Content Provider simple app.

AndroidManifest.xml

<provider
    android:name=".provider.SimpleProvider"
    android:authorities="com.example.simplecontentprovider"
    android:enabled="true"
    android:exported="false">

</provider>

DatabaseContract.java

public class DatabaseContract {

    public static final String PATH_USERS = "users";
    public static final String PATH_COMPANIES = "companies";

    public static class UsersEntry implements BaseColumns {

        public static final Uri CONTENT_URI = SimpleProvider.BASE_URI
                .buildUpon()
                .appendPath(PATH_USERS)
                .build();

        public static final String CONTENT_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE +
                "/" + SimpleProvider.AUTHORITY +
                "/" + PATH_USERS;
        public static final String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE +
                "/" + SimpleProvider.AUTHORITY +
                "/" + PATH_USERS;

        public static final String TABLE_NAME = "users";

        public static final String KEY_NAME = "name";
        public static final String KEY_AGE = "age";

        public static final String CREATE_TABLE_QUERY = "CREATE TABLE " + TABLE_NAME +
                "(" +
                _ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
                KEY_NAME + " TEXT," +
                KEY_AGE + " INTEGER" +
                ")";
    }

    public static class CompaniesEntry implements BaseColumns {

        public static final Uri CONTENT_URI = SimpleProvider.BASE_URI
                .buildUpon()
                .appendPath(PATH_COMPANIES)
                .build();

        public static final String CONTENT_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE +
                "/" + SimpleProvider.AUTHORITY +
                "/" + PATH_COMPANIES;
        public static final String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE +
                "/" + SimpleProvider.AUTHORITY +
                "/" + PATH_COMPANIES;

        public static final String TABLE_NAME = "companies";

        public static final String KEY_NAME = "name";
        public static final String KEY_EMPLOYEES = "employees";
        public static final String KEY_NET_WORTH = "net_worth";

        public static final String CREATE_TABLE_QUERY = "CREATE TABLE " + TABLE_NAME +
                "(" +
                _ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
                KEY_NAME + " TEXT," +
                KEY_EMPLOYEES + " INTEGER," +
                KEY_NET_WORTH + " INTEGER" +
                ")";
    }
}

DatabaseHelper.java

public class DatabaseHelper extends SQLiteOpenHelper {

    private static final String DATABASE_NAME = "simpleDB";
    private static final int DATABASE_VERSION = 2;

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(UsersEntry.CREATE_TABLE_QUERY);
        db.execSQL(CompaniesEntry.CREATE_TABLE_QUERY);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + UsersEntry.TABLE_NAME);
        db.execSQL("DROP TABLE IF EXISTS " + CompaniesEntry.TABLE_NAME);
        onCreate(db);
    }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivityTAG_";

    private static final String SAMPLE_NAME = "Edwin";
    private static final int SAMPLE_AGE = 63;

    int mCounter = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void insertRows(View view) {
        Uri usersUri = DatabaseContract.UsersEntry.CONTENT_URI;

        ContentValues contentValues = new ContentValues();

        contentValues.put(DatabaseContract.UsersEntry.KEY_NAME, SAMPLE_NAME);
        contentValues.put(DatabaseContract.UsersEntry.KEY_AGE, SAMPLE_AGE + mCounter++);

        Uri resultUri = getContentResolver().insert(usersUri, contentValues);

        Log.d(TAG, "insertRows: " + resultUri);
    }

    public void logRows(View view) {
        Uri usersUri = DatabaseContract.UsersEntry.CONTENT_URI;

        Cursor resultCursor = getContentResolver().query(usersUri,
                null,
                null,
                null,
                null);

        resultCursor.moveToFirst();

        do {
            Log.d(TAG, "logRows: " + resultCursor.getString(resultCursor.getColumnIndex(DatabaseContract.UsersEntry.KEY_NAME)));
            Log.d(TAG, "logRows: " + resultCursor.getInt(resultCursor.getColumnIndex(DatabaseContract.UsersEntry.KEY_AGE)));
        } while (resultCursor.moveToNext());

        resultCursor.close();
    }
}

SimpleProvider.java

public class SimpleProvider extends ContentProvider {

    public static final String AUTHORITY = "com.example.simplecontentprovider";
    public static final Uri BASE_URI = Uri.parse("content://" + AUTHORITY);

    private static final UriMatcher sUriMatcher = buildUriMatcher();

    private static final int MATCH_USERS = 100;
    private static final int MATCH_COMPANIES = 200;

    private DatabaseHelper mDatabaseHelper;

    public SimpleProvider() {

    }

    public static UriMatcher buildUriMatcher() {
        UriMatcher uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

        uriMatcher.addURI(AUTHORITY, DatabaseContract.PATH_USERS, MATCH_USERS);
        uriMatcher.addURI(AUTHORITY, DatabaseContract.PATH_COMPANIES, MATCH_COMPANIES);

        return uriMatcher;
    }

    @Override
    public boolean onCreate() {
        mDatabaseHelper = new DatabaseHelper(getContext());
        return true;
    }

    @Override
    public String getType(Uri uri) {
        final int match = sUriMatcher.match(uri);

        switch (match) {
            case MATCH_USERS:
                return DatabaseContract.UsersEntry.CONTENT_TYPE;
            case MATCH_COMPANIES:
                return DatabaseContract.CompaniesEntry.CONTENT_TYPE;
            default:
                throw new UnsupportedOperationException("Unknown uri: " + uri);
        }
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection,
                        String[] selectionArgs, String sortOrder) {
        final SQLiteDatabase sqLiteDatabase = mDatabaseHelper.getReadableDatabase();
        final int match = sUriMatcher.match(uri);
        String tableName;

        switch (match) {
            case MATCH_USERS:
                tableName = DatabaseContract.UsersEntry.TABLE_NAME;
                break;
            case MATCH_COMPANIES:
                tableName = DatabaseContract.CompaniesEntry.TABLE_NAME;
                break;
            default:
                throw new UnsupportedOperationException("Unknown uri: " + uri);
        }

        return sqLiteDatabase.query(tableName,
                projection,
                selection,
                selectionArgs,
                null,
                null,
                sortOrder);
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        final SQLiteDatabase sqLiteDatabase = mDatabaseHelper.getWritableDatabase();
        final int match = sUriMatcher.match(uri);
        long resultId;
        Uri returnUri;

        switch (match) {
            case MATCH_USERS:
                resultId = sqLiteDatabase.insert(DatabaseContract.UsersEntry.TABLE_NAME, null, values);
                if (resultId > 0) {
                    returnUri = ContentUris.withAppendedId(DatabaseContract.UsersEntry.CONTENT_URI, resultId);
                } else {
                    throw new android.database.SQLException("Failed to insert row into " + uri);
                }
                break;
            case MATCH_COMPANIES:
                resultId = sqLiteDatabase.insert(DatabaseContract.CompaniesEntry.TABLE_NAME, null, values);
                if (resultId > 0) {
                    returnUri = ContentUris.withAppendedId(DatabaseContract.CompaniesEntry.CONTENT_URI, resultId);
                } 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 update(Uri uri, ContentValues values, String selection,
                      String[] selectionArgs) {
        // TODO: Implement this to handle requests to update one or more rows.
        throw new UnsupportedOperationException("Not yet implemented");
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        // Implement this to handle requests to delete one or more rows.
        throw new UnsupportedOperationException("Not yet implemented");
    }

}