本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。

將 MapLibre Native SDK for Android 與 Amazon Location Service 搭配使用

使用MapLibre原生SDK將互動式地圖內嵌至 Android 應用程式。

MapLibre Native SDK for Android 是以 Mapbox Native 為基礎的程式庫，且與 Amazon Location Service Maps 提供的樣式和動態磚相容API。您可以整合 MapLibre Native SDK for Android，將互動式地圖檢視與可擴展、可自訂的向量圖嵌入 Android 應用程式。

本教學課程說明如何將 MapLibre Native SDK for Android 與 Amazon Location 整合。此教學課程的範例應用程式可作為 Amazon Location Service 範例儲存庫的一部分GitHub。

建置應用程式：初始化

若要初始化您的應用程式：

建置應用程式：組態

若要使用 資源和 AWS 區域設定應用程式：

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="identityPoolId">us-east-1:54f2ba88-9390-498d-aaa5-0d97fb7ca3bd</string>
    <string name="mapName">ExampleMap</string>
    <string name="awsRegion">us-east-1</string>
</resources>

建置應用程式：活動配置

編輯 app/src/main/res/layout/activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="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=".MainActivity">
 
    <com.mapbox.mapboxsdk.maps.MapView
        android:id="@+id/mapView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:mapbox_cameraTargetLat="49.2819"
        app:mapbox_cameraTargetLng="-123.1187"
        app:mapbox_cameraZoom="12"
        app:mapbox_uiAttribution="false"
        app:mapbox_uiLogo="false" />
 
    <TextView
        android:id="@+id/attributionView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#80808080"
        android:padding="5sp"
        android:textColor="@android:color/black"
        android:textSize="10sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        tools:ignore="SmallSp" />
</androidx.constraintlayout.widget.ConstraintLayout>

建置應用程式：請求轉換

建立名為 的類別SigV4Interceptor來攔截AWS請求，並使用 Signature 第 4 版簽署請求。這將在建立主要活動時，向用來擷取地圖資源的HTTP用戶端註冊。

package aws.location.demo.okhttp
 
import com.amazonaws.DefaultRequest
import com.amazonaws.auth.AWS4Signer
import com.amazonaws.auth.AWSCredentialsProvider
import com.amazonaws.http.HttpMethodName
import com.amazonaws.util.IOUtils
import okhttp3.HttpUrl
import okhttp3.Interceptor
import okhttp3.Request
import okhttp3.Response
import okio.Buffer
import java.io.ByteArrayInputStream
import java.net.URI
 
class SigV4Interceptor(
    private val credentialsProvider: AWSCredentialsProvider,
    private val serviceName: String
) : Interceptor {
    override fun intercept(chain: Interceptor.Chain): Response {
        val originalRequest = chain.request()
 
        if (originalRequest.url().host().contains("amazonaws.com")) {
            val signer = if (originalRequest.url().encodedPath().contains("@")) {
                // the presence of "@" indicates that it doesn't need to be double URL-encoded
                AWS4Signer(false)
            } else {
                AWS4Signer()
            }
 
            val awsRequest = toAWSRequest(originalRequest, serviceName)
            signer.setServiceName(serviceName)
            signer.sign(awsRequest, credentialsProvider.credentials)
 
            return chain.proceed(toSignedOkHttpRequest(awsRequest, originalRequest))
        }
 
        return chain.proceed(originalRequest)
    }
 
    companion object {
        fun toAWSRequest(request: Request, serviceName: String): DefaultRequest<Any> {
            // clone the request (AWS-style) so that it can be populated with credentials
            val dr = DefaultRequest<Any>(serviceName)
 
            // copy request info
            dr.httpMethod = HttpMethodName.valueOf(request.method())
            with(request.url()) {
                dr.resourcePath = uri().path
                dr.endpoint = URI.create("${scheme()}://${host()}")
 
