ContentProvider: cursor object null when trying to acces data with ContentResolver

ContentProvider: cursor object null when trying to acces data with ContentResolver - android

I'm trying to share some data between my apps using ContentProvider. I have a problem with accessing the data with resolver in the second app: Cursor object is null after query. Can't figure out where I made a mistake in the code so I'm asking for help. Code of the first app which provides the data :
Provider in manifest :
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.piotr.planer">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name=".BroadcastEvent" />
<provider
android:authorities="com.example.piotr.planer.PlansProvider"
android:name=".PlansProvider"
android:exported="true"
android:multiprocess="true" >
</provider>
</application>
Provider class:
package com.example.piotr.planer;
public class PlansProvider extends ContentProvider {
// Unique namespace for provider
static final String PROVIDER_NAME = "com.example.piotr.planer.PlansProvider";
static final String URL = "content://" + PROVIDER_NAME + "/cpplans";
static final Uri CONTENT_URL = Uri.parse(URL);
// Defining columns in database
static final String id = "id";
static final String name = "name";
static final String date = "date";
static final int uriCode = 1;
private static HashMap<String, String> values;
// UriMatcher matches our unique Uris with our ContentProviders
static final UriMatcher uriMatcher;
// assigning these unique Uris
static {
uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
uriMatcher.addURI(PROVIDER_NAME, "cpplans", uriCode);
}
// Defining database
private SQLiteDatabase sqlDB;
static final String DATABASE_NAME = "myPlans";
static final String TABLE_NAME = "plans";
static final int DATABASE_VERSION = 1;
static final String CREATE_DB_TABLE = "CREATE TABLE " + TABLE_NAME +
" (id INTEGER PRIMARY KEY AUTOINCREMENT, " +
" name TEXT NOT NULL, " +
" date INTEGER);";
#Override
public boolean onCreate() {
// Creates Database
DatabaseHelper dbHelper = new DatabaseHelper(getContext());
sqlDB = dbHelper.getWritableDatabase();
if (sqlDB != null) {
return true;
}
return false;
}
#Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables(TABLE_NAME);
switch (uriMatcher.match(uri)) {
case uriCode:
queryBuilder.setProjectionMap(values);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
Cursor cursor = queryBuilder.query(sqlDB, projection, selection, selectionArgs, null, null, sortOrder);
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
#Override
public String getType(Uri uri) {
switch (uriMatcher.match(uri)) {
case uriCode:
return "vnd.android.cursor.dir/cpplans";
default:
throw new IllegalArgumentException("Unsupported URI " + uri);
}
}
#Override
public Uri insert(Uri uri, ContentValues values) {
long rowID = sqlDB.insert(TABLE_NAME, null, values);
if (rowID > 0) {
Uri _uri = ContentUris.withAppendedId(CONTENT_URL, rowID);
getContext().getContentResolver().notifyChange(_uri, null);
return uri;
} else {
Toast.makeText(getContext(), "Row insert failed", Toast.LENGTH_SHORT).show();
return null;
}
}
#Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
int rowsDeleted = 0;
switch (uriMatcher.match(uri)) {
case uriCode:
rowsDeleted = sqlDB.delete(TABLE_NAME, selection, selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return rowsDeleted;
}
#Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
int rowsUpdated = 0;
switch (uriMatcher.match(uri)) {
case uriCode:
rowsUpdated = sqlDB.update(TABLE_NAME, values, selection, selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return rowsUpdated;
}
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase sqlDB) {
sqlDB.execSQL(CREATE_DB_TABLE);
}
#Override
public void onUpgrade(SQLiteDatabase sqlDB, int oldVersion, int newVersion) {
sqlDB.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
onCreate(sqlDB);
}
}
}
The addPlanToProviderFunction() method:
private void addPlanToProvider(long timeInMillis, String eventName) {
ContentValues values = new ContentValues();
values.put(PlansProvider.name, eventName);
values.put(PlansProvider.date, timeInMillis);
Uri uri = mContext.getContentResolver().insert(PlansProvider.CONTENT_URL, values);
}
The class in the second app where I want to get the data:
package com.example.piotr.zadaniowiec;
public class PlanList extends AppCompatActivity {
static final Uri CONTENT_URL = Uri.parse("content://com.example.piotr.planer.PlansProvider.cpplans");
ContentResolver resolver;
TextView planListTextView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_plans_list);
planListTextView = findViewById(R.id.plan_list_text_view);
resolver = getContentResolver();
getPlans();
}
private void getPlans() {
String[] projection = new String[]{"id", "name", "date"};
Cursor cursor = resolver.query(CONTENT_URL, projection, null, null, null);
String planList = "";
if (cursor.moveToNext()) { // I get an error here
do {
String id = cursor.getString(cursor.getColumnIndex("id"));
String name = cursor.getString(cursor.getColumnIndex("name"));
long date = cursor.getLong(cursor.getColumnIndex("date"));
planList = planList + id + name + date + "\n";
} while (cursor.moveToNext());
}
planListTextView.setText(planList);
}
}
I get :
"NullPointerException: Attempt to invoke interface method 'boolean android.database.Cursor.moveToNext()' on a null object reference."
Thanks anyone for the help.

Your CONTENT_URL is in the wrong format - you need a / after the authority, not a .
static final Uri CONTENT_URL =
Uri.parse("content://com.example.piotr.planer.PlansProvider/cpplans");
As it is now, you're looking for the root path for a ContentProvider that has an authority of com.example.piotr.planer.PlansProvider.cpplans, which doesn't exist, hence the null Cursor.

