thông qua các key
                //gán nó vào các mảng tương ứng
                for (int i = 0; i &lt; jArray.length(); i++) {
                    json_data = jArray.getJSONObject(i);
                    phonenumber = json_data.getString("phonenumber");
                    address = json_data.getString("address");
                    name = json_data.getString("name");
                    url = json_data.getString("url");
                    code = json_data.getString("code");
                    phonenumberArray.add(phonenumber);
                    codeInvoiceArray.add(code);
                    nameArray.add(name);
                    addressArray.add(address);
                    urlArray.add(url);
                    ***if(mDb.test(code)==true)
                    {
                        mDb.insert(code, name, phonenumber, address, url, "Chuagiao");
                    }***
                }
            } catch (JSONException e) {
                Toast.makeText(getApplicationContext(), e.toString(),
                        Toast.LENGTH_LONG).show();

            } catch (ParseException e) {
                Toast.makeText(getApplicationContext(), e.toString(),
                        Toast.LENGTH_LONG).show();
            } catch (Exception e) {
                Toast.makeText(getApplicationContext(), e.toString(),
                        Toast.LENGTH_LONG).show();
            }
        }
        mDb.closeDB();
        return null;
    }
}
</code></pre>

<p>LOG ERROR</p>

<pre><code>12-12 11:08:31.979: W/dalvikvm(1384): threadid=14: thread exiting with uncaught    exception (group=0x40015560)
12-12 11:08:31.987: E/AndroidRuntime(1384): FATAL EXCEPTION: AsyncTask #4
12-12 11:08:31.987: E/AndroidRuntime(1384): java.lang.RuntimeException: An error occured while executing doInBackground()
12-12 11:08:31.987: E/AndroidRuntime(1384):     at android.os.AsyncTask$3.done(AsyncTask.java:200)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at java.util.concurrent.FutureTask.run(FutureTask.java:138)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at java.lang.Thread.run(Thread.java:1019)
12-12 11:08:31.987: E/AndroidRuntime(1384): Caused by: java.lang.RuntimeException: Can't  create handler inside thread that has not called Looper.prepare()
12-12 11:08:31.987: E/AndroidRuntime(1384):     at android.os.Handler.&lt;init&gt;(Handler.java:121)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at android.widget.Toast.&lt;init&gt;(Toast.java:68)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at android.widget.Toast.makeText(Toast.java:231)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at com.example.finishdemo.Hoadon$LoadData.doInBackground(Hoadon.java:437)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at com.example.finishdemo.Hoadon$LoadData.doInBackground(Hoadon.java:1)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at android.os.AsyncTask$2.call(AsyncTask.java:185)
12-12 11:08:31.987: E/AndroidRuntime(1384):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
12-12 11:08:31.987: E/AndroidRuntime(1384):     ... 4 more
12-12 11:08:33.347: E/WindowManager(1384): Activity com.example.finishdemo.Hoadon has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@405aa248 that was originally added here
12-12 11:08:33.347: E/WindowManager(1384): android.view.WindowLeaked: Activity com.example.finishdemo.Hoadon has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@405aa248 that was originally added here
12-12 11:08:33.347: E/WindowManager(1384):  at android.view.ViewRoot.&lt;init&gt;(ViewRoot.java:258)
12-12 11:08:33.347: E/WindowManager(1384):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
12-12 11:08:33.347: E/WindowManager(1384):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
12-12 11:08:33.347: E/WindowManager(1384):  at android.view.Window$LocalWindowManager.addView(Window.java:424)
12-12 11:08:33.347: E/WindowManager(1384):  at android.app.Dialog.show(Dialog.java:241)
12-12 11:08:33.347: E/WindowManager(1384):  at   android.app.ProgressDialog.show(ProgressDialog.java:107)
12-12 11:08:33.347: E/WindowManager(1384):  at android.app.ProgressDialog.show(ProgressDialog.java:90)
12-12 11:08:33.347: E/WindowManager(1384):  at android.app.ProgressDialog.show(ProgressDialog.java:85)
12-12 11:08:33.347: E/WindowManager(1384):  at com.example.finishdemo.Hoadon$LoadData.onPreExecute(Hoadon.java:291)
12-12 11:08:33.347: E/WindowManager(1384):  at android.os.AsyncTask.execute(AsyncTask.java:391)
12-12 11:08:33.347: E/WindowManager(1384):  at com.example.finishdemo.Hoadon$4$1.run(Hoadon.java:246)
12-12 11:08:33.347: E/WindowManager(1384):  at android.os.Handler.handleCallback(Handler.java:587)
12-12 11:08:33.347: E/WindowManager(1384):  at android.os.Handler.dispatchMessage(Handler.java:92)
12-12 11:08:33.347: E/WindowManager(1384):  at android.os.Looper.loop(Looper.java:130)
12-12 11:08:33.347: E/WindowManager(1384):  at android.app.ActivityThread.main(ActivityThread.java:3683)
12-12 11:08:33.347: E/WindowManager(1384):  at java.lang.reflect.Method.invokeNative(Native Method)
12-12 11:08:33.347: E/WindowManager(1384):  at java.lang.reflect.Method.invoke(Method.java:507)
12-12 11:08:33.347: E/WindowManager(1384):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
12-12 11:08:33.347: E/WindowManager(1384):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
12-12 11:08:33.347: E/WindowManager(1384):  at dalvik.system.NativeStart.main(Native Method)
</code></pre>
