Added feature to log SignalStrength and GPS coordinates to a separate logfile

app/src/main/AndroidManifest.xml

@@ -10,7 +10,10 @@
 
     <!-- Internet is used to connect to local and remote rtl_tcp instances -->
     <uses-permission android:name="android.permission.INTERNET" />
-
+
+    <!-- GPS is used for mapping signal strength -->
+    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
+
     <!-- Declare permissions to read and write the bookmarks database -->
     <permission android:name="com.mantz_it.rfanalyzer.permission.READ_BOOKMARKS"
                 android:label="Read access to the bookmarks of RF Analyzer" />

app/src/main/java/com/mantz_it/rfanalyzer/AnalyzerSurface.java

@@ -136,6 +136,7 @@ public class AnalyzerSurface extends SurfaceView implements SurfaceHolder.Callba
 	private int fontSize = FONT_SIZE_MEDIUM;		// Indicates the font size of the grid labels
 	private boolean showDebugInformation = false;
 
+	public static float averageSignalStrength = -9999;	// avg magnitude of the signal in the center of the selected channel. pulled out of draw() function to let GPS-logging access it
 
 	/**
 	 * Constructor. Will initialize the Paint instances and register the callback
@@ -1019,20 +1020,19 @@ public void draw(float[] mag, long frequency, int sampleRate, int frameRate, dou
 		}
 
 		// Update squelchSatisfied:
-		float averageSignalStrengh = -9999;		// avg magnitude of the signal in the center of the selected channel
 		if(demodulationEnabled) {
 			float sum = 0;
 			int chanStart = (int) ((channelFrequency - (frequency-sampleRate/2) - channelWidth/2) * samplesPerHz);
 			int chanEnd = (int)(chanStart + channelWidth * samplesPerHz);
 			if(chanStart > 0 && chanEnd <= mag.length) {
 				for (int i = chanStart; i < chanEnd; i++)
 					sum += mag[i];
-				averageSignalStrengh = sum / (chanEnd - chanStart);
-				if(averageSignalStrengh >= squelch && squelchSatisfied==false) {
+				averageSignalStrength = sum / (chanEnd - chanStart);
+				if(averageSignalStrength >= squelch && squelchSatisfied==false) {
 					squelchSatisfied = true;
 					this.squelchPaint.setColor(Color.GREEN);
 					rfControlInterface.updateSquelchSatisfied(squelchSatisfied);
-				} else if (averageSignalStrengh < squelch && squelchSatisfied==true) {
+				} else if (averageSignalStrength < squelch && squelchSatisfied==true) {
 					squelchSatisfied = false;
 					this.squelchPaint.setColor(Color.RED);
 					rfControlInterface.updateSquelchSatisfied(squelchSatisfied);
@@ -1053,7 +1053,7 @@ public void draw(float[] mag, long frequency, int sampleRate, int frameRate, dou
 					drawWaterfall(c);
 					drawFrequencyGrid(c);
 					drawPowerGrid(c);
-					drawPerformanceInfo(c, frameRate, load, averageSignalStrengh);
+					drawPerformanceInfo(c, frameRate, load, averageSignalStrength);
 				} else
 					Log.d(LOGTAG, "draw: Canvas is null.");
 			}

app/src/main/java/com/mantz_it/rfanalyzer/MainActivity.java

@@ -37,6 +37,10 @@
 import android.widget.Switch;
 import android.widget.TextView;
 import android.widget.Toast;
+import android.location.Location;
+import android.location.LocationListener;
+import android.location.LocationManager;
+import android.content.Context;
 
 import java.io.BufferedOutputStream;
 import java.io.File;
@@ -45,6 +49,9 @@
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Locale;
+import java.util.Calendar;
+import java.io.PrintWriter;
+import java.io.FileWriter;
 
 /**
  * <h1>RF Analyzer - Main Activity</h1>
@@ -71,7 +78,7 @@
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
-public class MainActivity extends AppCompatActivity implements IQSourceInterface.Callback, RFControlInterface {
+public class MainActivity extends AppCompatActivity implements IQSourceInterface.Callback, RFControlInterface, LocationListener {
 
 	private MenuItem mi_startStop = null;
 	private MenuItem mi_demodulationMode = null;
@@ -97,11 +104,15 @@ public class MainActivity extends AppCompatActivity implements IQSourceInterface
 																				// permission to open file for the file source
 	public static final int PERMISSION_REQUEST_RECORDING_WRITE_FILES = 1112;	// arbitrary value, used when requesting
 																				// permission to write file for the recording feature
+	public static final int PERMISSION_REQUEST_ACCESS_FINE_LOCATION = 1113; 	// arbitrary value, used when requesting
+																				// permission to access GPS
 	private static final int FILE_SOURCE = 0;
 	private static final int HACKRF_SOURCE = 1;
 	private static final int RTLSDR_SOURCE = 2;
 	private static final String[] SOURCE_NAMES = new String[] {"filesource", "hackrf", "rtlsdr"};
 
+	private LocationManager locationManager;
+
 	@Override
 	protected void onCreate(Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
@@ -143,6 +154,33 @@ protected void onCreate(Bundle savedInstanceState) {
 			}
 		}
 
+		// GPS file:
+		defaultFile = getString(R.string.pref_gpsfile_default);
+		if(preferences.getString(getString(R.string.pref_gpsfile), "").equals(defaultFile))
+			preferences.edit().putString(getString(R.string.pref_gpsfile), extStorage + "/" + defaultFile).apply();
+
+		// Start GPS if enabled:
+		if(preferences.getBoolean(getString(R.string.pref_gps), false)) {
+			// Request permission for GPS
+			if (ContextCompat.checkSelfPermission(this,
+					android.Manifest.permission.ACCESS_FINE_LOCATION)
+					!= PackageManager.PERMISSION_GRANTED) {
+					ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, PERMISSION_REQUEST_ACCESS_FINE_LOCATION);
+			}
+			else {
+				// Permissions OK - Activate GPS
+				locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
+				locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 1, this);
+			}
+
+			if (ContextCompat.checkSelfPermission(this, "android.permission.WRITE_EXTERNAL_STORAGE")
+					== PackageManager.PERMISSION_GRANTED) {
+			} else {
+				preferences.edit().putBoolean(getString(R.string.pref_gps), false).apply();
+				Log.i(LOGTAG, "onCreate: deactivate GPS logging because of missing storage permission.");
+			}
+		}
+
 		// Get version name:
 		try {
 			versionName = getPackageManager().getPackageInfo(getPackageName(), 0).versionName;
@@ -215,7 +253,46 @@ public void run() {
 		setVolumeControlStream(AudioManager.STREAM_MUSIC);
 	}
 
-	@Override
+
+    @Override
+    public void onLocationChanged(Location location) {
+		if (running && demodulationMode != Demodulator.DEMODULATION_OFF) {
+			// Message on screen
+			String msg = "Latitude: " + location.getLatitude() + "\n"
+						+ "Longitude: " + location.getLongitude() + "\n"
+						+ "SignalStrength: " + String.format(Locale.US, "%.1f dB", AnalyzerSurface.averageSignalStrength);
+			Toast.makeText(getBaseContext(), msg, Toast.LENGTH_SHORT).show();
+
+			// Log to disk
+			try {
+				Calendar c = Calendar.getInstance();
+				SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+				String datetime = df.format(c.getTime());
+
+				PrintWriter GPSLOG = new PrintWriter(new FileWriter(preferences.getString(getString(R.string.pref_gpsfile), ""), true));
+				GPSLOG.printf("%s\t%s\t%s\t%s\n", datetime, location.getLatitude(), location.getLongitude(), String.format(Locale.US, "%.1f", AnalyzerSurface.averageSignalStrength));
+				GPSLOG.flush();
+				GPSLOG.close();
+			} catch (Exception e) {
+				Log.e(LOGTAG, "onLocationChanged: couldn't log: " + e.getMessage());
+			}
+		}
+	}
+
+
+    @Override
+    public void onProviderDisabled(String provider) {
+    }
+
+    @Override
+    public void onProviderEnabled(String provider) {
+    }
+
+    @Override
+    public void onStatusChanged(String provider, int status, Bundle extras) {
+    }
+
+    @Override
 	protected void onDestroy() {
 		super.onDestroy();
 		// close source
@@ -245,6 +322,15 @@ protected void onDestroy() {
 				Log.e(LOGTAG, "onDestroy: RTL2832U is not installed");
 			}
 		}
+		// stop GPS if active:
+		boolean gps_enabled = false;
+		try {
+			gps_enabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
+		}
+		catch (Exception ex) {}
+		if(gps_enabled) {
+			locationManager.removeUpdates(this);
+		}
 	}
 
 	@Override
@@ -502,6 +588,14 @@ public void onRequestPermissionsResult(int requestCode, String permissions[], in
 				}
 				break;
 			}
+			case PERMISSION_REQUEST_ACCESS_FINE_LOCATION: {
+				// If request is cancelled, the result arrays are empty.
+				if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+					locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
+					locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 1, this);
+				}
+				break;
+			}
 		}
 	}
 

app/src/main/java/com/mantz_it/rfanalyzer/SettingsActivity.java

@@ -59,6 +59,7 @@ public void onRequestPermissionsResult(int requestCode, String permissions[], in
 					Log.i(LOGTAG, "onRequestPermissionResult: User denied to write files for logging. deactivate setting..");
 					SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
 					preferences.edit().putBoolean(getString(R.string.pref_logging), false).apply();
+					preferences.edit().putBoolean(getString(R.string.pref_gps), false).apply();
 				}
 			}
 		}

app/src/main/java/com/mantz_it/rfanalyzer/SettingsFragment.java

@@ -24,6 +24,7 @@
 import java.io.File;
 
 import static com.mantz_it.rfanalyzer.SettingsActivity.PERMISSION_REQUEST_LOGGING_WRITE_FILES;
+import static com.mantz_it.rfanalyzer.MainActivity.PERMISSION_REQUEST_ACCESS_FINE_LOCATION;
 
