Develop Reference

Creating a putExtra to another class won't work

So I am trying to pass data from my HomePage.class(my main activity) to my ContactHelper class but it just seems to crash.
This is the code that crashes the app:
Context context = view.getContext();
Intent i = new Intent(context, ContactHelper.class);
i.putExtra("name", displayName);
i.putExtra("phone", phone);
i.putExtra("email", contactEmail);
i.putExtra("amount", Amount);
i.putExtra("curDate", CurDate);
i.putExtra("dueDate", DueDate);
i.putExtra("curTime", TimeCur);
i.putExtra("timeDue", TimeDue);
//on below line we are starting a new activity,
context.startActivity(i);
Which is inside my getContacts function:
#SuppressLint("Range")
private void getContacts(View view) {
// this method is use to read contact from users device.
// on below line we are creating a string variables for
// our contact id and display name.
String contactId = "";
String displayName = "";
String phone = "";
String contactEmail = "";
String Amount = "0";
String CurDate = "11111111";
String DueDate = "99999999";
String TimeCur = "0";
String TimeDue = "0";
// on below line we are calling our content resolver for getting contacts
Cursor cursor = getContentResolver().query(ContactsContract.Contacts.CONTENT_URI, null, null, null, ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME + " ASC");
// on blow line we are checking the count for our cursor.
if (cursor.getCount() > 0) {
// if the count is greater than 0 then we are running a loop to move our cursor to next.
while (cursor.moveToNext()) {
// on below line we are getting the phone number.
int hasPhoneNumber = Integer.parseInt(cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER)));
if (hasPhoneNumber > 0) {
// we are checking if the has phone number is > 0
// on below line we are getting our contact id and user name for that contact
contactId = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts._ID));
displayName = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
// on below line we are calling a content resolver and making a query
Cursor phoneCursor = getContentResolver().query(
ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
null,
ContactsContract.CommonDataKinds.Phone.CONTACT_ID + " = ?",
new String[]{contactId},
null);
// on below line we are moving our cursor to next position.
if (phoneCursor.moveToNext()) {
// on below line we are getting the phone number for our users and then adding the name along with phone number in array list.
String phoneNumber = phoneCursor.getString(phoneCursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
contactsModalArrayList.add(new ContactsModal(displayName, phoneNumber));
}
// on below line we are closing our phone cursor.
phoneCursor.close();
}
}
Context context = view.getContext();
Intent i = new Intent(context, ContactHelper.class);
i.putExtra("name", displayName);
i.putExtra("phone", phone);
i.putExtra("email", contactEmail);
i.putExtra("amount", Amount);
i.putExtra("curDate", CurDate);
i.putExtra("dueDate", DueDate);
i.putExtra("curTime", TimeCur);
i.putExtra("timeDue", TimeDue);
//on below line we are starting a new activity,
context.startActivity(i);
}
// on below line we are closing our cursor.
cursor.close();
// on below line we are hiding our progress bar and notifying our adapter class.
loadingPB.setVisibility(View.GONE);
contactRVAdapter.notifyDataSetChanged();
}
I am trying to pass the intent to the class below to a function named getContactInfo:
package com.example.myan;
import android.app.AlertDialog;
import android.content.ContentProviderOperation;
import android.content.ContentResolver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.OperationApplicationException;
import android.database.Cursor;
import android.net.Uri;
import android.os.RemoteException;
import android.provider.ContactsContract;
import android.provider.ContactsContract.PhoneLookup;
import android.provider.ContactsContract.RawContacts;
import android.view.View;
import androidx.appcompat.app.AppCompatActivity;
import java.util.ArrayList;
public class ContactHelper extends AppCompatActivity {
static Context context;
static String number;
static String newName;
static String newNumber;
public static Cursor getContactCursor(ContentResolver contactHelper,
String startsWith) {
String[] projection = { ContactsContract.CommonDataKinds.Phone._ID,
ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME,
ContactsContract.CommonDataKinds.Phone.NUMBER };
Cursor cur = null;
try {
if (startsWith != null && !startsWith.equals("")) {
cur = contactHelper.query(
ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
projection,
ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME
+ " like \"" + startsWith + "%\"", null,
ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME
+ " ASC");
} else {
cur = contactHelper.query(
ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
projection, null, null,
ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME
+ " ASC");
}
cur.moveToFirst();
} catch (Exception e) {
e.printStackTrace();
}
return cur;
}
public void getContactInfo(View view) {
Intent intent = getIntent();
String getName = intent.getStringExtra("name");
String getPhone = intent.getStringExtra("phone");
String getEmail = intent.getStringExtra("email");
String getAmount = intent.getStringExtra("amount");
String getCurDate = intent.getStringExtra("curDate");
String getDueDate = intent.getStringExtra("dueDate");
String getCurTime = intent.getStringExtra("curTime");
String getTimeDue = intent.getStringExtra("timeDue");
Integer getFirstDate4thValue = Integer.valueOf(String.valueOf(intent.getStringExtra(getCurDate).charAt(3)));
Integer getFirstDate3rdValue = Integer.valueOf(String.valueOf(intent.getStringExtra(getCurDate).charAt(2)));
String getFirstDateNumber = String.valueOf(getFirstDate3rdValue) + String.valueOf(getFirstDate4thValue);
Integer getSecondDate4thValue = Integer.valueOf(String.valueOf(intent.getStringExtra(getDueDate).charAt(3)));
Integer getSecondDate3rdValue = Integer.valueOf(String.valueOf(intent.getStringExtra(getDueDate).charAt(2)));
String getSecondDateNumber = String.valueOf(getSecondDate3rdValue) + String.valueOf(getSecondDate4thValue);
if (Integer.valueOf(String.valueOf(intent.getStringExtra(getAmount))) > 0) {
view.findViewById(R.id.txtfront).setVisibility(View.VISIBLE);
}
if (Integer.valueOf(String.valueOf(intent.getStringExtra(getAmount))) == 0) {
view.findViewById(R.id.txtfront).setVisibility(View.GONE);
}
if (Integer.valueOf(getFirstDateNumber) != Integer.valueOf(getSecondDateNumber)) {
view.findViewById(R.id.txtDueToday).setVisibility(View.GONE);
}
if (Integer.valueOf(getFirstDateNumber) == Integer.valueOf(getSecondDateNumber)) {
view.findViewById(R.id.txtLate).setVisibility(View.GONE);
view.findViewById(R.id.txtDueToday).setVisibility(View.VISIBLE);
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
alertDialogBuilder.setMessage(intent.getStringExtra(getName) + " owes you $" + intent.getStringExtra(getAmount) + ".00 today at " + intent.getStringExtra(getTimeDue) + " O'Clock.");
alertDialogBuilder.setIcon(R.drawable.ic_launcher_background);
alertDialogBuilder.setTitle("MYAN");
alertDialogBuilder.setNegativeButton("ok", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
AlertDialog alertDialog = alertDialogBuilder.create();
alertDialog.show();
}
if (Integer.valueOf(getFirstDateNumber) > Integer.valueOf(getSecondDateNumber)) {
view.findViewById(R.id.txtLate).setVisibility(View.VISIBLE);
view.findViewById(R.id.txtDueToday).setVisibility(View.GONE);
