Develop Reference

I can't insert data

I'm making an app to insert data. But when I click on add button by giving all the details. App return me to previous page
This is the way I create insert class
public class InsertStudent extends AppCompatActivity {
Button instudent;
DBHelper dbHelper;
EditText sName,sDOB,sAddress;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_insert_student);
instudent = findViewById(R.id.btninsert);
sName = findViewById(R.id.insertname);
sDOB = findViewById(R.id.insertdob)
;
sAddress = findViewById(R.id.insertaddress);
Below is the way I coded to insert data
instudent.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String userName = sName.getText().toString();
String dateB = sDOB.getText().toString();
String addr = sAddress.getText().toString();
boolean count = dbHelper.addInfo(userName,dateB,addr );
if(count =true){
Toast.makeText(InsertStudent.this, "Inserted!", Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(InsertStudent.this, "Something went wrong!", Toast.LENGTH_SHORT).show();
}
}
});
This is addinfo method in DBHelper class
public boolean addInfo(String stdName, String stdDOB, String stdAddress){
SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(UserProfile.Users.COLUMN_STDNAME, stdName);
contentValues.put(UserProfile.Users.COLUMN_DATEOFBIRTH, stdDOB);
contentValues.put(UserProfile.Users.TABLE_ADDRESS, stdAddress);
long result = sqLiteDatabase.insert(UserProfile.Users.TABLE_NAME, null, contentValues);
if(result==1)
return false;
else
return true;
}
}

The insert method of "SQLiteDatabase" class doesn't return the
count, it's returns the id of the inserted row. so you are checking
if return result is 1, it's a true process, but it's not a way to
check the insert method. It means you need to check if there is any
return result, your insert action performed successfully, but if
there is a problem, the application will crash.
Make sure you created the table that you want to insert data in it.

