Android Help. Section 8. Eric Xiao

Transcription

1 Android Help Section 8 Eric Xiao

2 The Midterm That happened Any residual questions?

3 New Assignment! Make a low-fi prototype Must be interactive Use balsamiq or paper Test it with users 3 tasks Test task to show users how to use it (not one of your tasks) Only 1 user may be a student in this class Everyone takes notes, discuss notes Modify it

4 Outline Individual Programming Assignment 3 Location Sensing Android Camera API usage Display Image from Internet

5 Programming Assignment 3 getawaycam Take a picture Get geolocation and time from the metadata Retrieve picture from Flickr API that has the same location See picture from someone else s perspective View pictures Can t view any pictures taken with this app until you leave the location you took it from.

6 Location Services Demo Source code: Sample

7 Location Services Requires permissions: <uses- permission android:name= "android.permission.access_fine_location" /> <uses- permission android:name= "android.permission.access_coarse_location" />

8 Location Services High Level Initialize Location Manager Get best provider from location services Cell tower, Wifi, etc. Get last known location onlocationchanged(location location) Do something with new location Runs every time location changes

9 Location Services void checklocation(view v) { //initialize location manager manager = (LocationManager) getsystemservice(context.location_service); //get a location provider from location manager //empty criteria searches through all providers and returns the best one } String providername = manager.getbestprovider(new Criteria(), true); Location location = manager.getlastknownlocation(providername);

10 Location public void onlocationchanged(location location) { TextView tv = (TextView) findviewbyid(r.id.locationresults); if (location!= null) { tv.settext(location.getlatitude() + " latitude, " + location.getlongitude() + longitude"); } else { tv.settext("problem getting location"); } }

11 Location Services The cached location returned by getlastknownlocation may be inaccurate. To obtain updated location information, implement the LocationListener interface public class LocationActivity extends Activity implements LocationListener { This interface has 4 methods to override: onlocationchanged(location l) {} onproviderdisabled(string provider) {} onproviderenabled(string provider) {} onstatuschanged(string provider, int status, Bundle extras) {}

12 Location in the Emulator The Android emulator has configurable settings used to simulate location sensing. Start the emulator, then open your SDK folder and under \sdk\tools run monitor.bat In Android Debug Monitor click the Emulator Control tab. Edit the textboxes, then click Send to update the location.

13 Camera in Android High Level Make an intent to launch existing camera Also include property to save image after exiting Run onactivityresult() with picture data and save it

14 Camera in Android // create Intent to take a picture and return control to the calling application Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); Uri fileuri = getoutputmediafileuri(media_type_image); // create a file to save the image intent.putextra(mediastore.extra_output, fileuri); // set the image file name // start the image capture Intent startactivityforresult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);

15 Camera in Android protected void onactivityresult(int requestcode, int resultcode, Intent data) { if (requestcode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) { if (resultcode == RESULT_OK) { // Image captured and saved to fileuri specified in the Intent File file = new File(fileUri.getPath()); //if EXTRA_OUTPUT not specified, this will work Bitmap photo = data.getextras().get( data ); } else if (resultcode == RESULT_CANCELED) { // User cancelled the image capture } else { // Image capture failed, advise user } } }

16 Camera Links for problems/errors: onactivityresult-returned-from-a-camera-intentnull android-camera-onactivityresult-intent-is-null-if-ithad-extras built-in-camera-using-the-extra-mediastoreextra-output-stores-pictures-twice

17 Camera Example Code: android-camera-app-in-android-example.html

18 API Calls HttpClient client = new DefaultHttpClient(); HttpGet request = new HttpGet(); request.seturi(new URI(" set=public&from=0&to="+randomint +"&minx="+minlat+"&miny="+minlng +"&maxx="+maxlat+"&maxy="+maxlng +"&size=medium&mapfilter=true")); response = client.execute(request); //Parse string to get photo

19 Panoramio API Flickr is also an option still too Use any Photo API you d like

20 Displaying Image from the Internet ImageView iv = new ImageView; URL url = new URL(address); InputStream content = (InputStream)url.getContent(); Drawable d = Drawable.createFromStream(content, "src"); iv.setimagedrawable(d)

21 Display Image from Internet how-to-display-image-from-internet-in-android