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How Can I delete item on my SQliteOpenhelper [duplicate]

This question already has answers here:
How to delete items from sqlite database with SQLiteOpenHelper class
(2 answers)
Closed 2 years ago.
I save my recyclerview with SQliteopenhelper . I can add item with edittext varibles . I use Itemtouchhelper for swip to delete item . How can ı delete item on SQliteopenhelper . Can you be fast
todoactivity.java
public class todoactivity extends AppCompatActivity {
TextView title;
Button back;
ImageButton gorevo;
RecyclerView recyclerView;
List<String>Listsx = new ArrayList<>();
TodoActivityAdpter adapterx;
DatabaseHelper4 myDBxxx;
TextView textView;
CheckBox checkBox;
long id;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_todoactivity);
recyclerView=findViewById(R.id.recyclerviewxx);
recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
adapterx=new TodoActivityAdpter(Listsx);
recyclerView.setAdapter(adapterx);
title=findViewById(R.id.titlex);
textView=findViewById(R.id.text_viewx);
gorevo = findViewById(R.id.gorevo);
myDBxxx = new DatabaseHelper4(this);
Cursor datax = myDBxxx.getListContents();
if(datax.getCount() == 0){
}else{
while(datax.moveToNext()){
Listsx.add(datax.getString(1));
ListAdapter listAdapterx = new ArrayAdapter<>(this,R.layout.todoactivity_item,R.id.textitem,Listsx);
adapterx.notifyItemInserted(Listsx.size()-1);
}
}
gorevo.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
BottomSheetDialog bottomSheetDialog = new BottomSheetDialog(todoactivity.this);
bottomSheetDialog.setContentView(R.layout.bottomsheetlayout3);
bottomSheetDialog.show();
InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
inputMethodManager.toggleSoftInput(InputMethodManager.SHOW_FORCED,0);
EditText editText = bottomSheetDialog.findViewById(R.id.editx);
Button ekle = bottomSheetDialog.findViewById(R.id.ekle);
ekle.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String text = editText.getText().toString();
Listsx.add(text);
AddDataxxx(text);
adapterx.notifyItemInserted(Listsx.size()-1);
bottomSheetDialog.hide();
inputMethodManager.hideSoftInputFromWindow(view.getWindowToken(),0);
}
});
}
});
back=findViewById(R.id.back);
back.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent i = new Intent(todoactivity.this, pomodoroscreen.class);
startActivity(i);
overridePendingTransition(0,0);
}
});
ItemTouchHelper.SimpleCallback simpleCallback = new ItemTouchHelper.SimpleCallback(0,ItemTouchHelper.LEFT) {
#Override
public boolean onMove(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder, #NonNull RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(#NonNull RecyclerView.ViewHolder viewHolder, int direction) {
int positionx = viewHolder.getAdapterPosition();
Listsx.remove(positionx);
adapterx.notifyItemRemoved(positionx);
int id = recyclerView.getChildAt(positionx).getId();
myDBxxx.deleteItem(id);
}
};