How to check if database is empty in SQLite Android with DatabaseConnector class

I have a DatabaseConnector class where I want to check if the database is empty and then show an alert and a click on it will close the activity.
This is my DatabaseConnector class
public class DatabaseConnector {
// Declare Variables
private static final String DB_NAME = "MyNotes";
private static final String TABLE_NAME = "tablenotes";
private static final String TITLE = "title";
private static final String ID = "_id";
private static final String NOTE = "note";
private static final int DATABASE_VERSION = 2;
private SQLiteDatabase database;
private DatabaseHelper dbOpenHelper;
public static final String MAINCAT = "maincat";
public static final String SUBCAT = "subcat";
public DatabaseConnector(Context context) {
dbOpenHelper = new DatabaseHelper(context, DB_NAME, null,
DATABASE_VERSION);
}
// Open Database function
public void open() throws SQLException {
// Allow database to be in writable mode
database = dbOpenHelper.getWritableDatabase();
}
// Close Database function
public void close() {
if (database != null)
database.close();
}
// Create Database function
public void InsertNote(String title, String note , String maincat, String subcat) {
ContentValues newCon = new ContentValues();
newCon.put(TITLE, title);
newCon.put(NOTE, note);
newCon.put(MAINCAT, maincat);
newCon.put(SUBCAT, subcat);
open();
database.insert(TABLE_NAME, null, newCon);
close();
}
// Update Database function
public void UpdateNote(long id, String title, String note) {
ContentValues editCon = new ContentValues();
editCon.put(TITLE, title);
editCon.put(NOTE, note);
open();
database.update(TABLE_NAME, editCon, ID + "=" + id, null);
close();
}
// Delete Database function
public void DeleteNote(long id) {
open();
database.delete(TABLE_NAME, ID + "=" + id, null);
close();
}
// List all data function
//String selection = dbOpenHelper.MAINCAT + " = 'quiz'"
// +" AND " + dbOpenHelper.SUBCAT + " = 'test'";
// public Cursor ListAllNotes() {
// return database.query(TABLE_NAME, new String[] { ID, TITLE }, null,
// null, null, null, TITLE);
// }
public Cursor ListAllNotes(String selection) {
return database.query(TABLE_NAME, new String[] { ID, TITLE }, selection,
null, null, null, TITLE);
}
// Capture single data by ID
public Cursor GetOneNote(long id) {
return database.query(TABLE_NAME, null, ID + "=" + id, null, null,
null, null);
}
And here is the ListActivity wherein I want to close the Activity with an alert
public class dbMainactivty extends ListActivity {
// Declare Variables
public static final String ROW_ID = "row_id";
private static final String TITLE = "title";
private ListView noteListView;
private CursorAdapter noteAdapter;
#SuppressWarnings("deprecation")
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Tracker t = ((AnalyticsSampleApp)this.getApplication()).getTracker(TrackerName.APP_TRACKER);
t.setScreenName("dbMainactivty");
t.send(new HitBuilders.AppViewBuilder().build());
// Locate ListView
noteListView = getListView();
// setContentView(R.layout.list_note);
//noteListView = (ListView) findViewById(R.id.listview);
// Prepare ListView Item Click Listener
noteListView.setOnItemClickListener(viewNoteListener);
// Map all the titles into the ViewTitleNotes TextView
String[] from = new String[] { TITLE };
int[] to = new int[] { R.id.ViewTitleNotes };
// Create a SimpleCursorAdapter
noteAdapter = new SimpleCursorAdapter(dbMainactivty.this,
R.layout.list_note, null, from, to);
// Set the Adapter into SimpleCursorAdapter
setListAdapter(noteAdapter);
}
// Capture ListView item click
OnItemClickListener viewNoteListener = new OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// Open ViewNote activity
Intent viewnote = new Intent(dbMainactivty.this, ViewNote.class);
// Pass the ROW_ID to ViewNote activity
viewnote.putExtra(ROW_ID, arg3);
startActivity(viewnote);
}
};
#Override
protected void onResume() {
super.onResume();
// Execute GetNotes Asynctask on return to MainActivity
new GetNotes().execute((Object[]) null);
GoogleAnalytics.getInstance(dbMainactivty.this).reportActivityStart(this);
}
#Override
protected void onStop() {
Cursor cursor = noteAdapter.getCursor();
// Deactivates the Cursor
if (cursor != null)
cursor.deactivate();
noteAdapter.changeCursor(null);
super.onStop();
GoogleAnalytics.getInstance(dbMainactivty.this).reportActivityStop(this);
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
Intent i = null;
switch (item.getItemId()) {
case R.id.action_rate:
String webpage = "http://developer.android.com/index.html";
Intent intent2 = new Intent(Intent.ACTION_VIEW, Uri.parse(webpage));
startActivity(intent2);
overridePendingTransition(R.anim.slide_in, R.anim.slide_out);
case R.id.action_share:
i = new Intent();
i.setAction(Intent.ACTION_SEND);
//i.putExtra(Intent.EXTRA_TEXT, feed.getItem(pos).getTitle().toString()+ " to know the answer download http://developer.android.com/index.html");
i.setType("text/plain");
startActivity(i);
return true;
}
return super.onOptionsItemSelected(item);
};
// GetNotes AsyncTask
private class GetNotes extends AsyncTask<Object, Object, Cursor> {
DatabaseConnector dbConnector = new DatabaseConnector(dbMainactivty.this);
#Override
protected Cursor doInBackground(Object... params) {
// Open the database
dbConnector.open();
return dbConnector.ListAllNotes("maincat LIKE 'quiz' AND subcat LIKE 'test'");
}
#Override
protected void onPostExecute(Cursor result) {
noteAdapter.changeCursor(result);
// Close Database
dbConnector.close();
}
}
#Override
protected void onStart() {
super.onStart();
ConnectivityManager conMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
if (conMgr.getActiveNetworkInfo() == null) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage(
"Please check your Internet Connection.")
.setTitle("tilte")
.setCancelable(false)
.setPositiveButton("Exit",
new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog,
int id) {
//loader.cancel(true);
finish();
}
});
AlertDialog alert = builder.create();
alert.show();
} else {
Cursor cursor = noteAdapter.getCursor();
if(cursor != null && cursor.getCount() > 0){
cursor.moveToFirst();
//do your action
//Fetch your data
GoogleAnalytics.getInstance(dbMainactivty.this).reportActivityStart(this);
Toast.makeText(getBaseContext(), "Yipeee!", Toast.LENGTH_SHORT).show();
}
else {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage(
"oops nothing pinned yet! ....")
.setTitle("title")
.setCancelable(false)
.setPositiveButton("Exit",
new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog,
int id) {
//loader.cancel(true);
finish();
}
});
AlertDialog alert = builder.create();
alert.show();
Toast.makeText(getBaseContext(), "No records yet!", Toast.LENGTH_SHORT).show();
}
}
}
}
I am trying to check
cursor != null && cursor.getCount()>0 and if it turns false then show the alert that
nothing has been pinned yet
Should show up however even though if the cursor returns data the alert still shows up.