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
alertDialogBuilder.setMessage(intent.getStringExtra(getName) + " is late and has owed you on " + intent.getStringExtra(getDueDate) + " and owes you $" + intent.getStringExtra(getAmount) + ".00");
alertDialogBuilder.setIcon(R.drawable.myanlogo);
alertDialogBuilder.setTitle("MYAN");
alertDialogBuilder.setNegativeButton("ok", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
AlertDialog alertDialog = alertDialogBuilder.create();
alertDialog.show();
}
if (Integer.valueOf(getFirstDateNumber) < Integer.valueOf(getSecondDateNumber)) {
view.findViewById(R.id.txtLate).setVisibility(View.GONE);
}
}
public static long getContactID(ContentResolver contactHelper,
String phone) {
Uri contactUri = Uri.withAppendedPath(PhoneLookup.CONTENT_FILTER_URI,
Uri.encode(phone));
String[] projection = { PhoneLookup._ID };
Cursor cursor = null;
try {
cursor = contactHelper.query(contactUri, projection, null, null,
null);
if (cursor.moveToFirst()) {
int personID = cursor.getColumnIndex(PhoneLookup._ID);
return cursor.getLong(personID);
}
return -1;
} catch (Exception e) {
e.printStackTrace();
} finally {
if (cursor != null) {
cursor.close();
cursor = null;
}
}
return -1;
}
public static void deleteContact(ContentResolver contactHelper,
String number) {
ArrayList<ContentProviderOperation> ops = new ArrayList<ContentProviderOperation>();
String[] args = new String[] { String.valueOf(getContactID(
contactHelper, number)) };
ops.add(ContentProviderOperation.newDelete(RawContacts.CONTENT_URI)
.withSelection(RawContacts.CONTACT_ID + "=?", args).build());
try {
contactHelper.applyBatch(ContactsContract.AUTHORITY, ops);
} catch (RemoteException e) {
e.printStackTrace();
} catch (OperationApplicationException e) {
e.printStackTrace();
}
}
}
Why would it be crashing?
My ultimate goal here is to have objects in my ContactsRVAdapter to become visible and not visible, and also text change, like current date and time.
[This is the FloatingActionButton which I am trying to manipulate][1]
Which is in a RecyclerView
But I cant seem to reach the items in my FloatingActionButton(ContactsRVAdapter) in any way.
Here is my ContactsRVAdapter class:
package com.example.myan;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.amulyakhare.textdrawable.TextDrawable;
import com.amulyakhare.textdrawable.util.ColorGenerator;
import java.net.URISyntaxException;
import java.util.ArrayList;
class ContactRVAdapter extends RecyclerView.Adapter<ContactRVAdapter.ViewHolder> {
public static final String CHANNEL_1="CHANNEL1";
// creating variables for context and array list.
private Context context;
private ArrayList<ContactsModal> contactsModalArrayList;
private ContentResolver contactHelper;
private String number;
private TextView contactLate;
private View view;
private Intent intent;
// creating a constructor
public ContactRVAdapter(Context context, ArrayList<ContactsModal> contactsModalArrayList) {
this.context = context;
this.contactsModalArrayList = contactsModalArrayList;
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
// passing our layout file for displaying our card item
try {
return new ViewHolder(LayoutInflater.from(context).inflate(R.layout.contacts_rv_item, parent, false));
} catch (URISyntaxException e) {
e.printStackTrace();
}
return null;
}
// below method is use for filtering data in our array list
public void filterList(ArrayList<ContactsModal> filterlist) {
// on below line we are passing filtered
// array list in our original array list
contactsModalArrayList = filterlist;
notifyDataSetChanged();
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
// getting data from array list in our modal.
ContactsModal modal = contactsModalArrayList.get(position);
// on below line we are setting data to our text view.
holder.contactTV.setText(modal.getUserName());
ColorGenerator generator = ColorGenerator.MATERIAL; // or use DEFAULT
// generate random color
int color = generator.getRandomColor();
// below text drawable is a circular.
TextDrawable drawable2 = TextDrawable.builder().beginConfig()
.width(100) // width in px
.height(100) // height in px
.endConfig()
// as we are building a circular drawable
// we are calling a build round method.
// in that method we are passing our text and color.
.buildRound(modal.getUserName().substring(0, 1), color);
// setting image to our image view on below line.
holder.contactIV.setImageDrawable(drawable2);
// on below line we are adding on click listener to our item of recycler view.
holder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// on below line we are opening a new activity and passing data to it.
Intent i = new Intent(context, ContactDetailActivity.class);
i.putExtra("name", modal.getUserName());
i.putExtra("contact", modal.getContactNumber());
//on below line we are starting a new activity,
context.startActivity(i);
}
});
}
#Override
public int getItemCount() {
return contactsModalArrayList.size();
}
class ViewHolder extends RecyclerView.ViewHolder {
public ImageView contactLate;
public ImageView txtFront;
// on below line creating a variable
// for our image view and text view.
private ImageView contactIV;
private TextView contactTV;
private ImageView btnDeleteContact;
private ImageView textDueToday;
private Intent intent;
private String getName;
private String getPhone;
private String getEmail;
private String getAmount;
private String getCurDate;
private String getDateDue;
private String getCurTime;
private String getDueTime;
public ViewHolder(#NonNull View itemView) throws URISyntaxException {
super(itemView);
// initializing our image view and text view.
contactIV = itemView.findViewById(R.id.idIVContact);
contactTV = itemView.findViewById(R.id.idTVContactName);
//contactLate = itemView.findViewById(R.id.txtLate);
//txtFront = itemView.findViewById(R.id.txtfront);
//textDueToday = itemView.findViewById(R.id.txtDueToday);
}
}
}
So all I am trying to do is make it to where I can manipulate the objects inside ContactsRVAdapter class which is a Floating action button.
And my Logcat
FATAL EXCEPTION: main
Process: com.example.myan, PID: 1719
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myan/com.example.myan.HomePage}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.view.View.getContext()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3645)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3782)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:101)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2307)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.app.ActivityThread.main(ActivityThread.java:7872)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.view.View.getContext()' on a null object reference
at com.example.myan.HomePage.getContacts(HomePage.java:286)
at com.example.myan.HomePage.access$200(HomePage.java:39)
at com.example.myan.HomePage$4.onPermissionsChecked(HomePage.java:159)
at com.karumi.dexter.DexterInstance$1.run(Unknown Source:43)
at com.karumi.dexter.MainThread.execute(Unknown Source:6)
at com.karumi.dexter.DexterInstance.checkMultiplePermissions(Unknown Source:71)
at com.karumi.dexter.DexterInstance.checkPermissions(Unknown Source:0)
at com.karumi.dexter.Dexter.check(Unknown Source:10)
at com.example.myan.HomePage.requestPermissions(HomePage.java:187)
at com.example.myan.HomePage.onCreate(HomePage.java:69)
at android.app.Activity.performCreate(Activity.java:8305)
at android.app.Activity.performCreate(Activity.java:8284)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1417)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3626)

