We Keep Coding

How to get Sum of SQLite Column by matching id

The app: I have an app that creates multiple machines with:
id, name and location
each of these machines I have to let the user input the income respectively.
The problem: I need to SUM all income(money, date, note, machines_id) inputted from each machine AND display it in a TextView in a different Activity.
My question: How do I get the data from the rawQuery of my getIncomeOfMachine method to another Activity?
What I tried: Using Bundles, Intents, SharedPreferences from the DBHelper class.
DBHelper
public class DBHelpter extends SQLiteOpenHelper {
private static final String DB_NAME = "machines.db";
private static final int DB_VERSION = 1;
public static final String TABLE_MACHINES = "machines";
public static final String MACHINES_COLUMN_NAME = "name";
public static final String MACHINES_COLUMN_LOCATION = "location";
public static final String MACHINES_ID = "id";
public static final String TABLE_INCOME = "income";
public static final String INCOME_COLUMN_MONEY = "money";
public static final String INCOME_COLUMN_DATE = "date";
public static final String INCOME_COLUMN_NOTE = "note";
public static final String INCOME_ID = "id";
public static final String INCOME_COLUMN_MACHINES_ID = "machines_id";
private Context mContext;
public DBHelpter(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
String query1 = String.format("CREATE TABLE " + TABLE_MACHINES + "("
+ MACHINES_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ MACHINES_COLUMN_NAME + " TEXT NOT NULL, "
+ MACHINES_COLUMN_LOCATION + " TEXT NOT NULL)",
TABLE_MACHINES, MACHINES_COLUMN_NAME, MACHINES_COLUMN_LOCATION, MACHINES_ID);
String query2 = String.format("CREATE TABLE " + TABLE_INCOME + "("
+ INCOME_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ INCOME_COLUMN_MONEY + " REAL NOT NULL, "
+ INCOME_COLUMN_DATE + " DATE NOT NULL, "
+ INCOME_COLUMN_NOTE + " TEXT NOT NULL, "
+ INCOME_COLUMN_MACHINES_ID + " INTEGER NOT NULL)",
TABLE_INCOME, INCOME_ID, INCOME_COLUMN_MONEY, INCOME_COLUMN_DATE, INCOME_COLUMN_NOTE, INCOME_COLUMN_MACHINES_ID);
db.execSQL(query1);
db.execSQL(query2);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
String query1 = String.format("DROP TABLE IF EXISTS " + TABLE_MACHINES);
String query2 = String.format("DROP TABLE IF EXISTS " + TABLE_INCOME);
db.execSQL(query1);
db.execSQL(query2);
onCreate(db);
}
public void insertNewMachine(String name, String location){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(MACHINES_COLUMN_NAME, name);
values.put(MACHINES_COLUMN_LOCATION, location);
db.insertWithOnConflict(TABLE_MACHINES, null, values, SQLiteDatabase.CONFLICT_REPLACE);
db.close();
}
public void insertNewIncome(Double money, String date, String note, long machines_id){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(INCOME_COLUMN_MONEY, money);
values.put(INCOME_COLUMN_DATE, date);
values.put(INCOME_COLUMN_NOTE, note);
values.put(INCOME_COLUMN_MACHINES_ID, machines_id);
db.insertWithOnConflict(TABLE_INCOME, null, values, SQLiteDatabase.CONFLICT_REPLACE);
db.close();
}
public void getIncomeOfMachine(long machinesId){
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT machines_id, SUM(money) AS total FROM income WHERE machines_id = "+machinesId+"", null);
while (cursor.moveToFirst()){
String totalAmount = String.valueOf(cursor.getInt(0));
SharedPreferences mSharedPreferences = mContext.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor mEditor = mSharedPreferences.edit();
