I am using Loader to get data from db and I have some trouble whit distinct, in simple words - distinct doesn't work. here is my code:
private String[] CONTACTS_COLUMNS ={
"DISTINCT " + ContactsEntry.CONTACT_ID + " AS _id",
ContactsEntry.CONTACT_FROM,
ContactsEntry.CONTACT_NAME,
CardsPhonesEntry.CONTACT_PHONE,
CardsPhonesEntry.CARD_NUMBER
};
#Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new CursorLoader(getActivity(),
ContactsEntry.CONTENT_URI,
CONTACTS_COLUMNS,
mSelection, null, null);
}
here is some code from my contentProvider:
#Nullable
#Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
Cursor retCursor;
int match = sUriMatcher.match(uri);
switch (match){
case PEOPLE:
retCursor = getAllContacts(projection, selection, selectionArgs, sortOrder);
break;
default:
throw new UnsupportedOperationException("Unknown uri in query(): " + uri);
}
return retCursor;
}
private Cursor getAllContacts(String[] projection, String selection, String[] selectionArgs,
String sortOrder){
return sPeopleWithCardsAndPhones.query(
mDbHelper.getReadableDatabase(),
projection,
selection,
selectionArgs,
null, null,
sortOrder
);
}
static {
sPeopleWithCardsAndPhones = new SQLiteQueryBuilder();
sPeopleWithCardsAndPhones.setTables(
ContactsEntry.TABLE_NAME + " LEFT JOIN " + CardsPhonesEntry.TABLE_NAME + " ON " +
ContactsEntry.TABLE_NAME + "." + ContactsEntry.CONTACT_ID + " = " +
CardsPhonesEntry.TABLE_NAME + "." + CardsPhonesEntry.OWNER_ID
);
}
what i am doing wrong and why distinct doesn't want to work?
EDIT:
For example: I have 1 contact in first table, and in the second table there are 2 cards linked to this contact by contact_id;
I need to show list with only 1 item (first contact) without depending how much cards it has. and now when init loader - it shows me this contact twice, but not once.
Related
I am trying to retrieve the distinct values from my database using my contentprovider query and CursorLoader. While the CursorLoader does not allow a distinct specification, I discovered the setDistinct method that can be added to a querybuilder for adding this specification. I am not retrieving the desired result and curious as to why. My query looks like below
#Override
public Cursor query(Uri uri, String[] projection,
String selection, String[] selectionArgs, String sortOrder) {
// create SQLiteQueryBuilder for querying flower table
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables(Flower.TABLE_NAME);
queryBuilder.setDistinct(true);
switch (uriMatcher.match(uri)) {
case OneFlower: // contact with specified id will be selected
queryBuilder.appendWhere(
Flower._ID + "=" + uri.getLastPathSegment());
break;
case CONTACTS: // all contacts will be selected
break;
default:
throw new UnsupportedOperationException(
getContext().getString(R.string.invalid_query_uri) + uri);
}
Cursor cursor = queryBuilder.query(dbHelper.getReadableDatabase(),
projection, selection, selectionArgs, null, null, sortOrder);
// configure to watch for content changes
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
while my CursorLoader looks like this
#Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
switch (id) {
case LOADER_ID:
return new CursorLoader(
getContext(),
DatabaseDescription.Flower.CONTENT_URI,
FROM_COLUMNS,
COLUMN_LOCATION + "<> ''",
null,
COLUMN_LOCATION + " ASC"
);
default:
if (BuildConfig.DEBUG)
throw new IllegalArgumentException("no id handled!");
return null;
}
}
I have a sqlite database with "label" and "idea" tables in my Android app. made a foreign key on idea table as idea_label with int values that connected to label_table on its _id.
I use Loader to load my Cursor on the mainActivity that loads my idea table from the provider. As obvious it load idea_label int (But what I seek is to load the value from label_table which sets in label_body).
