Develop Reference

SQLITE DATABASE error in displaying data to listview

im getting problem in displaying my data from sqlite db
my apps stops working when run and display no errors.
please help me
DatabaseHelper.java
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "ExpDatee.db";
public static final String TABLE_NAME = "EXPDATE_TABLE";
public static final String COL_1 = "PRO_ID";
public static final String COL_2 = "PRO_NAME";
public static final String COL_3 = "PRO_EXPDATE";
public static final String COL_4 = "PRO_DAYTILLEXP";
/**
private static final String SQL_CREATE_TABLE_EXPDATE = "CREATE TABLE " + TABLE_NAME + "("
+ PRO_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ PRO_NAME + " TEXT NOT NULL, "
+ PRO_EXPDATE+ " TEXT NOT NULL, "
+ PRO_DAYTILLEXP + " TEXT NOT NULL, "
+ ");";
**/
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
// SQLiteDatabase db = this.getWritableDatabase();
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_NAME + "(PRO_ID INTEGER PRIMARY KEY AUTOINCREMENT, " +
"PRO_NAME TEXT, " +
"PRO_EXPDATE TEXT," +
" PRO_DAYTILLEXP TEXT )");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS "+TABLE_NAME);
onCreate(db);
}
//method to insert data
public boolean insertData(String PRO_NAME, String PRO_EXPDATE, String PRO_DAYTILLEXP)
{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL_2,PRO_NAME);
contentValues.put(COL_3,PRO_EXPDATE);
contentValues.put(COL_4,PRO_DAYTILLEXP);
Log.d(TAG, "ADD DATA : ADDING " + PRO_NAME + " TO " + TABLE_NAME);
Log.d(TAG, "ADD DATA : ADDING " + PRO_EXPDATE + " TO " + TABLE_NAME);
Log.d(TAG, "ADD DATA : ADDING " + PRO_DAYTILLEXP + " TO " + TABLE_NAME);
long result = db.insert(TABLE_NAME,null ,contentValues );
if (result == -1)
return false;
else
return true;
}
//get all data
public Cursor getData()
{
SQLiteDatabase db = this.getWritableDatabase();
String query = "SELECT * FROM" + TABLE_NAME;
Cursor data = db.rawQuery(query, null);
return data;
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
DatabaseHelper myDB;
EditText etProductName, etDaysBeforeExp, etExpDate;
Button btnAddItem, btnViewItem;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myDB = new DatabaseHelper(this);
etProductName = (EditText)findViewById(R.id.etProductName);
etDaysBeforeExp = (EditText)findViewById(R.id.etDaysBeforeExp);
etExpDate = (EditText)findViewById(R.id.etExpDate);
btnAddItem = (Button)findViewById(R.id.btnAddItem);
btnViewItem = (Button)findViewById(R.id.btnViewItem);
btnAddItem.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String PRO_NAME = etProductName.getText().toString();
String PRO_EXPDATE = etExpDate.getText().toString();
String PRO_DAYTILLEXP = etDaysBeforeExp.getText().toString();
if(etProductName.length() !=0)
{
AddData(PRO_NAME,PRO_EXPDATE,PRO_DAYTILLEXP);
etProductName.setText("");
etExpDate.setText("");
etDaysBeforeExp.setText("");
}
else
{
toastMessage("PLEASE INSERT VALUE");
}
}
});
btnViewItem.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, ListDataActivity.class);
startActivity(intent);
}
});
}
public void AddData(String PRO_NAME, String PRO_EXPDATE, String PRO_DAYTILLEXP)
{
boolean InsertData = myDB.insertData(PRO_NAME,PRO_EXPDATE,PRO_DAYTILLEXP);
if(InsertData)
{
toastMessage("DATA INSERTED");
}
else
{
toastMessage("DATA NOT INSERTED");
}
}
private void toastMessage(String message) {
Toast.makeText(this,message, Toast.LENGTH_LONG).show();
}
}
ListDataActivity.java
public class ListDataActivity extends AppCompatActivity {
DatabaseHelper myDB;
private ListView mListView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_data);
populateListView();
}
private void populateListView() {
Cursor data = myDB.getData();
ArrayList<String> listData = new ArrayList<>();
while (data.moveToNext())
{
listData.add(data.getString(1));
listData.add(data.getString(2));
listData.add(data.getString(3));
}
ListAdapter adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, listData);
mListView.setAdapter(adapter);
}
private void toastMessage(String message) {
Toast.makeText(this,message, Toast.LENGTH_LONG).show();
}
}

