I want to get callback about any audio notify.
I create observer:
getContentResolver().registerContentObserver(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, false, new MyContentObserver(_handler) { ...
I get onChange each time, then add or remove some song.
But I don't understood another: I copy to device some file (test.log). I don't get onChange after copy file. But If I remove this file I get onChange. But why?
Within your content provider you can define for which action a notification should be sent. Here is an example for the delete() action.
#Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
final SQLiteDatabase db = mOpenHelper.getWritableDatabase();
switch (sUriMatcher.match(uri)) {
case POSTS: {
int rowCount = db.delete(DatabaseProperties.TABLE_NAME_POSTS, selection, selectionArgs);
getContext().getContentResolver().notifyChange(uri, null);
return rowCount;
}
default: {
throw new UnsupportedOperationException("Unknown URI: " + uri);
}
}
}
The command you probably miss, is notifyChange().
Related
I have a fragment with a list of items, each item has an editable quantity. When I edit the quantity, the database is updated and I receive a new cursor in the fragment. This all works well, except when you update the quantity a number of times, the onLoadFinished method is not called anymore. This can happen after 5 updates or after 200 updates: I can't reproduce the bug on command. The update is executed in the database because when I close and open that screen, I can see the updated quantity. Nothing out of the ordinary happens in the code: onLoaderReset is not called, notifyChange gets called on the correct Uri in the contentprovider. Has anyone ever seen this issue?
When the quantity needs to get updated:
ContentValues cv = new ContentValues();
cv.put(CartTable.COLUMN_COUNT, quantity);
String selection = CartTable.COLUMN_ID + " = " + cartItemId;
contentResolver.update(CartContentProvider.CONTENT_URI, cv, selection, null);
The CartContentProvider:
#Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs)
{
int rowsUpdated;
switch (uriMatcher.match(uri))
{
case CART_ITEMS:
rowsUpdated = this.database.update(CartTable.TABLE_NAME, values, selection, selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI: " + uri);
}
if(rowsUpdated > 0)
{
this.getContext().getContentResolver().notifyChange(CONTENT_URI, null);
this.getContext().getContentResolver().notifyChange(CONTENT_URI_PRODUCTS, null);
this.getContext().getContentResolver().notifyChange(CONTENT_URI_PRODUCTS_PHOTOS, null);
this.getContext().getContentResolver().notifyChange(CONTENT_URI_PHOTOS, null);
}
return rowsUpdated;
}
When I create the CursorLoader:
return new CursorLoader(this.getView().getContext(), CartContentProvider.CONTENT_URI_PRODUCTS, projection, null, null, null);
So for example, I edit the quantity 20 times and 20 times onLoadFinished gets called with a new cursor. The 21st time and all times after that, the update happens but onLoadFinished is not called anymore.
When extra code is required, let me know!
Thanks in advance.
Try using the CursorLoader like this:
return new CursorLoader(this.getActivity(), CartContentProvider.CONTENT_URI_PRODUCTS, projection, null, null, null);
use the fragment's Activity context, Also check where are you implementing the LoaderCallbacks interface, in the activity or in the fragment?
I have registered a CursorLoader, but it is not receiving updates from my ContentProvider
The sequence of events is:
In a Fragment, register the CursorLoader with:
getLoaderManager().initLoader(LOADER_FAVS_ID, null, this);
Note I am using the support library version ,so this method is android.support.v4.app.Fragment.getLoaderManager()
The CursorLoader is registered, and a Cursor is loaded in the onLoadFinished:
#Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
Log.i(TAG, "onLoadFinished");
switch (loader.getId()) {
case LOADER_FAVS_ID:
Log.i(TAG,
"cursor notification uri: " + cursor.getNotificationUri());
mCursorAdapter.swapCursor(cursor);
break;
}
}
Which Logs cursor notification uri: content://com.myapp.mylocation/db_locations, for example. This is because I made sure to call cursor.setNotificationUri(getContext().getContentResolver(), uri); before returning the Cursor from my ContentProvider.
