Inputs and sensors

The Android SDK gives you access to the various inputs and sensors available with Glass EE2. This page provides you with an overview of the available features, implementation details, and helpful tips.

Touch gestures

You can use the Android SDK to enable access to raw data from the Glass touchpad. This is accomplished through a gesture detector that automatically detects common gestures on Glass such as tap, fling, and scroll.

You can also use this gesture detector in your apps to account for tap, swipe forward, swipe back, and swipe down. This is similar to previous Glass devices.

It's best to use these gestures in the following ways:

• Tap: Confirm or enter.
• Swipe forward, swipe back: Navigate through cards and screens.
• Swipe down: Back or exit.

For implementation details, read the sample gesture detector.

Detect gestures with the Android gesture detector

The Android GestureDetector lets you detect simple and complex gestures, such as those that use multiple fingers or scrolling.

Detect activity-level gestures

Detect gestures at the activity level only when it doesn't matter what part of your UI has focus. For example, if you want to bring up a menu when a user taps the touchpad, regardless of what view has focus, handle the MotionEvent inside the activity.

The following is an example of activity-level gesture detection that uses GestureDetector and implements GestureDetector.OnGestureListener to process recognized gestures, which are then handled and translated to the following:

• TAP
• SWIPE_FORWARD
• SWIPE_BACKWARD
• SWIPE_UP
• SWIPE_DOWN

Kotlin

class GlassGestureDetector(context: Context, private val onGestureListener: OnGestureListener) :
    GestureDetector.OnGestureListener {

    private val gestureDetector = GestureDetector(context, this)

    enum class Gesture {
        TAP,
        SWIPE_FORWARD,
        SWIPE_BACKWARD,
        SWIPE_UP,
        SWIPE_DOWN
    }

    interface OnGestureListener {
        fun onGesture(gesture: Gesture): Boolean
    }

    fun onTouchEvent(motionEvent: MotionEvent): Boolean {
        return gestureDetector.onTouchEvent(motionEvent)
    }

    override fun onDown(e: MotionEvent): Boolean {
        return false
    }

    override fun onShowPress(e: MotionEvent) {}

    override fun onSingleTapUp(e: MotionEvent): Boolean {
        return onGestureListener.onGesture(Gesture.TAP)
    }

    override fun onScroll(
        e1: MotionEvent,
        e2: MotionEvent,
        distanceX: Float,
        distanceY: Float
    ): Boolean {
        return false
    }

    override fun onLongPress(e: MotionEvent) {}

    /**
     * Swipe detection depends on the:
     * - movement tan value,
     * - movement distance,
     * - movement velocity.
     *
     * To prevent unintentional SWIPE_DOWN and SWIPE_UP gestures, they are detected if movement
     * angle is only between 60 and 120 degrees.
     * Any other detected swipes, will be considered as SWIPE_FORWARD and SWIPE_BACKWARD, depends
     * on deltaX value sign.
     *
     * ______________________________________________________________
     * |                     \        UP         /                    |
     * |                       \               /                      |
     * |                         60         120                       |
     * |                           \       /                          |
     * |                             \   /                            |
     * |  BACKWARD  <-------  0  ------------  180  ------>  FORWARD  |
     * |                             /   \                            |
     * |                           /       \                          |
     * |                         60         120                       |
     * |                       /               \                      |
     * |                     /       DOWN        \                    |
     * --------------------------------------------------------------
     */
    override fun onFling(
        e1: MotionEvent,
        e2: MotionEvent,
        velocityX: Float,
        velocityY: Float
    ): Boolean {
        val deltaX = e2.x - e1.x
        val deltaY = e2.y - e1.y
        val tan =
            if (deltaX != 0f) abs(deltaY / deltaX).toDouble() else java.lang.Double.MAX_VALUE

        return if (tan > TAN_60_DEGREES) {
            if (abs(deltaY) < SWIPE_DISTANCE_THRESHOLD_PX || Math.abs(velocityY) < SWIPE_VELOCITY_THRESHOLD_PX) {
                false
            } else if (deltaY < 0) {
                onGestureListener.onGesture(Gesture.SWIPE_UP)
            } else {
                onGestureListener.onGesture(Gesture.SWIPE_DOWN)
            }
        } else {
            if (Math.abs(deltaX) < SWIPE_DISTANCE_THRESHOLD_PX || Math.abs(velocityX) < SWIPE_VELOCITY_THRESHOLD_PX) {
                false
            } else if (deltaX < 0) {
                onGestureListener.onGesture(Gesture.SWIPE_FORWARD)
            } else {
                onGestureListener.onGesture(Gesture.SWIPE_BACKWARD)
            }
        }
    }

    companion object {

        private const val SWIPE_DISTANCE_THRESHOLD_PX = 100
        private const val SWIPE_VELOCITY_THRESHOLD_PX = 100
        private val TAN_60_DEGREES = tan(Math.toRadians(60.0))
    }
}

Java

  public class GlassGestureDetector implements GestureDetector.OnGestureListener {

   enum Gesture {
     TAP,
     SWIPE_FORWARD,
     SWIPE_BACKWARD,
     SWIPE_UP,
     SWIPE_DOWN,
   }

   interface OnGestureListener {
     boolean onGesture(Gesture gesture);
   }

   private static final int SWIPE_DISTANCE_THRESHOLD_PX = 100;
   private static final int SWIPE_VELOCITY_THRESHOLD_PX = 100;
   private static final double TAN_60_DEGREES = Math.tan(Math.toRadians(60));

   private GestureDetector gestureDetector;
   private OnGestureListener onGestureListener;

   public GlassGestureDetector(Context context, OnGestureListener onGestureListener) {
     gestureDetector = new GestureDetector(context, this);
     this.onGestureListener = onGestureListener;
   }

   public boolean onTouchEvent(MotionEvent motionEvent) {
     return gestureDetector.onTouchEvent(motionEvent);
   }

   @Override
   public boolean onDown(MotionEvent e) {
     return false;
   }

   @Override
   public void onShowPress(MotionEvent e) {
   }

   @Override
   public boolean onSingleTapUp(MotionEvent e) {
     return onGestureListener.onGesture(Gesture.TAP);
   }

   @Override
   public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
     return false;
   }

   @Override
   public void onLongPress(MotionEvent e) {
   }

   /**
    * Swipe detection depends on the:
    * - movement tan value,
    * - movement distance,
    * - movement velocity.
    *
    * To prevent unintentional SWIPE_DOWN and SWIPE_UP gestures, they are detected if movement
    * angle is only between 60 and 120 degrees.
    * Any other detected swipes, will be considered as SWIPE_FORWARD and SWIPE_BACKWARD, depends
    * on deltaX value sign.
    *
    *           ______________________________________________________________
    *          |                     \        UP         /                    |
    *          |                       \               /                      |
    *          |                         60         120                       |
    *          |                           \       /                          |
    *          |                             \   /                            |
    *          |  BACKWARD  <-------  0  ------------  180  ------>  FORWARD  |
    *          |                             /   \                            |
    *          |                           /       \                          |
    *          |                         60         120                       |
    *          |                       /               \                      |
    *          |                     /       DOWN        \                    |
    *           --------------------------------------------------------------
    */
   @Override
   public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
     final float deltaX = e2.getX() - e1.getX();
     final float deltaY = e2.getY() - e1.getY();
     final double tan = deltaX != 0 ? Math.abs(deltaY/deltaX) : Double.MAX_VALUE;