Initialized Listdataactivity
myDB = new DatabaseHelper(this);
Use Arrayadapter
ArrayAdapter<String> itemsAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, listData);
mListView.setAdapter(adapter);

Android Studio can't insert data into sqlitedatabase

I'm doing a small project for my mobile app subject. I need to link it with sqlitedatabase.
I've been the tutorial at the Youtube, I followed the tutorial step by step. I didn't got any error from the code.
I need to insert the value into the db and display it back but the user input didn't inserted into db so I couldn't display the data from the DB.
I hope someone could help me. I've been stuck for 2 days because of this problem with no error display.
DatabaseHelper.java
public class DatabaseHelper extends SQLiteOpenHelper
{
public static final String DATABASE_NAME = "STUDENT.DB";
//create table
public static final String TABLE_STUDENT = "STUDENT_TABLE";
public static final String COL_STD_ID = "STD_ID";
public static final String COL_STD_NAME = "STD_NAME";
public static final String COL_STD_EMAIL = "STD_EMAIL";
public static final String COL_STD_ADDRESS = "STD_ADDRESS";
public DatabaseHelper(Context context) {
super(context,DATABASE_NAME, null, 1);
Log.e("DATABASE OPERATION","Database created/opend...");
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_STUDENT +" (STD_ID INTEGER PRIMARY KEY AUTOINCREMENT,STD_NAME TEXT,STD_EMAIL TEXT, STD_ADDRESS TEXT)");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS "+ TABLE_STUDENT );
onCreate(db);
}
public boolean insertData(String STD_NAME, String STD_EMAIL, String STD_ADDRESS)
{
SQLiteDatabase db = this.getWritableDatabase();
//get the data from user into db
ContentValues contentValues = new ContentValues();
contentValues.put(COL_STD_NAME,STD_NAME);
contentValues.put(COL_STD_EMAIL,STD_EMAIL);
contentValues.put(COL_STD_ADDRESS,STD_ADDRESS);
//SEE WHETHER THE DATA INSERT INTO DB OR NOT
//IF RETURN -1, DATA NOT SUCCESSFUL INSERTED
long result = db.insert(TABLE_STUDENT,null,contentValues);
if (result == -1)
return false;
else
return true;
}
public Cursor getAllData() {
SQLiteDatabase db = this.getWritableDatabase();
Cursor result = db.rawQuery("SELECT * FROM " + TABLE_STUDENT,null);
return result;
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
DatabaseHelper myDB;
EditText etstdName, etstdEmail, etstdAddress;
Button btnInsertData, btnViewData;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myDB = new DatabaseHelper(this);
etstdName = (EditText)findViewById(R.id.etstdName);
etstdEmail = (EditText)findViewById(R.id.etstdEmail);
etstdAddress = (EditText)findViewById(R.id.etstdEmail);
btnViewData = (Button)findViewById(R.id.btnViewData);
btnInsertData = (Button)findViewById(R.id.btnInsertData);
InsertStdData();
}
// I think i get stuck at here but theres not error display at InsertStdData() methid
public void InsertStdData() {
btnInsertData.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
boolean isInserted = myDB.insertData(etstdName.getText().toString(),
etstdEmail.getText().toString(),
etstdAddress.getText().toString());
if(isInserted = true)
Toast.makeText(MainActivity.this,"Data successfully inserted.",Toast.LENGTH_LONG).show();
else
Toast.makeText(MainActivity.this,"Data not successfully inserted.",Toast.LENGTH_LONG).show();
}
});
}
public void viewStdData(View view) {
Cursor result = myDB.getAllData();
if(result.getCount() == 0) {
//showmessage method
showMessage("ERROR", "NO DATA FOUND");
return;
}
StringBuffer buffer = new StringBuffer();
while (result.moveToNext()){
buffer.append("STD_ID : "+result.getString(0)+"\n");
buffer.append("STD_NAME : "+result.getString(1)+"\n");
buffer.append("STD_EMAIL : "+result.getString(2)+"\n");
buffer.append("STD_ADDRESS :"+result.getString(3)+"\n\n");
}
//show all data
showMessage("DATA",buffer.toString());
}
public void showMessage(String title, String Message) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setCancelable(true);
builder.setTitle(title);
builder.setMessage(Message);
builder.show();
}
}