My loader on mainActivity class
#Override
public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
String[] projection = {
DatabaseContract.IdeaEntry._ID,
DatabaseContract.IdeaEntry.COLUMN_IDEA_NAME,
DatabaseContract.IdeaEntry.COLUMN_IDEA_DESCRIPTION,
DatabaseContract.IdeaEntry.COLUMN_IDEA_DATE,
DatabaseContract.IdeaEntry.COLUMN_IDEA_LABEL,
DatabaseContract.IdeaEntry.COLUMN_IDEA_ICON,
DatabaseContract.IdeaEntry.COLUMN_IDEA_IS_ACTIVE,
DatabaseContract.IdeaEntry.COLUMN_IDEA_IS_FAVORITE,
DatabaseContract.IdeaEntry.COLUMN_IDEA_IS_DONE,
DatabaseContract.IdeaEntry.COLUMN_IDEA_IS_ARCHIVED,
DatabaseContract.IdeaEntry.COLUMN_IDEA_ORDER,
};
return new CursorLoader(this,
DatabaseContract.IdeaEntry.CONTENT_URI_IDEA,
projection,
null, // selection
null, // selectionArgs
DatabaseContract.IdeaEntry.COLUMN_IDEA_ORDER // order
);
}
That calls this section on my provider class
#Nullable
#Override
public Cursor query(#NonNull Uri uri, #Nullable String[] projection, #Nullable String selection, #Nullable String[] selectionArgs, #Nullable String sortOrder) {
SQLiteDatabase database = mDatabaseHelper.getReadableDatabase();
Cursor cursor;
int match = sUriMatcher.match(uri);
switch (match){
case IDEAS:
cursor = database.query(DatabaseContract.IdeaEntry.IDEA_TABLE_NAME, projection, selection, selectionArgs, null, null, sortOrder);
Is there a way? trigger another loader? or my implementation is wrong in this case? any way or help that direct me to the right direction, will be very appreciated.
With SQLiteQueryBuilder you can join tables in setTables method and then just specify label_body column of label table in projection.
String[] projection = {
DatabaseContract.IdeaEntry._ID,
....
DatabaseContract.LabelEntry.COLUMN_LABEL_BODY,
};
...
SQLiteQueryBuilder builder = new SQLiteQueryBuilder();
builder.setTables("IDEA JOIN LABEL ON IDEA.IDEA_LABEL = LABEL._ID");
builder.query(database, projection, selection, selectionArgs, null, null, sortOrder);
Thanks to #gar_r to help and guide me , I did like this with DatabaseContract constants:
#Override
public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
String[] projection = {
DatabaseContract.IdeaEntry.IDEA_TABLE_NAME + "." + DatabaseContract.IdeaEntry._ID,
DatabaseContract.IdeaEntry.COLUMN_IDEA_NAME,
DatabaseContract.IdeaEntry.COLUMN_IDEA_DESCRIPTION,
DatabaseContract.IdeaEntry.COLUMN_IDEA_DATE,
DatabaseContract.IdeaEntry.COLUMN_IDEA_LABEL,
DatabaseContract.IdeaEntry.COLUMN_IDEA_ICON,
DatabaseContract.IdeaEntry.COLUMN_IDEA_IS_ACTIVE,
DatabaseContract.IdeaEntry.COLUMN_IDEA_IS_FAVORITE,
DatabaseContract.IdeaEntry.COLUMN_IDEA_IS_DONE,
DatabaseContract.IdeaEntry.COLUMN_IDEA_IS_ARCHIVED,
DatabaseContract.IdeaEntry.COLUMN_IDEA_ORDER,
DatabaseContract.LabelEntry.COLUMN_LABEL_BODY,
};
return new CursorLoader(this,
DatabaseContract.IdeaEntry.CONTENT_URI_IDEA,
projection,
null, // selection
null, // selectionArgs
DatabaseContract.IdeaEntry.COLUMN_IDEA_ORDER // order
);
}
That calls this section on my provider class
#Nullable
#Override
public Cursor query(#NonNull Uri uri, #Nullable String[] projection, #Nullable String selection, #Nullable String[] selectionArgs, #Nullable String sortOrder) {
SQLiteDatabase database = mDatabaseHelper.getReadableDatabase();
Cursor cursor;
int match = sUriMatcher.match(uri);
switch (match){
case IDEAS:
SQLiteQueryBuilder builder = new SQLiteQueryBuilder();
builder.setTables(DatabaseContract.IdeaEntry.IDEA_TABLE_NAME + " JOIN " + DatabaseContract.LabelEntry.LABEL_TABLE_NAME
+ " ON " + DatabaseContract.IdeaEntry.COLUMN_IDEA_LABEL + " = " + DatabaseContract.LabelEntry.LABEL_TABLE_NAME + "." + DatabaseContract.LabelEntry._ID);
cursor = builder.query(database, projection, selection, selectionArgs, null, null, sortOrder);
break;
I have a BIG transactions table. I want to to find a specific field(card number) in transactions inserted in last one minute, Therefore it is not reasonable to search the entire table. So i want to search just in top 20 rows.
