/* * Geopaparazzi - Digital field mapping on Android based devices * Copyright (C) 2016 HydroloGIS (www.hydrologis.com) * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package eu.geopaparazzi.library.database; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.support.v4.content.CursorLoader; import android.support.v4.os.CancellationSignal; import android.support.v4.os.OperationCanceledException; import java.io.FileDescriptor; import java.io.PrintWriter; public class RawSqlCursorLoader extends CursorLoader { final ForceLoadContentObserver mObserver; private Cursor mCursor; CancellationSignal mCancellationSignal; private SQLiteDatabase mDatabase; private String mSql; public RawSqlCursorLoader(Context context, SQLiteDatabase database, String sql) { super(context); mDatabase = database; mSql = sql; mObserver = new ForceLoadContentObserver(); } /* Runs on a worker thread */ @Override public Cursor loadInBackground() { synchronized (this) { if (isLoadInBackgroundCanceled()) { throw new OperationCanceledException(); } mCancellationSignal = new CancellationSignal(); } try { Cursor cursor = mDatabase.rawQuery(mSql, null); if (cursor != null) { try { // Ensure the cursor window is filled. cursor.getCount(); cursor.registerContentObserver(mObserver); } catch (RuntimeException ex) { cursor.close(); throw ex; } } return cursor; } finally { synchronized (this) { mCancellationSignal = null; } } } @Override public void cancelLoadInBackground() { super.cancelLoadInBackground(); synchronized (this) { if (mCancellationSignal != null) { mCancellationSignal.cancel(); } } } /* Runs on the UI thread */ @Override public void deliverResult(Cursor cursor) { if (isReset()) { // An async query came in while the loader is stopped if (cursor != null) { cursor.close(); } return; } Cursor oldCursor = mCursor; mCursor = cursor; if (isStarted()) { super.deliverResult(cursor); } if (oldCursor != null && oldCursor != cursor && !oldCursor.isClosed()) { oldCursor.close(); } } /** * Starts an asynchronous load of the contacts list data. When the result is ready the callbacks * will be called on the UI thread. If a previous load has been completed and is still valid * the result may be passed to the callbacks immediately. * <p/> * Must be called from the UI thread */ @Override protected void onStartLoading() { if (mCursor != null) { deliverResult(mCursor); } if (takeContentChanged() || mCursor == null) { forceLoad(); } } /** * Must be called from the UI thread */ @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; } @Override public void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args) { super.dump(prefix, fd, writer, args); writer.print(prefix); writer.print("mSql="); writer.println(mSql); writer.print(prefix); writer.print("mCursor="); writer.println(mCursor); } }