You called InsertStdData() but you didnt call viewStdData(View view) in your MainActivity.

can't get to show data from a database sqlite with a requirement JAVA ANDROID STUDIO

i can't get my data to show on my ListView. i created database handler with a query that says: "SELECT * FROM TABLE_NAME WHERE COLUMN_USERNAME = '"+Username+"'". i want to show Data that have the username i want only. But i cant seem to get it work. here is the code.
ViewEvent class with the List View
public class ViewEvent extends Activity {
private static String z = "";
private static final int _EDIT = 0, _DELETE = 1; // constants to be used later
static int longClickedItemIndex;
static List<Event> events = new ArrayList<Event>();
ArrayAdapter<Event> eventsAdapter;
ListView listViewEvents;
static DatabaseHandlerEvent helper;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.view_event);
Typeface myTypeFace = Typeface.createFromAsset(getAssets(), "Type Keys Filled.ttf");
TextView myTextview = (TextView) findViewById(R.id.textViewHead4);
myTextview.setTypeface(myTypeFace);
helper = new DatabaseHandlerEvent(getApplicationContext());
listViewEvents = (ListView) findViewById(R.id.listView);
registerForContextMenu(listViewEvents);
listViewEvents.setOnItemLongClickListener(
new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
longClickedItemIndex = position;
return false;
}
}
);
populateList();
SharedPreferences prfs = getSharedPreferences("AUTHENTICATION_FILE_NAME", Context.MODE_PRIVATE);
String Username = prfs.getString("Username", "");
if (helper.getEventCount() != 0 && events.size() == 0) {
events.addAll(helper.getAllEvent(Username));
}
}
public void registerForContextMenu(View view) {
view.setOnCreateContextMenuListener(this);
}
public void onButtonClick(View v){
if(v.getId() == R.id.bSignoutb){
Toast so = Toast.makeText(ViewEvent.this, "Signing out.. Redirecting to Login Page..." , Toast.LENGTH_SHORT);
so.show();
Intent i = new Intent(ViewEvent.this, MainActivity.class);
startActivity(i);
}
if(v.getId() == R.id.Bback){
Intent i = new Intent(ViewEvent.this, CreateEvent.class);
startActivity(i);
}
}
private void populateList() {
eventsAdapter = new eventListAdapter();
listViewEvents.setAdapter(eventsAdapter);
}
public class eventListAdapter extends ArrayAdapter<Event> {
public eventListAdapter() {
super(ViewEvent.this, R.layout.listview_event, events);
}
#Override
public View getView(int position, View view, ViewGroup parent) {
if (view == null) {
view = getLayoutInflater().inflate(R.layout.listview_event, parent, false);
}
Event currentEvent = events.get(position);
TextView name = (TextView) view.findViewById(R.id.textViewEventName);
name.setText(currentEvent.getName());
TextView location = (TextView) view.findViewById(R.id.textViewLocation);
location.setText(currentEvent.getLocation());
TextView date = (TextView) view.findViewById(R.id.textViewDate);
date.setText(currentEvent.getDate());
TextView description = (TextView) view.findViewById(R.id.textViewDescription);
description.setText(currentEvent.getDescription());
TextView time = (TextView) view.findViewById(R.id.textViewTime);
time.setText(currentEvent.getTime());
TextView testnia = (TextView) view.findViewById(R.id.testnia);
testnia.setText(currentEvent.getUsername());
return view;
}
}
public void onCreateContextMenu(ContextMenu menu, View view, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, view, menuInfo);
menu.setHeaderIcon(R.drawable.huhu);// find a suitable icon
menu.setHeaderTitle("Event options:");