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(simpleCallback);
itemTouchHelper.attachToRecyclerView(recyclerView);
}
public void AddDataxxx(String newEntry) {
boolean insertDatax = myDBxxx.addDataxxx(newEntry);
}
}
DatabaseHelper.java
public class DatabaseHelper4 extends SQLiteOpenHelper {
public static final String DATABASE_NAME4 = "mylistxxx.db";
public static final String TABLE_NAME4 = "mylist_dataxxx";
public static final String COL14 = "iDxxx";
public static final String COL24 = "ITEM1xxx";
public DatabaseHelper4(Context context) {
super(context, DATABASE_NAME4, null, 1);
}
#Override
public void onCreate(SQLiteDatabase dbxxx) {
String createTable = "CREATE TABLE " + TABLE_NAME4 + " (iDxxx INTEGER PRIMARY KEY AUTOINCREMENT, " +
" ITEM1xxx TEXT)";
dbxxx.execSQL(createTable);
}
#Override
public void onUpgrade(SQLiteDatabase dbxxx, int oldVersion, int newVersion) {
dbxxx.execSQL("DROP IF TABLE EXISTS " + TABLE_NAME4);
onCreate(dbxxx);
}
public boolean addDataxxx(String textt) {
SQLiteDatabase dbxxx = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL24, textt);
long result = dbxxx.insert(TABLE_NAME4, null, contentValues);
if (result == -1) {
return false;
} else {
return true;
}
}
public Cursor getListContents() {
SQLiteDatabase dbxxx = this.getWritableDatabase();
Cursor dataxxx = dbxxx.rawQuery("SELECT * FROM " + TABLE_NAME4, null);
return dataxxx;
}
public void deleteItem(int iDxxx) {
SQLiteDatabase db = getWritableDatabase();
db.execSQL("DELETE FROM " + TABLE_NAME4 + " WHERE " + COL14 + " = " +
iDxxx);
}
}
Adapter.java
public class TodoActivityAdpter extends RecyclerView.Adapter<TodoActivityAdpter.Holder> {
List<String>Listsx;
public TodoActivityAdpter(List<String>itemxxx){
this.Listsx = itemxxx;
}
#NonNull
#Override
public TodoActivityAdpter.Holder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.todoactivity_item,parent,false);
Holder holder = new Holder(view);
return holder;
}
#Override
public void onBindViewHolder(#NonNull TodoActivityAdpter.Holder holder, int position) {
holder.textView.setText(Listsx.get(position));
holder.checkBox.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (holder.checkBox.isChecked()) {
holder.textView.setTextColor(view.getResources().getColor(R.color.grey));
} else {
holder.textView.setTextColor(view.getResources().getColor(R.color.Color_black));
}
}
});
}
#Override
public int getItemCount() {
return Listsx.size();
}
public class Holder extends RecyclerView.ViewHolder {
CheckBox checkBox;
TextView textView;
List<String>Listsx;
RecyclerView recyclerView;
Context mContext;
public Holder(View view) {
super(view);
textView=view.findViewById(R.id.text_viewx);
checkBox=view.findViewById(R.id.checkbox);
recyclerView=view.findViewById(R.id.recyclerviewxx);
}
}
}
Thats my java classes . My activity is todoactivity . My SQliteopenhelper is DatabaseHelper.java . My Adapter is adapter.java . I can delete item on my recyclerview but ı cant delete item on my database