Related

Got Unknown URL content in Android

I am new to Android. I wanted to practice my knowledge about Content Provide, but my app somehow crush and tell me there is an unknown URL content. I try to search for solution but still can't fix the problem...
The logcat message:
2020-05-25 20:10:24.547 15120-15120/com.example.punchinandout E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.punchinandout, PID: 15120
java.lang.IllegalArgumentException: Unknown URL content://com.example.punchinandout.data/time
at android.content.ContentResolver.insert(ContentResolver.java:1535)
at com.example.punchinandout.MainActivity$1.onClick(MainActivity.java:65)
at android.view.View.performClick(View.java:6256)
at android.view.View$PerformClick.run(View.java:24701)
at android.os.Handler.handleCallback(Handler.java:789)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6541)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
My provider in Mainifest:
<provider
android:authorities="com.example.punchinandout"
android:name=".data.TimeProvider"
android:exported="false"/>
My Content Provider class:
package com.example.punchinandout.data;
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.util.Log;
import com.example.punchinandout.data.TimeContract.TimeEntry;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
public class TimeProvider extends ContentProvider {
private static final String TAG = TimeProvider.class.toString();
private static final int TIME = 100;
private static final int TIME_ID = 101;
private static final UriMatcher sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
//Determine which content URI we have.
static{
sUriMatcher.addURI(TimeContract.CONTENT_AUTHORITY, TimeContract.CONTENT_PATH, TIME);
sUriMatcher.addURI(TimeContract.CONTENT_AUTHORITY, TimeContract.CONTENT_PATH, TIME_ID);
}
private TimeHelper mDbHelper;
#Override
public boolean onCreate() {
mDbHelper = new TimeHelper(getContext());
return true;
}
#Nullable
#Override
public Cursor query(#NonNull Uri uri, #Nullable String[] projection, #Nullable String selection, #Nullable String[] selectionArgs, #Nullable String sortOrder) {
SQLiteDatabase database = mDbHelper.getReadableDatabase();
Cursor cursor;
int match = sUriMatcher.match(uri);
switch (match){
case TIME:
cursor = database.query(TimeEntry.TABLE_NAME, projection, selection, selectionArgs, null, null, sortOrder);
break;
case TIME_ID:
selection = TimeEntry._ID + "=?";
selectionArgs = new String[]{String.valueOf(ContentUris.parseId(uri))};
cursor = database.query(TimeEntry.TABLE_NAME, projection, selection, selectionArgs, null, null, sortOrder);
break;
default:
throw new IllegalArgumentException("Cannot query with unknown URI: " + uri);
}
cursor.setNotificationUri(getContext().getContentResolver(), uri); //Set notification URI on cursor, so that the cursor will update when the URI is updated.
return cursor;
}
#Nullable
#Override
public Uri insert(#NonNull Uri uri, #Nullable ContentValues values) {
int match = sUriMatcher.match(uri);
switch (match){
case TIME:
return insertTimeRecord(uri, values);
default:
throw new IllegalArgumentException("Insertion is no support for " + uri);
}
}
private Uri insertTimeRecord(Uri uri, ContentValues values){
//Sanity check
if (values.containsKey(TimeEntry.COLUMN_RECORD)){
String time_record = values.getAsString(TimeEntry.COLUMN_RECORD);
if (time_record == null){
throw new IllegalArgumentException("Time record cannot be empty.");
}
}
//If there are no values to update, then don't try to update the database.
if (values.size() == 0){
return null;
}
SQLiteDatabase database = mDbHelper.getWritableDatabase();
long newRowId = database.insert(TimeEntry.TABLE_NAME, null, values);
//Check if the insertion is success.
if (newRowId == -1){
Log.e(TAG, "Insertion fail with " + uri);
return null;
}
getContext().getContentResolver().notifyChange(uri, null); //Notify all listener the data has changed
return ContentUris.withAppendedId(uri, newRowId);
}
#Override
public int update(#NonNull Uri uri, #Nullable ContentValues values, #Nullable String selection, #Nullable String[] selectionArgs) {
int match = sUriMatcher.match(uri);
switch (match){
case TIME:
return updateTimeRecord(uri, values, selection, selectionArgs);
case TIME_ID:
selection = TimeEntry._ID + "=?";
selectionArgs = new String[]{String.valueOf(ContentUris.parseId(uri))};
return updateTimeRecord(uri, values, selection, selectionArgs);
default:
throw new IllegalArgumentException("Update fail with " + uri);
}
}
private int updateTimeRecord(Uri uri, ContentValues values, String selection, String[] selectionArgs){
//Sanity check
if (values.containsKey(TimeEntry.COLUMN_RECORD)){
String time_record = values.getAsString(TimeEntry.COLUMN_RECORD);
if (time_record == null){
return 0; //If the data is not inputted, update nothing in database.
}
}
//If there are no values to update, then don't try to update the database.
if (values.size() == 0){
return 0;
}
SQLiteDatabase database = mDbHelper.getWritableDatabase();
int rowUpdated = database.update(TimeEntry.TABLE_NAME, values, selection, selectionArgs);
if (rowUpdated != 0){
getContext().getContentResolver().notifyChange(uri, null); //Notify all listener the data has changed
}
return rowUpdated;
}
#Override
public int delete(#NonNull Uri uri, #Nullable String selection, #Nullable String[] selectionArgs) {
int match = sUriMatcher.match(uri);
switch (match){
case TIME:
return deleteTimeRecord(uri, selection, selectionArgs);
case TIME_ID:
selection = TimeEntry._ID + "=?";
selectionArgs = new String[]{String.valueOf(ContentUris.parseId(uri))};
return deleteTimeRecord(uri, selection, selectionArgs);
default:
throw new IllegalArgumentException("Delete fail with " + uri);
}
}
private int deleteTimeRecord(Uri uri, String selection, String[] selectionArgs){
SQLiteDatabase database = mDbHelper.getWritableDatabase();
int rowDelected = database.delete(TimeEntry.TABLE_NAME, selection, selectionArgs);
if (rowDelected != 0){
getContext().getContentResolver().notifyChange(uri, null); //Notify all listener the data has changed
}
return rowDelected;
}
#Nullable
#Override
public String getType(#NonNull Uri uri) {
int match = sUriMatcher.match(uri);
switch (match){
case TIME:
return TimeEntry.CONTENT_LIST_TYPE;
case TIME_ID:
return TimeEntry.CONTENT_ITEM_TYPE;
default:
throw new IllegalArgumentException("Unknown URI " + uri + " with match " + match);
}
}
}
My Contract class:
package com.example.punchinandout.data;
import android.content.ContentResolver;
import android.net.Uri;
import android.provider.BaseColumns;
public class TimeContract {
private TimeContract(){};
public static final String CONTENT_AUTHORITY = "com.example.punchinandout.data";
public static final Uri BASE_CONTENT_URI = Uri.parse("content://" + CONTENT_AUTHORITY);
public static final String CONTENT_PATH = "time";
public static final class TimeEntry implements BaseColumns {
public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, CONTENT_PATH);
//MIME type of all records.
public static final String CONTENT_LIST_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE + "/" + CONTENT_AUTHORITY + "/" + CONTENT_PATH;
//MIME type of single record.
public static final String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/" + CONTENT_AUTHORITY + "/" + CONTENT_PATH;
public static final String TABLE_NAME = "time";
public static final String _ID = BaseColumns._ID;
public static final String COLUMN_RECORD = "record";
}
}
Can someone help me? :(