menu.add(Menu.NONE, _EDIT, Menu.NONE, "Edit Event");
menu.add(Menu.NONE, _DELETE, Menu.NONE, "Delete Event");
}
public boolean onContextItemSelected(MenuItem item) {
switch (item.getItemId()) {
case _EDIT:
// editing a contact
Intent editContactIntent = new Intent(getApplicationContext(), EditEvent.class);
startActivityForResult(editContactIntent, 2); // reqcode=2
break;
case _DELETE:
helper.deleteEvent(events.get(longClickedItemIndex));
events.remove(longClickedItemIndex);
eventsAdapter.notifyDataSetChanged();
break;
}
return super.onContextItemSelected(item);
}
}
And this is my DataBaseHelperEvent class
public class DatabaseHandlerEvent extends SQLiteOpenHelper {
static DatabaseHelperUser helper;
Event event;
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "Events";
private static final String TABLE_NAME = "Events";
private static final String COLUMN_ID = "id",
COLUMN_NAME = "name", COLUMN_LOCATION = "location", COLUMN_DATE = "date",
COLUMN_TIME ="time", COLUMN_DESCRIPTION = "description", COLUMN_USERNAME = "username";
SQLiteDatabase db;
public DatabaseHandlerEvent(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_NAME + " (" +
COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
COLUMN_NAME + " TEXT, " + COLUMN_LOCATION + " TEXT, " +
COLUMN_DATE + " TEXT, " + COLUMN_TIME + " TEXT, " +
COLUMN_DESCRIPTION + " TEXT, " + COLUMN_USERNAME + " TEXT)"
);
}
public long createEvent (Event event) {
db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(COLUMN_NAME, event.getName());
values.put(COLUMN_LOCATION, event.getLocation());
values.put(COLUMN_DATE, event.getDate());
values.put(COLUMN_TIME, event.getTime());
values.put(COLUMN_DESCRIPTION, event.getDescription());
values.put(COLUMN_USERNAME, event.getUsername());
long result = db.insert(TABLE_NAME, null, values);
db.close();
return result;
}
public int updateEvent(Event event) {
db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(COLUMN_NAME, event.getName());
values.put(COLUMN_LOCATION, event.getLocation());
values.put(COLUMN_DATE, event.getDate());
values.put(COLUMN_TIME, event.getTime());
values.put(COLUMN_DESCRIPTION, event.getDescription());
int rowsAffected = db.update(TABLE_NAME, values, COLUMN_ID + "=?",
new String[]{String.valueOf(event.getId())});
db.close();
return rowsAffected;
}
public List<Event> getAllEvent(String Username) {
List<Event> events = new ArrayList<Event>();
db = this.getWritableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_NAME +" WHERE "+COLUMN_USERNAME+" = "+ "'"+Username+"'", null);
if (cursor.moveToFirst()) {
do {
events.add(new Event(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2),
cursor.getString(3), cursor.getString(4),
cursor.getString(5), cursor.getString(6)));
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return events;
}
public int getEventCount() {
db = this.getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_NAME, null);
int count = cursor.getCount();
cursor.close();
db.close();
return count;
}
public int deleteEvent(Event event) {
db = this.getWritableDatabase();
int rowsAffected = db.delete(TABLE_NAME, COLUMN_ID + "=?",
new String[]{String.valueOf(event.getId())});
db.close();
return rowsAffected;
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
String query = "DROP TABLE IF EXISTS "+TABLE_NAME;
db.execSQL(query);
this.onCreate(db);
}
}
So whenever i show my ListView, it will show nothing. How can i show the data that only have a specific username i want? thanks! Sorry for my bad english

