Added DB helper and related location code

code/ContextAnalyser/src/uk/co/md87/android/contextanalyser/DataHelper.java

@@ -0,0 +1,127 @@
+/*
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+package uk.co.md87.android.contextanalyser;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+import android.database.sqlite.SQLiteStatement;
+import android.location.Location;
+
+/**
+ *
+ * @author chris
+ */
+public class DataHelper {
+
+    private static final String LOCATIONS_TABLE = "locations";
+    private static final String DATABASE_NAME = "contextapi.db";
+    private static final int DATABASE_VERSION = 1;
+
+    private static final String INSERT_LOCATION = "insert into "
+      + LOCATIONS_TABLE + "(name, lat, lon) values (?, ?, ?)";
+    private static final String LOCATION_QUERY = "lat > %1$s - 0.005 and "
+            + "lat < %1$s + 0.005 and lon > %2$s - 0.01 and lon < %2$s + 0.01";
+
+    private final SQLiteStatement insertLocationStatement;
+
+    private final Context context;
+    private SQLiteDatabase db;
+
+    public DataHelper(final Context context) {
+        this.context = context;
+
+        final OpenHelper helper = new OpenHelper(context);
+        this.db = helper.getWritableDatabase();
+        this.insertLocationStatement = db.compileStatement(INSERT_LOCATION);
+    }
+
+    public long addLocation(final String name, final double lat, final double lon) {
+        insertLocationStatement.bindString(1, name);
+        insertLocationStatement.bindDouble(2, lat);
+        insertLocationStatement.bindDouble(3, lon);
+        return insertLocationStatement.executeInsert();
+    }
+
+    public LocationResult findLocation(final double lat, final double lon) {
+        final Cursor cursor = db.query(LOCATIONS_TABLE,
+                new String[] { "id", "name", "lat", "lon" },
+                String.format(LOCATION_QUERY, lat, lon), null, null, null, null);
+
+        if (cursor.moveToFirst()) {
+            do {
+                final float[] res = new float[1];
+                Location.distanceBetween(lat, lon, cursor.getDouble(2), cursor.getDouble(3), res);
+
+                if (res[0] <= 500) {
+                    return new LocationResult(cursor.getLong(0), cursor.getString(1),
+                            cursor.getDouble(2), cursor.getDouble(3));
+                }
+            } while (cursor.moveToNext());
+        }
+
+        if (cursor != null && !cursor.isClosed()) {
+            cursor.close();
+        }
+
+        return null;
+    }
+
+    public static class LocationResult {
+
+        private final long id;
+        private final String name;
+        private final double lat, lon;
+
+        public LocationResult(long id, String name, double lat, double lon) {
+            this.id = id;
+            this.name = name;
+            this.lat = lat;
+            this.lon = lon;
+        }
+
+        public long getId() {
+            return id;
+        }
+
+        public double getLat() {
+            return lat;
+        }
+
+        public double getLon() {
+            return lon;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+    }
+
+    private static class OpenHelper extends SQLiteOpenHelper {
+
+        public OpenHelper(final Context context) {
+            super(context, DATABASE_NAME, null, DATABASE_VERSION);
+        }
+
+        /** {@inheritDoc} */
+        @Override
+        public void onCreate(final SQLiteDatabase db) {
+            db.execSQL("CREATE TABLE " + LOCATIONS_TABLE
+                    + " (id INTEGER PRIMARY KEY, name TEXT, lon REAL, lat REAL)");
+        }
+
+        /** {@inheritDoc} */
+        @Override
+        public void onUpgrade(final SQLiteDatabase db, final int oldVersion,
+                final int newVersion) {
+            // Do nothing. Yet.
+        }
+
+    }
+
+}