I have fixed the problem!!
My provider in Mainifest is that:
<provider
android:authorities="com.example.punchinandout"
android:name=".data.TimeProvider"
android:exported="false"/>
And I change to :
<provider
android:authorities="com.example.punchinandout.data"
android:name=".data.TimeProvider"
android:exported="false"/>
Let the authorities be the same as the authority in Contract class and the problem is fixed!
Sorry for not placed the Mainifest in the question at first time as I had no idea where the problem in my app before.

Attempt to invoke interface method 'int android.database.Cursor.getCount()' on a null object reference [duplicate]

This question already has answers here:
java.lang.NullPointerException: Attempt to invoke interface method 'boolean android.database.Cursor.moveToFirst()' on a null object reference [duplicate]
(1 answer)
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 2 years ago.
I do have a problem that gives me a headache. I store some images of my city in the sqlite database via a custom content provider. However when I run my app I get a null cursor.
Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'int android.database.Cursor.getCount()' on a null object reference
at theo.testing.androidcustomloaders.fragments.MainActivityFragment.onActivityCreated(MainActivityFragment.java:74)
at android.support.v4.app.Fragment.performActivityCreated(Fragment.java:2089)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1133)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1290)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:801)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1677)
at android.support.v4.app.FragmentController.execPendingActions(FragmentController.java:388)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:604)
at android.support.v7.app.AppCompatActivity.onStart(AppCompatActivity.java:178)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1220)
at android.app.Activity.performStart(Activity.java:5992)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2358) 
at android.app.ActivityThread.access$800(ActivityThread.java:144) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:135) 
at android.app.ActivityThread.main(ActivityThread.java:5219) 
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:898) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693) 
That would mean the the info are not stored correctly or the Uri of my provider is somehow faulty. So.
MyCityContract
public class MyCityContract {
public static final String CONTENT_AUTHORITY = "theo.testing.customloaders";
public static final Uri BASE_CONTENT_URI = Uri.parse("content://" + CONTENT_AUTHORITY);
public static final class MyCityEntry implements BaseColumns{
//table name
public static final String TABLE_MY_CITY = "my_city";
//columns
public static final String _ID = "_id";
public static final String COLUMN_NAME = "name";
public static final String COLUMN_ICON = "icon";
// create content uri
public static final Uri CONTENT_URI = BASE_CONTENT_URI.buildUpon()
.appendPath(TABLE_MY_CITY).build();
// create cursor of base type directory for multiple entries
public static final String CONTENT_DIR_TYPE =
ContentResolver.CURSOR_DIR_BASE_TYPE + "/" + CONTENT_AUTHORITY + "/" + TABLE_MY_CITY;
// create cursor of base type item for single entry
public static final String CONTENT_ITEM_TYPE =
ContentResolver.CURSOR_ITEM_BASE_TYPE +"/" + CONTENT_AUTHORITY + "/" + TABLE_MY_CITY;
// for building URIs on insertion
public static Uri buildFlavorsUri(long id){
return ContentUris.withAppendedId(CONTENT_URI, id);
}
}
}
MyCityDbHelper
public class MyCityDbHelper extends SQLiteOpenHelper{
public static final String LOG_TAG = MyCityDbHelper.class.getSimpleName();
//name & version
public static final String DATABASE_NAME = "city.db";
public static final int DATABASE_VERSION = 4;
// Create the database
public MyCityDbHelper(Context context) {
super(context, DATABASE_NAME,null,DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
final String SQL_CREATE_MY_CITY_TABLE = "CREATE TABLE " +
MyCityContract.MyCityEntry.TABLE_MY_CITY + "(" + MyCityContract.MyCityEntry._ID +
" INTEGER PRIMARY KEY AUTOINCREMENT, " +
MyCityContract.MyCityEntry.COLUMN_NAME + " TEXT NOT NULL, " +
MyCityContract.MyCityEntry.COLUMN_ICON + " INTEGER NOT NULL);";
sqLiteDatabase.execSQL(SQL_CREATE_MY_CITY_TABLE);
}
#Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
Log.w(LOG_TAG, "Upgrading database from version " + oldVersion + " to " +
newVersion + ". OLD DATA WILL BE DESTROYED");
// Drop the table
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + MyCityContract.MyCityEntry.TABLE_MY_CITY);
sqLiteDatabase.execSQL("DELETE FROM SQLITE_SEQUENCE WHERE NAME = '" +
MyCityContract.MyCityEntry.TABLE_MY_CITY + "'");
// re-create database
onCreate(sqLiteDatabase);
}
}
MyCityProvider
public class MyCityProvider extends ContentProvider {
private static final String LOG_TAG = MyCityProvider.class.getSimpleName();
private static final UriMatcher sUriMatcher = buildUriMatcher();
private MyCityDbHelper myCityDbHelper;
//Codes for UriMatcher
private static final int MY_CITY = 100;
private static final int MY_CITY_WITH_ID = 200;
private static UriMatcher buildUriMatcher(){
// Build a UriMatcher by adding a specific code to return based on a match
// It's common to use NO_MATCH as the code for this case.
final UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
final String authority = MyCityContract.CONTENT_AUTHORITY;
//add code for each URI
matcher.addURI(authority,MyCityContract.MyCityEntry.TABLE_MY_CITY,MY_CITY);
matcher.addURI(authority,MyCityContract.MyCityEntry.TABLE_MY_CITY + "/#",MY_CITY_WITH_ID);
return matcher;
}
#Override
public boolean onCreate() {
myCityDbHelper = new MyCityDbHelper(getContext());
return true;
}
#Override
public String getType(Uri uri) {
final int match = sUriMatcher.match(uri);
switch (match){
case MY_CITY: {
return MyCityContract.MyCityEntry.CONTENT_DIR_TYPE;
}
case MY_CITY_WITH_ID:{
return MyCityContract.MyCityEntry.CONTENT_ITEM_TYPE;
}
default:{
throw new UnsupportedOperationException("Unknown uri: " + uri);
}
}
}
#Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder){
Cursor retCursor;
switch(sUriMatcher.match(uri)){
// All Flavors selected
case MY_CITY:{
retCursor = myCityDbHelper.getReadableDatabase().query(
MyCityContract.MyCityEntry.TABLE_MY_CITY,
projection,
selection,
selectionArgs,
null,
null,
sortOrder);
return retCursor;
}
// Individual flavor based on Id selected
case MY_CITY_WITH_ID:{
retCursor = myCityDbHelper.getReadableDatabase().query(
MyCityContract.MyCityEntry.TABLE_MY_CITY,
projection,
MyCityContract.MyCityEntry._ID + " = ?",
new String[] {String.valueOf(ContentUris.parseId(uri))},
null,
null,
sortOrder);
return retCursor;
}
default:{
// By default, we assume a bad URI
throw new UnsupportedOperationException("Unknown uri: " + uri);
}
}
}
#Override
public Uri insert(Uri uri, ContentValues contentValues) {
final SQLiteDatabase db = myCityDbHelper.getWritableDatabase();
Uri returnUri;
switch (sUriMatcher.match(uri)){
case MY_CITY:
long _id = db.insert(MyCityContract.MyCityEntry.TABLE_MY_CITY,null,contentValues);
Log.d("id",String.valueOf(_id));
