Location & maps

Location needs permission, and the permission has kinds: while-in-use or always, and on iOS precise or approximate. Ask for the least you need.

if (!Ti.Geolocation.hasLocationPermissions(Ti.Geolocation.AUTHORIZATION_WHEN_IN_USE)) {
  Ti.Geolocation.requestLocationPermissions(Ti.Geolocation.AUTHORIZATION_WHEN_IN_USE, (e) => {
    if (e.success) {
      locate();
    }
  });
} else {
  locate();
}

tiapp.xml needs the matching usage string on iOS:

<ios>
  <plist>
    <dict>
      <key>NSLocationWhenInUseUsageDescription</key>
      <string>Show which notes were written near you.</string>
    </dict>
  </plist>
</ios>

Asking for AUTHORIZATION_ALWAYS is a much bigger request, is reviewed harder, and on iOS the user is asked again later whether they meant it. Do not request it for a feature that works while the app is open.

One position

function locate() {
  Ti.Geolocation.getCurrentPosition((e) => {
    if (!e.success) {
      Ti.API.error(`location failed: ${e.error}`);
      return;
    }
    const { latitude, longitude, accuracy } = e.coords;
    Ti.API.info(`${latitude}, ${longitude} +/- ${accuracy}m`);
  });
}

accuracy on the result is a radius in metres, and it is the number that decides whether a fix is usable. A first fix indoors can be several hundred metres wide; treat anything above your tolerance as "not yet" rather than as an answer.

Tracking

Ti.Geolocation.accuracy = Ti.Geolocation.ACCURACY_HIGH;
Ti.Geolocation.distanceFilter = 10;

function onLocation(e) {
  if (!e.success) return;
  Ti.API.info(`moved to ${e.coords.latitude}, ${e.coords.longitude}`);
}

Ti.Geolocation.addEventListener('location', onLocation);

distanceFilter is metres of movement before another event, and it is the single most effective thing you can set: without it you get an event per fix, which is a battery complaint waiting to happen.

Remove the listener when the screen goes away. Location updates continue while a listener is attached, whether or not anything is looking at them.

win.addEventListener('close', () => {
  Ti.Geolocation.removeEventListener('location', onLocation);
});

Set accuracy to the loosest value that works. ACCURACY_HIGH powers the GPS radio; a "which city" feature does not need it.

Addresses

reverseGeocoder turns coordinates into an address and forwardGeocoder does the reverse. Both are network calls against a platform service, so they fail offline and are rate limited:

Ti.Geolocation.reverseGeocoder(latitude, longitude, (e) => {
  if (e.success && e.places.length) {
    Ti.API.info(e.places[0].address);
  }
});

Maps

Maps are not in the core SDK. ti.map is a module, maintained by TiDev, and it wraps Google Maps on Android and MapKit on iOS.

<modules>
  <module platform="android">ti.map</module>
  <module platform="iphone">ti.map</module>
</modules>

const Map = require('ti.map');

const view = Map.createView({
  mapType: Map.NORMAL_TYPE,
  region: { latitude: 51.5, longitude: -0.12, latitudeDelta: 0.05, longitudeDelta: 0.05 },
  annotations: [
    Map.createAnnotation({ latitude: 51.5, longitude: -0.12, title: 'Here' })
  ]
});
win.add(view);

Android additionally needs a Google Maps API key in tiapp.xml, and a build without one shows an empty grid rather than an error. If your map is blank grey squares, that is the reason.

See using modules for installing it, and the module's own reference for the full API.

Next

Notifications covers local and push.