Use loader to query for a cursor for the list adapter

This commit is contained in:
Phillip Hsu 2016-06-29 04:01:46 -07:00
parent 11c4be68b9
commit 7d0718387f
6 changed files with 289 additions and 129 deletions

View File

@ -0,0 +1,68 @@
package com.philliphsu.clock2.alarms;
import android.database.Cursor;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.ViewGroup;
import com.philliphsu.clock2.Alarm;
import com.philliphsu.clock2.OnListItemInteractionListener;
import com.philliphsu.clock2.model.AlarmDatabaseHelper.AlarmCursor;
/**
* Created by Phillip Hsu on 6/29/2016.
*
* TODO: Make this abstract for other data types.
*/
public class AlarmsCursorAdapter extends RecyclerView.Adapter<AlarmViewHolder> {
private static final String TAG = "AlarmsCursorAdapter";
private final OnListItemInteractionListener<Alarm> mListener;
private AlarmCursor mCursor;
public AlarmsCursorAdapter(OnListItemInteractionListener<Alarm> listener) {
mListener = listener;
setHasStableIds(true); // TODO: why do we need this?
}
@Override
public AlarmViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return new AlarmViewHolder(parent, mListener);
}
@Override
public void onBindViewHolder(AlarmViewHolder holder, int position) {
if (!mCursor.moveToPosition(position)) {
Log.e(TAG, "Failed to bind alarm " + position);
return;
}
holder.onBind(mCursor.getAlarm());
}
@Override
public int getItemCount() {
return mCursor == null ? 0 : mCursor.getCount();
}
@Override
public long getItemId(int position) {
if (mCursor == null || !mCursor.moveToPosition(position)) {
return super.getItemId(position); // -1
}
return mCursor.getId();
}
// TODO: Cursor param should be the appropriate subclass?
public void swapCursor(Cursor cursor) {
if (mCursor == cursor) {
return;
}
if (mCursor != null) {
mCursor.close();
}
mCursor = (AlarmCursor) cursor;
// There is no way to notify the adapter of individual
// item changes when the dataset is a cursor.
notifyDataSetChanged();
}
}

View File

@ -1,8 +1,10 @@
package com.philliphsu.clock2.alarms;
import android.content.Context;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.LoaderManager.LoaderCallbacks;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
@ -12,6 +14,7 @@ import android.view.ViewGroup;
import com.philliphsu.clock2.Alarm;
import com.philliphsu.clock2.OnListItemInteractionListener;
import com.philliphsu.clock2.R;
import com.philliphsu.clock2.model.AlarmsListCursorLoader;
import com.philliphsu.clock2.model.BaseRepository;
import com.philliphsu.clock2.model.DatabaseManager;
@ -24,10 +27,15 @@ import butterknife.ButterKnife;
* Activities containing this fragment MUST implement the {@link OnAlarmInteractionListener}
* interface.
*/
public class AlarmsFragment extends Fragment implements BaseRepository.DataObserver<Alarm> {
// TODO: Use native fragments since we're targeting API >=19?
// TODO: Use native LoaderCallbacks.
public class AlarmsFragment extends Fragment implements
BaseRepository.DataObserver<Alarm>, LoaderCallbacks<Cursor> {
private OnAlarmInteractionListener mListener;
@Deprecated
private AlarmsAdapter mAdapter;
private AlarmsCursorAdapter mCursorAdapter;
private DatabaseManager mDatabaseManager;
@Bind(R.id.list) RecyclerView mList;
@ -56,6 +64,8 @@ public class AlarmsFragment extends Fragment implements BaseRepository.DataObser
// TODO Read arguments
}
// Initialize the loader to load the list of runs
getLoaderManager().initLoader(0, null, this);
mDatabaseManager = DatabaseManager.getInstance(getActivity());
}
@ -67,8 +77,12 @@ public class AlarmsFragment extends Fragment implements BaseRepository.DataObser
// Set the adapter
Context context = view.getContext();
mList.setLayoutManager(new LinearLayoutManager(context));
// TODO: Create a new adapter subclass with constructor that
// has no dataset param. The Loader will set the Cursor after it
// has finished loading it.
mAdapter = new AlarmsAdapter(mDatabaseManager.getAlarms(), mListener);
mList.setAdapter(mAdapter);
mCursorAdapter = new AlarmsCursorAdapter(mListener);
mList.setAdapter(mCursorAdapter);
return view;
}
@ -84,6 +98,7 @@ public class AlarmsFragment extends Fragment implements BaseRepository.DataObser
super.onResume();
// TODO: Need to refresh the list's adapter for any item changes. Consider doing this in
// onNewActivity().
getLoaderManager().restartLoader(0, null, this);
}
@Override
@ -125,6 +140,23 @@ public class AlarmsFragment extends Fragment implements BaseRepository.DataObser
mAdapter.updateItem(oldItem, newItem);
}
@Override
public android.support.v4.content.Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new AlarmsListCursorLoader(getActivity());
}
@Override
public void onLoadFinished(android.support.v4.content.Loader<Cursor> loader, Cursor data) {
// Called on the main thread after loading is complete
mCursorAdapter.swapCursor(data);
}
@Override
public void onLoaderReset(android.support.v4.content.Loader<Cursor> loader) {
// The adapter's current cursor should not be used anymore
mCursorAdapter.swapCursor(null);
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated

View File

@ -6,6 +6,7 @@ import android.database.Cursor;
import android.database.CursorWrapper;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import com.philliphsu.clock2.Alarm;
@ -29,7 +30,7 @@ public class AlarmDatabaseHelper extends SQLiteOpenHelper {
// TODO: Consider creating an inner class that implements BaseColumns
// and defines all the columns.
// TODO: Consider statically defining index constants for each column,
// TODO: Consider defining index constants for each column,
// and then removing all cursor getColumnIndex() calls.
private static final String TABLE_ALARMS = "alarms";
private static final String COLUMN_ID = "_id";
@ -39,13 +40,8 @@ public class AlarmDatabaseHelper extends SQLiteOpenHelper {
private static final String COLUMN_RINGTONE = "ringtone";
private static final String COLUMN_VIBRATES = "vibrates";
private static final String COLUMN_ENABLED = "enabled";
private static final String COLUMN_RING_TIME_MILLIS = "ring_time_millis";
private static final String COLUMN_SNOOZING_UNTIL_MILLIS = "snoozing_until_millis";
// TODO: Consider creating an inner class that implements BaseColumns
// and defines all the columns.
private static final String TABLE_ALARM_RECURRING_DAYS = "alarm_recurring_days";
// TODO: change value to _id if changing this to a primary auto-incrementing key
private static final String COLUMN_ALARM_ID = "alarm_id";
private static final String COLUMN_SUNDAY = "sunday";
private static final String COLUMN_MONDAY = "monday";
private static final String COLUMN_TUESDAY = "tuesday";
@ -54,42 +50,18 @@ public class AlarmDatabaseHelper extends SQLiteOpenHelper {
private static final String COLUMN_FRIDAY = "friday";
private static final String COLUMN_SATURDAY = "saturday";
// Statically define column indices for the days so we don't have
// to call cursor.getColumnIndex(COLUMN_[DAY]). We offset the value
// by one because COLUMN_ALARM_ID is actually first.
private static final int INDEX_SUNDAY = SUNDAY + 1;
private static final int INDEX_MONDAY = MONDAY + 1;
private static final int INDEX_TUESDAY = TUESDAY + 1;
private static final int INDEX_WEDNESDAY = WEDNESDAY + 1;
private static final int INDEX_THURSDAY = THURSDAY + 1;
private static final int INDEX_FRIDAY = FRIDAY + 1;
private static final int INDEX_SATURDAY = SATURDAY + 1;
// https://www.sqlite.org/lang_select.html#orderby
// Rows are first sorted based on the results of evaluating the left-most expression in the
// ORDER BY list, then ties are broken by evaluating the second left-most expression and so on.
// The order in which two rows for which all ORDER BY expressions evaluate to equal values are
// returned is undefined. Each ORDER BY expression may be optionally followed by one of the keywords
// ASC (smaller values are returned first) or DESC (larger values are returned first). If neither
// ASC or DESC are specified, rows are sorted in ascending (smaller values first) order by default.
private static void createAlarmsTable(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_ALARMS + " ("
+ COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ COLUMN_HOUR + " INTEGER NOT NULL, "
+ COLUMN_MINUTES + " INTEGER NOT NULL, "
+ COLUMN_LABEL + " TEXT, "
+ COLUMN_RINGTONE + " TEXT NOT NULL, "
+ COLUMN_VIBRATES + " INTEGER NOT NULL, "
+ COLUMN_ENABLED + " INTEGER NOT NULL, "
+ COLUMN_SNOOZING_UNTIL_MILLIS + " INTEGER);");
}