First step, take a look at the lifecycle of your activity: http://www.android-app-market.com/wp-content/uploads/2012/03/Android-Activity-Lifecycle.png
As you can see onResume() is called after onStart() which means that checking the cursor on the onStart() can not work.
Secondly you are starting an AsyncTask (GetNotes) on the onResume() method which means you are running a parallel thread at this point and can't check for the result after calling new GetNotes().execute((Object[]) null);
Your problem is you need to check the emptiness of your cursor (cursor != null && cursor.getCount()>0) AFTER the data is loader which mean after the AsyncTask has completed. In other words, move the check for emptiness on your cursor inside the onPostExecute(Cursor result) method.

Sqlite data don't show after close the apps

This is my MainActivity.
public class MainActivity extends Activity {
EditText etName, etEmail;
DatabaseHelper dbHelper;
Button save;
// declare view
ListView lvEmployees;
// declare adapter
CustomizedAdapter adapter;
// datasource
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
etName = (EditText) findViewById(R.id.etName);
etEmail = (EditText) findViewById(R.id.etEmail);
save = (Button) findViewById(R.id.btnSave);
lvEmployees = (ListView) findViewById(R.id.lvEmployees);
dbHelper = new DatabaseHelper(this);
save.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
save(v);
}
});
}
public void save(View v) {
String name = etName.getText().toString();
String email = etEmail.getText().toString();
Employee employee = new Employee(name, email);
Toast.makeText(getApplicationContext(), employee.toString(),
Toast.LENGTH_LONG).show();
long inserted = dbHelper.insertEmployee(employee);
if (inserted >= 0) {
Toast.makeText(getApplicationContext(), "Data inserted",
Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(), "Data insertion failed...",
Toast.LENGTH_LONG).show();
}
ArrayList<Employee> employees = dbHelper.getAllEmployees();
if (employees != null && employees.size() > 0) {
adapter = new CustomizedAdapter(this, employees);
lvEmployees.setAdapter(adapter);
}
}
}
This is my DataBaseHelper.
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String DB_NAME = "task_management";
public static final int DB_VERSION = 1;
public static final String EMPLOYEE_TABLE = "employee";
public static final String ID_FIELD = "_id";
public static final String NAME_FIELD = "name";
public static final String EMAIL_FIELD = "email";
public static final String EMPLOYEE_TABLE_SQL = "CREATE TABLE "
+ EMPLOYEE_TABLE + " (" + ID_FIELD + " INTEGER PRIMARY KEY, "
+ NAME_FIELD + " TEXT, " + EMAIL_FIELD + " DATETIME);";
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
// create tables
db.execSQL(EMPLOYEE_TABLE_SQL);
Log.e("TABLE CREATE", EMPLOYEE_TABLE_SQL);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// upgrade logic
}
// insert
public long insertEmployee(Employee emp) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(NAME_FIELD, emp.getName());
values.put(EMAIL_FIELD, emp.getEmail());
long inserted = db.insert(EMPLOYEE_TABLE, null, values);
db.close();
return inserted;
}
// query
public ArrayList<Employee> getAllEmployees() {
ArrayList<Employee> allEmployees = new ArrayList<Employee>();
SQLiteDatabase db = this.getReadableDatabase();
// String[] columns={NAME_FIELD, EMAIL_FIELD, PHONE_FIELD};
// SELECT * FROM EMPLOYEE;
Cursor cursor = db.query(EMPLOYEE_TABLE, null, null, null, null, null,
null);
// Cursor cursor = db.rawQuery("SELECT * FROM EMPLOYEE", null);
if (cursor != null && cursor.getCount() > 0) {
cursor.moveToFirst();
for (int i = 0; i < cursor.getCount(); i++) {
//
int id = cursor.getInt(cursor.getColumnIndex(ID_FIELD));
String name = cursor.getString(cursor
.getColumnIndex(NAME_FIELD));
String email = cursor.getString(cursor
.getColumnIndex(EMAIL_FIELD));
Employee e = new Employee(id, name, email);
allEmployees.add(e);
cursor.moveToNext();
}
}
cursor.close();
db.close();
return allEmployees;
}
}
When i put data and pressed the save button then my data is saved and show in my ListView.
But when i close the apps and open it then i don't see any data in my ListView.
After putting data and pressed save button my new and existing data show in my ListView.
So how can i show my existing data in ListView after open my apps and without press the save button.