mEditor.putString("total_amount", totalAmount);
mEditor.commit();
}
cursor.close();
db.close();
}
public ArrayList<MachinesClass> getAllMachines(){
ArrayList<MachinesClass> machinesList = new ArrayList<>();
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM "+ TABLE_MACHINES, null);
while (cursor.moveToNext()){
final long id = cursor.getLong(cursor.getColumnIndex(MACHINES_ID));
final String name = cursor.getString(cursor.getColumnIndex(MACHINES_COLUMN_NAME));
final String location = cursor.getString(cursor.getColumnIndex(MACHINES_COLUMN_LOCATION));
machinesList.add(new MachinesClass(id, name, location));
}
cursor.close();
db.close();
return machinesList;
}
RecyclerViewAdapter
public class MachinesAdapter extends RecyclerView.Adapter<MachinesAdapter.ViewHolder> {
private ArrayList<MachinesClass> machinesList;
private LayoutInflater mInflater;
private DBHelpter mDBHelpter;
private Context mContext;
public static final String PREFS_NAME = "MyPrefsFile";
public MachinesAdapter(Context mContext, ArrayList<MachinesClass> machinesList){
this.mContext = mContext;
this.machinesList = machinesList;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.machines_list, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(ViewHolder holder, final int position) {
holder.mLocation.setText(machinesList.get(position).getLocation());
holder.v.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
SharedPreferences mSharedPreferences = mContext.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor mEditor = mSharedPreferences.edit();
mEditor.putString("location", machinesList.get(position).getLocation());
mEditor.putLong("machines_id", machinesList.get(position).getId());
mEditor.commit();
Bundle bundle = new Bundle();
bundle.putString("location", machinesList.get(position).getLocation());
Intent intent = new Intent(v.getContext(), MachineInfo.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtras(bundle);
mContext.startActivity(intent);
}
});
}
#Override
public int getItemCount() {
return machinesList != null ? machinesList.size() : 0;
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView mLocation, mMoney;
public LinearLayout mLinearLayout;
public View v;
public ViewHolder(View v) {
super(v);
mLinearLayout = (LinearLayout) v.findViewById(R.id.linearLayout);
mLocation = (TextView) v.findViewById(R.id.tvLocation);
mMoney = (TextView) v.findViewById(R.id.tvMoney);
this.v = v;
}
}
}
MachineInfo
public class MachineInfo extends AppCompatActivity {
private TextView mLocation, mMoney, mNotes;
private DBHelpter mDBHelpter;
private FloatingActionButton mFAB;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_machine_info);
mDBHelpter = new DBHelpter(getApplicationContext());
mLocation = (TextView) findViewById(R.id.tvLocation);
mMoney = (TextView) findViewById(R.id.tvMoney);
mNotes = (TextView) findViewById(R.id.tvNotes);
mFAB = (FloatingActionButton) findViewById(R.id.fabAddIncome);
SharedPreferences mSharedPreferences = getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
String total_amount = mSharedPreferences.getString("total_amount", null);
mMoney.setText(total_amount);
String location = mSharedPreferences.getString("location", null);
mLocation.setText(location);
mFAB.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(getApplicationContext(), IncomeCreation.class);
startActivity(i);
}
});
}
}
If you need any other Activity or layout, let me know!

