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Mobile Programming Lecture 9

Mobile Programming Lecture 9 . Bound Service, Location, Sensors, IntentFilter. Agenda. Bound Services Location Sensor Starting an Activity for a Result Understanding Implicit Intents. Bound Service.

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Mobile Programming Lecture 9

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  1. Mobile Programming Lecture 9 Bound Service, Location, Sensors, IntentFilter

  2. Agenda • Bound Services • Location • Sensor • Starting an Activity for a Result • Understanding Implicit Intents

  3. Bound Service When you create a Bound Service, you must provide an IBinder that provides the programming interface that clients can use to interact with the Service There are 3 ways that you can provide this interface: • Extending the Binder class • Using a Messenger • Using AIDL

  4. Bound Service

  5. Bound Service - 1 extending Binder • this is the preferred technique when your service is merely a background worker for your own application • the only reason you would not create your interface this way is because your service is used by other applications or across separate processes

  6. Bound Service - 1 extending Binder Here's how to set it up • In your service, create an instance of Binder thatreturns the current Service instance, which has public methods the client can call • Return this instance of Binder from the onBind() callback method • In the client, receive the Binder from the onServiceConnected() callback method and make calls to the bound service using the methods provided

  7. Bound Service - 1 extending Binder see BoundServiceBinderExample.tar ServiceConnection class monitors the connection between the client and the Service When a Service is bound, the binder returned is returned to the onServiceConnected() method of ServiceConnection

  8. Bound Service - 2 using Messenger • if you need your interface to work across different processes, you can create an interface for the service with a Messenger • the service defines a Handler that responds to different types of Message objects • Additionally, the client can define a Messenger of its own so the service can send messages back. • this is the simplest way to perform interprocess communication (IPC).

  9. Bound Service - 2 using Messenger Notice that the handleMessage() method in the Handler is where the service receives the incoming Message and decides what to do, based on the what member.

  10. Bound Service - 2 using Messenger see BoundServiceMessengerExample.tar

  11. Bound Service - 3 using the AIDL • Using AIDL is confusing • AIDL isn't used that often • We won't cover this

  12. Location Providers To obtain user location, you can use • GPS • most accurate • but • consumes battery power fast • takes a while to determine location • Network Location Provider

  13. Location - LocationManager Requesting Location Updates To get the user location, you need to use the LocationManager, which is a system service • This returns a Location object, which can tell you • latitude • longitude • distance between two locations (comparing to another Location object) • accuracy of the Location in meters • direction of travel in degrees • speed of travel in meters per second The Location, however, does not give you any human readable address such as street name, state, or country

  14. Location - Geocoder and Address Requesting Location Updates • You can use the Location object to obtain a human-readable address by using a Geocoder • Geocoder can give you a list of addresses (since it may not always be sure because of accuracy issues) • returns a List of Address objects, i.e. List<Address> • street name • city • state • country • zip code

  15. Location - Last Known Location Requesting Location Updates Since GPS and Wifi location are not quite instantaeous, you can get the last known location until one of them becomes available

  16. Location - Last Known Location final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); getButton = (Button) findViewById(R.id.button1); tv = (TextView) findViewById(R.id.textView1); getButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Location lastLoc = lm.getLastKnownLocation( LocationManager.NETWORK_PROVIDER); Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses; addresses = geo.getFromLocation(lastLoc.getLatitude(), lastLoc.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); } });

  17. Location - Last Known Location final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); getButton = (Button) findViewById(R.id.button1); tv = (TextView) findViewById(R.id.textView1); getButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Location lastLoc = lm.getLastKnownLocation( LocationManager.NETWORK_PROVIDER); Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses; addresses = geo.getFromLocation(lastLoc.getLatitude(), lastLoc.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); } }); Similar to getting the system service for the DownloadManager

  18. Location - Last Known Location final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); getButton = (Button) findViewById(R.id.button1); tv = (TextView) findViewById(R.id.textView1); getButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Location lastLoc = lm.getLastKnownLocation( LocationManager.NETWORK_PROVIDER); Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses; addresses = geo.getFromLocation(lastLoc.getLatitude(), lastLoc.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); } }); What was the last known location?

