Develop Reference

Never entering in cursor.moveToNext() in Android SQLite

I'm trying Official Documentation for Android this article. Creating Database, Table and inserting data is working fine. But I'm unable to get data from database. Here is the piece of code to retrieve data from table.
public Person searchDataInDB(String personCellString) {
SQLiteDatabase db = getReadableDatabase();
// Define a projection that specifies which columns from the database
// you will actually use after this query.
String[] projection = {
PersonTable.COLUMN_NAME_ID,
PersonTable.COLUMN_NAME_NAME,
PersonTable.COLUMN_NAME_CELL_NO,
PersonTable.COLUMN_NAME_ADDRESS
};
// Filter results WHERE "cell#" = 'Person Cell #'
String selection = SQLiteDBHelper.PersonTable.COLUMN_NAME_CELL_NO + " = ?";
String[] selectionArgs = {"'" + personCellString + "'"};
// How you want the results sorted in the resulting Cursor
// String sortOrder = SQLiteDBHelper.PersonTable.COLUMN_NAME_ID + " DESC";
Cursor cursor = db.query(
SQLiteDBHelper.PersonTable.TABLE_NAME, // The table to query
null, // The array of columns to return (pass null to get all)
selection, // The columns for the WHERE clause
selectionArgs, // The values for the WHERE clause
null, // don't group the rows
null, // don't filter by row groups
null // The sort order
);
String [] names = cursor.getColumnNames();
Log.e("SQLiteDB", "cursorCount = " + cursor.getCount() + ", cursorColumnCount = " + cursor.getColumnCount() + ", Column = " + names[0]);
Person person = null;
while (cursor.moveToNext()) {
int id = (int) cursor.getLong(
cursor.getColumnIndexOrThrow(PersonTable.COLUMN_NAME_ID));
Log.e("SQLiteDB", "moveToNext id = " + id);
String name = cursor.getString(
cursor.getColumnIndexOrThrow(SQLiteDBHelper.PersonTable.COLUMN_NAME_NAME));
Log.e("SQLiteDB", "moveToNext name = " + name);
String cellNo = cursor.getString(
cursor.getColumnIndexOrThrow(SQLiteDBHelper.PersonTable.COLUMN_NAME_CELL_NO));
Log.e("SQLiteDB", "moveToNext cell = " + cellNo);
String address = cursor.getString(
cursor.getColumnIndexOrThrow(SQLiteDBHelper.PersonTable.COLUMN_NAME_ADDRESS));
Log.e("SQLiteDB", "moveToNext address = " + address);
person = new Person(id, name, cellNo, address);
}
cursor.close();
return person;
}
It seems like my app does not enter in while loop i.e. while(cursor.moveToNext() So this method always returns initial value of person which is null. As a result, the first condition is always true from below code
Person person = dbHelper.searchDataInDB(personCellString);
if (person == null) {
Toast.makeText(mContext, "no such record exists in database!", Toast.LENGTH_LONG).show();
} else {
String personDetails = "Name = " + person.getName()
+ "Cell Number = " + person.getCellNumber()
+ "Address = " + person.getAddress();
personDetailsTV.setText(personDetails);
}
I'm using DB Browser for SQLite so I can see the records are successfully adding in the database.
What should I do with the above code to make it work?

What you are doing with this:
String[] selectionArgs = {"'" + personCellString + "'"};
is searching for the string value of personCellString enclosed inside single quotes and not for the actual value of the string personCellString.
Remove the single quotes:
String[] selectionArgs = {personCellString};
You don't have to worry about the string representation of personCellString in the final sql statement that will be constructed and executed which will contain them without explicitly setting them.

How to sort Uri Array by Date/Time?

Is it possible to sort an Array containing Uri's by date/time?
An Uri in my array looks like:
content://media/external/images/media/65
I have tried Collections.sort() but it wasn't possible with an Uri[]
Edit:
My Uri points to an image stored on the device. I want to sort the images by date and time and show it sorted in an GridView.