     if (tan > TAN_60_DEGREES) {
       if (Math.abs(deltaY) < SWIPE_DISTANCE_THRESHOLD_PX || Math.abs(velocityY) < SWIPE_VELOCITY_THRESHOLD_PX) {
         return false;
       } else if (deltaY < 0) {
         return onGestureListener.onGesture(Gesture.SWIPE_UP);
       } else {
         return onGestureListener.onGesture(Gesture.SWIPE_DOWN);
       }
     } else {
       if (Math.abs(deltaX) < SWIPE_DISTANCE_THRESHOLD_PX || Math.abs(velocityX) < SWIPE_VELOCITY_THRESHOLD_PX) {
         return false;
       } else if (deltaX < 0) {
         return onGestureListener.onGesture(Gesture.SWIPE_FORWARD);
       } else {
         return onGestureListener.onGesture(Gesture.SWIPE_BACKWARD);
       }
     }
   }
  }

Sample usage

In order to make use of activity-level gesture detection, you need to complete the following tasks:

1. Add the following declaration to your manifest file, inside the application declaration. This enables your app to receive the MotionEvent in the activity:

   <application>
   <!-- Copy below declaration into your manifest file -->
   <meta-data
     android:name="com.google.android.glass.TouchEnabledApplication"
     android:value="true" />
   </application>
   

2. Override the activity's dispatchTouchEvent(motionEvent) method to pass the motion events to the gesture detector's onTouchEvent(motionEvent) method.
3. Implement GlassGestureDetector.OnGestureListener in your activity.

The following is an example of an activity-level gesture detector:

Kotlin

class MainAcvitiy : AppCompatActivity(), GlassGestureDetector.OnGestureListener {

    private lateinit var glassGestureDetector: GlassGestureDetector

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        glassGestureDetector = GlassGestureDetector(this, this)
    }

    override fun onGesture(gesture: GlassGestureDetector.Gesture): Boolean {
        when (gesture) {
            TAP ->
                // Response for TAP gesture
                return true
            SWIPE_FORWARD ->
                // Response for SWIPE_FORWARD gesture
                return true
            SWIPE_BACKWARD ->
                // Response for SWIPE_BACKWARD gesture
                return true
            else -> return false
        }
    }

    override fun dispatchTouchEvent(ev: MotionEvent): Boolean {
        return if (glassGestureDetector.onTouchEvent(ev)) {
            true
        } else super.dispatchTouchEvent(ev)
    }
}

Java

  public class MainActivity extends AppCompatActivity implements OnGestureListener {

   private GlassGestureDetector glassGestureDetector;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_main);

     glassGestureDetector = new GlassGestureDetector(this, this);
   }

   @Override
   public boolean onGesture(Gesture gesture) {
     switch (gesture) {
       case TAP:
         // Response for TAP gesture
         return true;
       case SWIPE_FORWARD:
         // Response for SWIPE_FORWARD gesture
         return true;
       case SWIPE_BACKWARD:
         // Response for SWIPE_BACKWARD gesture
         return true;
       default:
         return false;
     }
   }

   @Override
   public boolean dispatchTouchEvent(MotionEvent ev) {
     if (glassGestureDetector.onTouchEvent(ev)) {
       return true;
     }
     return super.dispatchTouchEvent(ev);
   }
  }

Note: By default, the system handles a SWIPE_DOWN gesture as "Back." However after you add <meta-data android:name="com.google.android.glass.TouchEnabledApplication" android:value="true" />, you can choose to change it. In order to take full advantage of the device, remember to optimize which gestures you use. For example, ViewPager handles forward and backward swipes out of the box, so if you change SWIPE_FORWARD and SWIPE_BACKWARD, it won't work as expected.

Audio input

Glass Enterprise Edition 2 is a standard AOSP-based device that supports basic audio sources.

The following audio sources have advanced signal processing implemented:

• VOICE_COMMUNICATION
• VOICE_RECOGNITION

Voice recognition

Glass Enterprise Edition 2 supports a native implementation for speech recognition. This is supported only for English.