If you want to show data each time app starts, you would need to move your list populating code in onCreate
Move this code to onCreate instead of Save button's onClick
ArrayList<Employee> employees = dbHelper.getAllEmployees();
if (employees != null && employees.size() > 0) {
adapter = new CustomizedAdapter(this, employees);
lvEmployees.setAdapter(adapter);
}
Hope it helps.
P.S: If you need to repopulate list after Save button's click, make a separate function which contains this code. And call tha function in onCreate as well as in Save button's onClick

You are setting the adapter for the list view in your save method that is called only when you actually press the save button. Here's the part where you do it.
ArrayList<Employee> employees = dbHelper.getAllEmployees();
if (employees != null && employees.size() > 0) {
adapter = new CustomizedAdapter(this, employees);
lvEmployees.setAdapter(adapter);
}
Thats why there is no data in the listview when you open the app.
You should do this in your onCreate method, and in your save you should do something like this:
1. declare the the arraylist of employees along with listview;
ArrayList<Employee> employees;
in your oncreate call this code that you should remove from the save method
employees = dbHelper.getAllEmployees();
if (employees != null && employees.size() > 0) {
adapter = new CustomizedAdapter(this, employees);
lvEmployees.setAdapter(adapter);
}
in save method just add one more item to the list, and notify adapter that there has been a change in the data it's displaying.
employees.add(employee);
adapter.notifyDataSetChanged();

SQL query and force close challenge

here i tried to take name and password from database if the user have already an account, or sign up him by enter his data.
This is the first activity which has force close by clicking on first button to log into the data base
public class SelesMeter2Activity extends Activity implements OnClickListener {
EditText ed1;
EditText ed2;
Button b1;
Button b2;
SQLiteDatabase sql;
Cursor c;
Intent in;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ed1 = (EditText) findViewById(R.id.ed1);
ed2 = (EditText) findViewById(R.id.ed2);
b1 = (Button) findViewById(R.id.bt1);
b2 = (Button) findViewById(R.id.bt2);
b1.setOnClickListener(this);
b2.setOnClickListener(this);
sql = openOrCreateDatabase("db", 0, null);
sql.execSQL("CREATE TABLE if not exists "
+ "Employee2 (password integer NOT NULL PRIMARY KEY,name text NOT NULL)");
}
#Override
public void onClick(View arg0) {
// log in
if (arg0.getId() == R.id.bt1) {
int p = 0;
String name = ed1.getText().toString();
String sp = ed2.getText().toString();
try {
// Attempt to parse the number as an integer
p = Integer.parseInt(sp);
} catch (NumberFormatException nfe) {
// parseInt failed, so tell the user it's not a number
Toast.makeText(this,
"Sorry, " + sp + " is not a number. Please try again.",
Toast.LENGTH_LONG).show();
}
if (c.getCount() != 0) {
c = sql.rawQuery("select * from Employee", null);
while (c.moveToNext()) {
if (name.equals("c.getString(1)") && p == c.getInt(0)) {
in = new Intent(this, secondview.class);
startActivity(in);
break;
}
}
}
else {
Toast.makeText(this,
"please sign up first or enter " + "correct data", 2000)
.show();
}
} else if (arg0.getId() == R.id.bt2) {
// sign up
Intent in2 = new Intent(this, signup.class);
startActivity(in2);
}
}
}
the second class that enter the new user which is not working as expected,
the toast does not work :
public class signup extends Activity implements OnClickListener {
EditText e1;
EditText e2;
SQLiteDatabase sql;
Button b;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.singupx);
Intent in = getIntent();
e1 = (EditText) findViewById(R.id.ed1s);
e2 = (EditText) findViewById(R.id.ed2s);
b = (Button) findViewById(R.id.bt1s);
b.setOnClickListener(this);
}
#Override
public void onClick(View v) {
String n = e1.getText().toString();
String sp = e2.getText().toString();
try {
// Attempt to parse the number as an integer
int p = Integer.parseInt(sp);
// This insertion will *only* execute if the parseInt was successful
// sql.execSQL("insert into Employee2(password,name)values('"+n+"',"+p+")");
ContentValues values = new ContentValues();
values.put("password", p);
values.put("name", n);
sql.insert("Employee2", null, values);
Toast.makeText(this, "Data inserted", Toast.LENGTH_LONG).show();
Intent in2 = new Intent(this, secondview.class);
startActivity(in2);
} catch (NumberFormatException nfe) {
// parseInt failed, so tell the user it's not a number
Toast.makeText(this,
"Sorry, " + sp + " is not a number. Please try again.",
Toast.LENGTH_LONG).show();
}
}
}