Also note that my content provider returns a MergeCursor.
Some time later, a call is made to update() in my ContentProvider, and the following lines are executed:
Log.i(TAG,
"Notifying uri: " + uri.toString());
getContext().getContentResolver().notifyChange(
uri, null);
Which Logs Notifying loc uri: content://com.myapp.mylocation/db_locations, the same uri as above.
But onLoadFinished is never called, and my Cursor is never updated. I believe I have followed the advice I can find, all of which is basically this. Why else would onLoadFinished not be called after all of this?
Solved it, but since I haven't seen this documented, here's my solution.
I was returning a MergeCursor from my ContentProvider, basically just concatenating a list of cursors. I had
#Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
// Generate an array of Cursors
MergeCursor mergCursor = new MergeCursor(cursorArray);
// notify potential listeners
mergCursor.setNotificationUri(getContext().getContentResolver(), uri);
return mergCursor;
}
And my CursorLoader was never receiving the notification. However, as MergeCursor is basically just an Array of Cursor, you need to set the notification uri on each cursor in your MergeCursor.
#Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
// Generate an array of Cursors
// set the notification uris...
for (Cursor cursor : cursorArray) {
cursor.setNotificationUri(getContext().getContentResolver(), uri);
}
MergeCursor mergCursor = new MergeCursor(cursorArray);
return mergCursor;
}
Now everything works as expected!
I have a content provider, a content resolver, and a cursor loader. The loader is used to indirectly populate a listview (ie not a simple cursor adapter, rather an array adapter, since I need to use the cursor's results to gather other data).
When I change the underlying data, the listview does not re-populate as the onLoadFinished(Loader<Cursor>, Cursor) call back is not called.
As suggested while I'm writing this, there are a lot of questions on this issue.
eg
CursorLoader not updating after data change
And all the questions point out two things:
In your content provider query() method, you need to tell the cursor about notifications a'la
c.setNotificationUri(getContext().getContentResolver(), uri);
In your content provider insert/update/delete method, you need to notify on the URI:
getContext().getContentResolver().notifyChange(uri, null);
I'm doing those things.
I'm also NOT closing any of the cursors I get back.
Note, my content provider lives in a separate app (think of it as a content provider app -- no launcher main activity). A com.example.provider APK, and the com.example.app is calling (in the content resolver) via the content://com.example.provider/table URI etc. The content resolver (dbhelper) lives in a library project (com.example.appdb) that the activity links in. (This way, multiple projects can use the dbhelper via linking, and all content providers are installed via single APK)
I have turned on debugging in the loader manager, and can see where I force a refresh after the data changes (ie the loader being restarted and previous being marked inactive), but nothing that says anything is happening automatically -- rather, in response to my force refresh.
Any ideas why my loader isn't being refreshed ?
-- EDIT --
The loader create:
Log.d(TAG, "onCreateLoader ID: " + loaderID);
// typically a switch on the loader ID, and then
return dbHelper.getfoo()
Where getfoo() returns a cursor loader via:
return new CursorLoader(context, FOO_URI, foo_Fields, foo_query, foo_argArray, foo_sort );
Loader Finish takes the cursor and populates a table (and does some processing) -- nothing fancy there.
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
Log.d(TAG, "onLoadFinished id: " + loader.getId());
// switch on loader ID ..
FillTable(cursor, (FooAdapter) foo_info.listview.getAdapter();
Loader Reset clears the table.
