Android中基于JSON数据在地图添加多个标记的实现方法

Let's walk through implementing this feature step by step—from setting up your map to parsing the JSON and adding markers for pickup/drop locations.

Prerequisites #

First, make sure you have Google Maps integrated into your Android project:

1. Add the Maps SDK dependency to your app-level build.gradle:

   dependencies {
       implementation 'com.google.android.gms:play-services-maps:18.2.0'
       implementation 'com.google.code.gson:gson:2.10.1' // For JSON parsing
   }
   

2. Add your Google Maps API key to the AndroidManifest.xml:

   <meta-data
       android:name="com.google.android.geo.API_KEY"
       android:value="YOUR_GOOGLE_MAPS_API_KEY"/>
   

3. Add a MapFragment to your layout file (e.g., activity_main.xml):

   <fragment
       android:id="@+id/map_fragment"
       android:name="com.google.android.gms.maps.SupportMapFragment"
       android:layout_width="match_parent"
       android:layout_height="match_parent"/>
   

Step 1: Create Data Classes for JSON Parsing #

First, define classes to map your JSON structure. This makes parsing clean and type-safe.

Kotlin #

data class CustomerResponse(
    val customer: List<CustomerRequest>
)

data class CustomerRequest(
    val CustomerRequestId: Int,
    val CustomerId: Int,
    val CustomerName: String,
    val Phonenumber: String?,
    val PickupLat: String?,
    val PickupLng: String?,
    val DropLat: String?,
    val DropLng: String?,
    val FromLoc: String?,
    val ToLoc: String?
)

Java #

public class CustomerResponse {
    private List<CustomerRequest> customer;

    public List<CustomerRequest> getCustomer() { return customer; }
    public void setCustomer(List<CustomerRequest> customer) { this.customer = customer; }
}

public class CustomerRequest {
    private int CustomerRequestId;
    private int CustomerId;
    private String CustomerName;
    private String Phonenumber;
    private String PickupLat;
    private String PickupLng;
    private String DropLat;
    private String DropLng;
    private String FromLoc;
    private String ToLoc;

    // Getters and setters for all fields
    public int getCustomerRequestId() { return CustomerRequestId; }
    public void setCustomerRequestId(int customerRequestId) { CustomerRequestId = customerRequestId; }
    public String getCustomerName() { return CustomerName; }
    public void setCustomerName(String customerName) { CustomerName = customerName; }
    public String getPickupLat() { return PickupLat; }
    public void setPickupLat(String pickupLat) { PickupLat = pickupLat; }
    public String getPickupLng() { return PickupLng; }
    public void setPickupLng(String pickupLng) { PickupLng = pickupLng; }
    public String getDropLat() { return DropLat; }
    public void setDropLat(String dropLat) { DropLat = dropLat; }
    public String getDropLng() { return DropLng; }
    public void setDropLng(String dropLng) { DropLng = dropLng; }
    public String getFromLoc() { return FromLoc; }
    public void setFromLoc(String fromLoc) { FromLoc = fromLoc; }
    public String getToLoc() { return ToLoc; }
    public void setToLoc(String toLoc) { ToLoc = toLoc; }
}

Step 2: Parse the JSON Data #

Use Gson to convert your JSON string into a list of CustomerRequest objects. Always handle null values to avoid crashes!

Kotlin #

val jsonString = """{ "customer": [ { "CustomerRequestId": 30, "CustomerId": 24, "CustomerName": "Saravanan", "Phonenumber": "9095897331", "PickupLat": "13.0667902", "PickupLng": "80.2458975", "DropLat": "13.0824243", "DropLng": "80.27546889999999", "FromLoc": "19-22, College Rd, Subba Road Avenue, Nungambakkam, Chennai, Tamil Nadu 600006, India", "ToLoc": "Station Rd, Kannappar Thidal, Periyamet, Chennai, Tamil Nadu 600003, India" }, { "CustomerRequestId": 29, "CustomerId": 4, "CustomerName": "drive..." } ] }"""

val gson = Gson()
val customerResponse = gson.fromJson(jsonString, CustomerResponse::class.java)
val customerRequests = customerResponse.customer

Java #

String jsonString = "{ \"customer\": [ { \"CustomerRequestId\": 30, \"CustomerId\": 24, \"CustomerName\": \"Saravanan\", \"Phonenumber\": \"9095897331\", \"PickupLat\": \"13.0667902\", \"PickupLng\": \"80.2458975\", \"DropLat\": \"13.0824243\", \"DropLng\": \"80.27546889999999\", \"FromLoc\": \"19-22, College Rd, Subba Road Avenue, Nungambakkam, Chennai, Tamil Nadu 600006, India\", \"ToLoc\": \"Station Rd, Kannappar Thidal, Periyamet, Chennai, Tamil Nadu 600003, India\" }, { \"CustomerRequestId\": 29, \"CustomerId\": 4, \"CustomerName\": \"drive...\" } ] }";

Gson gson = new Gson();
CustomerResponse customerResponse = gson.fromJson(jsonString, CustomerResponse.class);
List<CustomerRequest> customerRequests = customerResponse.getCustomer();

Step 3: Add Markers to the Map #

Implement the OnMapReadyCallback interface to access the GoogleMap instance, then loop through your customer data to add markers for pickup and drop locations.

