title: android how do i delete duplicate entry from database
body: <p>Below is my code. I add application name in database and show that application in another screen but the problem is duplicate entry  will show  Main class help me plz. How do I remove duplicate entry from database.</p>
  
  <pre><code>public class SdcardAPkMgr extends ListActivity {
  DatabaseHandler db;
  
  
         public Drawable getAPKDrawable(String filePath) {
      Drawable dr = null;
      if (filePath != null) {
  
          String PATH_PackageParser = "android.content.pm.PackageParser";
          String PATH_AssetManager = "android.content.res.AssetManager";
          try {
              Class pkgParserCls = Class.forName(PATH_PackageParser);
              Class[] typeArgs = new Class[1];
              typeArgs[0] = String.class;
              Constructor pkgParserCt = 
               pkgParserCls.getConstructor(typeArgs);
              Object[] valueArgs = new Object[1];
              valueArgs[0] = filePath;
              Object pkgParser = pkgParserCt.newInstance(valueArgs);
              DisplayMetrics metrics = new DisplayMetrics();
              metrics.setToDefaults();
              // PackageParser.Package mPkgInfo =
              // packageParser.parsePackage(new
              // File(apkPath), apkPath,
              // metrics, 0);
              typeArgs = new Class[4];
              typeArgs[0] = File.class;
              typeArgs[1] = String.class;
              typeArgs[2] = DisplayMetrics.class;
              typeArgs[3] = Integer.TYPE;
              Method pkgParser_parsePackageMtd = pkgParserCls
                      .getDeclaredMethod("parsePackage", 
                   typeArgs);
              valueArgs = new Object[4];
              valueArgs[0] = new File(filePath);
              valueArgs[1] = filePath;
              valueArgs[2] = metrics;
              valueArgs[3] = 0;
              Object pkgParserPkg = pkgParser_parsePackageMtd.invoke(
                      pkgParser, valueArgs);
              Field appInfoFld = 
         pkgParserPkg.getClass().getDeclaredField(
                      "applicationInfo");
              ApplicationInfo info = (ApplicationInfo) appInfoFld 
                .get(pkgParserPkg);
  
              Class assetMagCls = Class.forName(PATH_AssetManager);
              Constructor assetMagCt = assetMagCls
                      .getConstructor((Class[]) null);
              Object assetMag = assetMagCt.newInstance((Object[]) null);
              typeArgs = new Class[1];
              typeArgs[0] = String.class;
              Method assetMag_addAssetPathMtd = assetMagCls
                      .getDeclaredMethod("addAssetPath", 
                typeArgs);
              valueArgs = new Object[1];
              valueArgs[0] = filePath;
              assetMag_addAssetPathMtd.invoke(assetMag, valueArgs);
              Resources res = getResources();
              typeArgs = new Class[3];
              typeArgs[0] = assetMag.getClass();
              typeArgs[1] = res.getDisplayMetrics().getClass();
              typeArgs[2] = res.getConfiguration().getClass();
              Constructor resCt = 
              Resources.class.getConstructor(typeArgs);
              valueArgs = new Object[3];
              valueArgs[0] = assetMag;
              valueArgs[1] = res.getDisplayMetrics();
              valueArgs[2] = res.getConfiguration();
              res = (Resources) resCt.newInstance(valueArgs);
              String label = null;
              if (info.labelRes != 0) {
                  label = (String) res.getText(info.labelRes);
                  Log.d("Insert: ", "Inserting ..");
                  db.addContact(new Contact(label));
  
  
  
  
  
  
  
  
  
                          public class MainActivity extends Activity implements 
                  OnItemClickListener {
  
     /* whether or not to include system apps */
     private static final boolean INCLUDE_SYSTEM_APPS = false;
     DatabaseHandler db;
  
  
  
  
                           private List&lt;App&gt; loadInstalledApps(boolean includeSysApps) {
            List&lt;App&gt; apps = new ArrayList&lt;App&gt;();
  
            // the package manager contains the information about all installed 
      apps
            PackageManager packageManager = getPackageManager();
  
            List&lt;PackageInfo&gt; packs = packageManager.getInstalledPackages(0); 
          //PackageManager.GET_META_DATA 
  
  
  
  
  
            for(int i=0; i &lt; packs.size(); i++) {
               PackageInfo p = packs.get(i);
               ApplicationInfo applicationInfo = p.applicationInfo;
               String name = 
        packageManager.getApplicationLabel(applicationInfo).toString();
  
  
  
               Log.d("Reading: ", "Reading all contacts..");
                  List&lt;Contact&gt; contacts = db.getAllContacts();       
  
                  for (Contact cn : contacts) {
                      String log = "Id: "+cn.getID()+" ,Name: " + 
        cn.getName() ;
  
                    //  String log = "Id: "+cn.getID()+" ,Name: " + 
        cn.getName() + " ,Phone: " + cn.getPhoneNumber();
                          // Writing Contacts to log
                  Log.d("Name: ", log);
  
  
  
