Google Maps!

https://developers.google.com/maps/documentation/android-api/

En del features

• Markers
   
• GPS location
   
• Kart!

MapsActivity

1. Finds the Map fragment
    
2. Loads the map
    
3. Creates a LatLng object
    
4. Adds a Marker
   (MarkerOptions)
    
5. Moves the camera (CameraUpdateFactory)

Sensorer!

https://d.android.com/guide/topics/sensors/sensors_overview.html

https://www.element14.com/community/servlet/JiveServlet/showImage/2-99301-190768/GrovePi-Grove+for+the+Raspberry+Pi+-+Grove+Sensors+(5).JPG

Vi bruker allerede en: GPS!

• "Unikt" for apps
   
• Lar deg se brukerens lokasjon (innenfor en viss radius)
   
• Special treatment: krever ikke hardware (COARSE)

… men husk å sjekke permission

Sensorer…

• Kommer i flere varianter
  • Accelerometer
  • Ambient temperature
  • Light
  • Proximity
     
• Alle finnes ikke på alle devices!
• Eller API-er!

Sensor-rammeverket

• SensorManager
  • Aksesser sensorer
  • Registrer lyttere
     
• Sensor
  • Få tak i en bestemt sensor for evaluering
     
• SensorEvent
  • Data, generator (sensor), presisjon, tid
     
• SensorEventListener
  • Duh

Runtime sensor detection

private SensorManager mSensorManager;

//  ...

mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);

if (mSensorManager.getDefaultSensor(Sensor.TYPE_PRESSURE) != null){
  // Success! There's a pressure sensor.
} else {
  // Failure! No pressure sensor.
}

https://d.android.com/guide/topics/sensors/sensors_overview.html

Sensor events

public class SensorActivity extends Activity implements SensorEventListener {

  private SensorManager mSensorManager;
  private Sensor mLight;

  @Override
  public void onCreate(Bundle state) {
    // ...
    mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
    mLight = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
  }

  @Override
  public void onAccuracyChanged(Sensor sensor, int accuracy) {
  }

  @Override
  public void onSensorChanged(SensorEvent e) {
    // access e.values, float array
  }
}

Hva gjør en sensor?

Sensor listeners

public class SensorActivity extends Activity implements SensorEventListener {

  private SensorManager mSensorManager;
  private Sensor mLight;

  // ...

  @Override
  protected void onResume() {
    super.onResume();
    mSensorManager.registerListener(this, mLight, SensorManager.SENSOR_DELAY_NORMAL);
  }

  @Override
  protected void onPause() {
    super.onPause();
    mSensorManager.unregisterListener(this);
  }
}

Filtrer ut app i Play

<uses-feature android:name="android.hardware.sensor.accelerometer"
              android:required="true" />

Hvis appen er helt avhengig av en sensor

List alle sensorer uansett, men med android:required="false"

Eksempel

https://github.com/theneva/OfficeAnalysisSensorThing

(Pass opp for AndroidAnnotations)

NFC

https://developer.android.com/guide/topics/connectivity/nfc/nfc.html

• Near Field Communication
   
• En liten mikrokontroller
   
• Sender ut en ID og/eller payload
   
• To viktige use cases
  • Les data (fra en device eller tag)
  • Skriv ("beam") data til en annen device

NFC access

Begynnelsen på IoT!

• Transport (containers)
• Reisekort
• Inngangskort (sikkerhet)
   
• Aktiv vs. passiv
  • Aktiv = powered av batteri (ranged)
  • Passiv = powered av NFC-leseren

Intent filter

<intent-filter>
    <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
    <category android:name="android.intent.category.DEFAULT"/>
    <data android:mimeType="text/plain" />
</intent-filter>


<intent-filter>
    <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
    <category android:name="android.intent.category.DEFAULT"/>
   <data android:scheme="http"
              android:host="developer.android.com"
              android:pathPrefix="/index.html" />
</intent-filter>

• Filtrer på mimeType eller noe annet
• Ikke trigg chooser-dialogen hvis mulig

Starter Activity-en med et intent

Tag/NDEF discovery

<intent-filter>
    <action android:name="android.nfc.action.TECH_DISCOVERED"/>
    <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
    <category android:name="android.intent.category.DEFAULT"/>
    <data android:mimeType="text/plain"/>
</intent-filter>

• Vær spesifikk
• Alt som trengs til innlevering 2

Tag encoding

https://developer.android.com/guide/topics/connectivity/nfc/nfc.html

Tag vendor

http://www.nxp.com/...

Hent ut data om tag

String action = getIntent().getAction();
if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(action)
        || NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)) {
    Tag tag = getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG);
    MifareUltralight ultralight = MifareUltralight.get(tag);

// ...

1. Connect
2. Read(/write)
3. Close

ultralight.connect();
byte[] payload = ultralight.readPages(8);
payloadTextView.setText(new String(payload));

NFC Tools

https://play.google.com/store/apps/details?id=com.wakdev.wdnfc&hl=en

• Android-app
• Nyttig for NFC
• Leser fra/skriver til tags!

SQLite DB

DBs for everyone!

• Alle Android-apper får en SQLite DB
   
• Trenger ikke be om permission en gang!
   
• Lokal lagring!
  • Spill?

Data types

https://www.sqlite.org/datatype3.html

Set up DB

https://www.sqlite.org/datatype3.html

public class DbHelper extends SQLiteOpenHelper {
    public static final String DB_NAME = "measurements";
    private static final int DB_VERSION = 1;

    public DbHelper(final Context context) {
        super(context, DB_NAME, null, DB_VERSION);
    }

    @Override
    public void onCreate(final SQLiteDatabase db) {
        String createTablesSQL =
                "create table light ("
                        + "id integer primary key autoincrement,"
                        + "value real,"
                        + "accuracy integer);";

        db.execSQL(createTablesSQL);
    }

    @Override
    public void onUpgrade(final SQLiteDatabase db, final int oldVersion, final int newVersion) {
        // do nothing
    }
}

Matching class

public class Light {
    private int id;
    private float light;
    private int accuracy;

    // java stuff
}

Data source: DB comm

public class LightDataSource {
    private SQLiteDatabase db;
    private DbHelper dbHelper;

    public LightDataSource(Context context) {
        dbHelper = new DbHelper(context);
    }

Data source (2)

public void saveLight(Light light) {
    ContentValues contentValues = new ContentValues();
    // table -> value
    contentValues.put("value", light.getValue());
    contentValues.put("accuracy", light.getAccuracy());
    long id = db.insert("light", null, contentValues);
}

Data source (3)

public List<Light> getLightMeasurements() {
    List<Light> lights = new ArrayList<>();
    String[] columns = { "id", "value", "accuracy" };
    Cursor cursor = db.query("light", columns, null, null, null, null, null);
    cursor.moveToFirst();

    while (!cursor.isAfterLast()) {
        lights.add(lightFromCursor(cursor));
        cursor.moveToNext();
    }

    return lights;
}

private Light lightFromCursor(final Cursor cursor) {
    Light light = new Light();
    light.setId(cursor.getInt(0));
    light.setValue(cursor.getFloat(1));
    light.setAccuracy(cursor.getInt(2));
    return light;
}