The speech recognition UI waits for a users to speak and then returns the transcribed text after they are done. To start the activity, follow these steps:

1. Call startActivityForResult() with the ACTION_RECOGNIZE_SPEECH intent. The following intent extras are supported when you start the activity:
   • EXTRA_PROMPT
   • EXTRA_RESULTS_PENDINGINTENT
   • EXTRA_RESULTS_PENDINGINTENT_BUNDLE
2. Override the onActivityResult() callback to receive the transcribed text from the EXTRA_RESULTS intent extra as shown in the following code sample. This callback is called when the user finishes speaking.

Kotlin

private const val SPEECH_REQUEST = 109

private fun displaySpeechRecognizer() {
    val intent = Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH)
    startActivityForResult(intent, SPEECH_REQUEST)
}

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent) {
    if (requestCode == SPEECH_REQUEST && resultCode == RESULT_OK) {
        val results: List<String>? =
            data.getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS)
        val spokenText = results?.get(0)
        // Do something with spokenText.
    }
    super.onActivityResult(requestCode, resultCode, data)
}

Java

private static final int SPEECH_REQUEST = 109;

private void displaySpeechRecognizer() {
    Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
    startActivityForResult(intent, SPEECH_REQUEST);
}

@Override
protected void onActivityResult(int requestCode, int resultCode,
        Intent data) {
    if (requestCode == SPEECH_REQUEST && resultCode == RESULT_OK) {
        List<String> results = data.getStringArrayListExtra(
                RecognizerIntent.EXTRA_RESULTS);
        String spokenText = results.get(0);
        // Do something with spokenText.
    }
    super.onActivityResult(requestCode, resultCode, data);
}

Note: Binding to the SpeechRecognizer service isn't allowed, therefore the SpeechRecognizer#startListening() method won't work.

For implementation details, read the sample voice recognition app.

Biasing for keywords

Speech recognition on Glass can be biased for a list of keywords. Biasing increases keyword recognition accuracy. To enable biasing for keywords, use the following:

Kotlin

val keywords = arrayOf("Example", "Biasing", "Keywords")

val intent = Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH)
intent.putExtra("recognition-phrases", keywords)

startActivityForResult(intent, SPEECH_REQUEST)

Java

final String[] keywords = {"Example", "Biasing", "Keywords"};

Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
intent.putExtra("recognition-phrases", keywords);

startActivityForResult(intent, SPEECH_REQUEST);

Voice commands

Voice commands allow users to carry out actions from activities. You build voice commands with the standard Android menu APIs, but users can invoke the menu items with voice commands instead of touch.

To enable voice commands for a particular activity, follow these steps:

1. Call getWindow().requestFeature(FEATURE_VOICE_COMMANDS) in the desired activity to enable voice commands. With this feature enabled, the microphone icon appears in the bottom left corner of the screen whenever this activity receives focus.
Note: The FEATURE_VOICE_COMMANDS constant is used for the same feature in the GDK, but it must be defined by the developer in EE2 because there's no longer an SDK.
2. Request the RECORD_AUDIO permission in your app.
3. Override onCreatePanelMenu() and inflate a menu resource.
4. Override onContextItemSelected() to handle the detected voice commands.

Kotlin

class VoiceCommandsActivity : AppCompatActivity() {

    companion object {
        const val FEATURE_VOICE_COMMANDS = 14
        const val REQUEST_PERMISSION_CODE = 200
        val PERMISSIONS = arrayOf(Manifest.permission.RECORD_AUDIO)
        val TAG = VoiceCommandsActivity::class.java.simpleName
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        window.requestFeature(FEATURE_VOICE_COMMANDS)
        setContentView(R.layout.activity_voice_commands)