private static void createRecurringDaysTable(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_ALARM_RECURRING_DAYS + " ("
// TODO: The ID can instead be a primary auto-incrementing key, since a recurrence entry
// will always be made in conjunction with an alarm entry.
+ COLUMN_ALARM_ID + " INTEGER REFERENCES " + TABLE_ALARMS + "(" + COLUMN_ID + "), "
+ COLUMN_SUNDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_MONDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_TUESDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_WEDNESDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_THURSDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_FRIDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_SATURDAY + " INTEGER NOT NULL DEFAULT 0);");
}
// First sort by ring time in ascending order (smaller values first),
// then break ties by sorting by id in ascending order.
private static final String SORT_ORDER =
COLUMN_RING_TIME_MILLIS + " ASC, " + COLUMN_ID + " ASC";
public AlarmDatabaseHelper(Context context) {
super(context, DB_NAME, null, VERSION_1);
@ -102,8 +74,23 @@ public class AlarmDatabaseHelper extends SQLiteOpenHelper {
// of the value. As soon as INTEGER values are read off of disk and into memory for processing,
// they are converted to the most general datatype (8-byte signed integer).
// 8 byte == 64 bits so this means they are read as longs...?
createAlarmsTable(db);
createRecurringDaysTable(db);
db.execSQL("CREATE TABLE " + TABLE_ALARMS + " ("
+ COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ COLUMN_HOUR + " INTEGER NOT NULL, "
+ COLUMN_MINUTES + " INTEGER NOT NULL, "
+ COLUMN_LABEL + " TEXT, "
+ COLUMN_RINGTONE + " TEXT NOT NULL, "
+ COLUMN_VIBRATES + " INTEGER NOT NULL, "
+ COLUMN_ENABLED + " INTEGER NOT NULL, "
+ COLUMN_RING_TIME_MILLIS + " INTEGER NOT NULL, "
+ COLUMN_SNOOZING_UNTIL_MILLIS + " INTEGER, "
+ COLUMN_SUNDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_MONDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_TUESDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_WEDNESDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_THURSDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_FRIDAY + " INTEGER NOT NULL DEFAULT 0, "
+ COLUMN_SATURDAY + " INTEGER NOT NULL DEFAULT 0);");
}
@Override
@ -112,12 +99,10 @@ public class AlarmDatabaseHelper extends SQLiteOpenHelper {
// to the schema in the new version.
}
// TODO: Consider changing param to Alarm.Builder so the Alarm that will be
// built can have its ID set.
public long insertAlarm(Alarm alarm) {
long id = getWritableDatabase().insert(TABLE_ALARMS, null, toContentValues(alarm));
long id = getWritableDatabase().insert(TABLE_ALARMS,
null, toContentValues(alarm));
alarm.setId(id);
getWritableDatabase().insert(TABLE_ALARM_RECURRING_DAYS, null, toRecurrenceContentValues(id, alarm));
return id;
}
@ -128,56 +113,30 @@ public class AlarmDatabaseHelper extends SQLiteOpenHelper {
public int updateAlarm(Alarm oldAlarm, Alarm newAlarm) {
newAlarm.setId(oldAlarm.id());
SQLiteDatabase db = getWritableDatabase();
int rowsUpdatedInAlarmsTable = db.update(TABLE_ALARMS,
return db.update(TABLE_ALARMS,
toContentValues(newAlarm),
COLUMN_ID + " = " + newAlarm.id(),
null);
int rowsUpdatedInRecurrencesTable = db.update(TABLE_ALARM_RECURRING_DAYS,
toRecurrenceContentValues(newAlarm.id(), newAlarm),
COLUMN_ALARM_ID + " = " + newAlarm.id(),
null);