public void onLoaderReset(Loader<Cursor> loader) {
Log.d(TAG, "onLoaderReset id: " + loader.getId());
// normally a switch on loader ID
((FooAdapter)foo_info.listview.getAdapter()).clear();
The content provider does:
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
Cursor cursor;
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
SQLiteDatabase db = dbHelper.getReadableDatabase();
switch (sUriMatcher.match(uri)) {
case FOO:
qb.setTables(FOO);
qb.setProjectionMap(FooProjectionMap);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, sortOrder);
c.setNotificationUri(getContext().getContentResolver(), uri);
return c;
}
Then insert/update is similar:
public Uri insert(Uri uri, ContentValues initialValues) {
ContentValues values;
if (initialValues != null) {
values = new ContentValues(initialValues);
} else {
values = new ContentValues();
}
String tableName;
Uri contentUri;
switch (sUriMatcher.match(uri)) {
case FOO:
tableName = FOOTABLE;
contentUri = FOO_URI;
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
SQLiteDatabase db = dbHelper.getWritableDatabase();
long rowId = db.insert(tableName, null, values);
if (rowId > 0) {
Uri objUri = ContentUris.withAppendedId(contentUri, rowId);
getContext().getContentResolver().notifyChange(objUri, null);
return objUri;
}
throw new SQLException("Failed to insert row into " + uri);
}
I see that you aren't calling swapCursor or changeCursor in your onLoadFinished and onLoaderReset. You need to do that for your adapter to access the data loaded into the new cursor.
in onLoadFinished, call something like:
mAdapter.swapCursor(cursor)
In onLoaderReset, call this to remove references to the old cursor:
mAdapter.swapCursor(null)
Where mAdapter is your listView's adapter.
More info: http://developer.android.com/guide/components/loaders.html#onLoadFinished
So, for anyone who looks this up and has this problem:
Make certain that the URI you register the cursor on, and the URI you notify the cursor on are the same.
In my case, I was using a different URI to query than was used in other code that modified the underlying table. There wasn't an easy fix to make notification work, so I kept resetting the loader in OnResume() as the solution.
This is not a direct answer to this specific problem, but may help others in a similar situation. In my case, I had a join and even though I used the full tablename.columnname in the projection and query. It ended up using the wrong ID values anyway. So be sure to check your ContentProvider or SQL syntax.
i have implemented update() of ContentProvider and notifying to observer using getContext().getContentResolver().notifyChange(uri, null);
my obvious need is that whenever just one row is effected i want to notify with row specific uri, but could not find way to do so.
an additional query like "select id where selectionArgs" can do this but this will be a foolish way.
onchange(boolean, uri) get complete uri instead of specific row, easy to understand that this is because ContentProvider.update() is sending the same.
some code for more clarity
update() method of MyContentProvider
#Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
Log.d("TAG", "update " + uri.getPath());
int count = 0;
switch (uriMatcher.match(uri)) {
case BOOKS:
count = booksDB.update(DATABASE_TABLE, values, selection, selectionArgs);
break;
case BOOK_ID:
count = booksDB.update(DATABASE_TABLE, values,
_ID + " = " + uri.getPathSegments().get(1)
+ (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : ""),
selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
if (count == 1) {
Cursor c = query(uri, new String[] { _ID }, selection, selectionArgs, null);
long rowId = Long.valueOf(c.getString(c.getColumnIndex(_ID)));
uri = ContentUris.withAppendedId(CONTENT_URI, rowId);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
i will update table some how like
getContentResolver().update(MyContentProvider.CONTENT_URI, values1, MyContentProvider._ID+"<?", new String[]{"3"}));
frankly saying, code has barely related to question, just trying to give you some context
In your provider method, just return the uri with the id appended
#Override
public Uri insert(Uri uri, ContentValues values) {
Log.i(TAG, "insert " + uri);
final SQLiteDatabase db = mOpenHelper.getWritableDatabase();
final int match = URI_MATCHER.match(uri);
Uri returnUri;
switch (match) {
case MESSAGE: {
long _id = db.insert(MessageContract.MessageEntry.TABLE_NAME, null, values);
if (_id > 0)
returnUri = ContentUris.withAppendedId(MessageContract.MessageEntry.CONTENT_URI, _id);
else
throw new android.database.SQLException("Failed to insert row into " + uri);
break;
}
default:
throw new UnsupportedOperationException("Unknown uri: " + uri);
}
getContext().getContentResolver().notifyChange(returnUri, null);
return returnUri;
}
And register your observer with true for descendents.