try this code...
Intent i = new Intent(this, ContactHelper.class);
The crash is in your view. You are passing view of an activity, which doesn't exist or has been finished.
Context context = view.getContext();
In this function, pass context of existing activity.
private void getContacts(View view) {
...
}

Check the datatypes of the data that you are parsing in Another activities. It should be parcelable or serializable.

Android Studio: Database search functions fine but unable to display all records via button

Much like the title says. I have followed my class tutorials but chunks seem to be missing and it gets a bit confusing flicking between video lectures and pdf's when you're not too well versed in such.
When the app is executed the user can search for a song by year, or display all records within the database. However, originally all records would display from clicking the search by year button instead of the display all button. The search function works as intended but the display all button I cannot seem to figure out, despite following my lecturer's tutorials.
The first section of code is "MainActivity.java" and the second is "OpenDatabse.java"
package com.example.dbcopyexample1;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class MainActivity extends AppCompatActivity
{
private static String DATABASE_PATH_AND_NAME;
private static String CHECK_DATABASES_FOLDER;
//private static final String DATABASE_NAME = "music.db";
private static final String LOG_TAG = "MUSIC_DB";
Context ctx;
OpenDatabase sqh;
SQLiteDatabase sqdb;
// Control Objects
EditText searchByYearEditText;
Button searchButton;
TextView numRecordTextView;
Button displayAllRecordsButton;
TextView resultsTextView;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setupDatabaseStrings();
setUpDatabase();
InitDataBase(); // open the music.db for reading and writing
//sqh.DisplayRecords( sqdb ); // Display the songtable records to the run window
setupControls();
numRecordTextView.setText( Integer.toString( sqh.numberOfRecordsInSongtable( sqdb ) ) );
} // protected void onCreate(Bundle savedInstanceState)
protected void setupControls()
{
searchByYearEditText = findViewById(R.id.searchByYearEditText);
searchButton = findViewById(R.id.searchButton);
searchButton.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View view)
{
resultsTextView.setText( sqh.searchByYearInSongtable( sqdb,
searchByYearEditText.getText().toString()) );
}
});
numRecordTextView = findViewById(R.id.numRecordTextView);
displayAllRecordsButton = findViewById(R.id.displayAllRecordsButton);
displayAllRecordsButton.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View view)
{
}
});
resultsTextView = findViewById(R.id.resultsTextView);
} // protected void setupControls()
protected void setupDatabaseStrings()
{
// Full path to where we will copy music.db to on the emulator!
DATABASE_PATH_AND_NAME = "/data/data/" + getApplicationContext().getPackageName() +
"/databases/" + OpenDatabase.DATABASE_NAME;
// Used to check if the "databases" folder exists
CHECK_DATABASES_FOLDER = "/data/data/" + getApplicationContext().getPackageName() +
"/databases";
// Debug information
Log.i("DATABASE_PATH_AND_NAME","DATABASE_PATH_AND_NAME = " + DATABASE_PATH_AND_NAME);
Log.i("CHECK_DATABASES_FOLDER","CHECK_DATABASES_FOLDER = " + CHECK_DATABASES_FOLDER);
} // protected void setupDatabaseStrings()
protected void setUpDatabase()
{
ctx = this.getBaseContext();
Log.w("CTX","ctx = " + ctx);
Log.w("getBaseContext()","getBaseContext = " + getBaseContext());
try
{
CopyDataBaseFromAsset();
}
catch (IOException e)
{
e.printStackTrace();
}
} // protected void setUpDatabase()
protected void CopyDataBaseFromAsset() throws IOException
{
Log.w( LOG_TAG , "Starting copying...");
String outputFileName = DATABASE_PATH_AND_NAME;
File databaseFolder = new File( CHECK_DATABASES_FOLDER );
// databases folder exists ? No - Create it and copy !!!
if ( !databaseFolder.exists() )
{
databaseFolder.mkdir();
// Open the sqlite database "music.db" found in the assets folder
InputStream in = ctx.getAssets().open(OpenDatabase.DATABASE_NAME);
OutputStream out = new FileOutputStream(outputFileName);
byte[] buffer = new byte[1024];
int length;
while ( (length = in.read(buffer)) > 0 )
{
out.write(buffer,0,length);
} // while ( (length = in.read(buffer)) > 0 )
out.flush();
out.close();
in.close();
Log.w(LOG_TAG, "Completed.");
} // if ( !databaseFolder.exists() )
} // protected void CopyDataBaseFromAsset() throws IOException
public void InitDataBase()
{
// Init the SQLite Helper Class
sqh = new OpenDatabase(this);
// RETRIEVE A READABLE AND WRITEABLE DATABASE
sqdb = sqh.getWritableDatabase();
} // public void InitDataBase()
public void DisplayRecords()
{
Cursor c = sqdb.rawQuery("SELECT * FROM songtable", null);
if (c != null)
{
if (c.moveToFirst())
{
do
{
String id = c.getString(0);
String songtitle = c.getString(1);
String year = c.getString(2);
String artist = c.getString(3);
String album = c.getString(4);
Log.w("SONG_TABLE", "ID = " + id + " Songtitle = " + songtitle);
} while (c.moveToNext());
}
}
c.close();
} // public void DisplayRecords()
} // public class MainActivity extends AppCompatActivity
package com.example.dbcopyexample1;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class OpenDatabase extends SQLiteOpenHelper
{
public static final String DATABASE_NAME = "music.db";
// TOGGLE THIS NUMBER FOR UPDATING TABLES AND DATABASE
private static final int DATABASE_VERSION = 1;
OpenDatabase(Context context)
{
super( context, DATABASE_NAME, null, DATABASE_VERSION );
} // OpenDatabase(Context context)
#Override
public void onCreate(SQLiteDatabase db)
{
} // public void onCreate(SQLiteDatabase db)
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
} // public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
public String searchByYearInSongtable(SQLiteDatabase sqdb, String searchYear)
{
String result = "";
Cursor c = sqdb.rawQuery("SELECT * FROM songtable where year = '" + searchYear + "'",
null);
if (c != null) {
if (c.moveToFirst()) {
do {
String id = c.getString(0);
result = result + id + ",";
String songtitle = c.getString(1);
result = result + songtitle + ",";
String year = c.getString(2);
result = result + year + ",";
String artist = c.getString(3);
result = result + artist + ",";
String album = c.getString(4);
result = result + album + "\n"; // new line control character
Log.w("SONG_TABLE", "ID = " + id + " Songtitle = " + songtitle);
} while (c.moveToNext());
} else
{
result = "No Records Found for the Search Year = " + searchYear;
}
}
c.close();
return result;
} // public String allRecordsInSongtable(SQLiteDatabase sqdb)
public int numberOfRecordsInSongtable(SQLiteDatabase sqdb)
{
int count = 0;
Cursor c = sqdb.rawQuery("SELECT count(*) FROM songtable", null);
if (c != null)
{
if (c.moveToFirst())
{
do
{
String id = c.getString(0);
count = Integer.parseInt( id );
} while (c.moveToNext());
}
}
c.close();
return count;
} // public int numberOfRecordsInSongtable(SQLiteDatabase sqdb)
} // public class OpenDatabase extends SQLiteOpenHelper

