Question

我正在按照MapBox的指南实施导航到Android应用程序。在显示用户位置的最后一步，将以下代码添加到MainActivity.java：

mapView.getMapAsync(new OnMapReadyCallback() {
@Override
public void onMapReady(final MapboxMap mapboxMap) {
    map = mapboxMap;
    enableLocationPlugin();
};
});

运行应用时出现多个错误。 Picture

mapView.getMapAsync有一个无法解决的符号错误。
Android Studio在预期时会被括号弄糊涂的几个错误;或{。
以下指南我已经导入了所需的所有插件和sdks但是OnMapReadyCallback函数（上面使用过的）的import语句似乎处于非活动状态，因为Android studio告诉我它是一个未使用的import语句。 Picture here

此错误缺少文档，但Google地图已记录了类似的问题。它们的实现与MapBox的实现不同，因此它们的解决方案不兼容。

如何解决这些错误，最重要的是能够运行应用程序并继续学习教程指南？

可以在此处找到完整的MainActivity.Java代码。

    package com.mettre.mettre;

import java.util.List;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import com.mapbox.mapboxsdk.Mapbox;
import com.mapbox.mapboxsdk.maps.MapView;
import com.mapbox.mapboxsdk.maps.MapboxMap;
import com.mapbox.mapboxsdk.maps.OnMapReadyCallback;

// classes needed to add location layer
import com.mapbox.geojson.Point;
import com.mapbox.mapboxsdk.maps.MapboxMap;
import com.mapbox.mapboxsdk.maps.OnMapReadyCallback;

import android.location.Location;

import com.mapbox.mapboxsdk.geometry.LatLng;

import android.support.annotation.NonNull;

import com.mapbox.mapboxsdk.camera.CameraUpdateFactory;
import com.mapbox.mapboxsdk.plugins.locationlayer.LocationLayerMode;
import com.mapbox.mapboxsdk.plugins.locationlayer.LocationLayerPlugin;
import com.mapbox.services.android.location.LostLocationEngine;
import com.mapbox.services.android.navigation.ui.v5.NavigationViewOptions;
import com.mapbox.services.android.telemetry.location.LocationEngine;
import com.mapbox.services.android.telemetry.location.LocationEngineListener;
import com.mapbox.services.android.telemetry.location.LocationEnginePriority;
import com.mapbox.services.android.telemetry.permissions.PermissionsListener;
import com.mapbox.services.android.telemetry.permissions.PermissionsManager;


public abstract class MainActivity extends AppCompatActivity implements LocationEngineListener, PermissionsListener{

    private MapView mapView;
    // variables for adding location layer
    private MapboxMap map;
    private PermissionsManager permissionsManager;
    private LocationLayerPlugin locationPlugin;
    private LocationEngine locationEngine;
    private Location originLocation;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Mapbox.getInstance(this, getString(R.string.access_token));
        setContentView(R.layout.activity_main);
        mapView = (MapView) findViewById(R.id.mapView);
        mapView.onCreate(savedInstanceState);
    }

    // Add the mapView's own lifecycle methods to the activity's lifecycle methods
    /*@Override
    public void onStart() {
        super.onStart();
        mapView.onStart();
    }

    @Override
    public void onResume() {
        super.onResume();
        mapView.onResume();
    }

    @Override
    public void onPause() {
        super.onPause();
        mapView.onPause();
    }

    @Override
    public void onStop() {
        super.onStop();
        mapView.onStop();
    }

    @Override
    public void onLowMemory() {
        super.onLowMemory();
        mapView.onLowMemory();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mapView.onDestroy();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        mapView.onSaveInstanceState(outState);
    }
    */

    @SuppressWarnings( {"MissingPermission"})
    private void enableLocationPlugin() {
        // Check if permissions are enabled and if not request
        if (PermissionsManager.areLocationPermissionsGranted(this)) {
            // Create an instance of LOST location engine
            initializeLocationEngine();

            locationPlugin = new LocationLayerPlugin(mapView, map, locationEngine);
            locationPlugin.setLocationLayerEnabled(LocationLayerMode.TRACKING);
        } else {
            permissionsManager = new PermissionsManager(this);
            permissionsManager.requestLocationPermissions(this);
        }
    }

    @SuppressWarnings( {"MissingPermission"})
    private void initializeLocationEngine() {
        locationEngine = new LostLocationEngine(MainActivity.this);
        locationEngine.setPriority(LocationEnginePriority.HIGH_ACCURACY);
        locationEngine.activate();

        Location lastLocation = locationEngine.getLastLocation();
        if (lastLocation != null) {
            originLocation = lastLocation;
            setCameraPosition(lastLocation);
        } else {
            locationEngine.addLocationEngineListener(this);
        }
    }

    private void setCameraPosition(Location location) {
        map.animateCamera(CameraUpdateFactory.newLatLngZoom(
                new LatLng(location.getLatitude(), location.getLongitude()), 13));
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        permissionsManager.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }

    @Override
    public void onExplanationNeeded(List<String> permissionsToExplain) {

    }

    @Override
    public void onPermissionResult(boolean granted) {
        if (granted) {
            enableLocationPlugin();
        } else {
            finish();
        }
    }

    @Override
    @SuppressWarnings( {"MissingPermission"})
    public void onConnected() {
        locationEngine.requestLocationUpdates();
    }

    @Override
    public void onLocationChanged(Location location) {
        if (location != null) {
            originLocation = location;
            setCameraPosition(location);
            locationEngine.removeLocationEngineListener(this);
        }
    }

    @Override
    @SuppressWarnings( {"MissingPermission"})
    protected void onStart() {
        super.onStart();
        if (locationEngine != null) {
            locationEngine.requestLocationUpdates();
        }
        if (locationPlugin != null) {
            locationPlugin.onStart();
        }
        mapView.onStart();
    }

    @Override
    protected void onStop() {
        super.onStop();
        if (locationEngine != null) {
            locationEngine.removeLocationUpdates();
        }
        if (locationPlugin != null) {
            locationPlugin.onStop();
        }
        mapView.onStop();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mapView.onDestroy();
        if (locationEngine != null) {
            locationEngine.deactivate();
        }
    }

    @Override
    public void onLowMemory() {
        super.onLowMemory();
        mapView.onLowMemory();
    }

    @Override
    protected void onResume() {
        super.onResume();
        mapView.onResume();
    }

    @Override
    protected void onPause() {
        super.onPause();
        mapView.onPause();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        mapView.onSaveInstanceState(outState);
    }

    mapView.getMapAsync(new OnMapReadyCallback() {
        @Override
        public void onMapReady(final MapboxMap mapboxMap) {
            map = mapboxMap;
            enableLocationPlugin();
        };
    });

}

Here is the errors from Android Studio when compiling:

MapBox导航指南后出错

0 个答案: