added missing semicolons

switched to relative timestamps
reduced file footprint
fixed layout issues
removed layout margins
more robust data-folder detection
fixed some potential timing issues
reduced rotation matrix calculation (only with MAG_SENSOR)
added data-rate calculation
reduced UI-updates

app/src/main/java/de/fhws/indoor/sensorreadout/MainActivity.java

@@ -34,13 +34,13 @@ import de.fhws.indoor.sensorreadout.sensors.SensorType;
 public class MainActivity extends Activity {
 
     private final ArrayList<mySensor> sensors = new ArrayList<mySensor>();
-    private final ArrayList<TextView> txtFields = new ArrayList<TextView>();
     private final Logger logger = new Logger(this);
     private Button btnStart;
     private Button btnStop;
     private Button btnGround;
     private int groundTruthCounter = 0;
     private boolean isInitialized = false;
+
     final private int MY_PERMISSIONS_REQUEST_READ_BT = 123;
     final private int MY_PERMISSIONS_REQUEST_READ_HEART = 321;
 
@@ -195,24 +195,6 @@ public class MainActivity extends Activity {
             @Override public void onData(final SensorType id, final String csv) {return; }
         });
 
-        final LinearLayout lay = (LinearLayout) findViewById(R.id.layoutMain);
-        lay.setOrientation(LinearLayout.HORIZONTAL);
-        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
-        params.setMargins(10,10,10,10);
-
-        // fixed number of textfields
-        for (int i = 0; i < 16; ++i) {
-            final TextView tv = new TextView(this);
-
-            //Set margin and color
-            tv.setTextColor(Color.parseColor("#2fbf78"));
-            tv.setLayoutParams(params);
-
-            lay.addView(tv);
-            txtFields.add(tv);
-        }
-
-
         // bluetooth permission
         if(ActivityCompat.shouldShowRequestPermissionRationale(this,
                 Manifest.permission.ACCESS_FINE_LOCATION)) {
@@ -236,17 +218,18 @@ public class MainActivity extends Activity {
 
 
     private void start() {
+        loadCounterAny = 0;
         logger.start();
-        txtFields.get(2).setText(logger.getFile().getAbsolutePath());
+        final TextView txt = (TextView) findViewById(R.id.txtFile);
+        txt.setText(logger.getFile().getAbsolutePath());
         for (final mySensor s : sensors) {s.onResume(this);}
     }
 
     private void stop() {
-        logger.stop();
-        for(int i = 0; i < txtFields.size(); i++) {
-            txtFields.get(i).setText("");
-        }
         for (final mySensor s : sensors) {s.onPause(this);}
+        logger.stop();
+        ((TextView) findViewById(R.id.txtWifi)).setText("");
+        ((TextView) findViewById(R.id.txtBeacon)).setText("");
     }
 
     /** new sensor data */
@@ -261,13 +244,18 @@ public class MainActivity extends Activity {
             @Override public void run() {
 
                 if (id == SensorType.WIFI) {
-                    txtFields.get(0).setText( ((++loadCounterWifi % 2) == 0) ? "wi" : "WI");
+                    final TextView txt = (TextView) findViewById(R.id.txtWifi);
+                    txt.setText( ((++loadCounterWifi % 2) == 0) ? "wi" : "WI");
                 } else if (id == SensorType.IBEACON){
-                    txtFields.get(1).setText( ((++loadCounterBeacon % 2) == 0) ? "ib" : "IB");
+                    final TextView txt = (TextView) findViewById(R.id.txtBeacon);
+                    txt.setText( ((++loadCounterBeacon % 2) == 0) ? "ib" : "IB");
                 }
 
-                if (++loadCounterAny % 10 == 0) {
+                // dump buffer stats every x entries
-                    txtFields.get(2).setText( (logger.getSize() / 1024) + " kb - " + logger.getNumEntries());
+                if (++loadCounterAny % 100 == 0) {
+                    final TextView txt = (TextView) findViewById(R.id.txtBuffer);
+                    final int kbPerMin = (int) (logger.getSize() / 1024 * 1000 * 60 / (System.currentTimeMillis() - logger.getStartTS()));
+                    txt.setText( (logger.getSize() / 1024) + "kb, " + logger.getNumEntries() + ", " + kbPerMin + "kb/min");
                 }
 
