Android recyleview listing using with database not working

Android recyleview listing using with database not working - java

I am developing an app for listing details in database. The listing is not working. but it is showing in log as fine. Why my recyclerview listling is not working. when i am using bean1 = new Bean(cn.getName(), cn.getNumber(), cn.getSpeeddial()) it shows error.
My codes are shown below.
SpeedDialViewActivity.java
public class SpeedDialViewActivity extends AppCompatActivity {
private List<Bean> beanList = new ArrayList<>();
private RecyclerView recyclerView;
private ViewAdapter mAdapter;
Context context;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_speed_dial_view);
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
mAdapter = new ViewAdapter(beanList);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(mAdapter);
prepareData();
}
private void prepareData() {
DatabaseHandler handler = new DatabaseHandler(getApplicationContext());
Log.d("Reading: ", "Reading all contacts..");
List<Bean> beanList = handler.getAllContacts();
//Cursor cursor = (Cursor) handler.getAllContacts();
//Bean bean1;
for (Bean cn : beanList) {
String log = "Id: " + cn.getId() + " ,Name: " + cn.getName() + " ,Phone: " + cn.getNumber();
// Writing Contacts to log
Log.d("Name: ", log);
// bean1 = new Bean(cn.getName(), cn.getNumber(), cn.getSpeeddial()); // Error occurring
// beanList.add(bean1);
}
}
}
DatabaseHandler.java
public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "speeddial";
private static final String TABLE_CONTACTS = "contacts";
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_PH_NO = "phone_number";
private static final String KEY_SPEED_DIAL = "speed_dial_number";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#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" + KEY_SPEED_DIAL + " TEXT" + ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
#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);
}
void addContact(Bean bean) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, bean.getName()); // Contact Name
values.put(KEY_PH_NO, bean.getNumber()); // Contact Phone
values.put(KEY_PH_NO, bean.getSpeeddial()); // Contact Phone
// Inserting Row
db.insert(TABLE_CONTACTS, null, values);
db.close(); // Closing database connection
}
Bean getBean(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
KEY_NAME, KEY_PH_NO }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Bean bean = new Bean(Integer.parseInt(cursor.getString(0)),cursor.getString(1), cursor.getString(2), cursor.getString(3));
// return contact
return bean;
}
public List<Bean> getAllContacts() {
List<Bean> contactList = new ArrayList<Bean>();
// 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 {
Bean contact = new Bean();
contact.setId(Integer.parseInt(cursor.getString(0)));
contact.setName(cursor.getString(1));
contact.setNumber(cursor.getString(2));
// Adding contact to list
contactList.add(contact);
} while (cursor.moveToNext());
}
// return contact list
return contactList;
}
}
ViewAdapter.java
public class ViewAdapter extends RecyclerView.Adapter<ViewAdapter.MyViewHolder> {
private List<Bean> beanList;
public class MyViewHolder extends RecyclerView.ViewHolder {
public TextView name, number, speeddial_number;
public MyViewHolder(View view) {
super(view);
name = (TextView) view.findViewById(R.id.name);
number = (TextView) view.findViewById(R.id.number);
speeddial_number = (TextView) view.findViewById(R.id.speeddialNumber);
}
}
public ViewAdapter(List<Bean> beanList){
this.beanList = beanList;
}
#Override
public ViewAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.speeddial_list_row, parent, false);
return new MyViewHolder(itemView);
}
#Override
public void onBindViewHolder(ViewAdapter.MyViewHolder holder, int position) {
Bean bean = beanList.get(position);
holder.name.setText(bean.getName());
holder.number.setText(bean.getNumber());
holder.speeddial_number.setText(bean.getSpeeddial());
}
#Override
public int getItemCount() {
return beanList.size();
}
}
Bean.java
public class Bean{
private int id;
private String name;
private String number;
private String speeddial;
public Bean(int id, String name, String number, String speeddial) {
this.id=id;
this.name=name;
this.number=number;
this.speeddial=speeddial;
}
public Bean(String name, String number, String speeddial) {
this.name=name;
this.number=number;
this.speeddial=speeddial;
}
public Bean() {
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public String getSpeeddial() {
return speeddial;
}
public void setSpeeddial(String speeddial) {
this.speeddial = speeddial;
}
}
The error is java.lang.RuntimeException: Unable to start activity ComponentInfo{com.app.appname/com.app.appname}: java.util.ConcurrentModificationException
Please help me

