您的应用可以监听用户沿着路线导航时发生的事件。
概览
使用以下接口监听导航事件:
Navigator.ArrivalListener
提供onArrival()
回调,该回调会在设备到达目的地时触发。RoadSnappedLocationProvider.LocationListener
提供onLocationChanged()
回调,该回调会在设备的位置发生变化时触发。Navigator.RemainingTimeOrDistanceChangedListener
提供onRemainingTimeOrDistanceChanged()
回调,当到达下一个目的地的时间或距离发生超过给定量级的变化时,系统会触发该回调。Navigator.RouteChangedListener
提供onRouteChanged()
回调,该回调会在路线发生变化时触发。
查看代码
显示/隐藏导航 activity 的 Java 代码。
package com.example.navsdkmultidestination; import android.content.pm.PackageManager; import android.location.Location; import android.os.Bundle; import android.util.Log; import android.widget.Toast; import androidx.annotation.NonNull; import androidx.appcompat.app.AppCompatActivity; import androidx.core.app.ActivityCompat; import androidx.core.content.ContextCompat; import com.google.android.gms.maps.GoogleMap.CameraPerspective; import com.google.android.libraries.navigation.ArrivalEvent; import com.google.android.libraries.navigation.ListenableResultFuture; import com.google.android.libraries.navigation.NavigationApi; import com.google.android.libraries.navigation.Navigator; import com.google.android.libraries.navigation.RoadSnappedLocationProvider; import com.google.android.libraries.navigation.SimulationOptions; import com.google.android.libraries.navigation.SupportNavigationFragment; import com.google.android.libraries.navigation.TimeAndDistance; import com.google.android.libraries.navigation.Waypoint; import java.util.ArrayList; import java.util.List; /** * An activity that displays a map and a navigation UI, guiding the user from their current location * to multiple destinations, also known as waypoints. */ public class NavigationActivityMultiDestination extends AppCompatActivity { private static final String TAG = NavigationActivityMultiDestination.class.getSimpleName(); private static final String DISPLAY_BOTH = "both"; private static final String DISPLAY_TOAST = "toast"; private static final String DISPLAY_LOG = "log"; private Navigator mNavigator; private RoadSnappedLocationProvider mRoadSnappedLocationProvider; private SupportNavigationFragment mNavFragment; private final List<Waypoint> mWaypoints = new ArrayList<>(); private Navigator.ArrivalListener mArrivalListener; private Navigator.RouteChangedListener mRouteChangedListener; private Navigator.RemainingTimeOrDistanceChangedListener mRemainingTimeOrDistanceChangedListener; private RoadSnappedLocationProvider.LocationListener mLocationListener; private Bundle mSavedInstanceState; private static final String KEY_JOURNEY_IN_PROGRESS = "journey_in_progress"; private boolean mJourneyInProgress = false; // Set fields for requesting location permission. private static final int PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1; private boolean mLocationPermissionGranted; /** * Sets up the navigator when the activity is created. * * @param savedInstanceState The activity state bundle. */ @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Save the navigator state, used to determine whether a journey is in progress. mSavedInstanceState = savedInstanceState; if (mSavedInstanceState != null && mSavedInstanceState.containsKey(KEY_JOURNEY_IN_PROGRESS)) { mJourneyInProgress = (mSavedInstanceState.getInt(KEY_JOURNEY_IN_PROGRESS) != 0); } setContentView(R.layout.activity_main); // Initialize the Navigation SDK. initializeNavigationSdk(); } /** Releases navigation listeners when the activity is destroyed. */ @Override protected void onDestroy() { super.onDestroy(); if ((mJourneyInProgress) && (this.isFinishing())) { mNavigator.removeArrivalListener(mArrivalListener); mNavigator.removeRouteChangedListener(mRouteChangedListener); mNavigator.removeRemainingTimeOrDistanceChangedListener( mRemainingTimeOrDistanceChangedListener); if (mRoadSnappedLocationProvider != null) { mRoadSnappedLocationProvider.removeLocationListener(mLocationListener); } displayMessage("OnDestroy: Released navigation