// insert unless it is already contained in the database
if(_id>0){
returnUri = MyCityContract.MyCityEntry.buildFlavorsUri(_id);
}else {
throw new android.database.SQLException("Failed to insert row into: " + uri);
}
break;
default: {
throw new UnsupportedOperationException("Unknown uri: " + uri );
}
}
getContext().getContentResolver().notifyChange(uri,null);
return returnUri;
}
#Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
final SQLiteDatabase db = myCityDbHelper.getWritableDatabase();
final int match = sUriMatcher.match(uri);
int numDeleted;
switch(match){
case MY_CITY:
numDeleted = db.delete(
MyCityContract.MyCityEntry.TABLE_MY_CITY, selection, selectionArgs);
// reset _ID
db.execSQL("DELETE FROM SQLITE_SEQUENCE WHERE NAME = '" +
MyCityContract.MyCityEntry.TABLE_MY_CITY + "'");
break;
case MY_CITY_WITH_ID:
numDeleted = db.delete(MyCityContract.MyCityEntry.TABLE_MY_CITY,
MyCityContract.MyCityEntry._ID + " = ?",
new String[]{String.valueOf(ContentUris.parseId(uri))});
// reset _ID
db.execSQL("DELETE FROM SQLITE_SEQUENCE WHERE NAME = '" +
MyCityContract.MyCityEntry.TABLE_MY_CITY + "'");
break;
default:
throw new UnsupportedOperationException("Unknown uri: " + uri);
}
return numDeleted;
}
#Override
public int bulkInsert(Uri uri, ContentValues[] values){
final SQLiteDatabase db = myCityDbHelper.getWritableDatabase();
final int match = sUriMatcher.match(uri);
switch(match){
case MY_CITY:
// allows for multiple transactions
db.beginTransaction();
// keep track of successful inserts
int numInserted = 0;
try{
for(ContentValues value : values){
if (value == null){
throw new IllegalArgumentException("Cannot have null content values");
}
long _id = -1;
try{
_id = db.insertOrThrow(MyCityContract.MyCityEntry.TABLE_MY_CITY,
null, value);
}catch(SQLiteConstraintException e) {
Log.w(LOG_TAG, "Attempting to insert " +
value.getAsString(
MyCityContract.MyCityEntry.COLUMN_NAME)
+ " but value is already in database.");
}
if (_id != -1){
numInserted++;
}
}
if(numInserted > 0){
// If no errors, declare a successful transaction.
// database will not populate if this is not called
db.setTransactionSuccessful();
}
} finally {
// all transactions occur at once
db.endTransaction();
}
if (numInserted > 0){
// if there was successful insertion, notify the content resolver that there
// was a change
getContext().getContentResolver().notifyChange(uri, null);
}
return numInserted;
default:
return super.bulkInsert(uri, values);
}
}
#Override
public int update(Uri uri, ContentValues contentValues, String selection, String[] selectionArgs){
final SQLiteDatabase db = myCityDbHelper.getWritableDatabase();
int numUpdated = 0;
if (contentValues == null){
throw new IllegalArgumentException("Cannot have null content values");
}
switch(sUriMatcher.match(uri)){
case MY_CITY:{
numUpdated = db.update(MyCityContract.MyCityEntry.TABLE_MY_CITY,
contentValues,
selection,
selectionArgs);
break;
}
case MY_CITY_WITH_ID: {
numUpdated = db.update(MyCityContract.MyCityEntry.TABLE_MY_CITY,
contentValues,
MyCityContract.MyCityEntry._ID + " = ?",
new String[] {String.valueOf(ContentUris.parseId(uri))});
break;
}
default:{
throw new UnsupportedOperationException("Unknown uri: " + uri);
}
}
if (numUpdated > 0){
getContext().getContentResolver().notifyChange(uri, null);
}
return numUpdated;
}
}
MainActivityFragment
public class MainActivityFragment extends Fragment implements LoaderManager.LoaderCallbacks<Cursor>{
private static final String LOG_TAG = MainActivityFragment.class.getSimpleName();
private MyCityAdpapter myCityAdpapter;
private static final int CURSOR_LOADER_ID = 0;
private GridView mGridView;
MyCity[] mMyCity = {
new MyCity("Ancient Theatre - Larisa", R.drawable.larissa1),
new MyCity("Ancient Theatre - Larisa", R.drawable.larissa2),
new MyCity("Municipality park", R.drawable.larissa3),
new MyCity("Municipality park", R.drawable.larissa4),
new MyCity("Old trains",R.drawable.larissa5),
new MyCity("Old trains",R.drawable.larissa6),
new MyCity("Church",
R.drawable.larissa7),
new MyCity("Church",
R.drawable.larissa8),
new MyCity("Alcazar park",
R.drawable.larissa9),
new MyCity("Alcazar park",
R.drawable.larissa10),
new MyCity("AEL FC Arena",
R.drawable.larissa11),
new MyCity("AEL FC Arena",
R.drawable.larissa12),
new MyCity("Larissa Fair",
R.drawable.larissa13),
new MyCity("Larissa Fair",
R.drawable.larissa14),
new MyCity("Larissa Fair",
R.drawable.larissa15),
new MyCity("Larissa Fair",
R.drawable.larissa16)
};
public MainActivityFragment() {
// Required empty public constructor
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
Cursor c =
getActivity().getContentResolver().query(MyCityContract.MyCityEntry.CONTENT_URI,
new String[]{MyCityContract.MyCityEntry._ID},
null,
null,
null);
if (c.getCount() == 0){
insertData();
}
// initialize loader
getLoaderManager().initLoader(CURSOR_LOADER_ID, null, this);
super.onActivityCreated(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
// inflate fragment_main layout
final View rootView = inflater.inflate(R.layout.fragment_main_activity, container, false);
// initialize our FlavorAdapter
myCityAdpapter = new MyCityAdpapter(getActivity(), null, 0, CURSOR_LOADER_ID);
// initialize mGridView to the GridView in fragment_main.xml
mGridView = (GridView) rootView.findViewById(R.id.flavors_grid);
// set mGridView adapter to our CursorAdapter
mGridView.setAdapter(myCityAdpapter);
return rootView;
}
// insert data into database
public void insertData(){
ContentValues[] cityValuesArr = new ContentValues[mMyCity.length];
// Loop through static array of MyCity, add each to an instance of ContentValues
// in the array of ContentValues
for(int i = 0; i < mMyCity.length; i++){
cityValuesArr[i] = new ContentValues();
cityValuesArr[i].put(MyCityContract.MyCityEntry.COLUMN_ICON, mMyCity[i].image);
cityValuesArr[i].put(MyCityContract.MyCityEntry.COLUMN_NAME,
mMyCity[i].name);
}
// bulkInsert our ContentValues array
getActivity().getContentResolver().bulkInsert(MyCityContract.MyCityEntry.CONTENT_URI,
cityValuesArr);
}
#Override
public Loader<Cursor> onCreateLoader(int id, Bundle args){
return new CursorLoader(getActivity(),
MyCityContract.MyCityEntry.CONTENT_URI,
null,
null,
null,
null);
}
#Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
myCityAdpapter.swapCursor(data);
}
#Override
public void onLoaderReset(Loader<Cursor> loader){
myCityAdpapter.swapCursor(null);
}
}
I read the Cursor inside the onCreateView(...) method of my Fragment
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
Cursor c =
getActivity().getContentResolver().query(MyCityContract.MyCityEntry.CONTENT_URI,
new String[]{MyCityContract.MyCityEntry._ID},
null,
null,
null);
if (c.getCount() == 0){
insertData();
}
// initialize loader
getLoaderManager().initLoader(CURSOR_LOADER_ID, null, this);
super.onActivityCreated(savedInstanceState);
}
and this is where I am thrown the null Cursor exception.
Any ideas?
Thanks,
Theo.
EDIT
I changed this if condition from
if (c.getCount() == 0){
insertData();
}
to
if (c == null){
insertData();
}
and I am getting this exception!
Caused by: java.lang.IllegalArgumentException: Unknown URL content://theo.testing.customloaders/my_city
So there is be an error with provider. hmm...