getContentResolver().registerContentObserver(MessageContract.MessageEntry.CONTENT_URI, true, mContentObserver);
To get the id from a Uri you can use ContentUris.parseId(uri)
Unfortunately I'm not able to suggest easy solution (because I'm not aware of full code and updates You need to run), there's some ways we You could try (some of them I've implemented in mine applications):
Provide ids in ContentValues - this way looks not applicable for Your case and it needs loop with calls to notifyChange();
Provide specific Uri for requests with queries (only some specific apps needs many various queries in selection, usually it's much easier to include query parameter in Uri). After another part of the program get notification with that specific Uri it will be able to check if it's 'current item' was updated and act appropriately (e.g. simplest case with list of articles and one article open in separate activity; then You update list of articles in the background from server You might need to update currently open article also and so, need to know if it was updated). You should be able to check particular item on the side of the observer using just received Uri, because it (Uri) will contain parameter(s) You've used for query;
You can pass the ID via ContentValues, and append it to the notification url. This way you don't have to make a separate query.
#Override
public int update(#NonNull Uri uri, ContentValues values, String selection, String[] selectionArgs) {
int rows = _database.update(getTableName(), values, selection, selectionArgs);
if (rows > 0) {
Uri itemUri = ContentUris.withAppendedId(uri, values.getAsLong(DatabaseModel.COLUMN_ID)); // DatabaseModel.COLUMN_ID is "_id"
getContext().getContentResolver().notifyChange(itemUri, null);
}
return rows;
}
This is what I have, but its failing saying that the table does not exists. I am positive it does incase anyone asks that. But this is some of the code that does that:
What gets called
/*Constants*/
public static final String AUTHORITY = "content://com.smartcal.eventprovider";
private static final int EVENTS_INFO = 1;
baseUri = Uri.withAppendedPath(baseUri, "events_info");
return new CursorLoader(this, baseUri, args.getStringArray("projection"),
args.getString("selection"), args.getStringArray("selectionArgs"), args.getBoolean("sortOrder") ? args.getString("sortOrder") : null );
What matches is
private String getTable(Uri uri) {
String table = "";
switch(sUriMatcher.match(uri)){
case EVENTS_INFO: table = "events_info";
}
return table;
}
private static final UriMatcher sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
static
{
sUriMatcher.addURI(AUTHORITY, "events_info", 1);
}
And my query() method in custom ContentProvider
#Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
database = openHelper.getWritableDatabase();
return database.query(getTable(uri), projection, selection, selectionArgs, null, null, null);
}
Error:
06-19 17:34:14.366: E/AndroidRuntime(686): Caused by:
java.lang.IllegalStateException: Invalid tables
EDIT:
When using Alex's IllegalArgumentException, this is what I got back from the error:
06-19 19:17:42.277: E/AndroidRuntime(1134): Caused by:
java.lang.IllegalArgumentException: Unknown URI
content://com.smartcal.eventprovider/events_info
As you can tell, it should match, assuming the sUriMatcher.addURI() method is working correctly.
Your problem might stem from the fact that your code isn't very well organized...
First thing,
private String getTable(Uri uri) {
switch(sUriMatcher.match(uri)) {
case EVENTS_INFO:
return "events_info"; // return
/** PROVIDE A DEFAULT CASE HERE **/
default:
// If the URI doesn't match any of the known patterns, throw an exception.
throw new IllegalArgumentException("Unknown URI " + uri);
}
}
Second thing,
/** Use constants, not raw ints **/
sUriMatcher.addURI(AUTHORITY, "events_info", EVENT_INFO);
Other than that, you might want to provide some more info.
Have you already installed the app and is the table new? If so, and you are not updating the schema in your sql helper class, you need to uninstall the app first. Then install the app in your emulator device. The db is only created once, and the create method in the sql helper will not be called after that first time, even if you are installing or running a new build/apk.