You can easily delete item from your table by just below code.
//Add method in your database class.
public void deleteItem(int iDxxx) {
SQLiteDatabase db = getWritableDatabase();
db.execSQL("DELETE FROM " + TABLE_NAME4 + " WHERE " + COL14 + " =
" + iDxxx);
}
and Just Call this method from where you are deleting item.

SQLite Database not showing data to custom ListView

I'm attempting to get the data that is saved in my the SQLite database into a custom ListView in my app. It seems the adaptor is working okay because it inflating the layout, however, there is no data in the views. I'm hoping it is a simple fix and I appreciate any input on this :)
Activity where data will be shown:
public class SavedGameScreen extends AppCompatActivity {
ListView lv1;
ArrayList<GameStats> arrayList;
MyAdaptor myAdaptor;
DatabaseHelper databaseHelper;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_saved_game_screen);
lv1 = findViewById(R.id.lv1);
databaseHelper = new DatabaseHelper(this);
arrayList = new ArrayList<>();
loadData();
}
private void loadData() {
arrayList = databaseHelper.getAllData();
myAdaptor = new MyAdaptor(this, arrayList);
lv1.setAdapter(myAdaptor);
myAdaptor.notifyDataSetChanged();
}
}
Database Helper:
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "savedGames.db";
public static final String TABLE_NAME = "savedGamesTable";
public static final String COL_1 = "ID";
public static final String COL_2 = "lName";
public static final String COL_3 = "lScore";
public static final String COL_4 = "rName";
public static final String COL_5 = "rScore";
public static final String COL_6 = "notes";
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
}
#Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL("create table "+TABLE_NAME+" (ID INTEGER PRIMARY KEY AUTOINCREMENT, lName TEXT," +
"lScore INTEGER, rName TEXT, rScore INTEGER, notes TEXT)");
}
#Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS "+ TABLE_NAME);
onCreate(sqLiteDatabase);
}
public boolean insertData(String lName, int lScore, String rName, int rScore, String notes) {
SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL_2, lName);
contentValues.put(COL_3, lScore);
contentValues.put(COL_4, rName);
contentValues.put(COL_5, rScore);
contentValues.put(COL_6, notes);
long result = sqLiteDatabase.insert(TABLE_NAME, null, contentValues);
if(result == -1) {
return false;
}
else{
return true;
}
}
public ArrayList<GameStats> getAllData() {
ArrayList<GameStats> arrayList = new ArrayList<>();
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM savedGamesTable", null);
while(cursor.moveToNext()){
int id = cursor.getInt(0);
String lName = cursor.getString(1);
int lScore = cursor.getInt(2);
String rName = cursor.getString(3);
int rScore = cursor.getInt(4);
String notes = cursor.getString(5);
GameStats gameStats = new GameStats(id, lName, lScore, rName, rScore, notes);
arrayList.add(gameStats);
}
return arrayList;
}
}
myAdaptor:
public class MyAdaptor extends BaseAdapter {
Context context;
ArrayList<GameStats> arrayList;
public MyAdaptor(Context context, ArrayList<GameStats> arrayList){
this.context = context;
this.arrayList = arrayList;
}
#Override
public int getCount() {
return this.arrayList.size();
}
#Override
public Object getItem(int position) {
return arrayList.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.activity_saved_games, null);
TextView lName = convertView.findViewById(R.id.lName);
TextView lScore = convertView.findViewById(R.id.lScore);
TextView rName = convertView.findViewById(R.id.rName);
TextView rScore = convertView.findViewById(R.id.rScore);
TextView notes = convertView.findViewById(R.id.notes);
GameStats gameStats = arrayList.get(position);
lName.setText(gameStats.getlName());
lScore.setText(String.valueOf(gameStats.getlScore()));
rName.setText(gameStats.getrName());
rScore.setText(String.valueOf(gameStats.getrScore()));
notes.setText(gameStats.getNotes());
return convertView;
}
}
Below is what I am getting when I try to view the data
Model class:
public class GameStats {
int id, lScore, rScore;
String lName, rName, notes;
public GameStats(int id, String lName, int lScore, String rName, int rScore, String notes) {
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getlScore() {
return lScore;
}
public void setlScore(int lScore) {
this.lScore = lScore;
}
public int getrScore() {
return rScore;
}
public void setrScore(int rScore) {
this.rScore = rScore;
}
public String getlName() {
return lName;
}
public void setlName(String lName) {
this.lName = lName;
}
public String getrName() {
return rName;
}
public void setrName(String rName) {
this.rName = rName;
}
public String getNotes() {
return notes;
}
public void setNotes(String notes) {
this.notes = notes;
}
}

