| /* |
| * Copyright (C) 2012 The Android Open Source Project |
| * |
| * Licensed 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 |
| * |
| * 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 com.android.server.location; |
| |
| import android.location.Location; |
| |
| /** |
| * Represents a simple circular GeoFence. |
| */ |
| public class Geofence { |
| public final static int FLAG_ENTER = 0x01; |
| public final static int FLAG_EXIT = 0x02; |
| |
| static final int STATE_UNKNOWN = 0; |
| static final int STATE_INSIDE = 1; |
| static final int STATE_OUTSIDE = 2; |
| |
| final double mLatitude; |
| final double mLongitude; |
| final float mRadius; |
| final Location mLocation; |
| |
| int mState; // current state |
| double mDistance; // current distance to center of fence |
| |
| public Geofence(double latitude, double longitude, float radius, Location prevLocation) { |
| mState = STATE_UNKNOWN; |
| |
| mLatitude = latitude; |
| mLongitude = longitude; |
| mRadius = radius; |
| |
| mLocation = new Location(""); |
| mLocation.setLatitude(latitude); |
| mLocation.setLongitude(longitude); |
| |
| if (prevLocation != null) { |
| processLocation(prevLocation); |
| } |
| } |
| |
| /** |
| * Process a new location. |
| * @return FLAG_ENTER or FLAG_EXIT if the fence was crossed, 0 otherwise |
| */ |
| public int processLocation(Location location) { |
| mDistance = mLocation.distanceTo(location); |
| |
| int prevState = mState; |
| //TODO: inside/outside detection could be made more rigorous |
| boolean inside = mDistance <= Math.max(mRadius, location.getAccuracy()); |
| if (inside) { |
| mState = STATE_INSIDE; |
| } else { |
| mState = STATE_OUTSIDE; |
| } |
| |
| if (prevState != 0 && mState != prevState) { |
| if (mState == STATE_INSIDE) return FLAG_ENTER; |
| if (mState == STATE_OUTSIDE) return FLAG_EXIT; |
| } |
| return 0; |
| } |
| |
| public double getDistance() { |
| return mDistance; |
| } |
| |
| @Override |
| public String toString() { |
| String state; |
| switch (mState) { |
| case STATE_INSIDE: |
| state = "IN"; |
| break; |
| case STATE_OUTSIDE: |
| state = "OUT"; |
| break; |
| default: |
| state = "?"; |
| } |
| return String.format("(%.4f, %.4f r=%.0f d=%.0f %s)", mLatitude, mLongitude, mRadius, |
| mDistance, state); |
| } |
| } |