You are not adding the contacts you are fetching in the list and not doing notify data set changed. Change your onPrepare() method as follows
private void prepareData() {
DatabaseHandler handler = new DatabaseHandler(getApplicationContext());
Log.d("Reading: ", "Reading all contacts..");
List<Bean> beanList = handler.getAllContacts();
this.beanList.addAll(beanList);
mAdapter.notifyDatasetChanged();
}

pass the same list in prepareData(beanList) and add items in this list. And change your method to something likeprepareData(List<Bean> beanList>).after successfully adding, simply call mAdapter.notifyDataSetChanged() method so your adapter could know that some items have been added into the list.

You have not mention android:name in application tag in manifest file.
So you simple use context object or use SpeedDialViewActivity.this
DatabaseHandler handler = new DatabaseHandler(mContext);
or
DatabaseHandler handler = new DatabaseHandler(SpeedDialViewActivity.this);
private void prepareData() {
DatabaseHandler handler = new DatabaseHandler(SpeedDialViewActivity.this);
Log.d("Reading: ", "Reading all contacts..");
List<Bean> beanList = handler.getAllContacts();
//Cursor cursor = (Cursor) handler.getAllContacts();
//Bean bean1;
for (Bean cn : beanList) {
String log = "Id: " + cn.getId() + " ,Name: " + cn.getName() + " ,Phone: " + cn.getNumber();
// Writing Contacts to log
Log.d("Name: ", log);
// bean1 = new Bean(cn.getName(), cn.getNumber(), cn.getSpeeddial()); // Error occurring
// beanList.add(bean1);
}
}

Related

How to delete item if exist using sqlite?