             }

app/src/main/java/de/fhws/indoor/sensorreadout/sensors/DataFolder.java

@@ -24,24 +24,33 @@ public class DataFolder {
     public DataFolder(Context context, String folderName){
         this.context = context;
 
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+        // 1) try external data folder
-            folder = new File(context.getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS), folderName);
+        folder = new File(context.getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS), folderName);
-        } else if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
+        if (isOK(folder)) {return;}
-            folder = new File(Environment.getExternalStorageDirectory() + "/" + folderName);
-        } else {
-            folder = new File(context.getApplicationInfo().dataDir);
-        }
 
-        // build folders
+        // 2) try sd-card folder
+        folder = new File(Environment.getExternalStorageDirectory() + "/" + folderName);
+        if (isOK(folder)) {return;}
+
+        // 3) try internal data folder
+        folder = new File(context.getApplicationInfo().dataDir);
+        if (isOK(folder)) {return;}
+
+        // all failed
+        throw new MyException("failed to create/access storage folder");
+
+    }
+
+    /** ensure the given folder is OK */
+    private static final boolean isOK(final File folder) {
         folder.mkdirs();
-
+        final boolean ok =  folder.exists() && folder.isDirectory();
-        // sanity check:
+        if (ok) {
-        if (!folder.exists() || !folder.isDirectory()) {
-            throw new MyException("failed to create/access storage folder: " + folder.getAbsolutePath());
-        } else {
             Log.d("dataFolder", "using: " + folder);
+        } else {
+            Log.d("dataFolder", "not OK: " + folder);
         }
-
+        return ok;
     }
 
     public File getFolder(){

app/src/main/java/de/fhws/indoor/sensorreadout/sensors/Logger.java

@@ -21,6 +21,9 @@ public final class Logger {
 	private Context context;
 	private int entries = 0;
 
+	/** timestamp of logging start. all entries are relative to this one */
+	private long startTS = 0;
+
 	public Logger(Context context) {
 		this.context = context;
 	}
@@ -32,14 +35,17 @@ public final class Logger {
 		sb.setLength(0);
 		entries = 0;
 
+		// starting timestamp
+		startTS = System.currentTimeMillis();
+
 		// open the output-file immeditaly (to get permission errors)
 		// but do NOT yet write anything to the file
-		DataFolder folder = new DataFolder(context, "sensorOutFiles");
+		final DataFolder folder = new DataFolder(context, "sensorOutFiles");
-		file = new File(folder.getFolder(), System.currentTimeMillis() + ".csv");
+		file = new File(folder.getFolder(), startTS + ".csv");
-		Log.d("logger", "will write to: " + file.toString());
 
 		try {
 			fos = new FileOutputStream(file);
+			Log.d("logger", "will write to: " + file.toString());
 		} catch (final Exception e) {
 			throw new MyException("error while opening log-file", e);
 		}
@@ -69,20 +75,25 @@ public final class Logger {
 	/** add a new CSV entry for the given sensor number to the internal buffer */
 	public final void addCSV(final SensorType sensorNr, final String csv) {
 		synchronized (this) {
-			sb.append(System.currentTimeMillis());
+			final long relTS = System.currentTimeMillis() - startTS;
+			sb.append(relTS);	// relative timestamp (uses less space)
 			sb.append(';');
 			sb.append(sensorNr.id());
 			sb.append(';');
 			sb.append(csv);
-			sb.append("\n");
+			sb.append('\n');
 			++entries;
 		}
 		debug();
 	}
 
+	public final long getStartTS() {
+		return startTS;
+	}
+
 	int cnt = 0;
 	private final void debug() {
-		if (++cnt % 10 == 0) {
+		if (++cnt % 500 == 0) {
 			Log.d("buffer", "size: " + sb.length());
 		}
 	}

app/src/main/java/de/fhws/indoor/sensorreadout/sensors/PhoneSensors.java

@@ -85,8 +85,10 @@ public class PhoneSensors extends mySensor implements SensorEventListener{
 			final StringBuilder sb = new StringBuilder();
 
 			// constructor smartphone details
-			sb.append("Device: " + android.os.Build.MODEL).append(NL);
+			sb.append("[Device]").append(NL);
-			sb.append("Android: " + Build.VERSION.RELEASE).append(NL);
+			sb.append("\tModel: " + android.os.Build.MODEL).append(NL);
+			sb.append("\tAndroid: " + Build.VERSION.RELEASE).append(NL);
+			sb.append(NL);
 