Cant Find Database file in Eclipse for Android

I have been doing an android database application project recently.When i tried to execute. I cant find the folder 'databases' in the file explorer of the DDMS. I checked the following path /data/data/packagename/databases,but there i could not find databases folder and my database file.
I have attached the code for database helper class
please help me if there is any error that is preventing me from creating the database or is it wrong with my eclipse. Because even some of my existing projects also don't show up with the databases folder inside them.
DBclass.java:
package pack.andyxdb;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DBclass {
public static final String KEY_TIMESTAMP = "Timestamp";
public static final String KEY_UNIQUEID = "UniqueID";
public static final String KEY_DEVICETYPE = "Devicetype";
public static final String KEY_RSSI = "RSSI";
private static final String DATABASE_NAME = "DannyZ.db";
private static final String DATABASE_TABLE = "Data";
private static final int DATABASE_VERSION = 1;
private final Context ourContext;
private DbHelper dbh;
private SQLiteDatabase odb;
private static final String USER_MASTER_CREATE =
"CREATE TABLE IF NOT EXISTS " + DATABASE_TABLE+ "("
+ KEY_TIMESTAMP + " INTEGER ,"
+ KEY_UNIQUEID + " INTEGER, " + KEY_DEVICETYPE + " TEXT, " + KEY_RSSI + " INTEGER PRIMARY KEY )";
//CREATE TABLE `DannyZ` (
private static class DbHelper extends SQLiteOpenHelper {
public DbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(USER_MASTER_CREATE);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// if DATABASE VERSION changes
// Drop old tables and call super.onCreate()
}
}
public DBclass(Context c) {
ourContext = c;
dbh = new DbHelper(ourContext);
}
public DBclass open() throws SQLException {
odb = dbh.getWritableDatabase();
return this;
}
public void close() {
dbh.close();
}
public long insertrecord(int timestamp, int uniqueID,String Device, int RSSI) throws SQLException{
// Log.d("", col1);
// Log.d("", col2);
ContentValues IV = new ContentValues();
IV.put(KEY_TIMESTAMP, timestamp);
IV.put(KEY_UNIQUEID, uniqueID );
IV.put(KEY_DEVICETYPE, Device != "");
IV.put(KEY_RSSI, RSSI );
return odb.insert(DATABASE_TABLE, null, IV);
// returns a number >0 if inserting data is successful
}
public void updateRow(long rowID, String col1, String col2,String col3,String col4) {
ContentValues values = new ContentValues();
values.put(KEY_TIMESTAMP, col1);
values.put(KEY_UNIQUEID, col2);
values.put(KEY_DEVICETYPE, col3);
values.put(KEY_RSSI, col4);
try {
odb.update(DATABASE_TABLE, values, KEY_RSSI + "=" + rowID, null);
} catch (Exception e) {
}
}
public boolean delete() {
return odb.delete(DATABASE_TABLE, null, null) > 0;
}
public Cursor getAllTitles() {
// using simple SQL query