I spend much time on SQLite and I have a problem in deleting an item if it exist!
I'm working in Bookmark App that save links from webview into listview using SQLite, my problem is can't check if the item is exist > don't create a link.
this is my BookmarksDatabase used for sqlite:
public class BookmarksDatabase extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "bookmarks.db";
private static final String TABLE_NAME = "bookmarks_data";
private static final String COL1 = "ID";
private static final String COL2 = "ITEM1";
private static final String COL3 = "ITEM2";
public BookmarksDatabase(Context context) {
super(context, DATABASE_NAME, null, 1);
}
#Override
public void onCreate(SQLiteDatabase db) {
String createTable = "CREATE TABLE " + TABLE_NAME + " (ID INTEGER PRIMARY KEY AUTOINCREMENT, " + " ITEM1 TEXT, " + " ITEM2 TEXT)";
db.execSQL(createTable);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
onCreate(db);
}
public boolean addData(String item1, String item2) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL2, item1);
contentValues.put(COL3, item2);
long result = db.insert(TABLE_NAME, null, contentValues);
// if date as inserted incorrectly it will return -1
return result != -1;
}
public Cursor getListContents() {
SQLiteDatabase db = this.getWritableDatabase();
return db.rawQuery("SELECT * FROM " + TABLE_NAME, null);
}
public ArrayList<Bookmarks> getAllData() {
ArrayList<Bookmarks> arrayList = new ArrayList<>();
SQLiteDatabase db = this.getWritableDatabase();
Cursor data = db.rawQuery("SELECT * FROM " + TABLE_NAME, null);
while (data.moveToNext()) {
int id = data.getInt(0);
String title = data.getString(1);
String link = data.getString(2);
Bookmarks bookmarks = new Bookmarks(id, title, link);
arrayList.add(bookmarks);
}
return arrayList;
}
public int deleteSpecificContents(int id) {
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TABLE_NAME, COL1 + "=?", new String[]{Integer.toString(id)});
}
}
this is my code used in MainActivity to fetch items on listview
/*---------------- Bookmark Tab, sqlite databases integrated ---------------*/
private void showBookmarksScreen() {
// initialize a dialog in the main activity
final Dialog bookmarksScreen = new Dialog(this);
bookmarksScreen.requestWindowFeature(Window.FEATURE_NO_TITLE);
bookmarksScreen.setContentView(R.layout.activity_bookmark);
bookmarksScreen.setCancelable(true);
final ListView listView = bookmarksScreen.findViewById(R.id.bookmark_list);
RelativeLayout bookmarkEmpty = bookmarksScreen.findViewById(R.id.bookmark_empty);
// create an array and call bookmark
// database to retrive data then
// fetch it into list view
arrayList = new ArrayList<>();
arrayList = bookmarkDB.getAllData();
// get all data from sqlite database
Cursor data = bookmarkDB.getListContents();
// check if no bookmarks
// then show view that inform
// user that there is no bookmarks
if(data.getCount() == 0 ) {
bookmarkEmpty.setVisibility(View.VISIBLE);
}
bookmarkListAdpater = new BookmarkListAdpater(this, arrayList);
listView.setAdapter(bookmarkListAdpater);
bookmarkListAdpater.notifyDataSetChanged();
// load link on item click
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
TextView link = view.findViewById(R.id.list_link);
String convertedLink = link.getText().toString();
webView.loadUrl(convertedLink);
bookmarksScreen.dismiss();
}
});
// ask user to delete bookmark on item long click
listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) {
// initialize a dialog in the main activity
final Dialog deleteDialog = new Dialog(MainActivity.this);
deleteDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
deleteDialog.setContentView(R.layout.activity_confirm);
// confirm message or dialog can't be
// canceled so we set it to false
deleteDialog.setCancelable(false);
TextView deleteMessage = deleteDialog.findViewById(R.id.confirm_text);
TextView deleteConfirm = deleteDialog.findViewById(R.id.confirm_allow);
TextView deleteCancel = deleteDialog.findViewById(R.id.confirm_deny);
deleteMessage.setText(getString(R.string.delete_bookmark));
// confirm button
deleteConfirm.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Cursor data = bookmarkDB.getListContents();
int i = 0;
while(data.moveToNext()){
if(i == position){
break;
}
i++;
}
bookmarkDB.deleteSpecificContents(data.getInt(0));
deleteDialog.dismiss();
bookmarksScreen.dismiss();
customToast(getString(R.string.bookmark_deleted), 0);
}
});
// confirm cancel
deleteCancel.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
deleteDialog.dismiss();
}
});
deleteDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
deleteDialog.show();
return true;
}
});
bookmarksScreen.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
bookmarksScreen.getWindow().setLayout(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.MATCH_PARENT);
bookmarksScreen.show();
}
My Model
public class Bookmarks {
int id;
String title, link;
public Bookmarks(int id, String title, String link) {
this.id = id;
this.title = title;
this.link = link;
}
public Bookmarks() {}
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 String getLink() {
return link;
}
public void setLink(String link) {
this.link = link;
}
}
any ideas? thanks.

Try using below to delete item from DB
bookmarkDB.deleteSpecificContents(arrayList.get(position).getId(0));
If you want to check item exists or not before adding then add below code in your BookmarksDatabase
public boolean isExists(String link) {
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_NAME + " WHERE " + COL3 + "='" + link + "'", null);
return cursor.getCount() > 0;
}
And then check
if(bookmarkDB.isExists(link))
//Already Exist
else
//Not Exist, add now