 			// construct sensor details
 			dumpSensor(sb, SensorType.ACCELEROMETER, acc);
@@ -113,11 +115,13 @@ public class PhoneSensors extends mySensor implements SensorEventListener{
 
 	/** dump all details of the given sensor into the provided stringbuilder */
 	private void dumpSensor(final StringBuilder sb, final SensorType type, final Sensor sensor) {
-		sb.append("Sensor").append(NL);
+		sb.append("[Sensor]").append(NL);
-		sb.append("id: ").append(type.ordinal()).append(NL);
+		sb.append("\tour_id: ").append(type.id()).append(NL);
-		sb.append("type: ").append(type).append(NL);
+		sb.append("\ttype: ").append(type).append(NL);
+
 		if (sensor != null) {
 			sb.append("\tVendor: ").append(sensor.getVendor()).append(NL);
+			sb.append("\tName: ").append(sensor.getName()).append(NL);
 			sb.append("\tVersion: ").append(sensor.getVersion()).append(NL);
 			sb.append("\tMinDelay: ").append(sensor.getMinDelay()).append(NL);
 			//sb.append("\tMaxDelay: ").append(sensor.getMaxDelay()).append(NL);
@@ -280,7 +284,10 @@ public class PhoneSensors extends mySensor implements SensorEventListener{
 
 			// keep a local copy (needed for orientation matrix)
 			System.arraycopy(event.values, 0, mGravity, 0, 3);
-			updateOrientation();
+
+			// NOTE:
+			// @see TYPE_MAGNETIC_FIELD
+			//updateOrientation();
 
 		}
 
@@ -297,6 +304,10 @@ public class PhoneSensors extends mySensor implements SensorEventListener{
 
 			// keep a local copy (needed for orientation matrix)
 			System.arraycopy(event.values, 0, mGeomagnetic, 0, 3);
+
+			// NOTE
+			// @see TYPE_ACCELEROMETER
+			// only MAG updates the current orientation as MAG is usually slower than ACC and this reduces the file-footprint
 			updateOrientation();
 
         }
@@ -319,29 +330,43 @@ public class PhoneSensors extends mySensor implements SensorEventListener{
 		if (!success) {return;}
 
 		// derive orientation-vector using the rotation matrix
-		float orientation[] = new float[3];
+		float orientationNew[] = new float[3];
-		SensorManager.getOrientation(R, orientation);
+		SensorManager.getOrientation(R, orientationNew);
 
 		// inform listeners
 		if (listener != null) {
 
+			// orientation vector
 			listener.onData(SensorType.ORIENTATION_NEW,
-				Float.toString(orientation[0]) + ";" +
+				Float.toString(orientationNew[0]) + ";" +
-				Float.toString(orientation[1]) + ";" +
+				Float.toString(orientationNew[1]) + ";" +
-				Float.toString(orientation[2])
+				Float.toString(orientationNew[2])
 			);
 
+			// rotation matrix
+			final StringBuilder sb = new StringBuilder(1024);
+			sb.append(R[0]).append(';');
+			sb.append(R[1]).append(';');
+			sb.append(R[2]).append(';');
+			sb.append(R[3]).append(';');
+			sb.append(R[4]).append(';');
+			sb.append(R[5]).append(';');
+			sb.append(R[6]).append(';');
+			sb.append(R[7]).append(';');
+			sb.append(R[8]);
+
 			//Write the whole rotationMatrix R into the Listener.
-			listener.onData(SensorType.ROTATION_MATRIX,
+			listener.onData(SensorType.ROTATION_MATRIX, sb.toString());
-				Float.toString(R[0]) + ";" +
+
-				Float.toString(R[1]) + ";" +
+//				Float.toString(R[0]) + ";" +
-				Float.toString(R[2]) + ";" +
+//				Float.toString(R[1]) + ";" +
-				Float.toString(R[3]) + ";" +
+//				Float.toString(R[2]) + ";" +
-				Float.toString(R[4]) + ";" +
+//				Float.toString(R[3]) + ";" +
-				Float.toString(R[5]) + ";" +
+//				Float.toString(R[4]) + ";" +
-				Float.toString(R[6]) + ";" +
+//				Float.toString(R[5]) + ";" +
-				Float.toString(R[7]) + ";" +
+//				Float.toString(R[6]) + ";" +
-				Float.toString(R[8])
+//				Float.toString(R[7]) + ";" +
+//				Float.toString(R[8])
 //				Float.toString(R[9]) + ";" +
 //				Float.toString(R[10]) + ";" +
 //				Float.toString(R[11]) + ";" +
@@ -349,7 +374,7 @@ public class PhoneSensors extends mySensor implements SensorEventListener{
 //				Float.toString(R[13]) + ";" +
 //				Float.toString(R[14]) + ";" +
 //				Float.toString(R[15])
-			);
+//			);
 