        //
               if ( ((name).contains(cn.getName())))
                       {
               App app = new App();
  
       app.setTitle(p.applicationInfo.loadLabel(packageManager).toString());
               app.setPackageName(p.packageName);
               app.setVersionName(p.versionName);
               app.setVersionCode(p.versionCode);
               CharSequence description = 
      p.applicationInfo.loadDescription(packageManager);
               app.setDescription(description != null ? description.toString() : 
          "");
               apps.add(app);
            }
            }}
            return apps;
         }
  
  
  
  
  
  
  
                           package com.gfsmart.filemanager;
  
  
  import android.database.sqlite.SQLiteOpenHelper;
  
     public class DatabaseHandler extends SQLiteOpenHelper {
  
  // All Static variables
  // Database Version
  private static final int DATABASE_VERSION = 1;
  
  // Database Name
  private static final String DATABASE_NAME = "contactsManager";
  
  // Contacts table name
  private static final String TABLE_CONTACTS = "contacts";
  
  // Contacts Table Columns names
  private static final String KEY_ID = "id";
  private static final String KEY_NAME = "name";
  //private static final String KEY_PH_NO = "phone_number";
  
  public DatabaseHandler(Context context) {
      super(context, DATABASE_NAME, null, DATABASE_VERSION);
  }
  
  // Creating Tables
  @Override
  public void onCreate(SQLiteDatabase db) {
  //  String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"+ KEY_PH_NO + " TEXT" + ")";
  
      String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT)";
  
      db.execSQL(CREATE_CONTACTS_TABLE);
  }
  
  // Upgrading database
  @Override
  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
      // Drop older table if existed
      db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
  
      // Create tables again
      onCreate(db);
  }
  
  /**
   * All CRUD(Create, Read, Update, Delete) Operations
   */
  
  // Adding new contact
  void addContact(Contact contact) {
      SQLiteDatabase db = this.getWritableDatabase();
  
      ContentValues values = new ContentValues();
      values.put(KEY_NAME, contact.getName()); // Contact Name
  //  values.put(KEY_PH_NO, contact.getPhoneNumber()); // Contact Phone
  
      // Inserting Row
      db.insert(TABLE_CONTACTS, null, values);
      db.close(); // Closing database connection
  }
  
  // Getting single contact
  Contact getContact(int id) {
      SQLiteDatabase db = this.getReadableDatabase();
  
      Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
              KEY_NAME }, KEY_ID + "=?",
              new String[] { String.valueOf(id) }, null, null, null, 
     null);
      if (cursor != null)
          cursor.moveToFirst();
  
      Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),
              cursor.getString(1));
      // return contact
      return contact;
  }
  
  // Getting All Contacts
  public List&lt;Contact&gt; getAllContacts() {
      List&lt;Contact&gt; contactList = new ArrayList&lt;Contact&gt;();
      // Select All Query
      String selectQuery = "SELECT  * FROM " + TABLE_CONTACTS;
  
      SQLiteDatabase db = this.getWritableDatabase();
      Cursor cursor = db.rawQuery(selectQuery, null);
  
      // looping through all rows and adding to list
      if (cursor.moveToFirst()) {
          do {
              Contact contact = new Contact();
              contact.setID(Integer.parseInt(cursor.getString(0)));
              contact.setName(cursor.getString(1));
              //contact.setPhoneNumber(cursor.getString(2));
              // Adding contact to list
              contactList.add(contact);
          } while (cursor.moveToNext());
      }
  
      // return contact list
      return contactList;
  }
  
  // Updating single contact
  public int updateContact(Contact contact) {
      SQLiteDatabase db = this.getWritableDatabase();
  
      ContentValues values = new ContentValues();
      values.put(KEY_NAME, contact.getName());
  //  values.put(KEY_PH_NO, contact.getPhoneNumber());
  
      // updating row
      return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",
              new String[] { String.valueOf(contact.getID()) });
  }
  
  // Deleting single contact
  public void deleteContact(Contact contact) {
      SQLiteDatabase db = this.getWritableDatabase();
      db.delete(TABLE_CONTACTS, KEY_ID + " = ?",
              new String[] { String.valueOf(contact.getID()) });
      db.close();
  }
  
  
  // Getting contacts Count
  public int getContactsCount() {
      String countQuery = "SELECT  * FROM " + TABLE_CONTACTS;
      SQLiteDatabase db = this.getReadableDatabase();
      Cursor cursor = db.rawQuery(countQuery, null);
      cursor.close();
  
      // return count
      return cursor.getCount();
  }
  
            }
  
  
  
  
  
  
  
                         public class Contact {
  
  //private variables
  int _id;
  String _name;
  
  
  // Empty constructor
  public Contact(){
  
  }
  // constructor
  public Contact(int id, String name){
      this._id = id;
      this._name = name;
  
  }
  
  // constructor
  public Contact(String name){
      this._name = name;
  
  }
  // getting ID
  public int getID(){
      return this._id;
  }
  
  // setting id
  public void setID(int id){
      this._id = id;
  }
  
  // getting name
  public String getName(){
      return this._name;
  }
  
  // setting name
  public void setName(String name){
      this._name = name;
  }
  </code></pre>