return odb.rawQuery("select * from " + DATABASE_TABLE + "ORDER BY "+KEY_RSSI, null);
}
public Cursor getallCols(String id) throws SQLException {
Cursor mCursor = odb.query(DATABASE_TABLE, new String[] { KEY_TIMESTAMP,
KEY_UNIQUEID, KEY_DEVICETYPE, KEY_RSSI }, null, null, null, null, null);
Log.e("getallcols zmv", "opening successfull");
return mCursor;
}
public Cursor getColsById(String id) throws SQLException {
Cursor mCursor = odb.query(DATABASE_TABLE, new String[] { KEY_TIMESTAMP,
KEY_UNIQUEID,KEY_DEVICETYPE }, KEY_RSSI + " = " + id, null, null, null, null);
Log.e("getallcols zmv", "opening successfull");
return mCursor;
}
}
also my MainActivity.java code is here. Here i try to insert the data into database by making use of submit button. When i hit submit button the app does not stay for long time and says unfortunately myapp has stopped.my curious concern has been is my database being created or not?
please do help me thanks
MainActivity:
public class MainActivity extends Activity {
private ListView list_lv;
private EditText txt1;
private EditText txt2;
private EditText txt3;
private EditText txt4;
private Button btn1;
private Button btn2;
private DBclass db;
private ArrayList<String> collist_1;
private ArrayList<String> collist_2;
private ArrayList<String> collist_3;
private ArrayList<String> collist_4;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
collist_1 = new ArrayList<String>();
collist_2 = new ArrayList<String>();
collist_3 = new ArrayList<String>();
collist_4 = new ArrayList<String>();
items();
// getData();
}
private void items() {
btn1 = (Button) findViewById(R.id.button1);
btn2 = (Button) findViewById(R.id.button2);
txt1 = (EditText) findViewById(R.id.editText1);
txt2 = (EditText) findViewById(R.id.editText2);
txt3 = (EditText) findViewById(R.id.editText3);
txt4 = (EditText) findViewById(R.id.editText4);
// list_lv = (ListView) findViewById(R.id.dblist);
btn2.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
//getData();
viewData();
}
private void viewData() {
Intent i = new Intent(MainActivity.this, viewActivity.class);
startActivity(i);
}
});
btn1.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
submitData();
}
});
}
protected void submitData() {
int a = Integer.parseInt( txt1.getText().toString());
int b = Integer.parseInt( txt2.getText().toString());
String c = txt3.getText().toString();
int d = Integer.parseInt( txt4.getText().toString());
db = new DBclass(this);
long num = 0;
try {
db.open();
num = db.insertrecord(a, b,c,d);
db.close();
} catch (SQLException e) {
Toast.makeText(this, "Error Duplicate value"+e,2000).show();
} finally {
//getData();
}
if (num > 0)
Toast.makeText(this, "Row number: " + num, 2000).show();
else if (num == -1)
Toast.makeText(this, "Error Duplicate value", 4000).show();
else
Toast.makeText(this, "Error while inserting", 2000).show();
}
}

