Android 应用 Kotlin：未解决的参考：地图

问题描述

我已遵循本指南 https://developers.google.com/maps/documentation/android-sdk/start#None-kotlin，当我开始“部署和运行您的应用”时，程序在我的 Maps.Activity.kt 中显示“未解析的参考：地图”

package com.dinmor.festivalmaps
// copyright 2020 Google LLC
//
// Licensed under the Apache License,Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,software
// distributed under the License is distributed on an "AS IS" BASIS,// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.



import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle

import com.google.android.gms.maps.CameraUpdateFactory
import com.google.android.gms.maps.GoogleMap
import com.google.android.gms.maps.OnMapReadyCallback
import com.google.android.gms.maps.SupportMapFragment
import com.google.android.gms.maps.model.LatLng
import com.google.android.gms.maps.model.MarkerOptions
import com.google.maps.example.R

internal class MapsActivity : AppCompatActivity(),OnMapReadyCallback {

    private lateinit var mMap: GoogleMap
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_maps)
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        val mapFragment = supportFragmentManager
            .findFragmentById(R.id.map) as SupportMapFragment
        mapFragment.getMapAsync(this)
    }

    /**
     * Manipulates the map once available.
     * This callback is triggered when the map is ready to be used.
     * This is where we can add markers or lines,add listeners or move the camera. In this case,* we just add a marker near Sydney,Australia.
     * If Google Play services is not installed on the device,the user will be prompted to install
     * it inside the SupportMapFragment. This method will only be triggered once the user has
     * installed Google Play services and returned to the app.
     */
    override fun onMapReady(googleMap: GoogleMap) {
        mMap = googleMap

        // Add a marker in Sydney and move the camera
        val sydney = LatLng(-34.0,151.0)
        mMap.addMarker(MarkerOptions()
            .position(sydney)
            .title("Marker in Sydney"))
        mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney))
    }
}

更具体地说是在行

import com.google.maps.example.R

有谁知道为什么会出现这个错误？我已经完成了指南中的所有内容：/

解决方法

尝试在此处匹配： [https://github.com/googlemaps/android-samples/tree/main/tutorials/kotlin][1]

也许你错过了任何依赖