Locators and Geodecoding

Introduction
- Android can get the phone's location by GPS or Network.
- The GPS is more accurate, but works only outdoors and uses more power.
- It is necessary to set permissions and indicate the hardware in the manifest, and ask permission from the user.
```
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
```
  Say that you need the hardware ...
```
    <uses-feature android:name="android.hardware.location.gps" />
    <uses-feature android:name="android.hardware.location.network" />
```
  You can ask for only coarse location, if that's good enough.
- The way to get accurate location is using the Google Play services location APIs. This talks to Google, i.e., assumes internet connection. You get less accurate location without internet.
- Location can be either foreground location or background location. For API 28 you get both anyway, but next year things will change!
- Send fake GPS coordinates from emulator ... menu option. It's not possible to get network location.
- Locations are provided as latitude/longitude values, with extra information such as a time stamp, accuracy, etc.
Obtaining Location using Google Services
- The Fused Location Provider API intelligently combines different signals.
- Create a FusedLocationProviderClient to request location updates.
- Create a LocationRequest to specify your needs. LocationRequest is deprecated, but you need API 31 to use the new LocationRequest.Builder.
- Received updates in a LocationCallback
- Remove updates using removeLocationUpdates.
- Add implementation 'com.google.android.gms:play-services-location:21.0.1' to the dependencies in build.gradle.
See the Android documentation for ideas on how to optimize obtaining location.
Geodecoding
- Latitude/longitude values might not be useful for users. Thus it is often necessary to decode these into, e.g., place names.
- Android, and various online services provide this information.
- The Google Geocoder
  - This is a paid service.
  - You send a URL, and get back an XML mess to pull apart.
- The Android Geocoder
  - Requires a backend service that is not provided in the core Android framework.
  - We'll use this - it's free
  - Do not rely on this for mission-critical apps.
- In both cases it is necessary to set permission in the manifest
```
    <uses-permission android:name="android.permission.INTERNET" />
```
Example
MainActivity.java
activity_main.xml
SensorLocatorDecode.java
strings.xml
dimens.xml
AndroidManifest.xml
build.gradle