You have not called your DisplayRecords() function to display records on tap of displayAllRecordsButton.
displayAllRecordsButton = findViewById(R.id.displayAllRecordsButton);
displayAllRecordsButton.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View view)
{
DisplayRecords();
}
});
Also, in the DisplayRecords() method, you need to set text to the text view.
Below is your code I edited to display records.
public void DisplayRecords()
{
String result = "";
Cursor c = sqdb.rawQuery("SELECT * FROM songtable", null);
if (c != null)
{
if (c.moveToFirst())
{
do
{
String id = c.getString(0);
String songtitle = c.getString(1);
String year = c.getString(2);
String artist = c.getString(3);
String album = c.getString(4);
Log.w("SONG_TABLE", "ID = " + id + " Songtitle = " + songtitle);
result = result + "ID = " + id + "Song Title = " + songtitle + "Artist = " + artist + "Album = " + album + "Year = " + year + "\n";
} while (c.moveToNext());
}
}
c.close();
resultsTextView.setText(result);
} // public void DisplayRecords()

Getting -1 for one of my columns in SQLiteDatabase

Creating an app for seeing pets in the store, where I've created a database and a table called shelter.db and pets respectively. I've created a contract class to store all the constants related to the database, a class called PetDbHelper that extends SQLiteOpenHelper. I have two activities CatalogActivity and EditorActivity. In CatalogActivity, I'm trying to read the table and here I tried to get the column indices of each column but the last column named 'weight' returns -1 which means as you may know 'no column exists' and in EditorActivity, I'm trying to insert pets in the table. I've checked everything but have no clue what's wrong with my code.
Here's the PetContract class:
package com.example.android.pets.data;
import android.provider.BaseColumns;
public final class PetsContract {
public static final class PetEntry implements BaseColumns {
// CONSTANTS FOR TABLE AND COLUMN NAMES
public static final String TABLE_NAME = "pets";
public static final String _ID = BaseColumns._ID;
public static final String COLUMN_PET_NAME = "name";
public static final String COLUMN_PET_BREED = "breed";
public static final String COLUMN_PET_GENDER = "gender";
public static final String COLUMN_PET_WEIGHT = " weight";
// CONSTANTS FOR GENDER
public static final int GENDER_UNKNOWN = 0;
public static final int GENDER_MALE = 1;
public static final int GENDER_FEMALE = 2;
}
}
Here's the PetDbHelper that extends SQLiteOpenHelper class:
package com.example.android.pets.data;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class PetDbHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "shelter.db";
private static final int DATABASE_VERSION = 1;
public PetDbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
String CREATE_TABLE = "CREATE TABLE " + PetsContract.PetEntry.TABLE_NAME
+ " (" + PetsContract.PetEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ PetsContract.PetEntry.COLUMN_PET_NAME + " TEXT NOT NULL, "
+ PetsContract.PetEntry.COLUMN_PET_BREED + " TEXT, "
+ PetsContract.PetEntry.COLUMN_PET_GENDER + " INTEGER NOT NULL, "
+ PetsContract.PetEntry.COLUMN_PET_WEIGHT + " INTEGER NOT NULL DEFAULT 0);";
db.execSQL(CREATE_TABLE);
}
#Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
}
}
Here's the code of CatalogActivity.java that is related to database:
/**
* Displays list of pets that were entered and stored in the app.
*/
public class CatalogActivity extends AppCompatActivity {
private PetDbHelper mDbHelper;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_catalog);
mDbHelper = new PetDbHelper(this);
private void displayDatabaseInfo() {
// To access our database, we instantiate our subclass of
SQLiteOpenHelper
// and pass the context, which is the current activity.
// CREATE AND/OR OPEN A DATABASE TO READ FROM IT
SQLiteDatabase db = mDbHelper.getReadableDatabase();
// String[] projection = {PetEntry._ID, PetEntry.COLUMN_PET_NAME, PetEntry.COLUMN_PET_BREED, PetEntry.COLUMN_PET_GENDER, PetEntry.COLUMN_PET_WEIGHT};
Cursor cursor = db.query(PetEntry.TABLE_NAME, null, null, null, null, null, null);
//Cursor cursor = db.rawQuery("SELECT * FROM pets", null);
TextView displayView = (TextView) findViewById(R.id.text_view_pet);
try {
// Create a header in the Text View that looks like this:
//
// The pets table contains <number of rows in Cursor> pets.
// _id - name - breed - gender - weight
//
// In the while loop below, iterate through the rows of the cursor and display
// the information from each column in this order.
displayView.setText("The pets table contains " + cursor.getColumnCount() + " pets.\n\n");
displayView.append(PetEntry._ID + " - " +
PetEntry.COLUMN_PET_NAME + " - " +
PetEntry.COLUMN_PET_BREED + " - " +
PetEntry.COLUMN_PET_GENDER + " - " +
PetEntry.COLUMN_PET_WEIGHT );
// Figure out the index of each column
int idColumnIndex = cursor.getColumnIndex(PetEntry._ID);
int nameColumnIndex = cursor.getColumnIndex(PetEntry.COLUMN_PET_NAME);
int breedColumnIndex = cursor.getColumnIndex(PetEntry.COLUMN_PET_BREED);
int genderColumnIndex = cursor.getColumnIndex(PetEntry.COLUMN_PET_GENDER);
int weightColumnIndex = cursor.getColumnIndex(PetEntry.COLUMN_PET_WEIGHT);
Toast.makeText(this,
"weight_index ?" + weightColumnIndex + "\n"
+ "id_index" + idColumnIndex + "\n"
+ "name_index" + nameColumnIndex + "\n"
+ "breed_index" + breedColumnIndex + "\n"
+ "gender_index" + genderColumnIndex , Toast.LENGTH_LONG).show();
} finally {
// Always close the cursor when you're done reading from it. This releases all its
// resources and makes it invalid.
cursor.close();
}
}
#Override
protected void onStart() {
super.onStart();
displayDatabaseInfo();
}
I know that's a lot of code, and here's the last piece of code of EditorActivity.java class: (excluded the code related to spinner object)
**
* Allows user to create a new pet or edit an existing one.
*/
public class EditorActivity extends AppCompatActivity {
/** EditText field to enter the pet's name */
private EditText mNameEditText;
/** EditText field to enter the pet's breed */
private EditText mBreedEditText;
/** EditText field to enter the pet's weight */
private EditText mWeightEditText;
/** EditText field to enter the pet's gender */
private Spinner mGenderSpinner;
/**
* Gender of the pet. The possible values are:
* 0 for unknown gender, 1 for male, 2 for female.
*/
private int mGender = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_editor);
// Find all relevant views that we will need to read user input from
mNameEditText = (EditText) findViewById(R.id.edit_pet_name);
mBreedEditText = (EditText) findViewById(R.id.edit_pet_breed);
mWeightEditText = (EditText) findViewById(R.id.edit_pet_weight);
mGenderSpinner = (Spinner) findViewById(R.id.spinner_gender);
}
private void addPet() {
String name = mNameEditText.getText().toString().trim();
String breed = mBreedEditText.getText().toString().trim();
int weight = Integer.parseInt(mWeightEditText.getText().toString().trim());
ContentValues values = new ContentValues();
values.put(COLUMN_PET_NAME, name);
values.put(COLUMN_PET_BREED, breed);
values.put(COLUMN_PET_GENDER, mGender);
values.put(COLUMN_PET_WEIGHT, weight);
PetDbHelper mDbHelper = new PetDbHelper(this);
SQLiteDatabase db = mDbHelper.getWritableDatabase();
long result = db.insert(TABLE_NAME, null, values);
if (result != -1) {
Toast.makeText(this, "Pet saved with id: " + result, Toast.LENGTH_SHORT).show();
} else {Toast.makeText(this, "Error with saving pet", Toast.LENGTH_SHORT).show();}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu options from the res/menu/menu_editor.xml file.
// This adds menu items to the app bar.
getMenuInflater().inflate(R.menu.menu_editor, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// User clicked on a menu option in the app bar overflow menu
switch (item.getItemId()) {
// Respond to a click on the "Save" menu option
case R.id.action_save:
// Save pet into the database
addPet();
// Exit the activity
finish();
return true;
// Respond to a click on the "Delete" menu option
case R.id.action_delete:
// Do nothing for now
return true;
// Respond to a click on the "Up" arrow button in the app bar
case android.R.id.home:
// Navigate back to parent activity (CatalogActivity)
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
}

Leading whitespace is ignored in SQL but it matters in map keys - column names and their indices are essentially stored in a map you can access with getColumnIndex().
public static final String COLUMN_PET_WEIGHT = " weight";
Remove the leading whitespace here.