How do I delete data from SQLITE database by ID

I am having a lot of trouble finding out how to delete data from my sqlite database by using ID.
How do I delete data from my sqlite databse by using ID?
final ItemTouchHelper.SimpleCallback itemTouchHelper = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
#Override
public boolean onMove(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder, #NonNull RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(#NonNull RecyclerView.ViewHolder viewHolder, int direction) {
list.remove(viewHolder.getAdapterPosition());
adapter.notifyDataSetChanged();
/////// I want to delete this data from my sqlite Data Base by using it's id. But how do I get the id?///////
}
};
Should that be done in the OnBindViewHolder?
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
holder.notePadTextView.setText(arrayListNote.get(position).getNote());
}
This is my custom adapter:
public class NotesCustomAdapter extends RecyclerView.Adapter{
private ArrayList arrayListNote;
private Context context;
public NotesCustomAdapter(ArrayList<newNote> arrayListNote, Context context) {
this.arrayListNote = arrayListNote;
this.context = context;
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.notepad_model,parent,false);
ViewHolder holder = new ViewHolder(view);
return holder;
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
holder.notePadTextView.setText(arrayListNote.get(position).getNote());
}
#Override
public int getItemCount() {
return arrayListNote.size();
}
public class ViewHolder extends RecyclerView.ViewHolder{
LinearLayout NotePadMode;
TextView notePadTextView;
public ViewHolder(#NonNull View itemView) {
super(itemView);
NotePadMode= itemView.findViewById(R.id.NotePadModel);
notePadTextView = itemView.findViewById(R.id.notePadTextView);
}
}
}
This is my SQlite Database:
public class DataBaseHelper extends SQLiteOpenHelper {
public static final String DATABSE_NAME = "AllWorkHours.db";
public static final String TABLE_NAME = "ALLWORKHOURS";
public static final String COL_0 = "ID";
public static final String COL_1 = "DATE";
public static final String COL_2 = "TIMESHIFTSTART";
public static final String COL_3 = "TIMESHIFTENDS";
public static final String COL_4 = "NOTES";
public static final String COL_5 = "NOTEMEMOS";
public static final int DATABASE_Version = 5;
public DataBaseHelper(Context context) {
super(context, DATABSE_NAME,null,DATABASE_Version);
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_NAME + "(ID INTEGER PRIMARY KEY AUTOINCREMENT, DATE TEXT, TIMESHIFTSTART INTEGER, TIMESHIFTENDS TEXT, NOTES TEXT, NOTEMEMOS TEXT)");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS ALLWORKHOURS");
onCreate(db);
}
public boolean addHours(String Date, String TimeShiftStart, String TimeShiftEnds, String Notes){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL_1, Date);
contentValues.put(COL_2, TimeShiftStart);
contentValues.put(COL_3, TimeShiftEnds);
contentValues.put(COL_4, Notes);
long inserted = db.insert(TABLE_NAME,null,contentValues);
if (inserted == -1){
return false;
}else{
return true;
}
}
public ArrayList<newShift> viewAllHours(){
ArrayList<newShift> arrayList = new ArrayList<>();
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_NAME, null);
while(cursor.moveToNext()){
int id = cursor.getInt(0);
String Date = cursor.getString(1);
String timestart = cursor.getString(2);
String timeEnds = cursor.getString(3);
String notes = cursor.getString(4);
newShift newShift = new newShift(id,Date,timestart,timeEnds,notes);
arrayList.add(newShift);
}
return arrayList;
}
public boolean addNotes(String NOTEMEMOS) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL_5, NOTEMEMOS);
long inserted = db.insert(TABLE_NAME, null, contentValues);
if (inserted == -1){
return false;
}else{
return true;
}
}
public ArrayList<newNote> ViewAllNotes() {
ArrayList<newNote> arrayList = new ArrayList<>();
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery("SELECT NOTEMEMOS FROM " + TABLE_NAME, null);
while(cursor.moveToNext()){
String notes = cursor.getString(0);
newNote newnote = new newNote(notes);
arrayList.add(newnote);
}
return arrayList;
}
}

You can try this
db.delete(table, whereClause, whereArgs)
after delete entry, refresh your view (listview)

You have to get Id of your model before remove like:
newShift obj = list.get(viewHolder.getAdapterPosition());
DataBaseHelper _yourdatabaseObject = youtDatabaseInstance();
_yourdatabaseObject.removeDataByID(""+obj.id);
list.remove(viewHolder.getAdapterPosition());
adapter.notifyDataSetChanged();
Make A function Of delete note in DataBaseHelper.
public void deleteMyNote(String id){
SQLiteDatabase db = this.getWritableDatabase();
db.execSQL("delete from "+ TABLE_NAME +" where ID='"+ id +"'");
}