 /**
  * <h1>RF Analyzer - Settings Fragment</h1>
@@ -167,6 +168,22 @@ public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, Strin
 						PERMISSION_REQUEST_LOGGING_WRITE_FILES);
 			}
 		}
+
+		// check WRITE_EXTERNAL_STORAGE and ACCESS_FINE_LOCATION permission if GPS is active:
+		if(sharedPreferences.getBoolean(getString(R.string.pref_gps), false)) {
+			if (ContextCompat.checkSelfPermission(this.getActivity(), "android.permission.WRITE_EXTERNAL_STORAGE")
+					!= PackageManager.PERMISSION_GRANTED) {
+				// request permission:
+				ActivityCompat.requestPermissions(this.getActivity(), new String[]{"android.permission.WRITE_EXTERNAL_STORAGE"},
+						PERMISSION_REQUEST_LOGGING_WRITE_FILES);
+			}
+			if (ContextCompat.checkSelfPermission(this.getActivity(), "android.permission.ACCESS_FINE_LOCATION")
+					!= PackageManager.PERMISSION_GRANTED) {
+				// request permission:
+				ActivityCompat.requestPermissions(this.getActivity(), new String[]{"android.permission.ACCESS_FINE_LOCATION"},
+						PERMISSION_REQUEST_ACCESS_FINE_LOCATION);
+			}
+		}
 	}
 
 	/**
@@ -260,13 +277,19 @@ public void updateSummaries() {
 		else
 			listPref.setSummary(getString(R.string.pref_frameRate_summ, listPref.getEntry()));
 
+		// GPSfile
+		editTextPref = (EditTextPreference) findPreference(getString(R.string.pref_gpsfile));
+		editTextPref.setSummary(getString(R.string.pref_gpsfile_summ, editTextPref.getText()));
+
 		// Logfile
 		editTextPref = (EditTextPreference) findPreference(getString(R.string.pref_logfile));
 		editTextPref.setSummary(getString(R.string.pref_logfile_summ, editTextPref.getText()));
 
 		// Shared preferences updated in e.g. the onRequestPermissionResult() method are
 		// not automatically updated in the preference fragment gui. do it manually:
 		SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this.getActivity());
+		switchPref = (SwitchPreference) findPreference(getString(R.string.pref_gps));
+		switchPref.setChecked(preferences.getBoolean(getString(R.string.pref_gps), false));
 		switchPref = (SwitchPreference) findPreference(getString(R.string.pref_logging));
 		switchPref.setChecked(preferences.getBoolean(getString(R.string.pref_logging), false));
 	}

app/src/main/res/values/strings.xml

@@ -192,12 +192,20 @@
     <string name="pref_frameRate_title">Frame Rate</string>
     <string name="pref_frameRate_default">10</string>
     <string name="pref_frameRate_summ">Frame rate is set to: %s</string>
+    <string name="pref_gps">pref_gps</string>
+    <string name="pref_gps_title">GPS</string>
+    <string name="pref_gps_summ_on">GPS is enabled</string>
+    <string name="pref_gps_summ_off">GPS is disabled</string>
     <string name="pref_logging">pref_logging</string>
     <string name="pref_logging_title">Logging</string>
     <string name="pref_logging_summ_on">Logging is enabled</string>
     <string name="pref_logging_summ_off">Logging is disabled</string>
     <string name="pref_showLog">pref_showLog</string>
     <string name="pref_showLog_title">Show Log</string>
+    <string name="pref_gpsfile">pref_gpsfile</string>
+    <string name="pref_gpsfile_title">GPS File</string>
+    <string name="pref_gpsfile_summ">File path: %s</string>
+    <string name="pref_gpsfile_default">RFAnalyzer/gps.txt</string>
     <string name="pref_logfile">pref_logfile</string>
     <string name="pref_logfile_title">Log File</string>
     <string name="pref_logfile_summ">File path: %s</string>

app/src/main/res/xml/preferences.xml

@@ -221,6 +221,17 @@
             android:entries="@array/pref_frameRate_entries"
             android:entryValues="@array/pref_frameRate_values"
             android:defaultValue="@string/pref_frameRate_default" />
+        <SwitchPreference
+            android:key="@string/pref_gps"
+            android:title="@string/pref_gps_title"
+            android:summaryOn="@string/pref_gps_summ_on"
+            android:summaryOff="@string/pref_gps_summ_off"
+            android:defaultValue="false" />
+        <EditTextPreference
+            android:key="@string/pref_gpsfile"
+            android:title="@string/pref_gpsfile_title"
+            android:dependency="@string/pref_gps"
+            android:defaultValue="@string/pref_gpsfile_default" />
         <SwitchPreference
             android:key="@string/pref_logging"
             android:title="@string/pref_logging_title"