With the same logic you're using:
SQLiteDatabase db = new DatabaseManager(context).getWritableDatabase();
String query = "SELECT * FROM " + TABLE_NAME + " WHERE " + ID_KEY + " = ?";
Cursor cursor = db.rawQuery(query, new String[]{Integer.toString(id)});
if(cursor.moveToFirst()){
db.delete(TABLE_NAME, ID_KEY + " = ?", new String[]{Integer.toString(id)});
}
cursor.close();
db.close();
Another possibility is changing the method return type to boolean and verifying the return count from the delete command:
public boolean deleteSpecificContents(int id) {
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TABLE_NAME, COL1 + "=?", new String[]{Integer.toString(id)}) > 0;
}

SQLIte database not able to delete entries

I have a SQLdatabase and I want to delete entries that are displayed in a list view using a button that is next to each entry on the list view. But currently it is not letting me delete.
This problem is located in the selectionargs variable as shown below. If I put a number e.g. 1, into the selectionargs manually it will work, but I have been trying to do it through the a variable that represents each entry. This does not result in an error but just goes straight to the toast message cannot delete. ac.ID refers to the adapter class and the ID of the list item entries.
Bookmark class:
public class Bookmark extends AppCompatActivity {
myAdapter myAdapter;
DBManager db;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bookmark);
db = new DBManager(this);
onLoadAttraction();
// onLoadTransport();
}
public void onLoadAttraction() {
ArrayList<Adapter> listData = new ArrayList<Adapter>();
listData.clear();
Cursor cursor = db.Query("BookmarkAttraction",null, null, null, DBManager.ColId);
if (cursor.moveToFirst()) {
do {
listData.add(new Adapter(
cursor.getString(cursor.getColumnIndex(DBManager.ColType))
, cursor.getString(cursor.getColumnIndex(DBManager.ColName))
, cursor.getString(cursor.getColumnIndex(DBManager.ColLocation))
, cursor.getString(cursor.getColumnIndex(DBManager.ColOpening))
, cursor.getString(cursor.getColumnIndex(DBManager.ColClosing))
, cursor.getString(cursor.getColumnIndex(DBManager.ColNearbyStop))
,null,null,null, null, null));
} while (cursor.moveToNext());
}
myAdapter = new myAdapter(listData);
ListView ls = (ListView) findViewById(R.id.listView);
ls.setAdapter(myAdapter);
}
public void onLoadTransport(){
ArrayList<Adapter> listData = new ArrayList<Adapter>();
listData.clear();
Cursor cursor = db.Query("BookmarkTransport",null, null, null, DBManager.ColId);
if (cursor.moveToFirst()) {
do {
listData.add(new Adapter(
cursor.getString(cursor.getColumnIndex(DBManager.ColType))
, cursor.getString(cursor.getColumnIndex(DBManager.ColName))
, cursor.getString(cursor.getColumnIndex(DBManager.ColLocation))
, null
, null
, null
,cursor.getString(cursor.getColumnIndex(DBManager.ColTime))
,cursor.getString(cursor.getColumnIndex(DBManager.ColNextStop))
, cursor.getString(cursor.getColumnIndex(DBManager.ColPhoneNumber))
,null,null));
} while (cursor.moveToNext());
}
myAdapter = new myAdapter(listData);
ListView ls = (ListView) findViewById(R.id.listView);
ls.setAdapter(myAdapter);
}
class myAdapter extends BaseAdapter {
public ArrayList<Adapter> listItem;
Adapter ac;
public myAdapter(ArrayList<Adapter> listItem) {
this.listItem = listItem;
}
#Override
public int getCount() {
return listItem.size();
}
#Override
public Object getItem(int position) {
return null;
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View view, ViewGroup viewGroup) {
LayoutInflater myInflator = getLayoutInflater();
final View myView = myInflator.inflate(R.layout.list_bookmark, null);
ac = listItem.get(position);
TextView Type = (TextView) myView.findViewById(R.id.BMType);
Type.setText(ac.Type);
TextView Name = (TextView) myView.findViewById(R.id.BMName);
Name.setText(ac.Name);
TextView Location = (TextView) myView.findViewById(R.id.BMLocation);
Location.setText(ac.Location);
TextView Opening = (TextView) myView.findViewById(R.id.BMOpen);
Opening.setText(ac.Opening);
TextView Closing = (TextView) myView.findViewById(R.id.BMClose);
Closing.setText(ac.Closing);
TextView NearbyStop1 = (TextView) myView.findViewById(R.id.BMNearbyStop);
NearbyStop1.setText(ac.NearbyStop);
Button buttonDelete = (Button)myView.findViewById(R.id.buttonDelete);
buttonDelete.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String[] selectionArgs = {ac.ID};