Data not being stored in SQLite database for some reason? Errors

i'm trying to store some data within a new my sql database and am getting logcat errors saying the table does not exist despite me creating a method to do this. Here is my code!
DataBaseHelper2.java -
package com.example.david.myview3;
/**
* Created by David on 23/03/2017.
*/
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DataBaseHelper2 extends SQLiteOpenHelper {
public DataBaseHelper2(Context context, String name, CursorFactory factory, int version) {
super(context, name, factory, version);
}
// Called when no database exists in disk and the helper class needs
// to create a new one.
#Override
public void onCreate(SQLiteDatabase _db) {
_db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE1);
_db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE2);
_db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE3);
_db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE4);
_db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE5);
}
// Called when there is a database version mismatch meaning that the version
// of the database on disk needs to be upgraded to the current version.
#Override
public void onUpgrade(SQLiteDatabase _db, int _oldVersion, int _newVersion) {
// Log the version upgrade.
Log.w("TaskDBAdapter", "Upgrading from version " + _oldVersion + " to " + _newVersion + ", which will destroy all old data");
// Upgrade the existing database to conform to the new version. Multiple
// previous versions can be handled by comparing _oldVersion and _newVersion
// values.
// The simplest case is to drop the old table and create a new one.
_db.execSQL("DROP TABLE IF EXISTS " + "TEMPLATE");
// Create a new one.
onCreate(_db);
}
}
SurveyDataBaseAdapter -
package com.example.david.myview3;
/**
* Created by David on 23/03/2017.
*/
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
public class SurveyDataBaseAdapter {
static final String DATABASE_NAME = "survey.db";
static final int DATABASE_VERSION = 1;
public static final int NAME_COLUMN = 1;
// TODO: Create public field for each column in your table.
// SQL Statement to create a new database.
static final String DATABASE_CREATE1 = "create table " + "USER" +
"( " + "ID" + " integer primary key autoincrement," + "ID int,NAME text); ";
static final String DATABASE_CREATE2 = "create table " + "QUESTION" +
"( " + "ID2" + " integer primary key autoincrement," + "QUESTION text,ANSWER1 text, ANSWER2 text, ANSWER3 text); ";
static final String DATABASE_CREATE3 = "create table " + "RESPONSE" +
"( " + "ID3" + " integer primary key autoincrement," + "ID int,QUESTION text, ANSWER int); ";
// Variable to hold the database instance
public SQLiteDatabase db2;
// Context of the application using the database.
private final Context context;
// Database open/upgrade helper
private DataBaseHelper2 dbHelper2;
public SurveyDataBaseAdapter(Context _context) {
context = _context;
dbHelper2= new DataBaseHelper2(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public SurveyDataBaseAdapter open() throws SQLException {
db2 = dbHelper2.getWritableDatabase();
return this;
}
public void close() {
db2.close();
}
public SQLiteDatabase getDatabaseInstance() {
return db2;
}
public void insertQuestion(String question, String answerOne, String answerTwo, String answerThree) {
ContentValues newValues = new ContentValues();
// Assign values for each row.
newValues.put("QUESTION", question);
newValues.put("ANSWER1", answerOne);
newValues.put("ANSWER2", answerTwo);
newValues.put("ANSWER3", answerThree);
// Insert the row into your table
db2.insert("QUESTION", null, newValues);
///Toast.makeText(context, "Reminder Is Successfully Saved", Toast.LENGTH_LONG).show();
}
//new try
public void insertEntry2(String question, String answer) {
ContentValues newValues2 = new ContentValues();
// Assign values for each row.
newValues2.put("QUESTION", question);
newValues2.put("ANSWER", answer);
// Insert the row into your table
db2.insert("SURVEY1", null, newValues2);
///Toast.makeText(context, "Reminder Is Successfully Saved", Toast.LENGTH_LONG).show();
}
public int deleteEntry(String UserName) {
//String id=String.valueOf(ID);
String where = "USERNAME=?";
int numberOFEntriesDeleted = db2.delete("LOGIN", where, new String[]{UserName});
// Toast.makeText(context, "Number fo Entry Deleted Successfully : "+numberOFEntriesDeleted, Toast.LENGTH_LONG).show();
return numberOFEntriesDeleted;
}
public String[] getQuestion() {
final String TABLE_NAME = "QUESTION";
String selectQuery = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getDatabaseInstance();
Cursor cursor = db2.rawQuery(selectQuery, null);
String[] data = null;
if(cursor.moveToFirst()) {
do {
// get the data into the array, or class variable
}while (cursor.moveToNext());
}
cursor.close();
return data;
}
public String getSingleEntry()
{
Cursor cursor=db2.query("QUESTION", null, null, null, null, null, null);
cursor.moveToFirst();
String question= cursor.getString(cursor.getColumnIndex("QUESTION"));
cursor.close();
return question;
}
public void updateEntry(String userName, String password) {
// Define the updated row content.
ContentValues updatedValues = new ContentValues();
// Assign values for each row.
updatedValues.put("USERNAME", userName);
updatedValues.put("PASSWORD", password);
String where = "USERNAME = ?";
db2.update("LOGIN", updatedValues, where, new String[]{userName});
}
}
CreateSurveyActivity.java
package com.example.david.myview3;
/**
* Created by David on 23/03/2017.
*/
import android.app.Activity;
import android.app.Dialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import android.content.Context;
import android.view.inputmethod.InputMethodManager;
public class CreateSurveyActivity extends DashBoardAppActivity {
EditText editQuestion, editAnswer1, editAnswer2, editAnswer3;
Button btnNext, btnComplete;
SurveyDataBaseAdapter SurveyDataBaseAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.photoalbum);
// get Instance of Database Adapter
SurveyDataBaseAdapter = new SurveyDataBaseAdapter(this);
SurveyDataBaseAdapter = SurveyDataBaseAdapter.open();
// Get References of Views
editQuestion = (EditText) findViewById(R.id.editTextQuestion);
editAnswer1 = (EditText) findViewById(R.id.editTextAnswer1);
editAnswer2 = (EditText) findViewById(R.id.editTextAnswer2);
editAnswer3 = (EditText) findViewById(R.id.editTextAnswer3);
// Get Refs of buttons
btnComplete = (Button) findViewById(R.id.buttonSignUP);
}
public void createSurvey(View V){
final Dialog dialog = new Dialog(CreateSurveyActivity.this);
dialog.setContentView(R.layout.photoalbum);
dialog.setTitle("Create");
// get the Refferences of views
final EditText editQuestion=(EditText)dialog.findViewById(R.id.editTextQuestion);
editQuestion.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
if (!hasFocus) {
hideKeyboard(v);
}
}
});
final EditText editAnswer1=(EditText)dialog.findViewById(R.id.editTextAnswer1);
editAnswer1.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
if (!hasFocus) {
hideKeyboard(v);
}
}
});
final EditText editAnswer2=(EditText)dialog.findViewById(R.id.editTextAnswer2);
editAnswer2.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
if (!hasFocus) {
hideKeyboard(v);
}
}
});
final EditText editAnswer3=(EditText)dialog.findViewById(R.id.editTextAnswer3);
editAnswer3.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
if (!hasFocus) {
hideKeyboard(v);
}
}
});
// Set On ClickListener
Button btnNext = (Button) dialog.findViewById(R.id.buttonNext);
btnNext.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
String question = editQuestion.getText().toString();
String answer1 = editAnswer1.getText().toString();
String answer2 = editAnswer2.getText().toString();
String answer3 = editAnswer3.getText().toString();
// check if any of the fields are vaccant
if (question.equals("") || answer1.equals("") || answer2.equals("") || answer3.equals("")) {
Toast.makeText(getApplicationContext(), "Field Vaccant", Toast.LENGTH_LONG).show();
return;
}
{
// Save the Data in Database
SurveyDataBaseAdapter.insertQuestion(question, answer1, answer2, answer3);
Toast.makeText(getApplicationContext(), "Question Successfully Created ", Toast.LENGTH_LONG).show();
}
}
});
dialog.show();
// try to send home on complete button press
//*
//btnNext = (Button) findViewById(R.id.buttonNext);
// btnNext.setOnClickListener(new View.OnClickListener() {
// final Intent intent = new Intent(context, DashHomeActivity.class);
//
// });
}
public void hideKeyboard(View view){
InputMethodManager inputMethodManager =(InputMethodManager)getSystemService(Activity.INPUT_METHOD_SERVICE);
inputMethodManager.hideSoftInputFromWindow(view.getWindowToken(), 0);
}
#Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
SurveyDataBaseAdapter.close();
}
}
logcat -
04-17 20:26:41.408 14322-14322/com.example.david.myview3 E/SQLiteLog: (1) no such table: QUESTION
04-17 20:26:41.408 14322-14322/com.example.david.myview3 E/SQLiteDatabase: Error inserting ...
android.database.sqlite.SQLiteException: no such table: QUESTION (code 1): , while compiling: INSERT INTO QUESTION(QUESTION,ANSWER3,ANSWER2,ANSWER1) VALUES (?,?,?,?)
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:919)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:530)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1547)
at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1404)
at com.example.david.myview3.SurveyDataBaseAdapter.insertQuestion(SurveyDataBase Adapter.java:59)
at com.example.david.myview3.CreateSurveyActivity$5.onClick(CreateSurveyActivity .java:117)
at android.view.View.performClick(View.java:4785)
at android.view.View$PerformClick.run(View.java:19869)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:155)
at android.app.ActivityThread.main(ActivityThread.java:5696)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:10 28)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:823)