You can query the content resolver for modified time.
Uri uri = Uri.parse("content://media/external/images/media/65");
String projection [] = {
MediaStore.Images.Media.DATA
, MediaStore.Images.Media.DISPLAY_NAME
, MediaStore.Images.Media.SIZE
, MediaStore.Images.Media.MIME_TYPE
, MediaStore.Images.Media.DATE_MODIFIED
, DocumentsContract.Document.COLUMN_LAST_MODIFIED
};
Cursor cursor = getContentResolver().query(uri, projection, null, null, null);
if ( cursor==null)
{
return;
}
cursor.moveToFirst();
String data = cursor.getString(0);
String displayName = cursor.getString(1);
String size = cursor.getString(2);
String mimeType = cursor.getString(3);
String dateModified = cursor.getString(4); // null
String dateModified2 = cursor.getString(5);
Toast.makeText(context,
"DISPLAY_NAME: " + displayName
+ "\nDATA: " + data
+ "\nSIZE: " + size
+ "\nmimeType: " + mimeType
+ "\n" +MediaStore.Images.Media.DATE_MODIFIED + ": " + dateModified
+ "\n" +DocumentsContract.Document.COLUMN_LAST_MODIFIED + ": " + dateModified2
, Toast.LENGTH_LONG).show();
cursor.close();
Even uris from the media store deliver null for
MediaStore.Images.Media.DATE_MODIFIED ("date_modified")
hence DocumentsContract.Document.COLUMN_LAST_MODIFIED ("last_modified")
which is good for all.
Add a try and some catch blocks.

How to retrieve id value based on other column value(SQLiteOpenHelper)?

I want to make a login option by verifying if the username and the password contain the same id. The problem is I don't know how to get the id value based on their column value (for example - player or 1234). The result i want to get is to compare between their id values so i can know if the username and the password are correct.

You could create a method in your SQLiteOpenhelper subclass to return true or false if the username and the password match e.g.
public boolean ifValidUserLogin(String username, String password) {
SQLitedarabase db = this.getWriteableDatabase();
Cursor csr = db.query(YOUR_TABLE_NAME,
null, // null equates to all columns
"username" + "=? AND " +
"password" + "=?", // the WHERE clause less WHERE
new String[]{username,password}, // the arguments that replace ?'s
null,null,null
};
boolean rv = (csr.getCount > 0);
csr.close();
return rv;
}
You then invoke this, probably in an activity, which would be along the lines of :-
MySQLiteOpenHelper myhlpr = new MySQLiteOpenhelper(this); // parms might be different
if (myhlpr.ifValidUserLogin(username_from_ui,password_from_ui)) {
// username and password match so do what you need to do here!
} else {
// mismatch so do what you need to do here!.
}
Notes
the call to the SQLiteDatabase query method equates to using the SQL SELECT * FROM table WHERE username=?????? AND password=??????? (??? denoting user input values)
YOUR_TABLE_NAME should be replaced by the name of the table as a String.
You may wish to have a look at query
If you wanted the id rather then you could use :-
public long getValidUserId(String username, String password) {
long rv = -1; // default to mismatch and thus no id (could use 0)
SQLitedarabase db = this.getWriteableDatabase();
Cursor csr = db.query(YOUR_TABLE_NAME,
null, // null equates to all columns
"username" + "=? AND " +
"password" + "=?", // the WHERE clause less WHERE
new String[]{username,password}, // the arguments that replace ?'s
null,null,null
};
if (csr.moveToFirst) {
rv = csr.getLong(csr.getColumnIndex("YOUR_ID_COLUMNNAME"));
}
csr.close();
return rv;
}
Obviously you'd call getValidUserId and check for a value > -1 for a match.

you can use query like :
"SELECT * FROM " + TABLE_EMP
+ " WHERE " + KEY_USERNAME + " = '" + userName + "'"
assuming your username must be unique to get the unique record.If you want more specific then you can add a condition for password too.