if (rowsUpdatedInAlarmsTable == rowsUpdatedInRecurrencesTable && rowsUpdatedInAlarmsTable == 1) {
return 1;
}
throw new IllegalStateException("rows updated in TABLE_ALARMS = " + rowsUpdatedInAlarmsTable +
", rows updated in TABLE_ALARM_RECURRING_DAYS = " + rowsUpdatedInRecurrencesTable);
}
public int updateAlarm(long id, Alarm newAlarm) {
newAlarm.setId(id);
SQLiteDatabase db = getWritableDatabase();
int rowsUpdatedInAlarmsTable = db.update(TABLE_ALARMS,
return db.update(TABLE_ALARMS,
toContentValues(newAlarm),
COLUMN_ID + " = " + id,
null);
int rowsUpdatedInRecurrencesTable = db.update(TABLE_ALARM_RECURRING_DAYS,
toRecurrenceContentValues(id, newAlarm),
COLUMN_ALARM_ID + " = " + id,
null);
if (rowsUpdatedInAlarmsTable == rowsUpdatedInRecurrencesTable && rowsUpdatedInAlarmsTable == 1) {
return 1;
}
throw new IllegalStateException("rows updated in TABLE_ALARMS = " + rowsUpdatedInAlarmsTable +
", rows updated in TABLE_ALARM_RECURRING_DAYS = " + rowsUpdatedInRecurrencesTable);
}
public int deleteAlarm(Alarm alarm) {
SQLiteDatabase db = getWritableDatabase();
int rowsDeletedInAlarmsTable = db.delete(TABLE_ALARMS,
return db.delete(TABLE_ALARMS,
COLUMN_ID + " = " + alarm.id(),
null);
int rowsDeletedInRecurrencesTable = db.delete(TABLE_ALARM_RECURRING_DAYS,
COLUMN_ALARM_ID + " = " + alarm.id(),
null);
if (rowsDeletedInAlarmsTable == rowsDeletedInRecurrencesTable && rowsDeletedInAlarmsTable == 1) {
return 1;
}
throw new IllegalStateException("rows deleted in TABLE_ALARMS = " + rowsDeletedInAlarmsTable +
", rows deleted in TABLE_ALARM_RECURRING_DAYS = " + rowsDeletedInRecurrencesTable);
}
public AlarmCursor queryAlarm(long id) {
Cursor alarmCursor = getReadableDatabase().query(TABLE_ALARMS,
Cursor c = getReadableDatabase().query(TABLE_ALARMS,
null, // All columns
COLUMN_ID + " = " + id, // Selection for this alarm id
null, // selection args, none b/c id already specified in selection
@ -185,24 +144,14 @@ public class AlarmDatabaseHelper extends SQLiteOpenHelper {
null, // order/sort by
null, // having
"1"); // limit 1 row
Cursor recurrenceCursor = getReadableDatabase().query(TABLE_ALARM_RECURRING_DAYS,
null, // All columns
COLUMN_ALARM_ID + " = " + id, // selection
null, // selection args
null, // group by
null, // order by
null, // having
"1");
return new AlarmCursor(alarmCursor, recurrenceCursor);
return new AlarmCursor(c);
}
public AlarmCursor queryAlarms() {
// Select all rows and columns from both tables
Cursor alarmCursor = getReadableDatabase().query(TABLE_ALARMS,
null, null, null, null, null, null);
Cursor recurrenceCursor = getReadableDatabase().query(TABLE_ALARM_RECURRING_DAYS,
null, null, null, null, null, null);
return new AlarmCursor(alarmCursor, recurrenceCursor);
// Select all rows and columns
Cursor c = getReadableDatabase().query(TABLE_ALARMS,
null, null, null, null, null, SORT_ORDER);
return new AlarmCursor(c);
}
private ContentValues toContentValues(Alarm alarm) {
@ -213,15 +162,8 @@ public class AlarmDatabaseHelper extends SQLiteOpenHelper {
values.put(COLUMN_RINGTONE, alarm.ringtone());
values.put(COLUMN_VIBRATES, alarm.vibrates());
values.put(COLUMN_ENABLED, alarm.isEnabled());
values.put(COLUMN_RING_TIME_MILLIS, alarm.ringsAt());
values.put(COLUMN_SNOOZING_UNTIL_MILLIS, alarm.snoozingUntil());
return values;
}
// Even though the current impl of insertAlarm() sets the given id on the alarm, we require it
// as a param just as an extra measure, in case you happen to not set it.