                // copy parameters
                for (p in queryParameterNames()) {
                    if (p != "") {
                        dr.addParameter(p, queryParameter(p))
                    }
                }
            }
 
            // copy headers
            for (h in request.headers().names()) {
                dr.addHeader(h, request.header(h))
            }
 
            // copy the request body
            val bodyBytes = request.body()?.let { body ->
                val buffer = Buffer()
                body.writeTo(buffer)
                IOUtils.toByteArray(buffer.inputStream())
            }
 
            dr.content = ByteArrayInputStream(bodyBytes ?: ByteArray(0))
 
            return dr
        }
 
        fun toSignedOkHttpRequest(
            awsRequest: DefaultRequest<Any>,
            originalRequest: Request
        ): Request {
            // copy signed request back into an OkHttp Request
            val builder = Request.Builder()
 
            // copy headers from the signed request
            for ((k, v) in awsRequest.headers) {
                builder.addHeader(k, v)
            }
 
            // start building an HttpUrl
            val urlBuilder = HttpUrl.Builder()
                .host(awsRequest.endpoint.host)
                .scheme(awsRequest.endpoint.scheme)
                .encodedPath(awsRequest.resourcePath)
 
            // copy parameters from the signed request
            for ((k, v) in awsRequest.parameters) {
                urlBuilder.addQueryParameter(k, v)
            }
 
            return builder.url(urlBuilder.build())
                .method(originalRequest.method(), originalRequest.body())
                .build()
        }
    }
}

建置應用程式：主要活動

主要活動負責初始化將向使用者顯示的檢視。這涉及：

MainActivity 也負責將生命週期事件轉送至地圖檢視，允許其在調用之間保留作用中視埠。

package aws.location.demo.maplibre
 
import android.os.Bundle
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import aws.location.demo.okhttp.SigV4Interceptor
import com.amazonaws.auth.CognitoCachingCredentialsProvider
import com.amazonaws.regions.Regions
import com.mapbox.mapboxsdk.Mapbox
import com.mapbox.mapboxsdk.maps.MapView
import com.mapbox.mapboxsdk.maps.Style
import com.mapbox.mapboxsdk.module.http.HttpRequestUtil
import okhttp3.OkHttpClient
 
private const val SERVICE_NAME = "geo"
 
class MainActivity : AppCompatActivity() {
    private var mapView: MapView? = null
 
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
 
        // configuration
        val identityPoolId = getString(R.string.identityPoolId)
        val region = getString(R.string.awsRegion)
        val mapName = getString(R.string.mapName)
 
        // Credential initialization
        val credentialProvider = CognitoCachingCredentialsProvider(
            applicationContext,
            identityPoolId,
            Regions.fromName(identityPoolId.split(":").first())
        )
 
        // initialize MapLibre
        Mapbox.getInstance(this, null)
        HttpRequestUtil.setOkHttpClient(
            OkHttpClient.Builder()
                .addInterceptor(SigV4Interceptor(credentialProvider, SERVICE_NAME))
                .build()
        )
 
        // initialize the view
        setContentView(R.layout.activity_main)
 
        // initialize the map view
        mapView = findViewById(R.id.mapView)
        mapView?.onCreate(savedInstanceState)
        mapView?.getMapAsync { map ->
            map.setStyle(
                Style.Builder()
                    .fromUri("https://maps.geo.${region}.amazonaws.com/maps/v0/maps/${mapName}/style-descriptor")
            ) { style ->
                findViewById<TextView>(R.id.attributionView).text = style.sources.first()?.attribution
            }
        }
    }
 
    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 onLowMemory() {
        super.onLowMemory()
        mapView?.onLowMemory()
    }
 
    override fun onDestroy() {
        super.onDestroy()
        mapView?.onDestroy()
    }
}

執行此應用程式會以您選擇的樣式顯示全螢幕地圖。此範例可作為 Amazon Location Service 範例儲存庫的一部分GitHub。