Access SQLite Helper From Adapter

Code
public class ChatData extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
public static final String DATABASE_NAME = "MessagePlus";
public ChatData(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(context, name, factory, version);
}
#Override
public void onCreate(SQLiteDatabase db) {
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
public Cursor getAllQuestions3(MessagesAdapter usageSettings2) {
return this.getWritableDatabase().query(TABLE_CHAT_DATA,null,null,null,null,null,null);
}
}
Adapter
final ChatData mHelper = new ChatData(this);
final Cursor csr = mHelper.getAllQuestions3(this);
Nothing is working for context in adapter. This shows message to change the Helper classes context to the Adapters name and if i do that theres a red line under context in the helper... If i directly try to access like ChatData.getWritableDatabase it shows that u cant access a non static method from a static class and if i make that method in helper static it shows error there saying class cant be static... one error is leading to another and i dont know what to do so can someone help me out please
EDIT
Full Adapter Code
public class MessagesAdapter extends RecyclerView.Adapter<MessagesAdapter.MessageViewHolder>{
private List<SQLiteHelper> mMessagesHelperList;
private FirebaseAuth mAuth;
ChatData mHelper = new ChatData(this);
Cursor csr = mHelper.getAllQuestions3();
public MessagesAdapter(List<SQLiteHelper> mMessagesHelperList) {
this.mMessagesHelperList = mMessagesHelperList;
}
public class MessageViewHolder extends RecyclerView.ViewHolder{
public TextView messageText;
public MessageViewHolder(View view) {
super(view);
messageText = (TextView)view.findViewById(R.id.message_text_layout);
}
}
#Override
public MessageViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View V = LayoutInflater.from(parent.getContext()).inflate(R.layout.custom_activity_chat,parent,false);
mAuth = FirebaseAuth.getInstance();
return new MessageViewHolder(V);
}
#Override
public void onBindViewHolder(final MessageViewHolder holder, int position) {
String mSender = null;
String mMessage = null;
String mTime;
String mSeen = null;
String mTimer;
String mType;
while (csr.moveToNext()) {
mSender = csr.getString(csr.getColumnIndex(KEY_SENDER));
mMessage = csr.getString(csr.getColumnIndex(KEY_MESSAGE));
mTime = csr.getString(csr.getColumnIndex(KEY_TIME));
mSeen = csr.getString(csr.getColumnIndex(KEY_SEEN));
mTimer = csr.getString(csr.getColumnIndex(KEY_TIMER));
mType = csr.getString(csr.getColumnIndex(KEY_TYPE));
}
SQLiteHelper messagesHelper = mMessagesHelperList.get(position);
#Override
public int getItemCount() {
return mMessagesHelperList.size();
}
}
Activity
final MainData mHelper = new MainData(this); //Change the name to your Helper Class name
final Cursor csr = myDBHlpr.getAllQuestions3(this);
messageList.setAdapter(mAdapter);
while (csr.moveToNext()) {
String mSender = csr.getString(csr.getColumnIndex(KEY_SENDER));
String mMessage = csr.getString(csr.getColumnIndex(KEY_MESSAGE));
String mTime = csr.getString(csr.getColumnIndex(KEY_TIME));
String mSeen = csr.getString(csr.getColumnIndex(KEY_SEEN));
String mTimer = csr.getString(csr.getColumnIndex(KEY_TIMER));
String mType = csr.getString(csr.getColumnIndex(KEY_TYPE));
messages.add(new SQLiteHelper(mSender, mMessage, mTime, mSeen, mTimer, mType));
}