Use SurveyDataBaseAdapter.DATABASE_CREATE1 instead of LoginDataBaseAdapter.DATABASE_CREATE1.
In your DataBaseHelper2.java, update onCreate() method as below:
#Override
public void onCreate(SQLiteDatabase _db) {
_db.execSQL(SurveyDataBaseAdapter.DATABASE_CREATE1);
_db.execSQL(SurveyDataBaseAdapter.DATABASE_CREATE2);
_db.execSQL(SurveyDataBaseAdapter.DATABASE_CREATE3);
}
In your SurveyDataBaseAdapter , update SQL table create statement as below:
static final String DATABASE_CREATE1 = "CREATE TABLE " + "USER" + "( " +
"ID INTEGER PRIMARY KEY AUTOINCREMENT, " +
"ID1 INTEGER, " + "NAME TEXT " + ")";
static final String DATABASE_CREATE2 = "CREATE TABLE " + "QUESTION" + "( " +
"ID2 INTEGER PRIMARY KEY AUTOINCREMENT, " +
"QUESTION TEXT, " + "ANSWER1 TEXT, " + "ANSWER2 TEXT, " + "ANSWER3 TEXT " + ")";
static final String DATABASE_CREATE3 = "CREATE TABLE " + "RESPONSE" + "( " +
"ID3 INTEGER PRIMARY KEY AUTOINCREMENT, " +
"ID INTEGER, " + "QUESTION TEXT, " + "ANSWER INTEGER " + ")";

Total price using rawQuery in android [closed]