First, I suggest a change to getIncomeOfMachine(). Since this method is in DBHelper, it should only be responsible for interacting with the database. It should not know anything about SharedPreferences or Activity. Instead, it should return the value retrieved from the database and let the caller decide what to do with that value. Since you know there is only one row in the resulting Cursor, you do not need a loop. Just move to the first row, get the total, and return it.
Second, since you are only passing a single value to an activity, and you presumably do not need to store it permanently for later use, you should use an Intent rather than SharedPreferences. Starting Another Activity has a clear example of sending a value to another activity. If you have problems using this example in your app, feel free to post a new question showing what you did and explaining the problem you encountered.

how to get data from android database into an arraylist

I'm very new at android programming and this is my first question on stack overflow ever. I am having trouble understanding where i have gone wrong in my code implementation. I'm trying to store data in a database and then extract it into an arraylist.
This is the class where i add data into the database in the button onclicklistener:
public class KarmaDescription extends AppCompatActivity {
Button button;
TasksDBHandler dbHandler;
int tId = 1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_karma_desc2min);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setHomeButtonEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setTitle("Overview");
button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
MyTasksGS myTask = new MyTasksGS(tId, "New Task Title", 2);
dbHandler.addTask(myTask);
Toast.makeText(KarmaDescription.this, "Task Added", Toast.LENGTH_SHORT).show();
}
});
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
onBackPressed();
}
return super.onOptionsItemSelected(item);
}
}
This is the class which manages the database:
public class TasksDBHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "tasks.db";
public static final String TABLE_TASKS = "tasks";
public static final String COLUMN_ID = "id";
public static final String COLUMN_TASKNAME = "taskname";
public static final String COLUMN_DAYSLEFT = "daysleft";
public TasksDBHandler(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(context, DATABASE_NAME, factory, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
String query = "CREATE TABLE " + TABLE_TASKS + "(" +
COLUMN_ID + " INTEGER PRIMARY KEY," +
COLUMN_TASKNAME + " TEXT," +
COLUMN_DAYSLEFT + " INTEGER" +
")";
db.execSQL(query);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_TASKS);
onCreate(db);
}
//Add a new row to the database
public void addTask(MyTasksGS myTask) {
ContentValues values = new ContentValues();
values.put(COLUMN_ID, myTask.getId());
values.put(COLUMN_TASKNAME, myTask.getTitle());
values.put(COLUMN_DAYSLEFT, myTask.getDaysRemaining());
SQLiteDatabase db = getWritableDatabase();
db.insert(TABLE_TASKS, null, values);
db.close();
}
//Delete row from the database
public void deleteTask(String taskID) {
SQLiteDatabase db = getWritableDatabase();
db.execSQL("DELETE FROM " + TABLE_TASKS + " WHERE " + COLUMN_ID + "=\"" + taskID + "\";");
}
//To put data into an arraylist
public List<MyTasksGS> getDataFromDB()
{
int id, daysRemaining;
String title;
List<MyTasksGS> tasksList = new ArrayList<MyTasksGS>();
String query = "SELECT * FROM " + TABLE_TASKS;
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.rawQuery(query, null);
cursor.moveToFirst();
while (cursor.moveToNext())
{
id = cursor.getInt(cursor.getColumnIndexOrThrow(COLUMN_ID));
title = cursor.getString(cursor.getColumnIndexOrThrow(COLUMN_TASKNAME));
daysRemaining = cursor.getInt(cursor.getColumnIndexOrThrow(COLUMN_DAYSLEFT));
MyTasksGS myTask = new MyTasksGS(id, title, daysRemaining);
tasksList.add(myTask);
}
return tasksList;
}
}
I'm trying to copy the arraylist data which is returned from the above class(using getDataFromDB function) into myTaskList here and im getting this error:
java.lang.NullPointerException: Attempt to invoke virtual method 'java.util.List com.example.prateek.karma.TasksDBHandler.getDataFromDB()' on a null object reference
public class MyTasksFragment extends Fragment {
Button taskComplete;
RecyclerView RVMyTasks;
static MyTasksAdapter mtAdapter;
List<MyTasksGS> myTaskList = new ArrayList<>();
TasksDBHandler dbHandler;
public MyTasksFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_my_tasks, container, false);
taskComplete = (Button) view.findViewById(R.id.taskComplete);
RVMyTasks = (RecyclerView) view.findViewById(R.id.RVMyTasks);
mtAdapter = new MyTasksAdapter(myTaskList);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getContext());
RVMyTasks.setLayoutManager(mLayoutManager);
RVMyTasks.setItemAnimator(new DefaultItemAnimator());
RVMyTasks.setAdapter(mtAdapter);
myTaskList = dbHandler.getDataFromDB();
mtAdapter.notifyDataSetChanged();
return view;
}
}
And this is the MyTasksGS class:
public class MyTasksGS {
String title;
int daysRemaining;
int id;
public MyTasksGS() {
}
public MyTasksGS(int id, String title, int daysRemaining) {
this.title = title;
this.daysRemaining = daysRemaining;
this.id = id;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public int getDaysRemaining() {
return daysRemaining;
}
public void setDaysRemaining(int daysRemaining) {
this.daysRemaining = daysRemaining;
}
}
I may have made a very silly mistake somewhere but im not able to find it. Any help is appreciated

