Android Geo howto

How to implement

Usecase: GEOClientActivity wants to show some info in a map

• (1) GEOClientActivity creates and sends an android ACTION_VIEW intent with coordinate in geo: format.
• (2) Android checks the manifests which apps-activities want "ACTION_VIEW" with uri-schema "geo:" and presents an Activity chooser with all capable apps-activities.
• Lets assume that the user chooses to view the item in GEOServiceActivity.
• Android creates GEOServiceActivity
• (3) In GEOServiceActivity.onCreate()
  • the intenet is retrieved
  • the intenet-s geo-uri is parsed
  • and processed (i.e. displayed in a map)

Note: Instead of ACTION_VIEW (to view something on the screen) you can also use ACTION_SEND if you want to share/process a shared location (i.e. to be send as email/sms).

GEOClientActivity .java : wants to "view geo"

import de.k3b.geo.io.GeoUri;
import de.k3b.geo.api.GeoPointDto;

public class GEOClientActivity extends Activity {
    ...
	private void onButtonClick[] {
		double lat = 52.1;
		double lon = 9.2;

		// no need for  de.k3b.geo-lib for simple request:
		String uriGeoSimple = String.format(Locale.ENGLISH, "geo:%f,%f", lat, lon);

		String uriGoogleMaps = String.format(Locale.ENGLISH, "http://maps.google.com/maps?q=loc:%f,%f", lat, lon);

		// use de.k3b.geo.io.GeoUri for more complex parameters
		GeoUri formater = new GeoUri(GeoUri.OPT_DEFAULT);
		GeoPointDto geo = new GeoPointDto()
			.setLatitude(52.1)
			.setLongitude(9.2)
			.setName("My geo point");
			.setZoomMin(14);
		String geoUri = formater.toUriString(geo);

		// (1) GEOClientActivity creates and sends an android ACTION_VIEW intent 
                    // with coordinate
		Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(geoUri));
		startActivity(intent);
	}
]

(2) AndroidManifest.xml tells android that GEOServiceActivity whants to process "view geo:"

<?xml version="1.0" encoding="utf-8"?>
<manifest ...>
	<application ... >
		<activity android:name=".GEOServiceActivity" ... >
			<intent-filter>
				<!-- (2) GEOServiceActivity wants to process "android.intent.action.VIEW" -->
				<action android:name="android.intent.action.VIEW" />
				<category android:name="android.intent.category.DEFAULT" />
				<category android:name="android.intent.category.BROWSABLE" />

				<!-- (2) GEOServiceActivity wants to process any mime type "*/*" -->
				<data android:mimeType="*/*" />
				
				<!-- (2) GEOServiceActivity wants to process uri schema "geo:" -->
				<data android:scheme="geo" />
			</intent-filter>
		</activity>
	</application>
</manifest>

(3) GEOServiceActivity.java in onCreate() geo data is retrieved and processed

import de.k3b.geo.io.GeoUri;
import de.k3b.geo.api.GeoPointDto;

public class GEOServiceActivity extends Activity {
		...
	@Override
	protected void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_gallery); 
		
		// (3) get geo-uri
		final Intent intent = getIntent();
		Uri uri = intent.getData();
		if (uri != null) {
			// (3) parse and process geo-uri
			GeoUri parser = new GeoUri(GeoUri.OPT_DEFAULT);
			IGeoPointInfo geo = parser.fromUri(uri.toString());
			if (geo != null) {
				// (3) process geo-data
				System.out.print(String.format("got lat=%f lon=%f", geo.getLatitude(),geo.getLongitude()));
			} // null means no geo data found
		}
	}
}

Here is example geo-picker-client code that asks for geo data:

private static final int GEO_RESULT_ID = 572;

public void showGeoPicker() {
    final Intent intent = new Intent();
    intent.setAction(Intent.ACTION_PICK);
    intent.setData(Uri.parse("geo:"));
	
    // optional: show user defined title in picker
	// intent.putExtra(EXTRA_TITLE, getString(R.string.geo_picker_title));

    try {
        startActivityForResult(Intent.createChooser(intent, getString(R.string.geo_edit_menu_title)), GEO_RESULT_ID);
        // this.startActivityForResult(intent, GEO_RESULT_ID);
    } catch (ActivityNotFoundException ex) {
        Toast.makeText(this, R.string.geo_picker_err_not_found,Toast.LENGTH_LONG).show();
    }
}

/**
 * Call back from sub-activities.
 */
@Override
protected void onActivityResult(final int requestCode,
                                final int resultCode, final Intent intent) {
    super.onActivityResult(requestCode, resultCode, intent);

    switch (requestCode) {
        case GEO_RESULT_ID:
			String pickedGeoUri = (intent != null) ? intent.getData() : null;
            onGeoChanged(pickedGeoUri);
            break;
        default:break;
    }
}