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Closed 8 years ago.
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I've been trying to get the price value from the database and try to make a grand total. I used the rawQuery but always crashed.I think theres a problem in my rawQuery..i still cant get the total after many times i've tried..
this is the code:
DBAdapter
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
// ------------------------------------ DBAdapter.java ---------------------------------------------
// TO USE:
// Change the package (at top) to match your project.
// Search for "TODO", and make the appropriate changes.
public class DBAdapter {
/////////////////////////////////////////////////////////////////////
// Constants & Data
/////////////////////////////////////////////////////////////////////
// For logging:
private static final String TAG = "DBAdapter";
// DB Fields
public static final String KEY_ROWID = "_id";
public static final int COL_ROWID = 0;
/*
* CHANGE 1:
*/
// TODO: Setup your fields here:
public static final String KEY_NAME = "name";
public static final String KEY_QUANTITY = "studentnum";
public static final String KEY_PRICE = "favcolour";
// TODO: Setup your field numbers here (0 = KEY_ROWID, 1=...)
public static final int COL_NAME = 1;
public static final int COL_QUANTITY = 2;
public static final int COL_PRICE = 3;
public static final String[] ALL_KEYS = new String[] {KEY_ROWID, KEY_NAME, KEY_QUANTITY, KEY_PRICE};
// DB info: it's name, and the table we are using (just one).
public static final String DATABASE_NAME = "MyDb";
public static final String DATABASE_TABLE = "mainTable";
// Track DB version if a new version of your app changes the format.
public static final int DATABASE_VERSION = 2;
private static final String DATABASE_CREATE_SQL =
"create table " + DATABASE_TABLE
+ " (" + KEY_ROWID + " integer primary key autoincrement, "
/*
* CHANGE 2:
*/
// TODO: Place your fields here!
// + KEY_{...} + " {type} not null"
// - Key is the column name you created above.
// - {type} is one of: text, integer, real, blob
// (http://www.sqlite.org/datatype3.html)
// - "not null" means it is a required field (must be given a value).
// NOTE: All must be comma separated (end of line!) Last one must have NO comma!!
+ KEY_NAME + " text not null, "
+ KEY_QUANTITY + " integer not null, "
+ KEY_PRICE + " string not null"
// Rest of creation:
+ ");";
// Context of application who uses us.
private final Context context;
private DatabaseHelper myDBHelper;
private SQLiteDatabase db;
/////////////////////////////////////////////////////////////////////
// Public methods:
/////////////////////////////////////////////////////////////////////
public DBAdapter(Context ctx) {
this.context = ctx;
myDBHelper = new DatabaseHelper(context);
}
// Open the database connection.
public DBAdapter open() {
db = myDBHelper.getWritableDatabase();
return this;
}
// Close the database connection.
public void close() {
myDBHelper.close();
}
// Add a new set of values to the database.
public long insertRow(String name, String studentNum, String favColour) {
/*
* CHANGE 3:
*/
// TODO: Update data in the row with new fields.
// TODO: Also change the function's arguments to be what you need!
// Create row's data:
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_NAME, name);
initialValues.put(KEY_QUANTITY, studentNum);
initialValues.put(KEY_PRICE, favColour);
// Insert it into the database.
return db.insert(DATABASE_TABLE, null, initialValues);
}
// Delete a row from the database, by rowId (primary key)
public boolean deleteRow(long rowId) {
String where = KEY_ROWID + "=" + rowId;
return db.delete(DATABASE_TABLE, where, null) != 0;
}
public Cursor getTotalPrice() {
Cursor c = db.rawQuery("SELECT SUM("+ KEY_PRICE +")from " + DATABASE_TABLE, null);
return c;
}
public void deleteAll() {
Cursor c = getAllRows();
long rowId = c.getColumnIndexOrThrow(KEY_ROWID);
if (c.moveToFirst()) {
do {
deleteRow(c.getLong((int) rowId));
} while (c.moveToNext());
}
c.close();
}
// Return all data in the database.
public Cursor getAllRows() {
String where = null;
Cursor c = db.query(true, DATABASE_TABLE, ALL_KEYS,
where, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
// Get a specific row (by rowId)
public Cursor getRow(long rowId) {
String where = KEY_ROWID + "=" + rowId;
Cursor c = db.query(true, DATABASE_TABLE, ALL_KEYS,
where, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
// Change an existing row to be equal to new data.
public boolean updateRow(long rowId, String name, int studentNum, String favColour) {
String where = KEY_ROWID + "=" + rowId;
/*
* CHANGE 4:
*/
// TODO: Update data in the row with new fields.
// TODO: Also change the function's arguments to be what you need!
// Create row's data:
ContentValues newValues = new ContentValues();
newValues.put(KEY_NAME, name);
newValues.put(KEY_QUANTITY, studentNum);
newValues.put(KEY_PRICE, favColour);