I think you has a problem at using getActivity in onActivityCreated in your MainActivity Fragment
getActivity "might" return null if called from within onActivityCreated...especially during a configuration change like orientation change because the activity gets destroyed...
move that initialization to onAttach...
following link helped me to find out
getActivity return null in fragment onActivityCreated in some rooted device

Ok. I fixed it. All I did was changing my authority name from
theo.testing.customloaders
to
theo.testing.customloaders.app

Failed to find provider info error

I am trying to have a contentprovider , but I am having trouble because I am getting an error of "Failed to find provider info for com.example.alex.hopefulyworks"
Here is the manifest and the contentprovider
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.alex.hopefulythisworks" >
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<provider android:name=".ColorContentProvider"
android:authorities="com.example.alex.hopefulythisworks.ColorContentProvider"
android:enabled="true"
android:exported="true" >
</provider>
</application>
</manifest>
package com.example.alex.hopefulythisworks;
....
public class ColorContentProvider extends ContentProvider {
private ColorHelper database;
private static final String AUTHORITY
= "com.example.alex.hopefulythisworks";
private static final String BASE_PATH
= "tasks";
public static final Uri CONTENT_URI
= Uri.parse("content://" + AUTHORITY + "/" + BASE_PATH);
public static final String CONTENT_URI_PREFIX
= "content://" + AUTHORITY + "/" + BASE_PATH + "/";
private static final UriMatcher sURIMatcher =
new UriMatcher(UriMatcher.NO_MATCH);
private static final int COLOR = 1;
private static final int COLOR_ROW = 2;
static {
sURIMatcher.addURI(AUTHORITY, BASE_PATH, COLOR);
sURIMatcher.addURI(AUTHORITY, BASE_PATH + "/#", COLOR_ROW);
}
#Override
public boolean onCreate() {
database = new ColorHelper(getContext());
Log.d("contentprovider" , "inside content provider oncreate ");
return false;
}
#Override
public Uri insert(Uri uri, ContentValues values) {
int uriType = sURIMatcher.match(uri);
SQLiteDatabase sqlDB = database.getWritableDatabase();
long id = 0;
switch (uriType) {
case COLOR:
id = sqlDB.insert(ColorTable.TABLE_TASK,
null, values);
break;
default:
throw new IllegalArgumentException("Unknown URI: "
+ uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return Uri.parse( CONTENT_URI_PREFIX + id);
}
#Override
public String getType(Uri uri) {
return null;
}
#Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
// check if the caller has requested a column which does not exists
ColorTable.validateProjection( projection );
// Using SQLiteQueryBuilder instead of query() method
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables( ColorTable.TABLE_TASK );
switch ( sURIMatcher.match(uri) ) {
case COLOR:
break;
case COLOR_ROW:
// add the task ID to the original query
queryBuilder.appendWhere( ColorTable.COLUMN_ID + "=" + uri.getLastPathSegment() );
break;
default:
throw new IllegalArgumentException("Invalid URI: " + uri);
}
System.out.println("before null check");
if(database == null){
System.out.println("database is null");
database = new ColorHelper(getContext());
}
System.out.println("after null check");
SQLiteDatabase db = database.getWritableDatabase();
Cursor cursor = queryBuilder.query( db, projection, selection,
selectionArgs, null, null, sortOrder);
// notify listeners
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
#Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
SQLiteDatabase sqlDB = database.getWritableDatabase();
int rowsDeleted = 0;
switch ( sURIMatcher.match(uri) ) {
case COLOR:
rowsDeleted = sqlDB.delete(ColorTable.TABLE_TASK, selection, selectionArgs);
break;
case COLOR_ROW:
String id = uri.getLastPathSegment();
if (TextUtils.isEmpty(selection)) {
rowsDeleted = sqlDB.delete( ColorTable.TABLE_TASK,
ColorTable.COLUMN_ID + "=" + id,
null);
} else {
rowsDeleted = sqlDB.delete( ColorTable.TABLE_TASK,
ColorTable.COLUMN_ID + "=" + id
+ " and " + selection,
selectionArgs);
}
break;
default:
throw new IllegalArgumentException("Invalid URI: " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return rowsDeleted;
}
#Override
public int update(Uri uri, ContentValues values, String selection , String[] selectionArgs) {
SQLiteDatabase sqlDB = database.getWritableDatabase();
int rowsUpdated = 0;
switch ( sURIMatcher.match(uri) ) {
case COLOR:
rowsUpdated = sqlDB.update( ColorTable.TABLE_TASK,
values,
selection,
selectionArgs);
break;
case COLOR_ROW:
String id = uri.getLastPathSegment();
if (TextUtils.isEmpty(selection)) {
rowsUpdated = sqlDB.update( ColorTable.TABLE_TASK,
values,
ColorTable .COLUMN_ID + "=" + id,
null );
} else {
rowsUpdated = sqlDB.update( ColorTable.TABLE_TASK,
values,
ColorTable.COLUMN_ID + "=" + id
+ " and " + selection,
selectionArgs);
}
break;
default:
throw new IllegalArgumentException("Invalid URI: " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return rowsUpdated;
}
}