In the SelesMeter2Activity you'll have a NullPointerException at the line:
if (c.getCount() != 0) {
as you don't initialize the Cursor before that line. Move the query before the above line:
c = sql.rawQuery("select * from Employee", null);
if (c.getCount() != 0) {
// ...
You should post the exception you get from the logcat.
Also regarding your signup activity please don't instantiate the first activity to access fields from it. Open the database again in the second activity and insert the values.

This is why you are getting error
// you are calling the `c.getCount();` before you are assigning
// It will throw null pointer exception
if (c.getCount() != 0) {
c = sql.rawQuery("select * from Employee", null);
while (c.moveToNext()) {
if (name.equals(c.getString(1)) && p == c.getInt(0)) {
in = new Intent(this, secondview.class);
startActivity(in);
break;
}
}
}
Change the logic like
c = sql.rawQuery("select * from Employee", null);
c.moveToFirst();
if(!c.isAfterLast()) {
do {
if (name.equals(c.getString(1)) && p == c.getInt(0)) {
in = new Intent(this, secondview.class);
startActivity(in);
break;
}
} while (c.moveToNext());
}
and name.equals("c.getString(1)") should be name.equals(c.getString(1))
EDIT
Example of insert method
ContentValues values = new ContentValues();
values.put("password", n);
values.put("name", p);
database.insert("Employee2", null, values);

clear editText input after saving info to database

My question is how can i clear the editText field after i have saved what i have written to it to the database? I currently can input text using the nameEditText field but when i click the InsertButton, it does not clear the for. I just want to clear the form not the value or string in the Database...This is the insert button i want to also use as a clear method:
class InsertButtonListener implements OnClickListener, android.view.View.OnClickListener
{
public void onClick(View v)
{
if("".equals(nameEditText.getText().toString()))
{
Toast toast = Toast.makeText(Entername.this, "Sorry, you must input both the name and the address!", Toast.LENGTH_LONG);
toast.show();
}
else
{
long flag = 0;
int id = 1;
SQLiteDatabase db = dbHelper.getWritableDatabase();
Cursor cursor = db.query("user_name", new String[]{"count(*) ID"}, null, null, null, null, null);
while(cursor.moveToNext())
{
int idFromDatabase = cursor.getInt(cursor.getColumnIndex("ID"));
if(idFromDatabase != 0)
{
id = 1 + idFromDatabase;
}
}
ContentValues values = new ContentValues();
values.put("ID", id);
values.put("name", nameEditText.getText().toString().trim());
//values.put("address", addressEditText.getText().toString().trim());
flag = db.insert("user_name", null, values);
if(flag != -1)
{
Toast toast = Toast.makeText(Entername.this, "You have successful inserted this record into database! ", Toast.LENGTH_LONG);
toast.show();
db.close();
return;
}
else
{
Toast toast = Toast.makeText(Entername.this, "An error occured when insert this record into database!", Toast.LENGTH_LONG);
toast.show();
db.close();
return;
}
}
}
public void onClick(DialogInterface dialog, int which)
{
// TODO Auto-generated method stub
}
}

You need to call:
nameEditText.setText("");
addressEditText.setText("");
So, do the following change in your if condition when adding to database is successful:
if(flag != -1)
{
Toast toast = Toast.makeText(Entername.this,
"You have successful inserted this record into database! ",
Toast.LENGTH_LONG);
toast.show();
db.close();
//clearing edittexts
nameEditText.setText("");
addressEditText.setText("");
return;
}

you last insert after editText in to set null values
EditText text;
text.setText("");