int count = db.Delete("BookmarkAttraction","ID=? ",selectionArgs);
if (count > 0) {
onLoadAttraction();
Toast.makeText(getApplicationContext(),"Data deleted", Toast.LENGTH_LONG).show();
}else{
Toast.makeText(getApplicationContext(),"Cannnot delete", Toast.LENGTH_LONG).show();
}
}
});
return myView;
}
}
}
DBManager class:
public class DBManager {
private SQLiteDatabase sqlDB;
static final String ColId = "ID";
static final String DBName = "InternalDB";
static final String TableName = "BookmarkAttraction";
static final String TableName2 = "BookmarkTransport";
static final String TableName3 = "Itinerary";
static final String ColItineraryName = "ItineraryName";
static final String ColDate = "Date";
static final String ColType = "Type";
static final String ColName = "Name";
static final String ColLocation = "Location";
static final String ColOpening = "OpeningTime";
static final String ColClosing = "ClosingTime";
static final String ColNearbyStop = "NerbyStop1";
static final String ColTime = "Time";
static final String ColNextStop = "NextStop";
static final String ColPhoneNumber = "PhoneNumber";
static final int DBVersion = 1;
static final String CreateTable = "CREATE TABLE IF NOT EXISTS " + TableName + "(ID INTEGER PRIMARY KEY AUTOINCREMENT," + ColType+ " TEXT," +
ColName+ " TEXT," + ColLocation+ " TEXT," + ColOpening+ " TEXT," +ColClosing+ " TEXT," + ColNearbyStop+ " TEXT);";
static final String CreateTabe2 = "CREATE TABLE IF NOT EXISTS " +TableName2 + "(ID INTEGER PRIMARY KEY AUTOINCREMENT,"
+ ColType + " TEXT,"
+ ColName + " TEXT,"
+ ColLocation + " TEXT,"
+ ColTime+ " TEXT,"
+ ColNextStop + " TEXT,"
+ ColPhoneNumber + " TEXT);";
static final String CreateTable3 = "CREATE TABLE IF NOT EXISTS " + TableName3 + "(ID INTEGER PRIMARY KEY AUTOINCREMENT," + ColItineraryName + " TEXT,"
+ ColDate + " TEXT," + ColName + " TEXT," + ColLocation + " TEXT," + ColTime + " TEXT);";
static class DBHelper extends SQLiteOpenHelper{
Context context;
DBHelper(Context context){
super(context, DBName, null, DBVersion);
this.context = context;
}
#Override
public void onCreate(SQLiteDatabase db) {
Toast.makeText(context,DBName,Toast.LENGTH_LONG).show();
db.execSQL(CreateTable);
Toast.makeText(context,"Table is created ", Toast.LENGTH_LONG).show();
db.execSQL(CreateTabe2);
Toast.makeText(context,"Transport table created", Toast.LENGTH_LONG).show();
db.execSQL(CreateTable3);
Toast.makeText(context,"Itin table created", Toast.LENGTH_LONG).show();
}
#Override
public void onUpgrade(SQLiteDatabase db, int i, int i1) {
db.execSQL("DROP TABLE IF EXISTS" + TableName);
db.execSQL("DROP TABLE IF EXISTS" + TableName2);
db.execSQL("DROP TABLE IF EXISTS" + TableName3);
onCreate(db);
}
}
public DBManager(Context context){
DBHelper db = new DBHelper(context);
sqlDB = db.getWritableDatabase();
}
public long Insert(String tablename,ContentValues values){
long ID = sqlDB.insert(tablename,"",values);
return ID;
}
public Cursor Query(String tablename, String [] projection, String selection, String [] selectionArgs, String sortOrder){
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
qb.setTables(tablename);
Cursor cursor = qb.query(sqlDB,projection, selection, selectionArgs,null,null,sortOrder);
return cursor;
}
public int Delete(String tablename,String selection, String[] selectionArgs){
int count = sqlDB.delete(tablename,selection,selectionArgs);
return count;
}
}
Adapter class:
public class Adapter {
public String ID;
public String Type;
public String Name;
public String Location;
public String Opening;
public String Closing;
public String NearbyStop;
public String Time;
public String NextStop;
public String PhoneNumber;
public String Latitude;
public String Longitude;
public Adapter(String type, String name, String location, String opening, String closing,
String nearbyStop, String time, String nextStop, String phoneNumber, String Latitude,
String Longitude) {
this.Type = type;
this.Name = name;
this.Location = location;
this.Opening = opening;
this.Closing = closing;
this.NearbyStop = nearbyStop;
this.Time = time;
this.NextStop = nextStop;
this.PhoneNumber = phoneNumber;
this.Latitude = Latitude;
this.Longitude = Longitude;
}
}
The code for the delete button is in my bookmark class with the DBManager holding the actual delete code. If anyone can help with this it would be greatly appreciated.