authorities need to have only the package name, and name is the complete package and class name.
<provider android:name="com.example.alex.hopefulythisworks.ColorContentProvider"
android:authorities="com.example.alex.hopefulythisworks"
android:enabled="true"
android:exported="true" >
</provider>
Remember that this needs to match the same that you're using to build the Uri:
private static final String AUTHORITY = "com.example.alex.hopefulythisworks";
Android docs

android:authorities="com.example.alex.hopefulythisworks.ColorContentProvider"
should be the same as
private static final String AUTHORITY
= "com.example.alex.hopefulythisworks";
so another solution is replace AUTHORITY to
private static final String AUTHORITY
= "com.example.alex.hopefulythisworks.ColorContentProvider";
Hope it helps.

Just make sure you're using fully qualified name as authority in your searchable as well in provider declared in manifest file like below:
<?xml version="1.0" encoding="utf-8"?>
<searchable xmlns:android="http://schemas.android.com/apk/res/android"
android:hint="#string/action_search"
android:label="#string/app_name"
android:searchSuggestAuthority="your_pakcage_name.SearchSuggestionProvider"
android:searchSuggestSelection=" ?" />
<provider
android:authorities="your_pakcage_name.SearchSuggestionProvider"
android:name="your_pakcage_name.SearchSuggestionProvider"
android:exported="true"
android:enabled="true"
android:multiprocess="true"/>
If you've sensitive information in your providers make sure exported is not true

<provider
android:name="com.example.absolutelysaurabh.todoapp.ColorContentProvider"
android:authorities="com.example.absolutelysaurabh.todoapp"
android:enabled="true"
android:exported="false" >
</provider>
IMPORTANT : Make sure in the "Contract" class u've also used the same AUTHORITY as used here i.e. "com.example.absolutelysaurabh.todoapp"

(SOLVED)
I got this issue with my AddStickerPackActivity.java in function createIntentToAddStickerPack
where I commented intent.putExtra(StickerPackDetailsActivity.EXTRA_STICKER_PACK_AUTHORITY, BuildConfig.CONTENT_PROVIDER_AUTHORITY); after watching some tutorials
Please check if you also find the same issue
Uncomment this line and make sure you are not importing any BuildConfig library, is it not required to import any BuildConfig

This might be old, the given answer works fine with APIs before API 30...
But for API 30 and API 31 checkout this:
Failed to find Content Provider in API 30

How to fix content provider url not found in android Content provider?