private ContentValues toRecurrenceContentValues(long id, Alarm alarm) {
ContentValues values = new ContentValues();
values.put(COLUMN_ALARM_ID, id); // *could* have used alarm.id() instead
values.put(COLUMN_SUNDAY, alarm.isRecurring(SUNDAY));
values.put(COLUMN_MONDAY, alarm.isRecurring(MONDAY));
values.put(COLUMN_TUESDAY, alarm.isRecurring(TUESDAY));
@ -232,13 +174,17 @@ public class AlarmDatabaseHelper extends SQLiteOpenHelper {
return values;
}
// An alternative method to creating an Alarm from a cursor is to
// make an Alarm constructor that takes an Cursor param. However,
// this method has the advantage of keeping all the constants
// contained within this file. Another advantage is the contents of
// the Alarm class remain as pure Java, which can facilitate unit testing
// because it has no dependence on Cursor, which is part of the Android
// SDK.
public static class AlarmCursor extends CursorWrapper {
private final Cursor mRecurrenceCursor;
public AlarmCursor(Cursor alarmCursor, Cursor recurrenceCursor) {
super(alarmCursor);
mRecurrenceCursor = recurrenceCursor;
public AlarmCursor(Cursor c) {
super(c);
}
/**
@ -248,34 +194,37 @@ public class AlarmDatabaseHelper extends SQLiteOpenHelper {
public Alarm getAlarm() {
if (isBeforeFirst() || isAfterLast())
return null;
// TODO: Use getColumnIndexOrThrow()
Alarm alarm = Alarm.builder()
.hour(getInt(getColumnIndex(COLUMN_HOUR)))
.minutes(getInt(getColumnIndex(COLUMN_MINUTES)))
.vibrates(getInt(getColumnIndex(COLUMN_VIBRATES)) == 1)
.vibrates(isTrue(COLUMN_VIBRATES))
.ringtone(getString(getColumnIndex(COLUMN_RINGTONE)))
.label(getString(getColumnIndex(COLUMN_LABEL)))
.build();
alarm.setId(getLong(getColumnIndex(COLUMN_ID)));
alarm.setEnabled(getInt(getColumnIndex(COLUMN_ENABLED)) == 1);
alarm.setEnabled(isTrue(COLUMN_ENABLED));
alarm.setSnoozing(getLong(getColumnIndex(COLUMN_SNOOZING_UNTIL_MILLIS)));
// DatabaseManager moves the primary cursor for you. However, you are responsible
// for moving the recurrence cursor yourself, because it is private to this class.
if (mRecurrenceCursor.moveToNext()) {
alarm.setRecurring(SUNDAY, isRecurring(INDEX_SUNDAY));
alarm.setRecurring(MONDAY, isRecurring(INDEX_MONDAY));
alarm.setRecurring(TUESDAY, isRecurring(INDEX_TUESDAY));
alarm.setRecurring(WEDNESDAY, isRecurring(INDEX_WEDNESDAY));
alarm.setRecurring(THURSDAY, isRecurring(INDEX_THURSDAY));
alarm.setRecurring(FRIDAY, isRecurring(INDEX_FRIDAY));
alarm.setRecurring(SATURDAY, isRecurring(INDEX_SATURDAY));
} else {
throw new IllegalStateException("No entry in recurrence table for alarm: " + alarm);
}
alarm.setRecurring(SUNDAY, isTrue(COLUMN_SUNDAY));
alarm.setRecurring(MONDAY, isTrue(COLUMN_MONDAY));
alarm.setRecurring(TUESDAY, isTrue(COLUMN_TUESDAY));
alarm.setRecurring(WEDNESDAY, isTrue(COLUMN_WEDNESDAY));
alarm.setRecurring(THURSDAY, isTrue(COLUMN_THURSDAY));
alarm.setRecurring(FRIDAY, isTrue(COLUMN_FRIDAY));
alarm.setRecurring(SATURDAY, isTrue(COLUMN_SATURDAY));
return alarm;
}
private boolean isRecurring(int dayColumnIndex) {
return mRecurrenceCursor.getInt(dayColumnIndex) == 1;
public long getId() {
if (isBeforeFirst() || isAfterLast()) {
Log.e(TAG, "Failed to retrieve id, cursor out of range");
return -1;
}
return getLong(getColumnIndexOrThrow(COLUMN_ID));
}
private boolean isTrue(String columnName) {
return getInt(getColumnIndex(columnName)) == 1;
}
}
}