  19. Location - Last Known Location final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); getButton = (Button) findViewById(R.id.button1); tv = (TextView) findViewById(R.id.textView1); getButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Location lastLoc = lm.getLastKnownLocation( LocationManager.NETWORK_PROVIDER); Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses; addresses = geo.getFromLocation(lastLoc.getLatitude(), lastLoc.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); } }); We need to use Geocoder to transform longitude and latitude to an address

  20. Location - Last Known Location final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); getButton = (Button) findViewById(R.id.button1); tv = (TextView) findViewById(R.id.textView1); getButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Location lastLoc = lm.getLastKnownLocation( LocationManager.NETWORK_PROVIDER); Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses; addresses = geo.getFromLocation(lastLoc.getLatitude(), lastLoc.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); } }); We will store address here

  21. Location - Last Known Location final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); getButton = (Button) findViewById(R.id.button1); tv = (TextView) findViewById(R.id.textView1); getButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Location lastLoc = lm.getLastKnownLocation( LocationManager.NETWORK_PROVIDER); Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses; addresses = geo.getFromLocation(lastLoc.getLatitude(), lastLoc.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); } }); Let's get a List of Addresses (although there may be only 1 sometimes)

  22. Location - Last Known Location final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); getButton = (Button) findViewById(R.id.button1); tv = (TextView) findViewById(R.id.textView1); getButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Location lastLoc = lm.getLastKnownLocation( LocationManager.NETWORK_PROVIDER); Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses; addresses = geo.getFromLocation(lastLoc.getLatitude(), lastLoc.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); } }); Pass the latitude ...

  23. Location - Last Known Location final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); getButton = (Button) findViewById(R.id.button1); tv = (TextView) findViewById(R.id.textView1); getButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Location lastLoc = lm.getLastKnownLocation( LocationManager.NETWORK_PROVIDER); Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses; addresses = geo.getFromLocation(lastLoc.getLatitude(), lastLoc.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); } }); the longitude ...

  24. Location - Last Known Location final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); getButton = (Button) findViewById(R.id.button1); tv = (TextView) findViewById(R.id.textView1); getButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Location lastLoc = lm.getLastKnownLocation( LocationManager.NETWORK_PROVIDER); Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses; addresses = geo.getFromLocation(lastLoc.getLatitude(), lastLoc.getLongitude(),1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); } }); and the max number of addresses that you want to be returned

  25. Location - Last Known Location final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); getButton = (Button) findViewById(R.id.button1); tv = (TextView) findViewById(R.id.textView1); getButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Location lastLoc = lm.getLastKnownLocation( LocationManager.NETWORK_PROVIDER); Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses; addresses = geo.getFromLocation(lastLoc.getLatitude(), lastLoc.getLongitude(),1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); } }); Get the first line of the first address in the list

  26. Location - Last Known Location See LastKnownLocationExample.tar

  27. Location - Location Updates Requesting Location Updates • To get actual location updates periodically, you should use a LocationListener • At some point, you should stop requesting location updates, possibly when • Activity loses focus • You no longer need the location

  28. Location - Location Updates final LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE); final LocationListener ll = new LocationListener() { @Override public void onStatusChanged(String provider, int status, Bundle extras) {} @Override public void onProviderEnabled(String provider) {} @Override public void onProviderDisabled(String provider) {} @Override public void onLocationChanged(Location location) { Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses = null; addresses = geo.getFromLocation(location.getLatitude(), location.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); lm.removeUpdates(this); } };

  29. Location - Location Updates final LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE); final LocationListener ll = new LocationListener() { @Override public void onStatusChanged(String provider, int status, Bundle extras) {} @Override public void onProviderEnabled(String provider) {} @Override public void onProviderDisabled(String provider) {} @Override public void onLocationChanged(Location location) { Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses = null; addresses = geo.getFromLocation(location.getLatitude(), location.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); lm.removeUpdates(this); } }; We need to register a LocationListener if we want to get updates on the location periodically

  30. Location - Location Updates final LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE); final LocationListener ll = new LocationListener() { @Override public void onStatusChanged(String provider, int status, Bundle extras) {} @Override public void onProviderEnabled(String provider) {} @Override public void onProviderDisabled(String provider) {} @Override public void onLocationChanged(Location location) { Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses = null; addresses = geo.getFromLocation(location.getLatitude(), location.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); lm.removeUpdates(this); } }; We're forced to override these methods, although we don't use them

  31. Location - Location Updates final LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE); final LocationListener ll = new LocationListener() { @Override public void onStatusChanged(String provider, int status, Bundle extras) {} @Override public void onProviderEnabled(String provider) {} @Override public void onProviderDisabled(String provider) {} @Override public void onLocationChanged(Location location) { Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses = null; addresses = geo.getFromLocation(location.getLatitude(), location.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); lm.removeUpdates(this); } }; In this callback method is where you code your response to a location change

  32. Location - Location Updates final LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE); final LocationListener ll = new LocationListener() { @Override public void onStatusChanged(String provider, int status, Bundle extras) {} @Override public void onProviderEnabled(String provider) {} @Override public void onProviderDisabled(String provider) {} @Override public void onLocationChanged(Location location) { Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses = null; addresses = geo.getFromLocation(location.getLatitude(), location.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); lm.removeUpdates(this); } }; Nothing new here ...