I have followed the below tutorial http://www.vogella.de/articles/AndroidSQLite/article.htm
But getting this exception after clicking on "confirm" button
01-20 10:18:14.585: E/AndroidRuntime(2006): Caused by: java.lang.IllegalArgumentException: Unknown URL content://com.example.todos.contentprovider/todos
01-20 10:18:14.585: E/AndroidRuntime(2006): at android.content.ContentResolver.insert(ContentResolver.java:910)
01-20 10:18:14.585: E/AndroidRuntime(2006): at com.example.todos.TodoDetailActivity.saveState(TodoDetailActivity.java:122)
01-20 10:18:14.585: E/AndroidRuntime(2006): at com.example.todos.TodoDetailActivity.onPause(TodoDetailActivity.java:100)
TodoDetailActivity
public class TodoDetailActivity extends Activity {
private Spinner mCategory;
private EditText mTitleText;
private EditText mBodyText;
private Uri todoUri;
#Override
protected void onCreate(Bundle bundle) {
super.onCreate(bundle);
setContentView(R.layout.todo_edit);
mCategory = (Spinner) findViewById(R.id.category);
mTitleText = (EditText) findViewById(R.id.todo_edit_summary);
mBodyText = (EditText) findViewById(R.id.todo_edit_description);
Button confirmButton = (Button) findViewById(R.id.todo_edit_button);
Bundle extras = getIntent().getExtras();
// check from the saved Instance
todoUri = (bundle == null) ? null : (Uri) bundle
.getParcelable(MyTodoContentProvider.CONTENT_ITEM_TYPE);
// Or passed from the other activity
if (extras != null) {
todoUri = extras
.getParcelable(MyTodoContentProvider.CONTENT_ITEM_TYPE);
fillData(todoUri);
}
confirmButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
if (TextUtils.isEmpty(mTitleText.getText().toString())) {
makeToast();
} else {
setResult(RESULT_OK);
finish();
}
}
});
}
private void fillData(Uri uri) {
String[] projection = { TodoTable.COLUMN_SUMMARY,
TodoTable.COLUMN_DESCRIPTION, TodoTable.COLUMN_CATEGORY };
Cursor cursor = getContentResolver().query(uri, projection, null, null,
null);
if (cursor != null) {
cursor.moveToFirst();
String category = cursor.getString(cursor
.getColumnIndexOrThrow(TodoTable.COLUMN_CATEGORY));
for (int i = 0; i < mCategory.getCount(); i++) {
String s = (String) mCategory.getItemAtPosition(i);
if (s.equalsIgnoreCase(category)) {
mCategory.setSelection(i);
}
}
mTitleText.setText(cursor.getString(cursor
.getColumnIndexOrThrow(TodoTable.COLUMN_SUMMARY)));
mBodyText.setText(cursor.getString(cursor
.getColumnIndexOrThrow(TodoTable.COLUMN_DESCRIPTION)));
// always close the cursor
cursor.close();
}
}
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
saveState();
outState.putParcelable(MyTodoContentProvider.CONTENT_ITEM_TYPE, todoUri);
}
#Override
protected void onPause() {
super.onPause();
saveState();
}
private void saveState() {
String category = (String) mCategory.getSelectedItem();
String summary = mTitleText.getText().toString();
String description = mBodyText.getText().toString();
// only save if either summary or description
// is available
if (description.length() == 0 && summary.length() == 0) {
return;
}
ContentValues values = new ContentValues();
values.put(TodoTable.COLUMN_CATEGORY, category);
values.put(TodoTable.COLUMN_SUMMARY, summary);
values.put(TodoTable.COLUMN_DESCRIPTION, description);
if (todoUri == null) {
// New todo
todoUri = getContentResolver().insert(
MyTodoContentProvider.CONTENT_URI, values);
} else {
// Update todo
getContentResolver().update(todoUri, values, null, null);
}
}
private void makeToast() {
Toast.makeText(TodoDetailActivity.this, "Please maintain a summary",
Toast.LENGTH_LONG).show();
}
}
MyTodoContentProvider
public class MyTodoContentProvider extends ContentProvider{
//database
private TodoDatabaseHelper database;
//Used for the uriMatcher
private static final int TODOS = 10;
private static final int TODO_ID = 20;
private static final String AUTHORITY = "com.example.todos.contentprovider";
private static final String BASE_PATH = "todos";
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY+ "/" + BASE_PATH);
public static final String CONTENT_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE +"/todos";
public static final String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/todo";
private static final UriMatcher sURIMatcher = new UriMatcher(UriMatcher.NO_MATCH);
static {
sURIMatcher.addURI(AUTHORITY, BASE_PATH, TODOS);
sURIMatcher.addURI(AUTHORITY, BASE_PATH + "/#", TODO_ID);
}
#Override
public boolean onCreate()
{
database = new TodoDatabaseHelper(getContext());
return false;
}
#Override
public Cursor query(Uri uri,String[] projection, String selection,
String[] selectionArgs, String sortOrder)
{
// Uisng SQLiteQueryBuilder instead of query() method
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
// check if the caller has requested a column which does not exists
checkColumns(projection);
//set the table
queryBuilder.setTables(TodoTable.TABLE_TODO);
int uriType = sURIMatcher.match(uri);
switch (uriType) {
case TODOS:
break;
case TODO_ID:
// adding the ID to the original query
queryBuilder.appendWhere(TodoTable.COLUMN_ID + "="
+ uri.getLastPathSegment());
break;
default:
throw new IllegalArgumentException("Unknown URI: " + uri);
}
SQLiteDatabase db = database.getWritableDatabase();
Cursor cursor = queryBuilder.query(db, projection, selection,
selectionArgs, null, null, sortOrder);
// make sure that potential listeners are getting notified
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
#Override
public String getType(Uri uri) {
return null;
}
#Override
public Uri insert(Uri uri, ContentValues values)
{
int uriType = sURIMatcher.match(uri);
SQLiteDatabase sqlDB = database.getWritableDatabase();
long id = 0;
switch (uriType) {
case TODOS:
id = sqlDB.insert(TodoTable.TABLE_TODO, null, values);
break;
default:
throw new IllegalArgumentException("Unknown URI: " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return Uri.parse(BASE_PATH + "/" + id);
}
#Override
public int delete(Uri uri, String selection,String[] selectionArgs)
{
int uriType = sURIMatcher.match(uri);
SQLiteDatabase sqlDB = database.getWritableDatabase();
int rowsDeleted = 0;
switch (uriType) {
case TODOS:
rowsDeleted = sqlDB.delete(TodoTable.TABLE_TODO,selection, selectionArgs);
break;
case TODO_ID:
String id = uri.getLastPathSegment();
if(TextUtils.isEmpty(selection))
{
rowsDeleted = sqlDB.delete(TodoTable.TABLE_TODO,TodoTable.COLUMN_ID + "=" + id,null);
}
else
{
rowsDeleted = sqlDB.delete(TodoTable.TABLE_TODO,TodoTable.COLUMN_ID + "=" + id + "and" + selection ,selectionArgs);
}
default:
throw new IllegalArgumentException("Unknown URI: " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return rowsDeleted;
}
#Override
public int update(Uri uri,ContentValues values,String selection,String[] selectionArgs)
{
int uriType = sURIMatcher.match(uri);
SQLiteDatabase sqlDb = database.getWritableDatabase();
int rowsUpdated = 0;
switch (uriType) {
case TODOS:
rowsUpdated = sqlDb.update(TodoTable.TABLE_TODO, values, selection, selectionArgs);
break;
case TODO_ID:
String id = uri.getLastPathSegment();
if(TextUtils.isEmpty(selection))
{
rowsUpdated = sqlDb.update(TodoTable.TABLE_TODO, values, TodoTable.COLUMN_ID + "=" + id, null);
}
else
{
rowsUpdated = sqlDb.update(TodoTable.TABLE_TODO, values, TodoTable.COLUMN_ID + "=" + id + "and" + selection, selectionArgs);
}
break;
default:
throw new IllegalArgumentException("Unknown URI: " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return rowsUpdated;
}
private void checkColumns(String[] projection)
{
String[] available = {TodoTable.COLUMN_CATEGORY,TodoTable.COLUMN_SUMMARY,TodoTable.COLUMN_DESCRIPTION,TodoTable.COLUMN_ID};
HashSet<String> requestedColumns = new HashSet<String>(Arrays.asList(projection));
HashSet<String> availableColumns = new HashSet<String>(Arrays.asList(available));
if(projection != null)
{
if (!availableColumns.containsAll(requestedColumns)) {
throw new IllegalArgumentException("Unknown columns in projection");
}
}
}
}
TodoDatabaseHelper
public class TodoDatabaseHelper extends SQLiteOpenHelper{
private static final String DATABASE_NAME = "todotable.db";
private static final int DATABASE_VERSION = 1;
public TodoDatabaseHelper(Context context)
{
super(context,DATABASE_NAME,null,DATABASE_VERSION);
}
//Method is called during creation of database
#Override
public void onCreate(SQLiteDatabase database)
{
TodoTable.onCreate(database);
}
// Method is called during an upgrade of the database,
// e.g. if you increase the database version
#Override
public void onUpgrade(SQLiteDatabase database, int oldVersion,
int newVersion) {
TodoTable.onUpgrade(database, oldVersion, newVersion);
}
}