View File

@ -0,0 +1,19 @@
package com.philliphsu.clock2.model;
import android.content.Context;
import android.database.Cursor;
/**
* Created by Phillip Hsu on 6/28/2016.
*/
public class AlarmsListCursorLoader extends SQLiteCursorLoader {
public AlarmsListCursorLoader(Context context) {
super(context);
}
@Override
protected Cursor loadCursor() {
return DatabaseManager.getInstance(getContext()).queryAlarms();
}
}

View File

@ -3,6 +3,7 @@ package com.philliphsu.clock2.model;
import android.content.Context;
import com.philliphsu.clock2.Alarm;
import com.philliphsu.clock2.model.AlarmDatabaseHelper.AlarmCursor;
import java.util.ArrayList;
@ -34,7 +35,8 @@ public class DatabaseManager {
}
/**
* @deprecated Use {@link #updateAlarm(long, Alarm)} instead
* @deprecated Use {@link #updateAlarm(long, Alarm)} instead, because all
* that is needed from the oldAlarm is its id.
*/
@Deprecated
public int updateAlarm(Alarm oldAlarm, Alarm newAlarm) {
@ -52,7 +54,7 @@ public class DatabaseManager {
// Since the query returns at most one row, just return the Alarm the row represents.
public Alarm getAlarm(long id) {
Alarm alarm = null;
AlarmDatabaseHelper.AlarmCursor cursor = mHelper.queryAlarm(id);
AlarmCursor cursor = mHelper.queryAlarm(id);
if (cursor != null && cursor.moveToFirst()) {
alarm = cursor.getAlarm();
cursor.close();
@ -60,9 +62,11 @@ public class DatabaseManager {
return alarm;
}
/** @deprecated Use {@link #queryAlarms()} */
@Deprecated
public ArrayList<Alarm> getAlarms() {
ArrayList<Alarm> alarms = new ArrayList<>();
AlarmDatabaseHelper.AlarmCursor cursor = mHelper.queryAlarms();
AlarmCursor cursor = mHelper.queryAlarms();
if (cursor != null) {
while (cursor.moveToNext()) {
alarms.add(cursor.getAlarm());
@ -71,4 +75,8 @@ public class DatabaseManager {
}
return alarms;
}
public AlarmCursor queryAlarms() {
return mHelper.queryAlarms();
}
}

View File

@ -0,0 +1,84 @@
package com.philliphsu.clock2.model;
import android.content.Context;
import android.database.Cursor;
import android.support.v4.content.AsyncTaskLoader;
/**
* Created by Phillip Hsu on 6/28/2016.
*
* Efficiently loads and holds a Cursor.
*/
public abstract class SQLiteCursorLoader extends AsyncTaskLoader<Cursor> {
private Cursor mCursor;
public SQLiteCursorLoader(Context context) {
super(context);
}
protected abstract Cursor loadCursor();
@Override
public Cursor loadInBackground() {
Cursor cursor = loadCursor();
if (cursor != null) {
// Ensure that the content window is filled
// Ensure that the data is available in memory once it is
// passed to the main thread
cursor.getCount();
}
return cursor;
}
@Override
public void deliverResult(Cursor data) {
Cursor oldCursor = mCursor;
mCursor = data;
if (isStarted()) {
super.deliverResult(data);
}
// Close the old cursor because it is no longer needed.
// Because an existing cursor may be cached and redelivered, it is important
// to make sure that the old cursor and the new cursor are not the
// same before the old cursor is closed.
if (oldCursor != null && oldCursor != data && !oldCursor.isClosed()) {
oldCursor.close();
}
}
// Refer to the docs if you wish to understand the rest of the API as used below.
@Override
protected void onStartLoading() {
if (mCursor != null) {
deliverResult(mCursor);
}
if (takeContentChanged() || mCursor == null) {
forceLoad();
}
}
@Override
protected void onStopLoading() {
// Attempt to cancel the current load task if possible.
cancelLoad();
}
@Override
public void onCanceled(Cursor cursor) {
if (cursor != null && !cursor.isClosed()) {
cursor.close();
}
}
@Override
protected void onReset() {
super.onReset();
// Ensure the loader is stopped
onStopLoading();
if (mCursor != null && !mCursor.isClosed()) {
mCursor.close();
}
mCursor = null;
}
}