Remove the ac field of your myAdapter class, and use it as a method variable inside the getView method.
Then use the ListView.setOnItemClickListener method to add an on click listener with positional awareness. (do this only once after you set the adapter) This way you can do listItem.get(position) to get the item in that position.

Display Data from SQL in custom ListView via SimpleCursorAdapter

i created a SQL Database and was able to safe data from three EditText Views and display it in a single TextView.
Then i thought it would be way better to display the data in a custom ListView, so i followed the developer guide and tried to display the data by a simpleCursorAdapter. But it did not work...i do not get any errors or anything, the data is just not shown...I guess there must be some missing connection between the Cursor, the Adapter or the DB...
i know that this kind of question is asked quite frequently, but i am unable to find my mistake, any help would be greatly appreciated:
MyDBHandlerFaecher.java:
public class MyDBHandlerFaecher extends SQLiteOpenHelper{
private static final int DATABASE_VERSION = 5;
private static final String DATABASE_NAME = "faecher.db";
public static final String TABLE_FAECHER = "Faechertable";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_NAME = "_faechername";
public static final String COLUMN_RAUM = "_faecherraum";
public static final String COLUMN_COLOR = "_faecherfarbe";
public MyDBHandlerFaecher(FaecherActivity context, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(context, DATABASE_NAME, factory, DATABASE_VERSION);
}
//Create the table
#Override
public void onCreate(SQLiteDatabase db) {
String query = "CREATE TABLE " + TABLE_FAECHER + "(" +
COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
COLUMN_NAME + " TEXT, " +
COLUMN_RAUM + " TEXT, " +
COLUMN_COLOR + " TEXT " +
");";
db.execSQL(query);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_FAECHER);
onCreate(db);
}
//Add a new row to the DB
public void addFach(Faecher fach){
ContentValues values = new ContentValues();
values.put(COLUMN_NAME, fach.get_faechername());
values.put(COLUMN_RAUM, fach.get_faecherraum());
values.put(COLUMN_COLOR, fach.get_faecherfarbe());
SQLiteDatabase db = getWritableDatabase();
db.insert(TABLE_FAECHER, null, values);
db.close();
}
//Delete row from DB
public void deleteFach(String name){
SQLiteDatabase db = getWritableDatabase();
//Delete the line in which the COLUMN_NAME is equal to the input
db.execSQL("DELETE FROM " + TABLE_FAECHER + " WHERE " + COLUMN_NAME + "=" + "\"" + name + "\"" + ";");
}
FaecherActivity.java
public class FaecherActivity extends AppCompatActivity{
EditText et_facheintrag;
EditText et_raumeintrag;
EditText et_farbeintrag;
ListView lv_faecher;
MyDBHandlerFaecher dbHandlerFaecher;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_faecher);
et_facheintrag = (EditText) findViewById(R.id.et_facheintrag);
et_raumeintrag = (EditText) findViewById(R.id.et_raumeintrag);
et_farbeintrag = (EditText) findViewById(R.id.et_farbeintrag);
lv_faecher = (ListView) findViewById(R.id.lv_faecher);
dbHandlerFaecher = new MyDBHandlerFaecher(this, null, null, 1);
printDatabase();
}
//Add fach to database
public void addButtonClicked(View view){
Faecher fach = new Faecher(et_facheintrag.getText().toString(), et_raumeintrag.getText().toString(), et_farbeintrag.getText().toString());
dbHandlerFaecher.addFach(fach);
printDatabase();
}
//delete fach from database
public void deleteButtonClicked(View view){
String inputText = et_facheintrag.getText().toString();
dbHandlerFaecher.deleteFach(inputText);
printDatabase();
}
public void printDatabase(){
String[] fromColumns = new String[]{"_faechername", "_faecherraum", "_faecherfarbe"};
int[] toViews = new int[]{R.id.facheintrag, R.id.raumeintrag, R.id.farbeintrag};
Cursor cursor;
cursor = getContentResolver().query(Uri.parse(MyDBHandlerFaecher.TABLE_FAECHER),null, null, null, null);
SimpleCursorAdapter fachadapter = new SimpleCursorAdapter(this, R.layout.faecher_row, cursor, fromColumns,toViews, 0);
lv_faecher.setAdapter(fachadapter);
}
}