You are using
private static final String AUTHORITY = "com.example.todos.contentprovider";
// It should same as you defined in manifest
So this
Caused by: java.lang.IllegalArgumentException: Unknown URL content://com.example.todos.contentprovider/todos
So make sure you define your ContentProvider with same authority in manifest.xml
<provider
android:authorities="com.example.todos.contentprovider"
android:name=".YOUR_ContentProvider" >
</provider>
Hope this will work for you.

Also ensure that you give android:exported="true" in manifest.xml, also ensure they are placed inside </application> not inside </activity>.
<provider
android:name="com.example.todos.contentprovider"
android:authorities="com.example.todos.contentprovider.MyTodoContentProvider"
android:exported="true">
</provider>

unsupported uri when accessing content provider

EDIT
I get a java.lang.IllegalArgumentException: Unsupported URI: content://com.example.locationreminder.remindercontentprovider/items
Shouldn't I be able to pick whatever name I want for the AUTHORITY string? as well as the content URI?
I have the following code:
public class ReminderContentProvider extends ContentProvider {
private DatabaseHelper mDbHelper;
public static final String AUTHORITY = "com.example.locationreminder.remindercontentprovider";
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/items");
public static final String TABLE_NAME = "reminder";
private static final int ALLROWS = 1;
private static final int SINGLE_ROW = 2;
public static interface ReminderColumns extends BaseColumns {
public static final Uri CONTENT_URI = ReminderContentProvider.CONTENT_URI;
public static final String TITLE = "Title";
public static final String DATE = "Date";
public static final String CONTENT_PATH = "items";
public static final String CONTENT_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE + "/vnd.locationreminder.items";
public static final String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/vnd.locationreminder.items";
}
static {
sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
sUriMatcher.addURI(AUTHORITY, ReminderColumns.CONTENT_PATH, ALLROWS);
sUriMatcher.addURI(AUTHORITY, ReminderColumns.CONTENT_PATH + "/#", SINGLE_ROW);
}
#Override
public boolean onCreate() {
mDbHelper = new DatabaseHelper(getContext());
return true;
}
#Override
public String getType(Uri uri) {
switch(sUriMatcher.match(uri)) {
case ALLROWS:
return ReminderColumns.CONTENT_TYPE;
case SINGLE_ROW:
return ReminderColumns.CONTENT_ITEM_TYPE;
default:
throw new IllegalArgumentException("Unsupported URI: " + uri);
}
}
#Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder builder = new SQLiteQueryBuilder();
builder.setTables(DatabaseHelper.REMINDER_TABLE_NAME);
switch (sUriMatcher.match(uri)) {
case ALLROWS:
// all nice and well
break;
case SINGLE_ROW:
// limit query to one row at most:
builder.appendWhere(ReminderColumns._ID + " = " + uri.getLastPathSegment());
break;
default:
throw new IllegalArgumentException("Unsupported URI: " + uri);
}
Cursor cursor = builder.query(mDbHelper.getWritableDatabase(), projection, selection, selectionArgs, null, null, sortOrder);
// if we want to be notified of any changes:
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
Note: I also implemented insert(), update() and delete() which aren't relevant for the error I get.
The manifest file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.locationreminder"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="15"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<provider
android:name="com.example.locationreminder.ReminderContentProvider"
android:authorities="com.example.locationreminder.remindercontentprovider"
android:singleUser="false" /> <!-- other users can't use this provider -->
<activity
android:name="com.example.locationreminder.MainActivity"
android:theme="#android:style/Theme.Holo.Light"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.example.locationreminder.NewReminderActivity"
android:label="#string/title_activity_new_reminder"
android:theme="#style/CalendarTheme.WithActionBar" >
</activity>
</application>
EDIT
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setTheme(android.R.style.Theme_Holo_Light);
setContentView(R.layout.activity_main);
Cursor cursor = managedQuery(ReminderContentProvider.CONTENT_URI, null, null, null, null);
mSimpleCursorAdapter = new SpecialAdapter(this,
R.layout.row,
cursor,
new String[]{ DatabaseHelper.KEY_ID, DatabaseHelper.KEY_TITLE, DatabaseHelper.KEY_DATE }
new int[] { R.id.titleID, R.id.dateTimeOrLocationID },
CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
getLoaderManager().initLoader(0, null, this);
ListView listView = (ListView) findViewById(R.id.list);
listView.setAdapter(mSimpleCursorAdapter);
}

Does the error happen when switch (sUriMatcher.match(uri)) falls to default case?
If so, then you need to pass uri that matches ALLROWS or SINGLE_ROW

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

ContentProvider: cursor object null when trying to acces data with ContentResolver - android

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