  33. Location - Location Updates final LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE); final LocationListener ll = new LocationListener() { @Override public void onStatusChanged(String provider, int status, Bundle extras) {} @Override public void onProviderEnabled(String provider) {} @Override public void onProviderDisabled(String provider) {} @Override public void onLocationChanged(Location location) { Geocoder geo = new Geocoder(getApplicationContext()); List<Address> addresses = null; addresses = geo.getFromLocation(location.getLatitude(), location.getLongitude(), 1); if(addresses != null) tv.setText(addresses.get(0).getAddressLine(0)); lm.removeUpdates(this); } }; Let's save battery life and stop listening for updates, although you may choose to stop listening for updates at some other point if you want to

  34. Location - Location Updates See LocationManagerExample.tar

  35. Location - Permissions • In order to receive location updates from NETWORK_PROVIDER or GPS_PROVIDER, you must request user permission by declaring one or both of the following permissions • ACCESS_COARSE_LOCATION • (Wifi location) • ACCESS_FINE_LOCATION • (GPS location)

  36. Location - Mock Location You can test your location-based features by mocking location data in the Emulator http://developer.android.com/guide/topics/location/obtaining-user-location.html#MockData The Emulator uses the GPS provider Found under the Emulator Control View in DDMS, under the Telephony View

  37. Sensor Accellerometer (Motion Sensor) Gyroscope (Motion Sensor) Light (Environment Sensor) Proximity: how close the face of a device is to an object Pressure and more See SensorListExample.tar

  38. SensorManager • SensorManager lets you access the device's sensors. Get an instance of this class by calling Context.getSystemService(SENSOR_SERVICE). • Always make sure to disable sensors you don't need, especially when your activity is paused • failing to do so can drain the battery in just a few hours • the system will not disable sensors automatically when the screen turns off.

  39. SensorEvent • The values for each sensor may change at some point • Set up an Event Listener to take action when these change • These values can be retrieved from a float values[] array, regardless of the type of Sensor

  40. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { SensorManager mSensorManager; Sensor mProximity; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE); mProximity = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY); } ... }

  41. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { SensorManager mSensorManager; Sensor mProximity; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE); mProximity = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY); } ... } Because we want to know when there's a SensorEvent, when values of the Sensor change

  42. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { SensorManager mSensorManager; Sensor mProximity; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE); mProximity = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY); } ... } Similar to how we got the Location service

  43. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { SensorManager mSensorManager; Sensor mProximity; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE); mProximity = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY); } ... } Let's get a Sensor

  44. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { SensorManager mSensorManager; Sensor mProximity; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE); mProximity = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY); } ... } The Proximity Sensor specifically

  45. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { SensorManager mSensorManager; Sensor mProximity; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE); mProximity = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY); } ... } The rest of the code for this class on the next slide

  46. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { ... protected void onResume() { super.onResume(); mSensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL); } protected void onPause() { super.onPause(); mSensorManager.unregisterListener(this); } public void onSensorChanged(SensorEvent event) { Toast.makeText(this, "Proximity = " + event.values[0], Toast.LENGTH_SHORT).show(); } } onCreate() is here somewhere, on the previous page

  47. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { ... protected void onResume() { super.onResume(); mSensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL); } protected void onPause() { super.onPause(); mSensorManager.unregisterListener(this); } public void onSensorChanged(SensorEvent event) { Toast.makeText(this, "Proximity = " + event.values[0], Toast.LENGTH_SHORT).show(); } } Note that this is onResume()

  48. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { ... protected void onResume() { super.onResume(); mSensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL); } protected void onPause() { super.onPause(); mSensorManager.unregisterListener(this); } public void onSensorChanged(SensorEvent event) { Toast.makeText(this, "Proximity = " + event.values[0], Toast.LENGTH_SHORT).show(); } } We only want to listen when the Activity is visible in this case, so we do this in onResume()

  49. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { ... protected void onResume() { super.onResume(); mSensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL); } protected void onPause() { super.onPause(); mSensorManager.unregisterListener(this); } public void onSensorChanged(SensorEvent event) { Toast.makeText(this, "Proximity = " + event.values[0], Toast.LENGTH_SHORT).show(); } } We pass a Context ...

  50. SensorEvent public class SensorExampleActivity extends Activity implements SensorEventListener { ... protected void onResume() { super.onResume(); mSensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL); } protected void onPause() { super.onPause(); mSensorManager.unregisterListener(this); } public void onSensorChanged(SensorEvent event) { Toast.makeText(this, "Proximity = " + event.values[0], Toast.LENGTH_SHORT).show(); } } a Sensor ...

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