        // Requesting permissions to enable voice commands menu
        ActivityCompat.requestPermissions(
            this,
            PERMISSIONS,
            REQUEST_PERMISSION_CODE
        )
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        if (requestCode == REQUEST_PERMISSION_CODE) {
            for (result in grantResults) {
                if (result != PackageManager.PERMISSION_GRANTED) {
                    Log.d(TAG, "Permission denied. Voice commands menu is disabled.")
                }
            }
        } else {
            super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        }
    }

    override fun onCreatePanelMenu(featureId: Int, menu: Menu): Boolean {
        menuInflater.inflate(R.menu.voice_commands_menu, menu)
        return true
    }

    override fun onContextItemSelected(item: MenuItem): Boolean {
        return when (item.itemId) {
            // Handle selected menu item
            R.id.edit -> {
                // Handle edit action
                true
            }
            else -> super.onContextItemSelected(item)
        }
    }
}

Java

public class VoiceCommandsActivity extends AppCompatActivity {

  private static final String TAG = VoiceCommandsActivity.class.getSimpleName();
  private static final int FEATURE_VOICE_COMMANDS = 14;
  private static final int REQUEST_PERMISSION_CODE = 200;
  private static final String[] PERMISSIONS = new String[]{Manifest.permission.RECORD_AUDIO};

  @Override
  protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().requestFeature(FEATURE_VOICE_COMMANDS);
    setContentView(R.layout.activity_voice_commands);

    // Requesting permissions to enable voice commands menu
    ActivityCompat.requestPermissions(this, PERMISSIONS, REQUEST_PERMISSION_CODE);
  }

  @Override
  public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    if (requestCode == REQUEST_PERMISSION_CODE) {
      for (int result : grantResults) {
        if (result != PackageManager.PERMISSION_GRANTED) {
          Log.d(TAG, "Permission denied. Voice commands menu is disabled.");
        }
      }
    } else {
      super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
  }

  @Override
  public boolean onCreatePanelMenu(int featureId, @NonNull Menu menu) {
    getMenuInflater().inflate(R.menu.voice_commands_menu, menu);
    return true;
  }

  @Override
  public boolean onContextItemSelected(@NonNull MenuItem item) {
    switch (item.getItemId()) {
      // Handle selected menu item
      case R.id.edit:
        // Handle edit action
        return true;
      default:
        return super.onContextItemSelected(item);
    }
  }
}

The following is an example of the menu resource used by the previous activity:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/delete"
        android:icon="@drawable/ic_delete"
        android:title="@string/delete"/>
    <item
        android:id="@+id/edit"
        android:icon="@drawable/ic_edit"
        android:title="@string/edit"/>
    <item
        android:id="@+id/find"
        android:icon="@drawable/ic_search"
        android:title="@string/find"/>
</menu>

Read the sample notes-taking app for a complete example.

Voice command list reloading

You can dynamically reload the voice command list. To do so, replace the menu resource in the onCreatePanelMenu() method, or modify the menu object in the onPreparePanel() method. To apply changes, call the invalidateOptionsMenu() method.

Kotlin

private val options = mutableListOf<String>()

fun onPreparePanel(featureId: Int, view: View?, menu: Menu): Boolean {
  if (featureId != FEATURE_VOICE_COMMANDS) {
    return super.onCreatePanelMenu(featureId, menu)
  }
  for (optionTitle in options) {
    menu.add(optionTitle)
  }
  return true
}

/**
 * Method showing example implementation of voice command list modification
 *
 * If you call [Activity.invalidateOptionsMenu] method, voice command  list will be
 * reloaded (onCreatePanelMenu and onPreparePanel methods will be called).
 */
private fun modifyVoiceCommandList() {
  options.add("Delete")
  options.add("Play")
  options.add("Pause")
  invalidateOptionsMenu()
}

Java

private final List<String> options = new ArrayList<>();

@Override
public boolean onPreparePanel(int featureId, View view, Menu menu) {
  if (featureId != FEATURE_VOICE_COMMANDS) {
    return super.onCreatePanelMenu(featureId, menu);
  }
  for (String optionTitle : options) {
    menu.add(optionTitle);
  }
  return true;
}