You need to instantiate the dbHandler, you are trying to use it without a valid instance. It causes the NullPointerException.
In your on onCreateView
before myTaskList = dbHandler.getDataFromDB();
add : dbHandler = new TasksDBHandler(getActivity());
use your class property DATABASE_NAME and DATABASE_VERSION instead of pass in constructor.
Change your TaskDBHandler constructor like this
public TasksDBHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

Android sqllite cannot remove item by position

I am working with sqllite. I have successfully create a database and I can input some values in my database. I can also show all values in listview.
Now I want to delete values by position (for example, if i click listview's 4th item i would to delete full this items)
This is my code:
public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "lvstone_2";
private static final String TABLE_CONTACTS = "CardTable1";
private static final String KEY_ID = "id";
private static final String KEY_Tittle = "name";
private static final String KEY_Description = "description";
private static final String KEY_Price = "price";
private static final String KEY_Counter = "counter";
private static final String KEY_Image = "image";
private final ArrayList<Contact> contact_list = new ArrayList<Contact>();
public static SQLiteDatabase db;
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_Tittle + " TEXT,"
+ KEY_Description + " TEXT,"
+ KEY_Price + " TEXT,"
+ KEY_Counter + " TEXT,"
+ KEY_Image + " TEXT"
+ ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
// Create tables again
onCreate(db);
}
// Adding new contact
public void Add_Contact(Contact contact) {
db = this.getWritableDatabase();
ContentValues values = new ContentValues();
if (!somethingExists(contact.getTitle())) {
values.put(KEY_Tittle, contact.getTitle()); // Contact title
values.put(KEY_Description, contact.getDescription()); // Contact//
// description
values.put(KEY_Price, contact.getPrice()); // Contact price
values.put(KEY_Counter, contact.getCounter()); // Contact image
values.put(KEY_Image, contact.getImage()); // Contact image
// Inserting Row
db.insert(TABLE_CONTACTS, null, values);
Log.e("Table Result isss", String.valueOf(values));
db.close(); // Closing database connection
}
}
public void deleteUser(String userName)
{
db = this.getWritableDatabase();
try
{
db.delete(DATABASE_NAME, "username = ?", new String[] { userName });
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
db.close();
}
}
// Getting single contact
Contact Get_Contact(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS,
new String[] { KEY_ID, KEY_Tittle, KEY_Description, KEY_Price,
KEY_Counter, KEY_Image }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Contact contact = new Contact(cursor.getString(0), cursor.getString(1),
cursor.getString(2), cursor.getString(4), cursor.getString(5));
// return contact
cursor.close();
db.close();
return contact;
}
public boolean somethingExists(String x) {
Cursor cursor = db.rawQuery("select * from " + TABLE_CONTACTS
+ " where name like '%" + x + "%'", null);
boolean exists = (cursor.getCount() > 0);
Log.e("Databaseeeeeeeee", String.valueOf(cursor));
cursor.close();
return exists;
}
public ArrayList<Contact> Get_Contacts() {
try {
contact_list.clear();
// 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.setTitle(cursor.getString(1));
contact.setDescription(cursor.getString(2));
contact.setPrice(cursor.getString(3));
contact.setCounter(cursor.getString(4));
contact.setImage(cursor.getString(5));
contact_list.add(contact);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return contact_list;
} catch (Exception e) {
// TODO: handle exception
Log.e("all_contact", "" + e);
}
return contact_list;
}
public int getProfilesCount() {
String countQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int cnt = cursor.getCount();
cursor.close();
return cnt;
}
}
My Adapter Code:
public class StradaSQLAdapter extends BaseAdapter {
Activity activity;
int layoutResourceId;
Contact user;
ArrayList<Contact> data = new ArrayList<Contact>();
public ImageLoader imageLoader;
UserHolder holder = null;
public int itemSelected = 0;
public StradaSQLAdapter(Activity act, int layoutResourceId,
ArrayList<Contact> data) {
this.layoutResourceId = layoutResourceId;
this.activity = act;
this.data = data;
imageLoader = new ImageLoader(act.getApplicationContext());
notifyDataSetChanged();
}
#Override
public View getView(final int position, View convertView, ViewGroup parent) {
View row = convertView;
if (row == null) {