Why dont you simply check if your password match your username and forget about the id?

Android SQLite SELECT Query

I have taken String value from a EditText and set it inside SELECT QUERY after WHERE condition
As
TextView tv = (TextView) findViewById(R.id.textView3);
EditTextet2 et = (EditText) findViewById(R.id.editText1);
String name = et.getText().toString();
Cursor c = db.rawQuery("SELECT * FROM tbl1 WHERE name = '"+name+"'", null);
c.moveToNext();
tv.setText(c.getString(c.getColumnIndex("email")));
But it doesn't work. Any suggestions?

Try trimming the string to make sure there is no extra white space:
Cursor c = db.rawQuery("SELECT * FROM tbl1 WHERE TRIM(name) = '"+name.trim()+"'", null);
Also use c.moveToFirst() like #thinksteep mentioned.

This is a complete code for select statements.
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery("SELECT column1,column2,column3 FROM table ", null);
if (c.moveToFirst()){
do {
// Passing values
String column1 = c.getString(0);
String column2 = c.getString(1);
String column3 = c.getString(2);
// Do something Here with values
} while(c.moveToNext());
}
c.close();
db.close();

Try using the following statement:
Cursor c = db.rawQuery("SELECT * FROM tbl1 WHERE name = ?", new String[] {name});
Android requires that WHERE clauses compare to a ?, and you then specify an equal number of ? in the second parameter of the query (where you currently have null).
And as Nambari mentioned, you should use c.moveToFirst() rather than c.moveToNext()
Also, could there be quotations in name? That could screw things up as well.

Here is the below code.
String areaTyp = "SELECT " +AREA_TYPE + " FROM "
+ AREA_TYPE_TABLE + " where `" + TYPE + "`="
+ id;
where id is the condition on which result will be displayed.

public User searchUser(String name) {
User u = new User();
SQLiteDatabase db = this.getWritableDatabase(); //get the database that was created in this instance
Cursor c = db.rawQuery("select * from " + TABLE_NAME_User+" where username =?", new String[]{name});
if (c.moveToLast()) {
u.setUsername(c.getString(1));
u.setEmail(c.getString(1));
u.setImgUrl(c.getString(2));
u.setScoreEng(c.getString(3));
u.setScoreFr(c.getString(4));
u.setScoreSpan(c.getString(5));
u.setScoreGer(c.getString(6));
u.setLevelFr(c.getString(7));
u.setLevelEng(c.getString(8));
u.setLevelSpan(c.getString(9));
u.setLevelGer(c.getString(10));
return u;
}else {
Log.e("error not found", "user can't be found or database empty");
return u;
}
}
this is my code to select one user and one only
so you initiate an empty object of your class then
you call your writable Database
use a cursor in case there many and you need one
here you have a choice Use : 1-
if (c.moveToLast()) { } //it return the last element in that cursor
or Use : 2-
if(c.moveToFirst()) { } //return the first object in the cursor
and don't forget in case the database is empty you'll have to deal with that in my case i just return an empty object
Good Luck

Detailed answer:
String[] selectionArgs = new String[]{name};
Cursor c = db.rawQuery(
"SELECT * FROM " + tabl1 +
" WHERE " + name + " = ? ", selectionArgs
);
selectionArgs : this takes the 'name' you desire to compare with, as argrument.
Here note "A Cursor object, which is positioned before the first entry of the table you refer to".
So,to move to first entry :
c.moveToFirst();
getColumnIndex(String ColumnName) : this returns the zero-based column index for the given column name.
tv.setText(c.getString(c.getColumnIndex("email")));
In case, you want to go searching through multiple rows for a given name under 'name' column then use loop as below:
if (cursor.moveToFirst()){
do{
////go traversing through loops
}while(cursor.moveToNext());
}
This should solve the problem.