Kotlin #

class MainActivity : AppCompatActivity(), OnMapReadyCallback {
    private lateinit var googleMap: GoogleMap
    private lateinit var customerRequests: List<CustomerRequest>

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        
        // Parse JSON here (from Step 2)
        
        val mapFragment = supportFragmentManager.findFragmentById(R.id.map_fragment) as SupportMapFragment
        mapFragment.getMapAsync(this)
    }

    override fun onMapReady(map: GoogleMap) {
        googleMap = map

        customerRequests.forEach { customer ->
            // Add Pickup Marker (green)
            customer.PickupLat?.let { lat ->
                customer.PickupLng?.let { lng ->
                    val pickupLatLng = LatLng(lat.toDouble(), lng.toDouble())
                    googleMap.addMarker(
                        MarkerOptions()
                            .position(pickupLatLng)
                            .title("Pickup: ${customer.CustomerName}")
                            .snippet("Request ID: ${customer.CustomerRequestId}\nLocation: ${customer.FromLoc}")
                            .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN))
                    )
                }
            }

            // Add Drop Marker (red)
            customer.DropLat?.let { lat ->
                customer.DropLng?.let { lng ->
                    val dropLatLng = LatLng(lat.toDouble(), lng.toDouble())
                    googleMap.addMarker(
                        MarkerOptions()
                            .position(dropLatLng)
                            .title("Drop: ${customer.CustomerName}")
                            .snippet("Request ID: ${customer.CustomerRequestId}\nLocation: ${customer.ToLoc}")
                            .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED))
                    )
                }
            }
        }

        // Optional: Auto-zoom to show all markers
        if (customerRequests.isNotEmpty()) {
            val boundsBuilder = LatLngBounds.Builder()
            customerRequests.forEach { customer ->
                customer.PickupLat?.let { lat ->
                    customer.PickupLng?.let { lng -> boundsBuilder.include(LatLng(lat.toDouble(), lng.toDouble())) }
                }
                customer.DropLat?.let { lat ->
                    customer.DropLng?.let { lng -> boundsBuilder.include(LatLng(lat.toDouble(), lng.toDouble())) }
                }
            }
            val bounds = boundsBuilder.build()
            googleMap.moveCamera(CameraUpdateFactory.newLatLngBounds(bounds, 100)) // 100px padding
        }
    }
}

Java #

public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {
    private GoogleMap googleMap;
    private List<CustomerRequest> customerRequests;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        // Parse JSON here (from Step 2)
        
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map_fragment);
        mapFragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap map) {
        googleMap = map;

        for (CustomerRequest customer : customerRequests) {
            // Add Pickup Marker (green)
            if (customer.getPickupLat() != null && customer.getPickupLng() != null) {
                double pickupLat = Double.parseDouble(customer.getPickupLat());
                double pickupLng = Double.parseDouble(customer.getPickupLng());
                LatLng pickupLatLng = new LatLng(pickupLat, pickupLng);
                googleMap.addMarker(new MarkerOptions()
                        .position(pickupLatLng)
                        .title("Pickup: " + customer.getCustomerName())
                        .snippet("Request ID: " + customer.getCustomerRequestId() + "\nLocation: " + customer.getFromLoc())
                        .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN)));
            }

            // Add Drop Marker (red)
            if (customer.getDropLat() != null && customer.getDropLng() != null) {
                double dropLat = Double.parseDouble(customer.getDropLat());
                double dropLng = Double.parseDouble(customer.getDropLng());
                LatLng dropLatLng = new LatLng(dropLat, dropLng);
                googleMap.addMarker(new MarkerOptions()
                        .position(dropLatLng)
                        .title("Drop: " + customer.getCustomerName())
                        .snippet("Request ID: " + customer.getCustomerRequestId() + "\nLocation: " + customer.getToLoc())
                        .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)));
            }
        }

        // Optional: Auto-zoom to show all markers
        if (!customerRequests.isEmpty()) {
            LatLngBounds.Builder boundsBuilder = new LatLngBounds.Builder();
            for (CustomerRequest customer : customerRequests) {
                if (customer.getPickupLat() != null && customer.getPickupLng() != null) {
                    double pickupLat = Double.parseDouble(customer.getPickupLat());
                    double pickupLng = Double.parseDouble(customer.getPickupLng());
                    boundsBuilder.include(new LatLng(pickupLat, pickupLng));
                }
                if (customer.getDropLat() != null && customer.getDropLng() != null) {
                    double dropLat = Double.parseDouble(customer.getDropLat());
                    double dropLng = Double.parseDouble(customer.getDropLng());
                    boundsBuilder.include(new LatLng(dropLat, dropLng));
                }
            }
            LatLngBounds bounds = boundsBuilder.build();
            googleMap.moveCamera(CameraUpdateFactory.newLatLngBounds(bounds, 100)); // 100px padding
        }
    }
}

Key Notes #

• Null Safety: We use null checks (let in Kotlin, if in Java) to skip markers for customers with missing coordinates—this prevents crashes from invalid data.
• Custom Markers: Replace the default colored markers with your own drawables using BitmapDescriptorFactory.fromResource(R.drawable.your_marker).
• API Key Restrictions: Always restrict your Google Maps API key to your Android app (using package name and SHA-1) to prevent unauthorized use.

内容的提问来源于stack exchange，提问作者Aravind