LayoutInflater inflater = LayoutInflater.from(activity);
holder = new UserHolder();
row = inflater.inflate(layoutResourceId, parent, false);
holder.Title = (TextView) row.findViewById(R.id.smalltitle1);
holder.counter = (TextView) row.findViewById(R.id.smallCounter1);
holder.dbcounter = (TextView) row
.findViewById(R.id.DBSliderCounter);
holder.Description = (TextView) row.findViewById(R.id.smallDesc1);
holder.layout = (RelativeLayout) row
.findViewById(R.id.DBSlideLayout);
holder.layoutmain = (RelativeLayout) row
.findViewById(R.id.DBSlideLayoutMain);
holder.Price = (TextView) row.findViewById(R.id.smallPrice1);
holder.pt = (ImageView) row.findViewById(R.id.smallthumb1);
holder.close = (ImageView) row.findViewById(R.id.DBSliderClose);
holder.c_minus = (ImageView) row.findViewById(R.id.counter_minus);
holder.c_plus = (ImageView) row.findViewById(R.id.counter_plus);
row.setTag(holder);
} else {
holder = (UserHolder) row.getTag();
}
user = data.get(position);
holder.Title.setText(user.getTitle());
holder.Description.setText(user.getDescription());
holder.Price.setText(user.getPrice() + " GEL");
holder.counter.setText(user.getCounter());
holder.dbcounter.setText(user.getCounter());
Log.e("image Url is........", data.get(position).toString());
imageLoader.DisplayImage(user.getImage(), holder.pt);
return row;
}
#Override
public int getCount() {
return data.size();
}
#Override
public Object getItem(int position) {
return data.get(position);
}
#Override
public long getItemId(int position) {
return 0;
}
public class UserHolder {
public TextView Price, counter, Description, Title, dbcounter;
public ImageView pt,close,c_plus,c_minus;
public RelativeLayout layout, layoutmain;
}
}
and my Main Java code:
public class StradaChartFragments extends Fragment {
public static ListView list;
ArrayList<Contact> contact_data = new ArrayList<Contact>();
StradaSQLAdapter cAdapter;
private DatabaseHandler dbHelper;
UserHolder holder;
private RelativeLayout.LayoutParams layoutParams;
int a;
private ArrayList<Contact> contact_array_from_db;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.strada_chart_fragment,
container, false);
dbHelper = new DatabaseHandler(getActivity());
list = (ListView) rootView.findViewById(R.id.chart_listview);
cAdapter = new StradaSQLAdapter(getActivity(),
R.layout.listview_row_db, contact_data);
contact_array_from_db = dbHelper.Get_Contacts();
Set_Referash_Data();
list.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
final int position, long id) {
holder = (UserHolder) view.getTag();
a = Integer.parseInt(holder.counter.getText().toString());
layoutParams = (RelativeLayout.LayoutParams) holder.layoutmain
.getLayoutParams();
if (holder.layout.getVisibility() != View.VISIBLE) {
ValueAnimator varl = ValueAnimator.ofInt(0, -170);
varl.setDuration(1000);
varl.addUpdateListener(new AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator animation) {
layoutParams.setMargins(
(Integer) animation.getAnimatedValue(), 0,
0, 0);
holder.layoutmain.setLayoutParams(layoutParams);
}
});
varl.start();
holder.layout.setVisibility(View.VISIBLE);
}
holder.close.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
ValueAnimator var2 = ValueAnimator.ofInt(-170, 0);
var2.setDuration(1000);
var2.addUpdateListener(new AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(
ValueAnimator animation) {
dbHelper.deleteUser(contact_array_from_db.get(position).getTitle());
dbHelper.close();
cAdapter.notifyDataSetChanged();
layoutParams.setMargins(0, 0,
(Integer) animation.getAnimatedValue(),
0);
holder.layoutmain.setLayoutParams(layoutParams);
holder.layout.setVisibility(View.INVISIBLE);
}
});
var2.start();
}
});
}
});
return rootView;
}
public void Set_Referash_Data() {
contact_data.clear();
for (int i = 0; i < contact_array_from_db.size(); i++) {
String title = contact_array_from_db.get(i).getTitle();
String Description = contact_array_from_db.get(i).getDescription();
String Price = contact_array_from_db.get(i).getPrice();
String Counter = contact_array_from_db.get(i).getCounter();
String image = contact_array_from_db.get(i).getImage();
Contact cnt = new Contact();
cnt.setTitle(title);
cnt.setDescription(Description);
cnt.setPrice(Price);
cnt.setCounter(Counter);
cnt.setImage(image);
contact_data.add(cnt);
}
dbHelper.close();
cAdapter.notifyDataSetChanged();
list.setAdapter(cAdapter);
Log.e("Adapter issss ...", String.valueOf(cAdapter));
}
I found one example about how to delete title but it's not working.
How could I delete user by position in listview 'onclick' listener?
Any help would be great, thanks