// Insert it into the database.
return db.update(DATABASE_TABLE, newValues, where, null) != 0;
}
/////////////////////////////////////////////////////////////////////
// Private Helper Classes:
/////////////////////////////////////////////////////////////////////
/**
* Private class which handles database creation and upgrading.
* Used to handle low-level database access.
*/
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase _db) {
_db.execSQL(DATABASE_CREATE_SQL);
}
#Override
public void onUpgrade(SQLiteDatabase _db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading application's database from version " + oldVersion
+ " to " + newVersion + ", which will destroy all old data!");
// Destroy old database:
_db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
// Recreate new database:
onCreate(_db);
}
}
}
Listprice:
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.*;
/**
* Created by User on 6/2/2015.
*/
public class Listprice extends ActionBarActivity {
DBAdapter myDb;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listprice);
openDB();
TextView textView = (TextView) findViewById(R.id.order90);
TextView textView1 = (TextView) findViewById(R.id.quan90);
TextView textView2 = (TextView) findViewById(R.id.price90);
TextView textView3 = (TextView) findViewById(R.id.totalprice);
Bundle extras = getIntent().getExtras();
if (extras != null) {
String newText = extras.getString("firstmessage");
String newText1 = extras.getString("secondmessage");
String newText2 = extras.getString("thirdmessage");
if (newText != null) {
textView.setText(newText);
}
if (newText1 != null) {
textView1.setText(newText1);
}
if (newText2 != null) {
textView2.setText(newText2);
}
}
String num1 = textView.getText().toString().trim();
int num2 = Integer.parseInt(textView1.getText().toString());
int num3 = Integer.parseInt(textView2.getText().toString());
int num4 = num2 * num3;
registerListClickCallBack();
myDb.insertRow(num1, "Quantity = " + num2, ""+num4);
populateListViewFromDB();
Cursor sum=myDb.getTotalPrice();
textView3.setText(""+sum);
}
private void populateListViewFromDB() {
Cursor cursor = myDb.getAllRows();
//Query for the record we just added.
//Use the ID:
startManagingCursor(cursor);
String[] fromFieldNames = new String[]
{DBAdapter.KEY_NAME, DBAdapter.KEY_QUANTITY, DBAdapter.KEY_PRICE};
int[] toViewIDs = new int[]
{R.id.item_name, R.id.quantities, R.id.pricest};
SimpleCursorAdapter myCursorAdapter =
new SimpleCursorAdapter(
this,
R.layout.item_layout,
cursor,
fromFieldNames,
toViewIDs
);
// Set the adapter for the list view
ListView myList = (ListView) findViewById(R.id.listViewFromDB);
myList.setAdapter(myCursorAdapter);
}
private void openDB(){
myDb = new DBAdapter(this);
myDb.open();
}
#Override
protected void onDestroy() {
super.onDestroy();
closeDB();
}
private void closeDB() {
myDb.close();
}
private void registerListClickCallBack() {
ListView myList = (ListView) findViewById(R.id.listViewFromDB);
myList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View viewClicked,
int position, long idInDB) {
updateItemForId(idInDB);
}
});
}
private void updateItemForId(final long idInDB) {
final Cursor cursor = myDb.getRow(idInDB);
if (cursor.moveToFirst()) {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(Listprice.this);
// Setting Dialog Title
alertDialog.setTitle("Confirm Delete...");
// Setting Dialog Message
alertDialog.setMessage("Are you sure you want delete this?");
// Setting Positive "Yes" Button
alertDialog.setPositiveButton("YES", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
// Write your code here to invoke YES event
Toast.makeText(getApplicationContext(), "You clicked on YES", Toast.LENGTH_SHORT).show();
myDb.deleteRow(idInDB);
populateListViewFromDB();
}
});
// Setting Negative "NO" Button
alertDialog.setNegativeButton("NO", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// Write your code here to invoke NO event
Toast.makeText(getApplicationContext(), "You clicked on NO", Toast.LENGTH_SHORT).show();
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
cursor.close();
populateListViewFromDB();
}
public void clear(View view) {
myDb.deleteAll();
populateListViewFromDB();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void addFood(View view) {
Intent gotofood = new Intent(this, food.class);
startActivity(gotofood);
}
public void addDrinks(View view) {
Intent gotodrinks = new Intent(this, drink.class);
startActivity(gotodrinks);
}
public void gotomainmaenu(View view) {
Intent gotomain = new Intent(this, MainActivity.class);
startActivity(gotomain);
}
}

It sounds like you want the sum of each item's price multiplied by that item's quantity. If so, this should work:
public double getTotalPrice() {
String sql = "select sum(" + KEY_QUANTITY + " * " + KEY_PRICE + ") from "
+ DATABASE_TABLE;
Cursor cursor = db.rawQuery(sql, null);
if (cursor.moveToFirst()) {
return cursor.getDouble(0);
}
return 0;
}