Examples

Shared preferences

activity_lab_shared_preferences
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:mapbox="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".examples.basics.SimpleMapViewActivity">
<androidx.constraintlayout.widget.Guideline
android:id="@+id/guideline10"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
mapbox:layout_constraintGuide_begin="512dp" />
<com.mapbox.mapboxsdk.maps.MapView
android:id="@+id/mapView"
android:layout_width="match_parent"
android:layout_height="0dp"
mapbox:layout_constraintBottom_toTopOf="@+id/guideline10"
mapbox:layout_constraintEnd_toEndOf="parent"
mapbox:layout_constraintStart_toStartOf="parent"
mapbox:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/shared_pref_saved_lat_textview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_marginLeft="32dp"
android:layout_marginTop="24dp"
android:text="@string/saved_lat_textview"
mapbox:layout_constraintStart_toStartOf="parent"
mapbox:layout_constraintTop_toTopOf="@+id/guideline10" />
<TextView
android:id="@+id/shared_pref_saved_long_textview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_marginLeft="32dp"
android:layout_marginTop="24dp"
android:text="@string/saved_long_textview"
mapbox:layout_constraintStart_toStartOf="parent"
mapbox:layout_constraintTop_toBottomOf="@+id/shared_pref_saved_lat_textview" />
</androidx.constraintlayout.widget.ConstraintLayout>
HillShadeActivity
package com.mapbox.mapboxandroiddemo.examples.labs;
import android.content.SharedPreferences;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.widget.TextView;
import android.widget.Toast;
import com.mapbox.geojson.Point;
import com.mapbox.mapboxandroiddemo.R;
import com.mapbox.mapboxsdk.Mapbox;
import com.mapbox.mapboxsdk.camera.CameraPosition;
import com.mapbox.mapboxsdk.camera.CameraUpdateFactory;
import com.mapbox.mapboxsdk.geometry.LatLng;
import com.mapbox.mapboxsdk.maps.MapView;
import com.mapbox.mapboxsdk.maps.MapboxMap;
import com.mapbox.mapboxsdk.maps.OnMapReadyCallback;
import com.mapbox.mapboxsdk.maps.Style;
import com.mapbox.mapboxsdk.style.layers.PropertyFactory;
import com.mapbox.mapboxsdk.style.layers.SymbolLayer;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.iconAllowOverlap;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.iconOffset;
/**
* Use shared preferences to save and retrieve data, so that the data can be displayed after closing the app.
*/
public class SharedPreferencesActivity extends AppCompatActivity implements OnMapReadyCallback,
MapboxMap.OnMapClickListener {
private static final String SAVED_LAT_KEY = "SAVED_LAT_KEY";
private static final String SAVED_LONG_KEY = "SAVED_LONG_KEY";
private static final String CLICK_LOCATION_SOURCE_ID = "CLICK_LOCATION_SOURCE_ID";
private static final String CLICK_LOCATION_ICON_ID = "CLICK_LOCATION_ICON_ID";
private static final String CLICK_LOCATION_LAYER_ID = "CLICK_LOCATION_LAYER_ID";
private MapView mapView;
private MapboxMap mapboxMap;
private SharedPreferences sharedPreferences;
private TextView longTextView;
private TextView latTextView;
private double savedLat;
private double savedLong;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
// Mapbox access token is configured here. This needs to be called either in your application
// object or in the same activity which contains the mapview.
Mapbox.getInstance(this, getString(R.string.access_token));
// This contains the MapView in XML and needs to be called after the access token is configured.
setContentView(R.layout.activity_lab_shared_preferences);
longTextView = findViewById(R.id.shared_pref_saved_long_textview);
latTextView = findViewById(R.id.shared_pref_saved_lat_textview);
longTextView.setText(String.format(getString(R.string.saved_long_textview), String.valueOf(0)));
latTextView.setText(String.format(getString(R.string.saved_lat_textview), String.valueOf(0)));
mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(this);
}
@Override
public void onMapReady(@NonNull MapboxMap mapboxMap) {
SharedPreferencesActivity.this.mapboxMap = mapboxMap;
mapboxMap.setStyle(
// Set the map to Mapbox's daytime traffic style
new Style.Builder().fromUri(Style.TRAFFIC_DAY)
// Add the SymbolLayer icon image to the map style
.withImage(CLICK_LOCATION_ICON_ID, BitmapFactory.decodeResource(
SharedPreferencesActivity.this.getResources(), R.drawable.red_marker))
// Adding a GeoJson source for the SymbolLayer icons.
.withSource(new GeoJsonSource(CLICK_LOCATION_SOURCE_ID))
// Adding the actual SymbolLayer to the map style. An offset is added that the bottom of the red
// marker icon gets fixed to the coordinate, rather than the middle of the icon being fixed to
// the coordinate point. This is offset is not always needed and is dependent on the image
// that you use for the SymbolLayer icon.