db.delete(DATABASE_NAME, "username = ?", new String[] { userName });
You'll need to use the table name here, if all else is correct.

Deleting row from sql database

The delete method of my sql database doesn't remove the entry from the database. It gives a null pointer exception:
10-18 00:44:25.069: E/AndroidRuntime(17968): java.lang.NullPointerException
10-18 00:44:25.069: E/AndroidRuntime(17968): at com.weather.app.LocationDB.deleteLocation(LocationDB.java:98)
public class LocationDB extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "locationManager";
private static final String TABLE_LOCATIONS = "locations";
private static final String KEY_ID = "id";
private static final String KEY_LOCATION = "location";
private static final String KEY_COUNTRY = "country";
private SQLiteDatabase db;
public LocationDB(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_LOCATIONS + " ( "
+ KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_LOCATION
+ " TEXT, " + KEY_COUNTRY
+ " TEXT, " + " INTEGER)";
db.execSQL(sql);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldV, int newV) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_LOCATIONS);
onCreate(db);
}
public void addLocation(LocationName location) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_LOCATION, location.getTaskName());
values.put(KEY_COUNTRY, location.getTaskCountry());
db.insert(TABLE_LOCATIONS, null, values);
}
public List<LocationName> getAllLocations() {
List<LocationName> locList = new ArrayList<LocationName>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_LOCATIONS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
LocationName task = new LocationName();
task.setId(cursor.getInt(0));
task.setTaskName(cursor.getString(1));
task.setTaskCountry(cursor.getString(2));
// Adding contact to list
locList.add(task);
} while (cursor.moveToNext());
}
return locList;
}
public boolean deleteLocation(long rowId) {
return db.delete(TABLE_LOCATIONS, KEY_ID + "=" + rowId, null) > 0;
}
}
Then entry is not removed even when the app is restarted, the addLocation method for adding a row works fine.
LocationSettings Activity:
public class LocationSettings extends Activity {
protected static LocationDB db;
static List<LocationName> list;
MyAdapter adapt;
private static TextView name;
private ListView listView;
private static final int DLG_EXAMPLE1 = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_location_settings);
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
db = new LocationDB(this);
list = db.getAllTasks();
adapt = new MyAdapter(this, R.layout.drawer_list_item, list);
listView = (ListView) findViewById(R.id.left_drawer);
listView.setAdapter(adapt);
SwipeDismissListViewTouchListener touchListener =
new SwipeDismissListViewTouchListener(
listView,
new SwipeDismissListViewTouchListener.DismissCallbacks() {
#Override
public boolean canDismiss(int position) {
return true;
}
#Override
public void onDismiss(ListView listView, int[] reverseSortedPositions) {
for (int position : reverseSortedPositions) {
db.deleteTask(position);
adapt.remove(adapt.getItem(position));
}
}
});
listView.setOnItemClickListener(new DrawerItemClickListener());
listView.setOnTouchListener(touchListener);
}
public class DrawerItemClickListener implements ListView.OnItemClickListener {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
db.deleteTask(position);
adapt.notifyDataSetChanged();
}
}
private class MyAdapter extends ArrayAdapter<LocationName> {
Context context;
List<LocationName> taskList = new ArrayList<LocationName>();
int layoutResourceId;
public MyAdapter(Context context, int layoutResourceId,
List<LocationName> objects) {
super(context, layoutResourceId, objects);
this.layoutResourceId = layoutResourceId;
this.taskList = objects;
this.context = context;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.drawer_list_item,parent, false);
name = (TextView) convertView.findViewById(R.id.text1);
}
LocationName current = taskList.get(position);
name.setText(current.getTaskName());
return convertView;
}
}
}