The following will likely cause some of your issues. That is you are saying that the method should be passed a MesagesAdapter, when as it stands there is no reason to pass anything into the getAllQuestions3 method.
public Cursor getAllQuestions3(MessagesAdapter usageSettings2) {
return this.getWritableDatabase().query(TABLE_CHAT_DATA,null,null,null,null,null,null);
}
Trying changing the above to
public Cursor getAllQuestions3() {
return this.getWritableDatabase().query(TABLE_CHAT_DATA,null,null,null,null,null,null);
}
and use
ChatData mHelper = new ChatData(this);
Cursor csr = mHelper.getAllQuestions3();
instead of
final ChatData mHelper = new ChatData(this,ChatData.DATABASE_NAME,null,ChatData.DATABASE_VERSION);
final Cursor csr = mHelper.getAllQuestions3(this);
Noting that the above lines should be in the Activity's onCreate method or a method invoked from onCreate so that you have a valid context (i.e. this).
Edit 1
Note that the above has been changed as according to ChatData you need to provided 4 parameters for the instantiation of a ChatData object.
I'd suggest changing the constructor to :-
public ChatData(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
and then you could use ChatData mHelper = new ChatData(this);.
Working Example
The following is a working example based upon the code you have given.
The database helper ChatData.java
public class ChatData extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
public static final String DATABASE_NAME = "MessagePlus";
public static final String TABLE_CHAT_DATA = "chatdata";
public static final String COL_CHATDATA_ID = BaseColumns._ID;
public static final String COL_CHATDATA_TIMESTAMP = "timestamp";
public static final String COL_CHATDATA_MESSAGE = "message";
public static final String COL_CHATDATA_USER = "user";
public ChatData(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
String crt_sql = "CREATE TABLE IF NOT EXISTS " + TABLE_CHAT_DATA + "(" +
COL_CHATDATA_ID + " INTEGER PRIMARY KEY, " +
COL_CHATDATA_TIMESTAMP + " TEXT DEFAULT CURRENT_TIMESTAMP," +
COL_CHATDATA_MESSAGE + " TEXT, " +
COL_CHATDATA_USER + " INTEGER" +
")";
db.execSQL(crt_sql);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
public Cursor getAllQuestions3() {
return this.getWritableDatabase().query(TABLE_CHAT_DATA,null,null,null,null,null,null);
}
public long addMessage(String message, long user) {
ContentValues cv = new ContentValues();
cv.put(COL_CHATDATA_MESSAGE,message);
cv.put(COL_CHATDATA_USER,user);
SQLiteDatabase db = this.getWritableDatabase();
return db.insert(TABLE_CHAT_DATA,null,cv);
}
}
Note modified to crate a table and to allow rows to be added to the table.
Note the constructor.
The Custom Adapter (Cursor Adapter) MessageAdapter.java
public class MessageAdapter extends CursorAdapter {
public MessageAdapter(Context context, Cursor c, boolean autoRequery) {
super(context, c, autoRequery);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
return super.getView(position, convertView, parent);
}
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
View rv = LayoutInflater.from(context).inflate(
R.layout.messagelist_item,
parent,
false
);
return rv;
}
#Override
public void bindView(View view, Context context, Cursor cursor) {
TextView mUser = view.findViewById(R.id.user);
TextView mTimestamp = view.findViewById(R.id.timestamp);
TextView mMessage = view.findViewById(R.id.message);
mUser.setText(cursor.getString(cursor.getColumnIndex(ChatData.COL_CHATDATA_USER)));
mTimestamp.setText(cursor.getString(cursor.getColumnIndex(ChatData.COL_CHATDATA_TIMESTAMP)));
mMessage.setText(cursor.getString(cursor.getColumnIndex(ChatData.COL_CHATDATA_MESSAGE)));
}
}
The layout used in the list messagelist_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/user"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content" />
<TextView
android:id="#+id/timestamp"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
/>
<TextView
android:id="#+id/message"
android:layout_width="0dp"
android:layout_weight="8"
android:layout_height="wrap_content" />
</LinearLayout>
The code in the Activity to list the messages via the adapter (MainActivty.java)
public class MainActivity extends AppCompatActivity {
ChatData mDBHlpr;
Cursor mCsr;
MessageAdapter mMesaageAdapter;
ListView mMessageList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mMessageList = this.findViewById(R.id.messagelist);
mDBHlpr = new ChatData(this);
addSomeData();
mCsr = mDBHlpr.getAllQuestions3();
mMesaageAdapter = new MessageAdapter(this,mCsr,false);
mMessageList.setAdapter(mMesaageAdapter);
}
private void addSomeData() {
mDBHlpr.addMessage("Hello",1);
mDBHlpr.addMessage("Hi",2);
mDBHlpr.addMessage("How are you?",1);
mDBHlpr.addMessage("I'm OK thanks, and you?",2);
mDBHlpr.addMessage("Good.",1);
}
}
Result