i found code that works for me: i found out that the cursor in my DBHandler class was not empty, but it was empty in my FaecherActivity...so i created a custom SimpleCursorAdapter, and modified my code this way:
FaecherActivity:
public class FaecherActivity extends AppCompatActivity{
EditText et_facheintrag;
EditText et_raumeintrag;
EditText et_farbeintrag;
ListView lv_faecher;
MyDBHandlerFaecher dbHandlerFaecher;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_faecher);
et_facheintrag = (EditText) findViewById(R.id.et_facheintrag);
et_raumeintrag = (EditText) findViewById(R.id.et_raumeintrag);
et_farbeintrag = (EditText) findViewById(R.id.et_farbeintrag);
lv_faecher = (ListView) findViewById(R.id.lv_faecher);
dbHandlerFaecher = new MyDBHandlerFaecher(this, null, null, 1);
printDatabase();
}
//Add fach to database
public void addButtonClicked(View view){
Faecher fach = new Faecher(et_facheintrag.getText().toString(), et_raumeintrag.getText().toString(),
et_farbeintrag.getText().toString());
dbHandlerFaecher.addFach(fach);
printDatabase();
}
public void deleteButtonClicked(View view){
String inputText = et_facheintrag.getText().toString();
dbHandlerFaecher.deleteFach(inputText);
printDatabase();
}
public void printDatabase(){
String[] fromColumns = dbHandlerFaecher.databaseToStringArray();
int[] toViews = new int[]{R.id.facheintrag, R.id.raumeintrag, R.id.farbeintrag};
Cursor cursor;
cursor = dbHandlerFaecher.getWritableDatabase().rawQuery(" SELECT * FROM " + MyDBHandlerFaecher.TABLE_FAECHER + " WHERE 1 ", null);
//check if cursor is empty
if (cursor != null && cursor.getCount()>0) {
Log.d("Event", "Records do exist2");
}
else {
Log.d("Event", "Records do not exist2");
}
SimpleCursorAdapter fachadapter = new FaecherRowAdapter(this, R.layout.faecher_row, cursor, fromColumns,toViews, 0);
lv_faecher.setAdapter(fachadapter);
MyDBHandlerFaecher:
public class MyDBHandlerFaecher extends SQLiteOpenHelper{
private static final int DATABASE_VERSION = 5;
private static final String DATABASE_NAME = "faecher.db";
public static final String TABLE_FAECHER = "Faechertable";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_NAME = "_faechername";
public static final String COLUMN_RAUM = "_faecherraum";
public static final String COLUMN_COLOR = "_faecherfarbe";
public MyDBHandlerFaecher(FaecherActivity context, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(context, DATABASE_NAME, factory, DATABASE_VERSION);
}
//Create the table
#Override
public void onCreate(SQLiteDatabase db) {
String query = "CREATE TABLE " + TABLE_FAECHER + "(" +
COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
COLUMN_NAME + " TEXT, " +
COLUMN_RAUM + " TEXT, " +
COLUMN_COLOR + " TEXT " +
");";
db.execSQL(query);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_FAECHER);
onCreate(db);
}
//Add a new row to the DB
public void addFach(Faecher fach){
ContentValues values = new ContentValues();