you forget to initialize db before calling delete method in deleteLocation.
public int deleteLocation(long rowId) {
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TABLE_LOCATIONS, KEY_ID + " = ?",
new String[] { String.valueOf(rowId) });
}

Using the suggested following fragment of code from #ρяσѕρєяK:
public int deleteLocation(long rowId) {
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TABLE_LOCATIONS, KEY_ID + " = ?",
new String[] { String.valueOf(rowId) });
}
has changed the signature of your method generating that error. I think that
public boolean deleteLocation(long rowId) {
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TABLE_LOCATIONS, KEY_ID + " = ?",
new String[] { String.valueOf(rowId) }) > 0;
}
will solve your problem.

SQlite delete function is not deleting entries

Im having trouble getting individual items to delete in a database my application is using. I know the method gets called, but nothing in my list is ever removed. Im not getting any errors which is making it tough to track down. Assistance would be awesome.
public class MainActivity extends Activity{
//Global Variables
ListView lv;
Intent addM, viewM;
public DBAdapter movieDatabase;
String tempTitle, tempYear;
int request_Code = 1;
int request_code2 = 2;
SimpleCursorAdapter dataAdapter;
Cursor cursor;
Button addButton;
long testID;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//creates the database
movieDatabase = new DBAdapter(this);
movieDatabase.open();
//movieDatabase.deleteAllMovies();
//creates the intents to start the sub activities
addM = new Intent(this, AddMovie.class);
viewM = new Intent(this, MovieView.class);
}
//handles the return of the activity addMovie
public void onActivityResult(int requestCode, int resultCode,
Intent data)
{
super.onActivityResult(requestCode, resultCode, data);
if(resultCode == RESULT_OK)
{
switch(requestCode)
{
case 1:
dbAddMovie(data.getStringExtra("title"),
data.getStringExtra("year"));
break;
case 2:
testID = data.getLongExtra("rowid", -1);
dMovie(testID);
break;
}
}
}
//adds item to the movie list
public void dbAddMovie(String mT, String mY)
{
movieDatabase.open();
movieDatabase.insertMovie(mT, mY);
Toast.makeText(this, "Movie: " + mT + " added to database",
Toast.LENGTH_SHORT).show();
}
//deletes an entry into the database
public void dMovie(long rowid)
{
//Toast.makeText(this, "Deleting: " + rowid,
Toast.LENGTH_SHORT).show();
movieDatabase.deleteMovie(rowid);
movieDatabase.getAllMovies();
}
//displays the database as a list
public void displayListView()
{
addButton = (Button) findViewById(R.id.add);
addButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivityForResult(addM, 1);
}
});
cursor = movieDatabase.getAllMovies();
//columns to use
String[] columns = new String[]
{
movieDatabase.KEY_TITLE,
};
//xml data to bind the data to
int[] to = new int[]
{
R.id.column2,
};
//adapter to display the database as a list
dataAdapter = new SimpleCursorAdapter(this,
R.layout.complexrow, cursor, columns, to, 0);
//gets the List view resource
lv = (ListView) findViewById(R.id.movielist);
//sets the list view to use the adapter
lv.setAdapter(dataAdapter);
//handles the list click events
lv.setOnItemClickListener(new
AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View
v, int position,
long id) {
Cursor cursor = (Cursor)
parent.getItemAtPosition(position);
Bundle mDet = new Bundle();
mDet.putString("title",