.withLayer(new SymbolLayer(CLICK_LOCATION_LAYER_ID, CLICK_LOCATION_SOURCE_ID)
.withProperties(PropertyFactory.iconImage(CLICK_LOCATION_ICON_ID),
iconAllowOverlap(true),
iconOffset(new Float[] {0f, -9f}))
), new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
mapboxMap.addOnMapClickListener(SharedPreferencesActivity.this);
// Get the coordinates from shared preferences
savedLong = getCoordinateFromSharedPref(SAVED_LONG_KEY);
savedLat = getCoordinateFromSharedPref(SAVED_LAT_KEY);
// Coordinates haven't been saved if both == 0
if (savedLong == 0 && savedLat == 0) {
Toast.makeText(SharedPreferencesActivity.this,
getString(R.string.tap_on_map_save_to_shared_pref), Toast.LENGTH_SHORT).show();
longTextView.setText(String.format(getString(R.string.saved_long_textview),
getString(R.string.not_saved_yet)));
latTextView.setText(String.format(getString(R.string.saved_lat_textview),
getString(R.string.not_saved_yet)));
} else {
// Move the camera to the previously-saved coordinates
mapboxMap.animateCamera(CameraUpdateFactory
.newCameraPosition(new CameraPosition.Builder()
.target(new LatLng(savedLat, savedLong))
.zoom(4)
.build()), 1200);
Toast.makeText(SharedPreferencesActivity.this,
getString(R.string.shared_pref_marker_placement), Toast.LENGTH_SHORT).show();
// Move the marker to the previously-saved coordinates
moveMarkerToLngLat(savedLong, savedLat);
longTextView.setText(String.format(
getString(R.string.saved_long_textview), String.valueOf(savedLong)));
latTextView.setText(String.format(
getString(R.string.saved_lat_textview), String.valueOf(savedLat)));
}
}
});
}
@Override
public boolean onMapClick(@NonNull LatLng mapClickPoint) {
double clickLatitude = mapClickPoint.getLatitude();
double clickLongitude = mapClickPoint.getLongitude();
longTextView.setText(String.format(
getString(R.string.saved_long_textview), String.valueOf(clickLongitude)));
latTextView.setText(String.format(
getString(R.string.saved_lat_textview), String.valueOf(clickLatitude)));
// Save the map click point coordinates to shared preferences
if (sharedPreferences != null) {
putCoordinateToSharedPref(SAVED_LAT_KEY, clickLatitude);
putCoordinateToSharedPref(SAVED_LONG_KEY, clickLongitude);
}
// Move the marker to the newly-saved coordinates
moveMarkerToLngLat(clickLongitude, clickLatitude);
return true;
}
/**
* Move the SymbolLayer icon to a new location
*
* @param newLong the new longitude
* @param newLat the new latitude
*/
private void moveMarkerToLngLat(double newLong, double newLat) {
// Move and display the click center layer's red marker icon to
// wherever the map was clicked on
mapboxMap.getStyle(new Style.OnStyleLoaded() {
@Override
public void onStyleLoaded(@NonNull Style style) {
GeoJsonSource clickLocationSource = style.getSourceAs(CLICK_LOCATION_SOURCE_ID);
if (clickLocationSource != null) {
clickLocationSource.setGeoJson(Point.fromLngLat(newLong, newLat));
}
}
});
}
/**
* Save a specific number to shared preferences
*
* @param key the number's key
* @param value the actual number
*/
private void putCoordinateToSharedPref(final String key, final double value) {
sharedPreferences.edit().putLong(key, Double.doubleToRawLongBits(value)).apply();
}
/**
* Retrieve a specific number from shared preferences
*
* @param key the key to use for retrieval
* @return the saved number
*/
double getCoordinateFromSharedPref(final String key) {
return Double.longBitsToDouble(sharedPreferences.getLong(key, 0));
}
// Add the mapView lifecycle to the activity's lifecycle methods
@Override
public void onResume() {
super.onResume();
mapView.onResume();
}
@Override
protected void onStart() {
super.onStart();
mapView.onStart();
}
@Override
protected void onStop() {
super.onStop();
mapView.onStop();
}
@Override
public void onPause() {
super.onPause();
mapView.onPause();
}
@Override
public void onLowMemory() {
super.onLowMemory();
mapView.onLowMemory();
}
@Override
protected void onDestroy() {
super.onDestroy();
if (mapboxMap != null) {
mapboxMap.removeOnMapClickListener(this);
}
mapView.onDestroy();
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mapView.onSaveInstanceState(outState);
}
}
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