How to delete a particular row from SQLite database

I have created a list view. On button click the data is added in list and also stored in an SQLite database. I have also added the image on the right-hand side of list, on click of which a particular row data is deleted, but I also want to delete data from SQLite. How could I do this?
Main Activity.Java
public class MainActivity extends Activity {
EditText editText;
Button Button,Button1;
ListView listView;
ArrayList<String> listItems;
BaseAdapter adapter;
private DataBaseHandler mHelper;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mHelper=new DataBaseHandler(this);
editText = (EditText) findViewById(R.id.editText);
Button = (Button) findViewById(R.id.Button);
listView = (ListView) findViewById(R.id.listview);
listItems = new ArrayList<String>();
adapter =new BaseAdapter()
{
#Override
public View getView(final int arg0, View arg1, ViewGroup arg2)
{
LayoutInflater inflater = getLayoutInflater();
arg1 = inflater.inflate(R.layout.custom, null);
TextView textview = (TextView)arg1. findViewById(R.id.textView1);
textview.setText(listItems.get(arg0));
ImageView image = (ImageView)arg1. findViewById(R.id.imageView1);
image.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
listItems.remove(arg0);
listView.setAdapter(adapter);
Toast.makeText(MainActivity.this, "Item has been successfully deleted", Toast.LENGTH_LONG)
.show();
}
});
return arg1;
}
#Override
public long getItemId(int arg0) {
return 0;
}
#Override
public Object getItem(int arg0) {
return null;
}
#Override
public int getCount() {
//code to set the list item size according to array data size
return listItems.size();
}
};
listView.setAdapter(adapter);
Button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v)
{
listItems= mHelper.addListItem(editText.getText().toString());
adapter.notifyDataSetChanged();
listView.setSelection(listView.getAdapter().getCount()-1);
editText.getText().clear();
}
});
}
}
DATABASE HANDLER.JAVA
public class DataBaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "MyDatabase.db";
private static final String TABLE_LIST = "MyListItem";
private static final String KEY_ID = "id";
private static final String KEY_ListItem = "listitem";
public static final String KEY_NAME = null;
public DataBaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db)
{
String CREATE_LIST_TABLE = "CREATE TABLE " + TABLE_LIST + "(" + KEY_ID
+ " integer primary key autoincrement," + KEY_ListItem + " TEXT" + ")";
db.execSQL(CREATE_LIST_TABLE);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_LIST);
onCreate(db);
}
ArrayList<String> addListItem(String listItem)
{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ListItem, listItem);
db.insert(TABLE_LIST, null, values);
ArrayList<String> items=new ArrayList<String>();
String selectQuery = "SELECT * FROM " + TABLE_LIST;
Cursor cursor = db.rawQuery(selectQuery, null);
cursor.moveToFirst();
while (!cursor.isAfterLast())
{
items.add(cursor.getString(1));
cursor.moveToNext();
}
cursor.close();
db.close();
return items;
}
Cursor getListItem()
{
String selectQuery = "SELECT * FROM " + TABLE_LIST;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
return cursor;
}
}

To delete single data entry(i.e. Row) make a method in database handler:
public void delete(int id) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_NAME, KEY_ID + "=?",
new String[] { String.valueOf(id) }); // KEY_ID= id of row and third parameter is argument.
db.close();
}
This method will delete single row which ID is given.

You will need to make a method deleteItem in your DataBaseHandler class. Which will do something like,
db.delete(TABLE_LIST , KEY_ID + "=" + yourIdToBeDeleted, null);
And make a call to this method from your delete button/image's onClick as:
mHelper.deleteItem(idOfItemToBeDeleted);
Hope it helps.