 		}
 

app/src/main/java/de/fhws/indoor/sensorreadout/sensors/WiFi.java

@@ -30,15 +30,15 @@ public class WiFi extends mySensor {
 
 		this.receiver = new BroadcastReceiver() {
 			@Override public void onReceive(Context context, Intent intent) {
-				final StringBuilder sb = new StringBuilder();
+				final StringBuilder sb = new StringBuilder(1024);
 				final List<ScanResult> res = wifi.getScanResults();
 				for(final ScanResult sr : res) {
-					sb.append(Helper.stripMAC(sr.BSSID)).append(";");
+					sb.append(Helper.stripMAC(sr.BSSID)).append(';');
-					sb.append(sr.frequency).append(";");
+					sb.append(sr.frequency).append(';');
-					sb.append(sr.level);
+					sb.append(sr.level).append(';');
 				}
-				startScan();
 				if (listener != null && isReceiverRegistered) {listener.onData(sb.toString());}
+				startScan();
 				//Log.d("wifi", sb.toString());
 			}
 		};

app/src/main/res/layout/activity_main.xml

@@ -1,28 +1,12 @@
 <?xml version="1.0" encoding="utf-8"?>
+
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
-android:layout_width="match_parent"
+    android:layout_width="match_parent"
-android:layout_height="match_parent"
+    android:layout_height="match_parent"
-xmlns:tools="http://schemas.android.com/tools"
+    xmlns:tools="http://schemas.android.com/tools"
-android:keepScreenOn="true"
+    android:keepScreenOn="true"
-tools:context="de.fhws.indoor.sensorreadout.MainActivity">
+    tools:context="de.fhws.indoor.sensorreadout.MainActivity"
-
+    android:background="#333">
-<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-        xmlns:tools="http://schemas.android.com/tools"
-        android:layout_width="match_parent"
-        android:layout_height="match_parent"
-        android:paddingLeft="@dimen/activity_horizontal_margin"
-        android:paddingRight="@dimen/activity_horizontal_margin"
-        android:paddingTop="@dimen/activity_vertical_margin"
-        android:paddingBottom="@dimen/activity_vertical_margin"
-        android:orientation="vertical"
-        tools:context=".MainActivity"
-        android:background="#333">
-
-
-
-    <RelativeLayout
-        android:layout_width="match_parent"
-        android:layout_height="match_parent">
 
             <Button
                 android:layout_width="50dp"
@@ -66,16 +50,46 @@ tools:context="de.fhws.indoor.sensorreadout.MainActivity">
                 android:background="#64bbe5"
                 />
 
-    </RelativeLayout>
+    <TextView
-</LinearLayout>
+        android:layout_below="@+id/btnGround"
+        android:id="@+id/txtFile"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:textColor="#ffffff"
+        android:text="-"
+        />
 
     <LinearLayout
+        android:layout_below="@+id/txtFile"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent"
-        android:background="#222"
+        android:layout_marginTop="0dip"
-        android:layout_marginTop="126dip"
         android:orientation="horizontal"
         android:id="@+id/layoutMain">
+
+        <TextView
+            android:id="@+id/txtWifi"
+            android:textColor="#ffffff"
+            android:layout_width="30dp"
+            android:layout_height="wrap_content"
+            android:text="-"
+            />
+        <TextView
+            android:id="@+id/txtBeacon"
+            android:textColor="#ffffff"
+            android:layout_width="30dp"
+            android:layout_height="wrap_content"
+            android:text="-"
+            />
+        <TextView
+            android:id="@+id/txtBuffer"
+            android:textColor="#ffffff"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="-"
+            />
+
+
     </LinearLayout>
 
 </RelativeLayout>