Space station current location
SpaceStationLocationActivity.kt
package com.mapbox.maps.testapp.examples
import android.graphics.BitmapFactory
import android.os.Bundle
import android.os.Handler
import android.os.Looper
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.mapbox.geojson.Feature
import com.mapbox.geojson.FeatureCollection
import com.mapbox.geojson.Point
import com.mapbox.maps.*
import com.mapbox.maps.extension.style.layers.addLayer
import com.mapbox.maps.extension.style.layers.generated.symbolLayer
import com.mapbox.maps.extension.style.sources.addSource
import com.mapbox.maps.extension.style.sources.generated.GeoJsonSource
import com.mapbox.maps.extension.style.sources.generated.geoJsonSource
import com.mapbox.maps.extension.style.sources.getSource
import com.mapbox.maps.plugin.animation.MapAnimationOptions.Companion.mapAnimationOptions
import com.mapbox.maps.plugin.animation.flyTo
import com.mapbox.maps.testapp.R
import com.mapbox.maps.testapp.model.IssModel
import retrofit2.Call
import retrofit2.Callback
import retrofit2.Response
import retrofit2.Retrofit
import retrofit2.converter.gson.GsonConverterFactory
import retrofit2.http.GET
/**
* Display the space station's real-time location
*/
class SpaceStationLocationActivity : AppCompatActivity() {
private val handler = Handler(Looper.getMainLooper())
private var runnable: (() -> Unit) = {}
private var call: Call<IssModel>? = null
private lateinit var mapboxMap: MapboxMap
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val mapView = MapView(this, MapInitOptions(context = this, styleUri = Style.SATELLITE_STREETS))
setContentView(mapView)
mapboxMap = mapView.mapboxMap
mapboxMap.getStyle {
initSpaceStationSymbolLayer(it)
callApi()
showHintToast()
}
mapboxMap.setCamera(CameraOptions.Builder().zoom(2.0).build())
}
private fun showHintToast() = Toast.makeText(
this@SpaceStationLocationActivity,
R.string.space_station_toast,
Toast.LENGTH_LONG
).show()
private fun callApi() {
// Build our client, The API we are using is very basic only returning a handful of
// information, mainly, the current latitude and longitude of the International Space Station.
val client = Retrofit.Builder()
.baseUrl("http://api.open-notify.org/")
.addConverterFactory(GsonConverterFactory.create())
.build()
val service = client.create(IssApiService::class.java)
// A handler is needed to called the API every x amount of seconds.
runnable = {
call = service.loadLocation()
call?.enqueue(object : Callback<IssModel?> {
override fun onResponse(
call: Call<IssModel?>,
response: Response<IssModel?>
) {
// We only need the latitude and longitude from the API.
val latitude = response.body()?.issPosition?.latitude
val longitude = response.body()?.issPosition?.longitude
if (latitude != null && longitude != null) {
updateMarkerPosition(longitude = longitude, latitude = latitude)
} else {
logW(TAG, "Wrong response position")
}
}
override fun onFailure(
call: Call<IssModel?>,
throwable: Throwable
) {
// If retrofit fails or the API was unreachable, an error will be called.
// to check if throwable is null, then give a custom message.
if (throwable.message == null) {
logE(TAG, "Http connection failed")
} else {
logE(TAG, "onFailure: ${throwable.message}")
}
}
})
// Schedule the next execution time for this runnable.
handler.postDelayed(runnable, apiCallTime.toLong())
}
// The first time this runs we don't need a delay so we immediately post.
handler.post(runnable)
}
private fun initSpaceStationSymbolLayer(style: Style) {
style.addImage(
"space-station-icon-id",
BitmapFactory.decodeResource(
this.resources, R.drawable.iss
)
)
style.addSource(
geoJsonSource("source-id") {
feature(Feature.fromGeometry(Point.fromLngLat(0.0, 0.0)))
}
)
style.addLayer(
symbolLayer("layer-id", "source-id") {
iconImage("space-station-icon-id")
iconIgnorePlacement(true)
iconAllowOverlap(true)
iconSize(.7)
}
)
}
private fun updateMarkerPosition(longitude: Double, latitude: Double) {
// This method is where we update the marker position once we have new coordinates. First we
// check if this is the first time we are executing this handler, the best way to do this is
// check if marker is null;
val geoPoint = Point.fromLngLat(longitude, latitude)
mapboxMap.getStyle {
val spaceStationSource = it.getSource("source-id") as? GeoJsonSource
spaceStationSource?.featureCollection(
FeatureCollection.fromFeature(
Feature.fromGeometry(
geoPoint
)
)
)
}
// Lastly, animate the camera to the new position so the user
// wont have to search for the marker and then return.
mapboxMap.flyTo(
CameraOptions.Builder().center(geoPoint).build(),
mapAnimationOptions { duration(300) }
)
}
// Interface used for Retrofit.
fun interface IssApiService {
@GET("iss-now")
fun loadLocation(): Call<IssModel>?
}
override fun onStart() {
super.onStart()
// When the user returns to the activity we want to resume the API calling.
handler.post(runnable)
}
override fun onStop() {
super.onStop()
// When the user leaves the activity, there is no need in calling the API since the map
// isn't in view.
handler.removeCallbacksAndMessages(null)
call?.cancel()
}
companion object {
private const val TAG = "SpaceStationActivity"
// apiCallTime is the time interval when we call the API in milliseconds, by default this is set
// to 2000 and you should only increase the value, reducing the interval will only cause server
// traffic, the latitude and longitude values aren't updated that frequently.
private const val apiCallTime = 2000
}
}
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