Here is the my code:
public boolean isCardTapedInLastMinute(String date, String time,String UID) {
String oneMinuteBefore = getOneMinuteBefore(time);
String tables = TRX.TABLE_NAME;
String[] columns = {TRX._ID};
String selection = TRX.COLUMN_NAME_TRX_DATE + " = ? AND " +
TRX.COLUMN_NAME_TRX_TIME + " >= ? AND " +
TRX.COLUMN_NAME_CARD_ID + " = ?";
String[] selectionArgs = {date, oneMinuteBefore, UID};
String sortOrder = TRX.COLUMN_NAME_TRX_DATE
+ BusDBContract.SORT_ORDER_DESC
+ ", "
+ TRX.COLUMN_NAME_TRX_TIME
+ BusDBContract.SORT_ORDER_DESC;
String limit = "1";
Cursor cursor = query(selection, selectionArgs, columns, tables, sortOrder, limit);
if (null == cursor) {
return false;
}
if (!cursor.moveToFirst()) {
cursor.close();
return false;
}
return true;
}
and the query method:
private Cursor queryWith(String selection, String[] selectionArgs, String[] columns, String tables, String sortOrder, String limit) {
SQLiteQueryBuilder builder = new SQLiteQueryBuilder();
builder.setTables(tables);
Cursor cursor;
try {
cursor = builder
.query(
mBusOH.getReadableDatabase(),
columns,
selection,
selectionArgs,
null,
null,
sortOrder,
limit);
} catch (SQLException e) {
Log.e(TAG, "[query]sql_exception: " + e.getMessage());
return null;
}
return cursor;
}
It is working correctly and it searches the entire table.
It takes about 50-100 ms to be performed for 15000 rows but it may be bigger and i want to optimize it by searching in top 20 rows.
What is the best way to do so?
EDIT: db scheme:
I have looked at this for a couple of days now and I completely can't work out why my content provider return 0 using the arguments I am passing it.
Here's my contentResolver code:
String[] expenditureProjection = {
BusinessOpsDatabase.COL_EXPEND_CAT_ID,
BusinessOpsDatabase.COL_EXPEND_DATE,
BusinessOpsDatabase.COL_EXPEND_AMOUNT,
BusinessOpsDatabase.COL_EXPEND_DESC,
BusinessOpsDatabase.COL_STERLING_EXCHANGE,
BusinessOpsDatabase.COL_COMPANY_ID,
BusinessOpsDatabase.CURRENCY_ID,
BusinessOpsDatabase.COL_MOD_DATE
};
// Defines a string to contain the selection clause
String selectionClause = null;
// An array to contain selection arguments
String[] selectionArgs = {expend_id.trim()};
selectionClause = BusinessOpsExpenditureProvider.EXPENDITURE_ID + "=?";
Log.d(TAG, expend_id+" Selected from list.");
Cursor expendCursor = getContentResolver().query(
BusinessOpsExpenditureProvider.CONTENT_URI, expenditureProjection, selectionClause, selectionArgs, null);
if (null == expendCursor) {
Log.d(TAG, "Expenditure cursor: Is null");
} else if (expendCursor.getCount() < 1) {
Log.d(TAG,"Expenditure cursor: Search was unsuccessful: "+expendCursor.getCount());
} else {
Log.d(TAG,"Expenditure cursor: Contains results");
int i=0;
expendCursor.moveToFirst();
// loop through cursor and populate country array
while (expendCursor.isAfterLast() == false)
{
expend_date_edit.setText(expendCursor.getString(1));
expend_amount_edit.setText(expendCursor.getString(3));
expend_desc_edit.setText(expendCursor.getString(4));
i++;
expendCursor.moveToNext();
}
}
Here's my content provider query method:
#Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
SQLiteDatabase db = mDB.getWritableDatabase();
// A convenience class to help build the query
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
qb.setTables(BusinessOpsDatabase.TABLE_EXPENDITURE);
switch (sURIMatcher.match(uri)) {
case EXPENDITURE:
if(selection != null && selectionArgs != null){
//values.get("company_contact");
String segment = uri.getLastPathSegment();
Log.d(TAG, "Last path segment: "+ segment);
String whereClause = BusinessOpsDatabase.EXPENDITURE_ID + "="+ selectionArgs[0];
Log.d(TAG, "Where clause: "+whereClause);
}
break;
case EXPENDITURE_ID:
// If this is a request for an individual status, limit the result set to that ID
qb.appendWhere(BusinessOpsDatabase.EXPENDITURE_ID + "=" + uri.getLastPathSegment());
break;
default:
throw new IllegalArgumentException("Unsupported URI: " + uri);
}
// Query the underlying database
Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, null);
// Notify the context's ContentResolver if the cursor result set changes
c.setNotificationUri(getContext().getContentResolver(), uri);
// Return the cursor to the result set
return c;
}
I'm printing the whereclause to the log and I see '_id=3' which should be fine because I have pulled off a copy of my SQLite database and I can see that the expenditure table has an _id 3 row in it. Any Ideas?
What an epic problem this has been. I found the error in my ContentResolver code.
selectionClause = BusinessOpsExpenditureProvider.EXPENDITURE_ID + "=?";
I was using the EXPENDITURE_ID variable from the provider rather than the database class. The line now reads.
selectionClause = BusinessOpsDatabase.EXPENDITURE_ID + "=?";
And works!
I am trying to get email ids of uses contacts. For that I am using Cursor Loader. There is one problem I am getting duplicate email ids also. How to remove email duplicacy. Should I use raw query "SELECT DISTINCT" instead of using CursorLoader or there is some other solution?
#Override
public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {
String[] projection = new String[] { ContactsContract.Contacts._ID, ContactsContract.Contacts.DISPLAY_NAME, ContactsContract.CommonDataKinds.Email.DATA};
String sortOrder = ContactsContract.Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC";
String selection = ContactsContract.Contacts.IN_VISIBLE_GROUP +"='1' AND " + Email.DATA +" IS NOT NULL AND " + Email.DATA +" != \"\" " ;
//showing only visible contacts
String[] selectionArgs = null;
return new CursorLoader(this, ContactsContract.CommonDataKinds.Email.CONTENT_URI, projection, selection, selectionArgs, sortOrder);
}
I recently ran into this problem. It appears that the CursorLoader does not have an implementation of "DISTINCT". My workaround adds a few lines to the onLoadFinish method and extends the BaseAdapter to accept a List parameter:
#Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
String projection[] = {
CommonDataKinds.Phone._ID,
CommonDataKinds.Phone.DISPLAY_NAME,
};
String select = "((" + CommonDataKinds.Phone.DISPLAY_NAME + " NOTNULL) and " + CommonDataKinds.Phone.HAS_PHONE_NUMBER + " > 0)";
String sort = CommonDataKinds.Phone.DISPLAY_NAME + " ASC";
CursorLoader loader = new CursorLoader(
mContext,
CommonDataKinds.Phone.CONTENT_URI,
projection,
select,
null,
sort
);
return loader;
}
#Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
List<String> displayNames = new ArrayList<String>();
cursor.moveToFirst();
while(!cursor.isAfterLast()){
String name = cursor.getString(cursor.getColumnIndex(CommonDataKinds.Phone.DISPLAY_NAME));
if(!displayNames.contains(name))
displayNames.add(name);
cursor.moveToNext();
}
mAdapter.swapCursor(displayNames);
}
Here is my BaseAdapter class:
public class AdapterAddContacts extends BaseAdapter{
private List<String> mData = new ArrayList<String>();
private Context mContext;
public AdapterAddContacts(Context context,List<String> displayNames){
mData = displayNames;
mContext = context;
}
#Override
public int getCount() {
if(mData != null)
return mData.size();
else
return 0;
}
#Override
public Object getItem(int pos) {
return mData.get(pos);
}
#Override
public long getItemId(int id) {
return id;
}
#Override
public View getView(int pos, View convertView, ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(mContext);
View view = inflater.inflate(R.layout.entry_add_contacts,parent,false);
String data = mData.get(pos);
TextView textName = (TextView)view.findViewById(R.id.my_contacts_add_display_name);
textName.setText(data);
textName.setTag(data);
return view;
}
public void swapCursor(List<String> displayNames){
mData = displayNames;
this.notifyDataSetChanged();
}
You should be able to modify this specifically for your needs.
