Java tutorial
/** * TrackerService.java * Implements the app's movement tracker service * The TrackerService creates a Track object and displays a notification * * This file is part of * TRACKBOOK - Movement Recorder for Android * * Copyright (c) 2016-17 - Y20K.org * Licensed under the MIT-License * http://opensource.org/licenses/MIT * * Trackbook uses osmdroid - OpenStreetMap-Tools for Android * https://github.com/osmdroid/osmdroid */ package org.y20k.trackbook; import android.app.Service; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.content.SharedPreferences; import android.database.ContentObserver; import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; import android.location.Location; import android.location.LocationListener; import android.location.LocationManager; import android.os.AsyncTask; import android.os.Bundle; import android.os.CountDownTimer; import android.os.Handler; import android.os.IBinder; import android.preference.PreferenceManager; import android.support.annotation.Nullable; import android.support.v4.content.LocalBroadcastManager; import android.widget.Toast; import org.y20k.trackbook.core.Track; import org.y20k.trackbook.core.WayPoint; import org.y20k.trackbook.helpers.LocationHelper; import org.y20k.trackbook.helpers.LogHelper; import org.y20k.trackbook.helpers.NotificationHelper; import org.y20k.trackbook.helpers.StorageHelper; import org.y20k.trackbook.helpers.TrackbookKeys; import java.util.List; /** * TrackerService class */ public class TrackerService extends Service implements TrackbookKeys, SensorEventListener { /* Define log tag */ private static final String LOG_TAG = TrackerService.class.getSimpleName(); /* Main class variables */ private Track mTrack; private CountDownTimer mTimer; private LocationManager mLocationManager; private SensorManager mSensorManager; private float mStepCountOffset; private LocationListener mGPSListener = null; private LocationListener mNetworkListener = null; private SettingsContentObserver mSettingsContentObserver; private Location mCurrentBestLocation; private BroadcastReceiver mTrackRequestReceiver; private boolean mTrackerServiceRunning; private boolean mLocationSystemSetting; @Override public int onStartCommand(Intent intent, int flags, int startId) { // listen for finished save operation mTrackRequestReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { sendTrackUpdate(); } }; IntentFilter trackRequestReceiverIntentFilter = new IntentFilter(ACTION_TRACK_REQUEST); LocalBroadcastManager.getInstance(this).registerReceiver(mTrackRequestReceiver, trackRequestReceiverIntentFilter); // acquire reference to Location Manager mLocationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE); // acquire reference to Sensor Manager mSensorManager = (SensorManager) this.getSystemService(Context.SENSOR_SERVICE); // get state of location system setting mLocationSystemSetting = LocationHelper.checkLocationSystemSetting(getApplicationContext()); // create content observer for changes in System Settings mSettingsContentObserver = new SettingsContentObserver(new Handler()); // check if user did turn off location in device settings if (!mLocationSystemSetting) { LogHelper.v(LOG_TAG, "Location Setting is turned off."); Toast.makeText(getApplicationContext(), R.string.toast_message_location_offline, Toast.LENGTH_LONG) .show(); stopTracking(); return START_STICKY; } // checking for empty intent if (intent == null) { LogHelper.v(LOG_TAG, "Null-Intent received. Stopping self."); stopSelf(); } // ACTION START else if (intent.getAction().equals(ACTION_START) && mLocationSystemSetting) { startTracking(intent); } // ACTION STOP else if (intent.getAction().equals(ACTION_STOP) || !mLocationSystemSetting) { stopTracking(); // save changed state of Floating Action Button SharedPreferences settings = PreferenceManager .getDefaultSharedPreferences(this.getApplicationContext()); SharedPreferences.Editor editor = settings.edit(); editor.putInt(PREFS_FAB_STATE, FAB_STATE_SAVE); editor.apply(); } // START_STICKY is used for services that are explicitly started and