Add Markers in Bulk

This example demonstrates how you can add markers in bulk.

BulkMarkerActivity.kt

package org.maplibre.android.testapp.activity.annotation

import android.app.ProgressDialog
import android.os.Bundle
import android.view.Menu
import android.view.View
import android.widget.AdapterView
import android.widget.AdapterView.OnItemSelectedListener
import android.widget.ArrayAdapter
import android.widget.Spinner
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext
import org.maplibre.android.annotations.MarkerOptions
import org.maplibre.android.geometry.LatLng
import org.maplibre.android.maps.MapView
import org.maplibre.android.maps.MapLibreMap
import org.maplibre.android.testapp.R
import org.maplibre.android.testapp.styles.TestStyles
import org.maplibre.android.testapp.utils.GeoParseUtil
import timber.log.Timber
import java.io.IOException
import java.text.DecimalFormat
import java.util.*
import kotlin.math.min

/**
 * Test activity showcasing adding a large amount of Markers.
 */
class BulkMarkerActivity : AppCompatActivity(), OnItemSelectedListener {
    private lateinit var maplibreMap: MapLibreMap
    private lateinit var mapView: MapView
    private var locations: List<LatLng>? = null
    private var progressDialog: ProgressDialog? = null
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_marker_bulk)
        mapView = findViewById(R.id.mapView)
        mapView.onCreate(savedInstanceState)
        mapView.getMapAsync { initMap(it) }
    }

    private fun initMap(maplibreMap: MapLibreMap) {
        this.maplibreMap = maplibreMap
        maplibreMap.setStyle(TestStyles.getPredefinedStyleWithFallback("Streets"))
    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        val spinnerAdapter = ArrayAdapter.createFromResource(
            this,
            R.array.bulk_marker_list,
            android.R.layout.simple_spinner_item
        )
        spinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
        menuInflater.inflate(R.menu.menu_bulk_marker, menu)
        val item = menu.findItem(R.id.spinner)
        val spinner = item.actionView as Spinner
        spinner.adapter = spinnerAdapter
        spinner.onItemSelectedListener = this@BulkMarkerActivity
        return true
    }

    override fun onItemSelected(parent: AdapterView<*>?, view: View, position: Int, id: Long) {
        val amount = Integer.valueOf(resources.getStringArray(R.array.bulk_marker_list)[position])
        if (locations == null) {
            progressDialog = ProgressDialog.show(this, "Loading", "Fetching markers", false)
            lifecycleScope.launch(Dispatchers.IO) {
                locations = loadLocationTask(this@BulkMarkerActivity)
                withContext(Dispatchers.Main) {
                    onLatLngListLoaded(locations, amount)
                }
            }
        } else {
            showMarkers(amount)
        }
    }

    private fun onLatLngListLoaded(latLngs: List<LatLng>?, amount: Int) {
        progressDialog!!.hide()
        locations = latLngs
        showMarkers(amount)
    }

    private fun showMarkers(amount: Int) {
        if (!this::maplibreMap.isInitialized || locations == null || mapView.isDestroyed) {
            return
        }
        maplibreMap.clear()
        showGlMarkers(min(amount, locations!!.size))
    }

    private fun showGlMarkers(amount: Int) {
        val markerOptionsList: MutableList<MarkerOptions> = ArrayList()
        val formatter = DecimalFormat("#.#####")
        val random = Random()
        var randomIndex: Int
        for (i in 0 until amount) {
            randomIndex = random.nextInt(locations!!.size)
            val latLng = locations!![randomIndex]
            markerOptionsList.add(
                MarkerOptions()
                    .position(latLng)
                    .title(i.toString())
                    .snippet(formatter.format(latLng.latitude) + "`, " + formatter.format(latLng.longitude))
            )
        }
        maplibreMap.addMarkers(markerOptionsList)
    }

    override fun onNothingSelected(parent: AdapterView<*>?) {
        // nothing selected, nothing to do!
    }

    override fun onStart() {
        super.onStart()
        mapView.onStart()
    }

    override fun onResume() {
        super.onResume()
        mapView.onResume()
    }

    override fun onPause() {
        super.onPause()
        mapView.onPause()
    }

    override fun onStop() {
        super.onStop()
        mapView.onStop()
    }

    override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)
        mapView.onSaveInstanceState(outState)
    }

    override fun onDestroy() {
        super.onDestroy()
        if (progressDialog != null) {
            progressDialog!!.dismiss()
        }
        mapView.onDestroy()
    }

    override fun onLowMemory() {
        super.onLowMemory()
        mapView.onLowMemory()
    }

    private fun loadLocationTask(
        activity: BulkMarkerActivity,
    ) : List<LatLng>? {
        try {
            val json = GeoParseUtil.loadStringFromAssets(
                activity.applicationContext,
                "points.geojson"
            )
            return GeoParseUtil.parseGeoJsonCoordinates(json)
        } catch (exception: IOException) {
            Timber.e(exception, "Could not add markers")
        }
        return null
    }
}