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将适用于安卓 MapLibre 的原生 SDK 与 Amazon Location Service 配合使用

使用MapLibre原生 SDK 将交互式地图嵌入到您的 Android 应用程序中。

Android MapLibre 原生 SDK 是一个基于 Mapbox Nativ e 的库，与亚马逊定位服务地图 API 提供的样式和图块兼容。您可以集成适用于 Android 的 MapLibre Native SDK，在您的 Android 应用程序中嵌入带有可缩放、可自定义的矢量地图的交互式地图视图。

本教程介绍如何将适用于 Android MapLibre 的原生 SDK 与亚马逊定位集成。本教程的示例应用程序已作为 Amazon Location Service 示例存储库的一部分提供GitHub。

构建应用程序：初始化

要初始化应用程序，请执行以下操作：

构建应用程序：配置

要使用您的资源和 AWS 区域配置应用程序，请执行以下操作：

<?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>

构建应用程序：活动布局

编辑 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>

构建应用程序：请求转换

创建一个名为 SigV4Interceptor，拦截 AWS 请求的类，并使用 Signature Version 4 对请求进行签名。创建主活动时，将在用于获取地图资源的 HTTP 客户端中进行注册。

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()
        }
    }
}

构建应用程序：主活动

主活动负责初始化将向用户显示的视图。这涉及：

MainActivity 还负责将生命周期事件转发到地图视图，使其能够在两次调用之间保持活动视区。

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()
    }
}

运行此应用程序会以您选择的样式显示全屏地图。此示例作为 Amazon Location Service 示例存储库的一部分提供GitHub。