/**
 * Method showing example implementation of voice command list modification
 *
 * If you call {@link Activity#invalidateOptionsMenu()} method, voice command  list will be
 * reloaded (onCreatePanelMenu and onPreparePanel methods will be called).
 */
private void modifyVoiceCommandList() {
  options.add("Delete");
  options.add("Play");
  options.add("Pause");
  invalidateOptionsMenu();
}

AppCompatActivity solution

To reload a voice command list in an activity that extends AppCompatActivity, use the sendBroadcast() method with the reload-voice-commands intent action:

Kotlin

sendBroadcast(Intent("reload-voice-commands"))

Java

sendBroadcast(new Intent("reload-voice-commands"));

Note: To display its menus, AppCompatActivity uses a different mechanism than other classes. For Glass EE2 implementations, invalidateOptionsMenu() method can't be used to reload the voice command list. Use sendBroadcast() instead, as shown in the previous example.

Enable and disable voice commands in runtime

You can enable and disable voice commands in runtime. To do so, return an appropriate value from the onCreatePanelMenu() method as follows:

• Set the value to true to enable.
• Set the value to false to disable.

Debug mode

To enable debug mode for voice commands, call getWindow().requestFeature(FEATURE_DEBUG_VOICE_COMMANDS) in the desired activity. Debug mode activates the following features:

• Logcat contains the log with the recognized phrase for debugging.
• UI overlay is displayed when an unrecognized command is detected, as shown:

Kotlin

class VoiceCommandsActivity : AppCompatActivity() {

    companion object {
        const val FEATURE_VOICE_COMMANDS = 14
        const val FEATURE_DEBUG_VOICE_COMMANDS = 15
        const val REQUEST_PERMISSION_CODE = 200
        val PERMISSIONS = arrayOf(Manifest.permission.RECORD_AUDIO)
        val TAG = VoiceCommandsActivity::class.java.simpleName
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        window.requestFeature(FEATURE_VOICE_COMMANDS)
        window.requestFeature(FEATURE_DEBUG_VOICE_COMMANDS)
        setContentView(R.layout.activity_voice_commands)

        // Requesting permissions to enable voice commands menu
        ActivityCompat.requestPermissions(
            this,
            PERMISSIONS,
            REQUEST_PERMISSION_CODE
        )
    }
    .
    .
    .
}

Java

public class VoiceCommandsActivity extends AppCompatActivity {

  private static final String TAG = VoiceCommandsActivity.class.getSimpleName();
  private static final int FEATURE_VOICE_COMMANDS = 14;
  private static final int FEATURE_DEBUG_VOICE_COMMANDS = 15;
  private static final int REQUEST_PERMISSION_CODE = 200;
  private static final String[] PERMISSIONS = new String[]{Manifest.permission.RECORD_AUDIO};

  @Override
  protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().requestFeature(FEATURE_VOICE_COMMANDS);
    getWindow().requestFeature(FEATURE_DEBUG_VOICE_COMMANDS);
    setContentView(R.layout.activity_voice_commands);

    // Requesting permissions to enable voice commands menu
    ActivityCompat.requestPermissions(this, PERMISSIONS, REQUEST_PERMISSION_CODE);
  }
  .
  .
  .
}

For implementation details, read the sample voice commands reloading app.

Text-to-Speech (TTS)

Text-to-Speech functionality converts digital text to synthesized speech output. For more information, visit Android Developers Documentation TextToSpeech.

Glass EE2 has the Google Text-to-Speech engine installed. It's set as the default TTS engine and works offline.

The following locales are bundled with the Google Text-to-Speech engine:

Bengali Mandarin Chinese Czech Danish German Greek English Spanish Estonian Finnish French Gujarati Hindi

Hungarian Indonesian Italian Japanese Javanese Austronesian Austroasiatic Kannada Korean Malayalam Norwegian Dutch

Polish Portuguese Russian Slovak Sundanese Swedish Tamil Telugu Thai Turkish Ukrainian Vietnamese

Camera

Glass Enterprise Edition 2 is equipped with an 8 megapixel, fixed-focus camera that has an f/2.4 aperture, 4:3 sensor aspect ratio, and 83° diagonal field of view (71° x 57° in landscape orientation). We recommended that you use the standard CameraX or Camera2 API.