Inspired by #mars, I have a solution that does not need a modification of the adapter. The idea is to delete the duplicates of the cursor; as there is no way to do it, we create a new cursor whithout the duplicates.
All the code is in onLoadFinished:
#Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
MatrixCursor newCursor = new MatrixCursor(PROJECTION); // Same projection used in loader
if (cursor.moveToFirst()) {
String lastName = "";
do {
if (cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME)).compareToIgnoreCase(lastName) != 0) {
newCursor.addRow(new Object[]{cursor.getString(0), cursor.getString(1), cursor.getString(2) ...}); // match the original cursor fields
lastName =cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
}
} while (cursor.moveToNext());
}
mContactsAdapter.swapCursor(newCursor);
}
I used a small hack in my project - an SQL injection, like that:
#Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new CursorLoader(
this,
MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
new String[] {
"DISTINCT "+ MediaStore.Images.Media.BUCKET_ID,
MediaStore.Images.Media.BUCKET_DISPLAY_NAME},
null, null, null);
}
This code returns only bundle names and their IDs from Gallery.
So, I'd rewrite your code like that:
#Override
public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {
String[] projection = new String[] {
"DISTINCT " + ContactsContract.Contacts._ID,
ContactsContract.Contacts.DISPLAY_NAME,
ContactsContract.CommonDataKinds.Email.DATA};
String sortOrder = ContactsContract.Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC";
String selection = ContactsContract.Contacts.IN_VISIBLE_GROUP +"='1' AND " + Email.DATA +" IS NOT NULL AND " + Email.DATA +" != \"\" " ;
//showing only visible contacts
String[] selectionArgs = null;
return new CursorLoader(this, ContactsContract.CommonDataKinds.Email.CONTENT_URI, projection, selection, selectionArgs, sortOrder);
}
You can put setDistinct in your content provider.
#Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
...
final SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
qb.setDistinct(true);
If you are worried about performance and don't want to play around with cursor again in onLoadFinished(), then there is a small hack
I combined following two solutions from SO.
select distinct value in android sqlite
CursorLoader with rawQuery
And here is my working solution:
#Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
String tableName;
/*
* Choose the table to query and a sort order based on the code returned
* for the incoming URI.
*/
switch (uriMatcher.match(uri)) {
case NOTIFICATION:
tableName = NOTIFICATIONS_TABLE_NAME;
break;
case NOTIFICATION_TIMESTAMP:
Cursor cursor = db.query(true, NOTIFICATIONS_TABLE_NAME, projection, selection, selectionArgs, TIMESTAMP, null, sortOrder, null);
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
case DOWNLOAD:
tableName = DOWNLOADS_TABLE;
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
if (selection != null) {
selection = selection + "=?";
}
Cursor cursor = db.query(tableName, projection, selection, selectionArgs, null, null, sortOrder);
// Tell the cursor what uri to watch, so it knows when its source data
// changes
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
If you see in this case Table name is same is first 2 cases but i created a dummy Uri to achieve this. May not be a very good approach but works perfectly.
I found a solution
Use DISTINCT keyword in selection Array.
String[] projection = new String[] { ContactsContract.Contacts._ID, ContactsContract.Contacts.DISPLAY_NAME, "DISTINCT" + ContactsContract.CommonDataKinds.Email.DATA};