Create object of helper class in your activity onCreate method for creating the database file in android app
DBclass db=new DBclass(context);
Hope this will help.

cursor.moveToFirst seems to be skipped

I'm new to Java and just tried to make a database. I managed to make a DB and all but when I want to read the values it seems to get an error.
This is my code for my settings activity (which asks for setting values and add them in the DB on a specific ID)
public class Settings extends Activity{
Button Save;
static Switch SwitchCalculations;
public static String bool;
public static List<Integer> list_id = new ArrayList<Integer>();
public static List<String> list_idname = new ArrayList<String>();
public static List<String> list_kind = new ArrayList<String>();
public static List<String> list_value = new ArrayList<String>();
static Integer[] arr_id;
static String[] arr_idname;
static String[] arr_kind;
static String[] arr_value;
public static final String TAG = "Settings";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.settings);
Save = (Button) findViewById(R.id.btnSave);
SwitchCalculations = (Switch) findViewById(R.id.switchCalcOnOff);
readData();
Save.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
writeData();
//Toast.makeText(this, "Data has been saved.", Toast.LENGTH_SHORT).show();
readData();
Save.setText("Opgeslagen");
}
});
}
public void writeData() {
int id = 1;
String idname = "switchCalcOnOff";
String kind = "switch";
boolean val = SwitchCalculations.isChecked();
String value = new Boolean(val).toString();
dbHelper_Settings dbh = new dbHelper_Settings(this);
SQLiteDatabase db = dbh.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(dbh.C_ID, id);
cv.put(dbh.C_IDNAME, idname);
cv.put(dbh.C_KIND, kind);
cv.put(dbh.C_VALUE, value);
if (dbh.C_ID.isEmpty() == true) {
db.insert(dbh.TABLE, null, cv);
Log.d(TAG, "Insert: Data has been saved.");
} else if (dbh.C_ID.isEmpty() == false) {
db.update(dbh.TABLE, cv, "n_id='1'", null);
Log.d(TAG, "Update: Data has been saved.");
} else {
Log.d(TAG, "gefaald");
}
db.close();
}
public void readData() {
dbHelper_Settings dbh = new dbHelper_Settings(this);
SQLiteDatabase db = dbh.getWritableDatabase();
List<String> list_value = new ArrayList<String>();
String[] arr_value;
list_value.clear();
Cursor cursor = db.rawQuery("SELECT " + dbh.C_VALUE + " FROM " + dbh.TABLE + ";", null);
if (cursor.moveToFirst()) {
do {
list_value.add(cursor.getString(0));
} while (cursor.moveToNext());
}
if (cursor != null && !cursor.isClosed()){
cursor.close();
}
db.close();
arr_value = new String[list_value.size()];
for (int i = 0; i < list_value.size(); i++){
arr_value[i] = list_value.get(i);
}
}
}
Then I have my dbHelper activity see below:
package com.amd.nutrixilium;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class dbHelper_Settings extends SQLiteOpenHelper{
private static final String TAG="dbHelper_Settings";
public static final String DB_NAME = "settings.db";
public static final int DB_VERSION = 10;
public final String TABLE = "settings";
public final String C_ID = "n_id"; // Special for id
public final String C_IDNAME = "n_idname";
public final String C_KIND = "n_kind";
public final String C_VALUE = "n_value";
Context context;
public dbHelper_Settings(Context context) {
super(context, DB_NAME, null, DB_VERSION);
this.context = context;
}
// oncreate wordt maar 1malig uitgevoerd per user voor aanmaken van database
#Override
public void onCreate(SQLiteDatabase db) {
String sql = String.format("create table %s (%s int primary key, %s TEXT, %s TEXT, %s TEXT)", TABLE, C_ID, C_IDNAME, C_KIND, C_VALUE);
Log.d(TAG, "onCreate sql: " + sql);
db.execSQL(sql);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("drop table if exists " + TABLE); // wist een oudere database versie
Log.d(TAG, "onUpgrate dropped table " + TABLE);
this.onCreate(db);
}
}
And the weird thing is I don't get any error messages here.
But I used Log.d(TAG, text) to check where the script is being skipped and that is at cursor.moveToFirst().
So can anyone help me with this problem?

Here, contrary to what you seem to expect, you actually check that a text constant is not empty:
if (dbh.C_ID.isEmpty() == true) {
It isn't : it always contains "n_id"
I think your intent was to find a record with that id and, depending on the result, either insert or update.
You should do just that: attempt a select via the helper, then insert or update as in the code above.
Edit:
Add to your helper something like this:
public boolean someRowsExist(SQLiteDatabase db) {
Cursor cursor = db.rawQuery("select EXISTS ( select 1 from " + TABLE + " )", new String[] {});
cursor.moveToFirst();
boolean exists = (cursor.getInt(0) == 1);
cursor.close();
return exists;
}
And use it to check if you have any rows in the DB:
if (dbh.someRowsExist(db)) { // instead of (dbh.C_ID.isEmpty() == true) {

Looks like you're having trouble debugging your query. Android provides a handy method DatabaseUtils.dumpCursorToString() that formats the entire Cursor into a String. You can then output the dump to LogCat and see if any rows were actually skipped.