Android Open Source - Fall_Prevention_2013 Content Provider Helper

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License

The source code is released under:

Apache License

Java Source Code

/*******************************************************************************
 * Licensed to UbiCollab.org under one or more contributor
 * license agreements.  See the NOTICE file distributed 
 * with this work for additional information regarding
 * copyright ownership. UbiCollab.org licenses this file
 * to you under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 * /*  ww  w .  j a v  a2  s . c  o  m*/
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 ******************************************************************************/
package ntnu.stud.valens.contentprovider.calculations;

import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.TimeUnit;

import android.annotation.SuppressLint;
import android.content.ContentProviderClient;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteConstraintException;
import android.net.Uri;
import android.os.RemoteException;
import android.util.Log;

/**
 * Class that provides an interface to the content provider for the calculation
 * subapp.
 * 
 * @author Elias
 */
@SuppressLint("NewApi")
public class ContentProviderHelper {

    private static final String TAG = "ntnu.stud.valens.contentprovider.calculations";

    private Context context;

    public ContentProviderHelper(Context context) {
        this.context = context;
    }

    /**
     * Fetches the timestamps of all raw steps that occurred between the two
     * timestamps start and stop. Sorts them by source and returns lists of
     * lists of timestamps where each list correlate to a source.
     * 
     * @param start - Get steps that occurred after this timestamp.
     * @param stop - Get steps that occurred before this timestamp.
     * @return A list of list of step timestamps.
     */
    public List<List<Long>> getRawSteps(Timestamp start, Timestamp stop) {
      Log.v(TAG, "getRawSteps");
        List<Long> rawSteps = new ArrayList<Long>();
        List<List<Long>> sortedSteps = new ArrayList<List<Long>>();

        // Find the content provider using a unique resource identifier (URI)
        Uri uri = Uri.parse("content://ntnu.stud.valens.contentprovider");
        ContentProviderClient stepsProvider = context.getContentResolver()
                .acquireContentProviderClient(uri);

        // Setting variables for the query
        uri = Uri.parse("content://ntnu.stud.valens.contentprovider/raw_steps");
        // sets the projection part of the query
        String[] projection = new String[] {
                "timestamp", "source"
        };
        // sets the selection part of the query
        String selection = "timestamp > " + start.getTime() +
                " AND timestamp < " + stop.getTime();

        // not used, therefore null
        String[] selectionArgs = null;
        // no need for sorting
        String sortOrder = "source DESC";

        // Try do ask the content provider for information
        Cursor cursor;
        try {
            cursor = stepsProvider.query(uri, projection, selection,
                    selectionArgs, sortOrder);
            Log.v(TAG, "Size of cursor:" + String.valueOf(cursor.getCount()));
            String prevSource = "";
            if (cursor.getCount() > 0) {
                cursor.moveToPosition(0);
                prevSource = cursor.getString(1);

                for (int i = 0; i < cursor.getCount(); i++) {
                    cursor.moveToPosition(i);
                    Log.v(TAG, "Cursor now at position: " + i + "/n" + "and is about to add : "
                            + String.valueOf(cursor.getLong(0)));
                    if (!prevSource.equals(cursor.getString(1))) {
                        Log.v(TAG, "Size of current rawsteps: " + rawSteps.size());
                        sortedSteps.add(new ArrayList<Long>(rawSteps));
                        prevSource = cursor.getString(1);
                        rawSteps.clear();
                    }
                    rawSteps.add(cursor.getLong(0));
                    
                }
                if(rawSteps.size()>0){
                sortedSteps.add(new ArrayList<Long>(rawSteps));
                }
                Log.v(TAG, "size of sortedSteps: " + sortedSteps.size());
            }
            else {
                Log.v(TAG, "No rows found in content provider. Exiting calculations.");
            }
            cursor.close();
        } catch (RemoteException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return sortedSteps;
    }

    /**
     * Returns timestamp for number of hours counting backwards
     * 
     * @param hours - 0 means current, 24 means 24 hours back, etc
     * @return
     */
    public static Timestamp getHoursBack(int hours) {

        return new Timestamp(System.currentTimeMillis()
                - TimeUnit.MILLISECONDS.convert(hours, TimeUnit.HOURS));
    }

    /**
     * @param steps
     */
    public void storeTrueSteps(List<Long> steps) {
        Uri uri = Uri
                .parse("content://ntnu.stud.valens.contentprovider/steps/");

        for (Long step : steps) {
          try {
            // Define the row to insert
            ContentValues rowToInsert = new ContentValues();
            rowToInsert.put("timestamp", step);
            // Insert row, hoping that everything works as expected.
            context.getContentResolver().insert(uri, rowToInsert);
          } catch (SQLiteConstraintException e) {
            Log.e(TAG, "SQLConstraintException when insterting step");
          }
        }
    }

    /**
     * @param gaitParameters
     */
    public void storeGaitParameters(double[] gaitParameters, List<Long> steps) {
        Uri uri = Uri
                .parse("content://ntnu.stud.valens.contentprovider/gaits/");
        double gaitSpeed = gaitParameters[0];
        double gaitVariability = gaitParameters[1];

        if (steps.size() > 0) {
            Collections.sort(steps);
            long start = steps.get(0);
            long stop = steps.get(steps.size() - 1);

            // Define the row to insert
            ContentValues rowToInsert = new ContentValues();
            rowToInsert.put("speed", gaitSpeed);
            rowToInsert.put("variability", gaitVariability);
            rowToInsert.put("start", start);
            rowToInsert.put("stop", stop);
            // Insert row, hoping that everything works as expected.
            context.getContentResolver().insert(uri, rowToInsert);
        }
    }

}

Java Source Code List

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