For implementation details, read the sample camera app.

Camera button

The camera button is the physical button on the hinge of the Glass Enterprise Edition 2 device. It can be handled just like a standard keyboard action and can be identified by the KeyEvent#KEYCODE_CAMERA keycode.

As of the OPM1.200313.001 OS update, intents with the following actions are sent from the Launcher application:

• MediaStore#ACTION_IMAGE_CAPTURE on the camera button short press.
• MediaStore#ACTION_VIDEO_CAPTURE on the camera button long press.

Note: By default, the preinstalled camera application opens when the camera button is pressed. A short press opens the app in photo mode and a long press opens it in video mode.

Sensors

There are a variety of sensors available to developers as they develop applications in Glass EE2.

The following standard Android sensors are supported on Glass:

• TYPE_ACCELEROMETER
• TYPE_GRAVITY
• TYPE_GYROSCOPE
• TYPE_LIGHT
• TYPE_LINEAR_ACCELERATION
• TYPE_MAGNETIC_FIELD
• TYPE_ORIENTATION (deprecated)
• TYPE_ROTATION_VECTOR

The following Android sensors aren't supported on Glass:

• TYPE_AMBIENT_TEMPERATURE
• TYPE_PRESSURE
• TYPE_PROXIMITY
• TYPE_RELATIVE_HUMIDITY
• TYPE_TEMPERATURE

The Glass sensor coordinate system is shown in the following illustration. It's relative to the Glass display. For more information, see Sensor coordinate system.

The accelerometer, gyroscope, and magnetometer are located on the optics pod of the Glass device, which users rotate to align the device with their sight. You can't measure the angle of the optics pod directly, so be aware of this when you use angles from these sensors for applications, such as a compass heading.

To preserve battery life, only listen to sensors when you need them. Consider the needs and lifecycle of the app when you decide when to start and stop listening to the sensors.

Sensor event callbacks run on the UI thread, so process events and returns as quickly as possible. If processing takes too long, push sensor events into a queue and use a background thread to handle them.

50 Hz is often a sufficient sampling rate to track head motion.

For more information on how to use sensors, see the Android developer guide.

Location services

The Glass Enterprise Edition 2 device isn't equipped with a GPS module and it doesn't provide the location of the user. However, it does have location services implemented, which is necessary to display a list of nearby Wi-Fi networks and Bluetooth devices.

If your application has device owner privileges, you can use it to programmatically change the value of the corresponding secure setting:

Kotlin

val devicePolicyManager = context
    .getSystemService(Context.DEVICE_POLICY_SERVICE) as DevicePolicyManager
if (devicePolicyManager.isDeviceOwnerApp(context.getPackageName())) {
    val componentName = ComponentName(context, MyDeviceAdmin::class.java)
    devicePolicyManager.setSecureSetting(
        componentName,
        Settings.Secure.LOCATION_MODE,
        Settings.Secure.LOCATION_MODE_SENSORS_ONLY.toString()
    )
}

Java

final DevicePolicyManager devicePolicyManager = (DevicePolicyManager) context
    .getSystemService(Context.DEVICE_POLICY_SERVICE);
if (devicePolicyManager.isDeviceOwnerApp(context.getPackageName())) {
  final ComponentName componentName = new ComponentName(context, MyDeviceAdmin.class);
  devicePolicyManager.setSecureSetting(componentName, Settings.Secure.LOCATION_MODE,
      String.valueOf(Settings.Secure.LOCATION_MODE_SENSORS_ONLY));
}

If you use a third-party MDM solution, the MDM solution must be able to change these settings for you.