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Diffstat (limited to 'location/java/android/location/GpsStatus.java')
| -rw-r--r-- | location/java/android/location/GpsStatus.java | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/location/java/android/location/GpsStatus.java b/location/java/android/location/GpsStatus.java new file mode 100644 index 0000000..a40b1fb --- /dev/null +++ b/location/java/android/location/GpsStatus.java @@ -0,0 +1,200 @@ +/* + * Copyright (C) 2008 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 android.location; + +import java.util.Iterator; +import java.util.NoSuchElementException; + + +/** + * This class represents the current state of the GPS engine. + * This class is used in conjunction with the {@link Listener} interface. + */ +public final class GpsStatus { + private static final int NUM_SATELLITES = 32; + + /* These package private values are modified by the LocationManager class */ + private int mTimeToFirstFix; + private GpsSatellite mSatellites[] = new GpsSatellite[NUM_SATELLITES]; + + private final class SatelliteIterator implements Iterator<GpsSatellite> { + + private GpsSatellite[] mSatellites; + int mIndex = 0; + + SatelliteIterator(GpsSatellite[] satellites) { + mSatellites = satellites; + } + + public boolean hasNext() { + for (int i = mIndex; i < mSatellites.length; i++) { + if (mSatellites[i].mValid) { + return true; + } + } + return false; + } + + public GpsSatellite next() { + while (mIndex < mSatellites.length) { + GpsSatellite satellite = mSatellites[mIndex++]; + if (satellite.mValid) { + return satellite; + } + } + throw new NoSuchElementException(); + } + + public void remove() { + throw new UnsupportedOperationException(); + } + } + + private Iterable<GpsSatellite> mSatelliteList = new Iterable<GpsSatellite>() { + public Iterator<GpsSatellite> iterator() { + return new SatelliteIterator(mSatellites); + } + }; + + /** + * Event sent when the GPS system has started. + */ + public static final int GPS_EVENT_STARTED = 1; + + /** + * Event sent when the GPS system has stopped. + */ + public static final int GPS_EVENT_STOPPED = 2; + + /** + * Event sent when the GPS system has received its first fix since starting. + * Call {@link #getTimeToFirstFix()} to find the time from start to first fix. + */ + public static final int GPS_EVENT_FIRST_FIX = 3; + + /** + * Event sent periodically to report GPS satellite status. + * Call {@link #getSatellites()} to retrieve the status for each satellite. + */ + public static final int GPS_EVENT_SATELLITE_STATUS = 4; + + /** + * Used for receiving notifications when GPS status has changed. + */ + public interface Listener { + /** + * Called to report changes in the GPS status. + * The event number is one of: + * <ul> + * <li> {@link GpsStatus#GPS_EVENT_STARTED} + * <li> {@link GpsStatus#GPS_EVENT_STOPPED} + * <li> {@link GpsStatus#GPS_EVENT_FIRST_FIX} + * <li> {@link GpsStatus#GPS_EVENT_SATELLITE_STATUS} + * </ul> + * + * When this method is called, the client should call + * {@link LocationManager#getGpsStatus} to get additional + * status information. + * + * @param event event number for this notification + */ + void onGpsStatusChanged(int event); + } + + GpsStatus() { + for (int i = 0; i < mSatellites.length; i++) { + mSatellites[i] = new GpsSatellite(i + 1); + } + } + + /** + * Used internally within {@link LocationManager} to copy GPS status + * data from the Location Manager Service to its cached GpsStatus instance. + * Is synchronized to ensure that GPS status updates are atomic. + */ + synchronized void setStatus(int svCount, int[] prns, float[] snrs, + float[] elevations, float[] azimuths, int ephemerisMask, + int almanacMask, int usedInFixMask) { + int i; + + for (i = 0; i < mSatellites.length; i++) { + mSatellites[i].mValid = false; + } + + for (i = 0; i < svCount; i++) { + int prn = prns[i] - 1; + int prnShift = (1 << prn); + GpsSatellite satellite = mSatellites[prn]; + + satellite.mValid = true; + satellite.mSnr = snrs[i]; + satellite.mElevation = elevations[i]; + satellite.mAzimuth = azimuths[i]; + satellite.mHasEphemeris = ((ephemerisMask & prnShift) != 0); + satellite.mHasAlmanac = ((almanacMask & prnShift) != 0); + satellite.mUsedInFix = ((usedInFixMask & prnShift) != 0); + } + } + + /** + * Used by {@link LocationManager#getGpsStatus} to copy LocationManager's + * cached GpsStatus instance to the client's copy. + * Since this method is only used within {@link LocationManager#getGpsStatus}, + * it does not need to be synchronized. + */ + void setStatus(GpsStatus status) { + mTimeToFirstFix = status.getTimeToFirstFix(); + + for (int i = 0; i < mSatellites.length; i++) { + mSatellites[i].setStatus(status.mSatellites[i]); + } + } + + void setTimeToFirstFix(int ttff) { + mTimeToFirstFix = ttff; + } + + /** + * Returns the time required to receive the first fix since the most recent + * restart of the GPS engine. + * + * @return time to first fix in milliseconds + */ + public int getTimeToFirstFix() { + return mTimeToFirstFix; + } + + /** + * Returns an array of {@link GpsSatellite} objects, which represent the + * current state of the GPS engine. + * + * @return the list of satellites + */ + public Iterable<GpsSatellite> getSatellites() { + return mSatelliteList; + } + + /** + * Returns the maximum number of satellites that can be in the satellite + * list that can be returned by {@link #getSatellites()}. + * + * @return the maximum number of satellites + */ + public int getMaxSatellites() { + return NUM_SATELLITES; + } +} |