values.put(COLUMN_NAME, fach.get_faechername());
values.put(COLUMN_RAUM, fach.get_faecherraum());
values.put(COLUMN_COLOR, fach.get_faecherfarbe());
SQLiteDatabase db = getWritableDatabase();
db.insert(TABLE_FAECHER, null, values);
db.close();
}
//Delete row from DB
public void deleteFach(String name){
SQLiteDatabase db = getWritableDatabase();
db.execSQL("DELETE FROM " + TABLE_FAECHER + " WHERE " + COLUMN_NAME + "=" + "\"" + name + "\"" + ";");
}
public String[] databaseToStringArray() {
String[] fromColumns = new String[]{COLUMN_NAME, COLUMN_RAUM, COLUMN_COLOR};
SQLiteDatabase db = getWritableDatabase();
Cursor cursor = db.rawQuery(" SELECT * FROM " + TABLE_FAECHER + " WHERE 1 ", null);
//check if cursor is empty or not
if (cursor != null && cursor.getCount()>0) {
Log.d("Event", "Records do exist");
}
else {
Log.d("Event", "Records do not exist");
}
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
cursor.moveToNext();
}
db.close();
return fromColumns;
}
}
FaecherRowAdapter:
public class FaecherRowAdapter extends SimpleCursorAdapter {
private int layout;
private Context context;
public FaecherRowAdapter(Context context, int layout, Cursor c, String[] from, int[] to, int flags) {
super(context, layout, c, from, to, flags);
this.layout = layout;
this.context = context;
}
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
Cursor c = getCursor();
final LayoutInflater inflater = LayoutInflater.from(context);
View v = inflater.inflate(R.layout.faecher_row, parent, false);
bindView(v, context, c);
return v;
}
#Override
public void bindView(View v, Context context, Cursor c) {
int fachNameColumn = c.getColumnIndex(MyDBHandlerFaecher.COLUMN_NAME);
int fachRaumColumn = c.getColumnIndex(MyDBHandlerFaecher.COLUMN_RAUM);
int fachFarbeColumn = c.getColumnIndex(MyDBHandlerFaecher.COLUMN_COLOR);
String fachName = c.getString(fachNameColumn);
String fachRaum = c.getString(fachRaumColumn);
String fachFarbe = c.getString(fachFarbeColumn);
//set the name of the entry
TextView facheintrag = (TextView) v.findViewById(R.id.facheintrag);
if (facheintrag != null){
facheintrag.setText(fachName);
}
TextView raumeintrag = (TextView) v.findViewById(R.id.raumeintrag);
if (raumeintrag != null){
raumeintrag.setText(fachRaum);
}
TextView farbeintrag = (TextView) v.findViewById(R.id.farbeintrag);
if (farbeintrag != null){
farbeintrag.setText(fachFarbe);
}
}
}

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.

We Keep Coding

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

Android recyleview listing using with database not working - java

pass the same list in prepareData(beanList) and add items in this list. And change your method to something likeprepareData(List<Bean> beanList>).after successfully adding, simply call mAdapter.notifyDataSetChanged() method so your adapter could know that some items have been added into the list.

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