Can get ID from received phone number, but not group

I have succeded in getting the ID and name from a phone number that is calling in. What I would like to to is to see which groups this ID belongs to. I have tried the following:
//Search for the information about the phone number, save the goupID(s)
Uri uri = Uri.withAppendedPath(ContactsContract.PhoneLookup.CONTENT_FILTER_URI, Uri.encode(aNumber));
ContentResolver cr = mService.getContentResolver();
Cursor myCursor = cr.query(uri, new String[]{PhoneLookup._ID, PhoneLookup.DISPLAY_NAME},null, null, null);
myCursor.moveToFirst();
//String contactID = myCursor.getString(myCursor.getColumnIndex(PhoneLookup._ID));
String contactID = myCursor.getString(myCursor.getColumnIndex(ContactsContract.Contacts._ID));
myCursor.close();
//Use the cursor to query for group with help of ID from the Phone look up
myCursor = cr.query(ContactsContract.Groups.CONTENT_URI,
new String[]{ContactsContract.Groups._ID},
ContactsContract.Groups._ID + " = ?",
new String[]{contactID},
null);
//Contact may be in more than one group
nbrOfGroups = myCursor.getCount();
groupName = new String [nbrOfGroups];
The problem is tha second query, where I would like to use the contactID that i found in the phone lookup, to see which groups that contacID belongs to. The result is no group, although the contact is added to a group in my contacs.
Any ideas? :)

Groups._ID is not same as Contact ID, instead it is the index for the table storing all the group information. After you get the contact ID you should get all the group membership for that contact from the data table by using the Group membership mimetype.
After getting the group ids you can query the Groups table to get the TITLE for all the groups
try with this code
//Search for the information about the phone number, save the goupID(s)
Uri uri = Uri.withAppendedPath(ContactsContract.PhoneLookup.CONTENT_FILTER_URI, Uri.encode("123123"));
ContentResolver cr = this.getContentResolver();
Cursor myCursor = cr.query(uri, new String[]{PhoneLookup._ID, PhoneLookup.DISPLAY_NAME},null, null, null);
myCursor.moveToFirst();
//String contactID = myCursor.getString(myCursor.getColumnIndex(PhoneLookup._ID));
String contactID = myCursor.getString(myCursor.getColumnIndex(ContactsContract.Contacts._ID));
myCursor.close();
//Use the cursor to query for group with help of contact ID from the Phone look up
myCursor = cr.query(ContactsContract.Data.CONTENT_URI,
new String[]{ContactsContract.Data.CONTACT_ID,
ContactsContract.CommonDataKinds.GroupMembership.GROUP_ROW_ID},
ContactsContract.Data.CONTACT_ID + " = ? " +
Data.MIMETYPE + "='" + ContactsContract.CommonDataKinds.GroupMembership.CONTENT_ITEM_TYPE + "'",
new String[]{contactID},
null);
//Contact may be in more than one group
int nbrOfGroups = myCursor.getCount();
int[] groupIds = new int[nbrOfGroups];
int index = 0;
// unfortunately group names are stored in Groups table
// so we need to query again
if (myCursor.moveToFirst()) {
do {
groupIds[index] = myCursor.getInt(1); // Group_row_id column
} while (myCursor.moveToNext());
}
myCursor.close();
// construct the selection
StringBuffer sb = new StringBuffer();
for (int i = 0; i < nbrOfGroups; i++) {
if (i != 0) {
sb.append(",");
}
sb.append(groupIds[i]);
}
String[] groupName = new String [nbrOfGroups];
myCursor = cr.query(ContactsContract.Groups.CONTENT_URI,
new String[]{ContactsContract.Groups.TITLE},
ContactsContract.Groups._ID + " IN (" + sb.toString() + ")",
null, null);
// finally got the names
if (myCursor.moveToFirst()) {
do {
groupName[index] = myCursor.getString(0); // Group_row_id column
} while (myCursor.moveToNext());
}
myCursor.close();