stopped as needed return START_STICKY; } @Nullable @Override public IBinder onBind(Intent intent) { return null; } @Override public void onDestroy() { LogHelper.v(LOG_TAG, "onDestroy called."); // remove receivers and listeners stopFindingLocation(); mSensorManager.unregisterListener(this); LocalBroadcastManager.getInstance(this).unregisterReceiver(mTrackRequestReceiver); // cancel notification stopForeground(true); super.onDestroy(); } @Override public void onSensorChanged(SensorEvent sensorEvent) { // save the step count offset / previously recorded steps if (mStepCountOffset == 0) { mStepCountOffset = sensorEvent.values[0] - 1; } // calculate step count float stepCount = sensorEvent.values[0] - mStepCountOffset; // set step count in track mTrack.setStepCount(stepCount); } @Override public void onAccuracyChanged(Sensor sensor, int i) { } /* Start tracking location */ private void startTracking(Intent intent) { LogHelper.v(LOG_TAG, "Service received command: START"); // create a new track mTrack = new Track(); // get last location if (intent.hasExtra(EXTRA_LAST_LOCATION)) { mCurrentBestLocation = intent.getParcelableExtra(EXTRA_LAST_LOCATION); } // get last location - fallback if (mCurrentBestLocation == null) { mCurrentBestLocation = LocationHelper.determineLastKnownLocation(mLocationManager); } // add last location as WayPoint to track addWayPointToTrack(); // set timer to retrieve new locations and to prevent endless tracking mTimer = new CountDownTimer(EIGHT_HOURS_IN_MILLISECONDS, FIFTEEN_SECONDS_IN_MILLISECONDS) { @Override public void onTick(long millisUntilFinished) { // update track duration long duration = EIGHT_HOURS_IN_MILLISECONDS - millisUntilFinished; mTrack.setDuration(duration); // try to add WayPoint to Track addWayPointToTrack(); // update notification NotificationHelper.update(mTrack, true); } @Override public void onFinish() { // remove listeners stopFindingLocation(); } }; mTimer.start(); // initialize step counter mStepCountOffset = 0; Sensor stepCounter = mSensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER); if (stepCounter != null) { mSensorManager.registerListener(this, stepCounter, SensorManager.SENSOR_DELAY_UI); } else { LogHelper.v(LOG_TAG, "Pedometer Sensor not available"); mTrack.setStepCount(-1); } // put up notification NotificationHelper.show(this, mTrack); // create gps and network location listeners startFindingLocation(); // register content observer for changes in System Settings this.getContentResolver().registerContentObserver(android.provider.Settings.Secure.CONTENT_URI, true, mSettingsContentObserver); } /* Stop tracking location */ private void stopTracking() { LogHelper.v(LOG_TAG, "Service received command: STOP"); // store current date and time mTrack.setRecordingEnd(); // stop timer mTimer.cancel(); // broadcast an updated track sendTrackUpdate(); // save a temp file in case the activity has been killed SaveTempTrackAsyncHelper saveTempTrackAsyncHelper = new SaveTempTrackAsyncHelper(); saveTempTrackAsyncHelper.execute(); // change notification NotificationHelper.update(mTrack, false); // remove listeners stopFindingLocation(); mSensorManager.unregisterListener(this); // disable content observer for changes in System Settings this.getContentResolver().unregisterContentObserver(mSettingsContentObserver); } /* Adds a new WayPoint to current track */ private void addWayPointToTrack() { // create new WayPoint WayPoint newWayPoint = null; // get number of previously tracked WayPoints int trackSize = mTrack.getWayPoints().size(); if (trackSize == 0) { // add first location to track newWayPoint = mTrack.addWayPoint(mCurrentBestLocation); } else { // get last WayPoint and compare it to current location Location lastWayPoint = mTrack.getWayPointLocation(trackSize - 1); // default value for average speed float averageSpeed = 0f; // compute average speed if new location come from network provider if (trackSize > 1 && mCurrentBestLocation.getProvider().equals(LocationManager.NETWORK_PROVIDER)) { Location firstWayPoint = mTrack.getWayPointLocation(0); float distance = firstWayPoint.distanceTo(lastWayPoint); long timeDifference = lastWayPoint.getElapsedRealtimeNanos() - firstWayPoint.getElapsedRealtimeNanos(); averageSpeed = distance / ((float) timeDifference / ONE_NANOSECOND); } if (LocationHelper.isNewWayPoint(lastWayPoint, mCurrentBestLocation, averageSpeed)) { // if new, add current best location to track newWayPoint = mTrack.addWayPoint(mCurrentBestLocation); } } // send local broadcast if new WayPoint added if (newWayPoint != null) { sendTrackUpdate(); } } /* Broadcasts a track update */ private void sendTrackUpdate() { Intent i = new Intent(); i.setAction(ACTION_TRACK_UPDATED); i.putExtra(EXTRA_TRACK, mTrack); i.putExtra(EXTRA_LAST_LOCATION, mCurrentBestLocation); LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(i); } /* Creates a location listener */ private LocationListener createLocationListener() { return new LocationListener() { public void onLocationChanged(Location location) { // check if the new location is better if (LocationHelper.isBetterLocation(location, mCurrentBestLocation)) { // save location mCurrentBestLocation = location; } } public void onStatusChanged(String provider, int status, Bundle extras) { LogHelper.v(LOG_TAG, "Location provider status change: " + provider + " | " + status); } public void onProviderEnabled(String provider) { LogHelper.v(LOG_TAG, "Location provider enabled: " + provider); } public void onProviderDisabled(String provider) { LogHelper.v(LOG_TAG, "Location provider disabled: " + provider); } }; } /* Creates gps and network location listeners */ private void startFindingLocation() { // register location listeners and request updates List locationProviders = mLocationManager.getAllProviders(); if (locationProviders.contains(LocationManager.GPS_PROVIDER)) { mGPSListener = createLocationListener(); mTrackerServiceRunning = true; } if (locationProviders.contains(LocationManager.NETWORK_PROVIDER)) { mNetworkListener = createLocationListener(); mTrackerServiceRunning = true; } LocationHelper.registerLocationListeners(mLocationManager, mGPSListener, mNetworkListener); } /* Removes gps and network location listeners */ private void stopFindingLocation() { // remove listeners LocationHelper.removeLocationListeners(mLocationManager, mGPSListener, mNetworkListener); mTrackerServiceRunning = false; // notify MainActivityMapFragment Intent i = new Intent(); i.setAction(ACTION_TRACKING_STOPPED); i.putExtra(EXTRA_TRACK, mTrack); i.putExtra(EXTRA_LAST_LOCATION, mCurrentBestLocation); LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(i); } /** * Inner class: SettingsContentObserver is a custom ContentObserver for changes in Android Settings */ public class SettingsContentObserver extends ContentObserver { public SettingsContentObserver(Handler handler) { super(handler); } @Override public boolean deliverSelfNotifications() { return super.deliverSelfNotifications(); } @Override public void onChange(boolean selfChange) { super.onChange(selfChange); LogHelper.v(LOG_TAG, "System Setting change detected."); // check if location setting was changed boolean previousLocationSystemSetting = mLocationSystemSetting; mLocationSystemSetting = LocationHelper.checkLocationSystemSetting(getApplicationContext()); if (previousLocationSystemSetting != mLocationSystemSetting && !mLocationSystemSetting && mTrackerServiceRunning) { LogHelper.v(LOG_TAG, "Location Setting turned off while tracking service running."); stopTracking(); stopForeground(true); } } } /** * End of inner class */ /** * Inner class: Saves track to external storage using AsyncTask */ private class SaveTempTrackAsyncHelper extends AsyncTask<Void, Void, Void> { @Override protected Void doInBackground(Void... voids) { LogHelper.v(LOG_TAG, "Saving temporary track object in background."); // save track object StorageHelper storageHelper = new StorageHelper(TrackerService.this); storageHelper.saveTrack(mTrack, FILE_TEMP_TRACK); return null; } @Override protected void onPostExecute(Void aVoid) { super.onPostExecute(aVoid); LogHelper.v(LOG_TAG, "Saving finished."); } } /** * End of inner class */ }