cursor.getString(cursor.getColumnIndex(movieDatabase.KEY_TITLE)));
mDet.putString("year",
cursor.getString(cursor.getColumnIndex(movieDatabase.KEY_YEAR)));
mDet.putInt("rId", position);
viewM.putExtras(mDet);
startActivityForResult(viewM, 2);
}
});
//dataAdapter.notifyDataSetChanged();
}
public void onResume()
{
super.onResume();
displayListView();
}
}
and my coresponding dbadapter class
public class DBAdapter {
public static final String KEY_ROWID = "_id";
public static final String KEY_TITLE = "title";
public static final String KEY_YEAR = "year";
private static final String TAG = "DBAdapter";
private static final String DATABASE_NAME = "MovieListDB";
private static final String DATABASE_TABLE = "MoviesTable";
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_CREATE = "create table MoviesTable (_id
integer primary key autoincrement, " +
"title text not null, year not null);";
private final Context context;
private DatabaseHelper DBHelper;
private SQLiteDatabase db;
public DBAdapter(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
try{
db.execSQL(DATABASE_CREATE);
} catch (SQLException e)
{
e.printStackTrace();
}
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion +
"which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS MoviesTable");
onCreate(db);
}
}
public DBAdapter open() throws SQLException
{
db = DBHelper.getWritableDatabase();
return this;
}
public void close()
{
DBHelper.close();
}
public long insertMovie(String title, String year)
{
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_TITLE, title);
initialValues.put(KEY_YEAR, year);
return db.insert(DATABASE_TABLE, null, initialValues);
}
public boolean deleteMovie(long rowID)
{
return db.delete(DATABASE_TABLE, KEY_ROWID + "='" + rowID+"'", null ) >-1;
}
public Cursor getAllMovies()
{
return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TITLE,
KEY_YEAR}, null, null, null, null, null);
}
public Cursor getMovie(long rowID) throws SQLException
{
Cursor mCursor =
db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
KEY_TITLE, KEY_YEAR}, KEY_ROWID + "=" + rowID, null, null, null, null, null);
if(mCursor != null)
{
mCursor.moveToFirst();
}
return mCursor;
}
public boolean updateContact(long rowID, String title, String year)
{
ContentValues args = new ContentValues();
args.put(KEY_TITLE, title);
args.put(KEY_YEAR, year);
return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowID, null) > 0;
}
public void deleteAllMovies() {
int doneDelete = 0;
doneDelete = db.delete(DATABASE_TABLE, null, null);
}
}

You're using the position returned from your listview as the row id in your database. This won't necessarily match up with your autoincremented "_id" in your database. position is just what position in the list it is.
You might want to think about using movieDatabase.KEY_ROWID as the key for your intents. Right now I see a mix of "rowid", "rId", "_id", and KEY_ROWID. It would simplify thing to just use the same key everywhere when referring to the same thing.
It looks like you continuously add bundles to the viewM intent. Is that true? If that's not your intent, you should either create a new intent for each click, or remove the previous bundles first.

I'm assuming KEY_ROWID is actually the name of the column? Try the following:
public boolean deleteMovie(long rowID)
{
return db.delete(DATABASE_TABLE, KEY_ROWID + "=?", new String[] { String.valueOf(rowID) }) >-1;
}