listeners.", DISPLAY_LOG); } } /** Saves the state of the app when the activity is paused. */ @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); if (mJourneyInProgress) { outState.putInt(KEY_JOURNEY_IN_PROGRESS, 1); } else { outState.putInt(KEY_JOURNEY_IN_PROGRESS, 0); } } /** * Starts the Navigation SDK and sets the camera to follow the device's location. Calls the * navigateToPlaces() method when the navigator is ready. */ private void initializeNavigationSdk() { /* * Request location permission, so that we can get the location of the * device. The result of the permission request is handled by a callback, * onRequestPermissionsResult. */ if (ContextCompat.checkSelfPermission( this.getApplicationContext(), android.Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) { mLocationPermissionGranted = true; } else { ActivityCompat.requestPermissions( this, new String[] {android.Manifest.permission.ACCESS_FINE_LOCATION}, PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION); } if (!mLocationPermissionGranted) { displayMessage( "Error loading Navigation SDK: " + "The user has not granted location permission.", DISPLAY_BOTH); return; } // Get a navigator. NavigationApi.getNavigator( this, new NavigationApi.NavigatorListener() { /** Sets up the navigation UI when the navigator is ready for use. */ @Override public void onNavigatorReady(Navigator navigator) { displayMessage("Navigator ready.", DISPLAY_BOTH); mNavigator = navigator; mNavFragment = (SupportNavigationFragment) getSupportFragmentManager().findFragmentById(R.id.navigation_fragment); // Set the camera to follow the device location with 'TILTED' driving view. mNavFragment.getMapAsync( googleMap -> googleMap.followMyLocation(CameraPerspective.TILTED)); // Navigate to the specified places. navigateToPlaces(); } /** * Handles errors from the Navigation SDK. * * @param errorCode The error code returned by the navigator. */ @Override public void onError(@NavigationApi.ErrorCode int errorCode) { switch (errorCode) { case NavigationApi.ErrorCode.NOT_AUTHORIZED: displayMessage( "Error loading Navigation SDK: Your API key is " + "invalid or not authorized to use the Navigation SDK.", DISPLAY_BOTH); break; case NavigationApi.ErrorCode.TERMS_NOT_ACCEPTED: displayMessage( "Error loading Navigation SDK: User did not accept " + "the Navigation Terms of Use.", DISPLAY_BOTH); break; case NavigationApi.ErrorCode.NETWORK_ERROR: displayMessage("Error loading Navigation SDK: Network error.", DISPLAY_BOTH); break; case NavigationApi.ErrorCode.LOCATION_PERMISSION_MISSING: displayMessage( "Error loading Navigation SDK: Location permission " + "is missing.", DISPLAY_BOTH); break; default: displayMessage("Error loading Navigation SDK: " + errorCode, DISPLAY_BOTH); } } }); } /** Requests directions from the user's current location to a list of waypoints. */ private void navigateToPlaces() { // Set up a waypoint for each place that we want to go to. createWaypoint("ChIJq6qq6jauEmsRJAf7FjrKnXI", "Sydney Star"); createWaypoint("ChIJ3S-JXmauEmsRUcIaWtf4MzE", "Sydney Opera House"); createWaypoint("ChIJLwgLFGmuEmsRzpDhHQuyyoU", "Sydney Conservatorium of Music"); // If this journey is already in progress, no need to restart navigation. // This can happen when the user rotates the device, or sends the app to the background. if (mSavedInstanceState != null && mSavedInstanceState.containsKey(KEY_JOURNEY_IN_PROGRESS) && mSavedInstanceState.getInt(KEY_JOURNEY_IN_PROGRESS) == 1) { return; } // Create a future to await the result of the asynchronous navigator task. ListenableResultFuture<Navigator.RouteStatus> pendingRoute = mNavigator.setDestinations(mWaypoints); // Define the action to perform when the SDK has determined the route. pendingRoute.setOnResultListener( new ListenableResultFuture.OnResultListener<Navigator.RouteStatus>() { @Override public void onResult(Navigator.RouteStatus code) { switch (code) { case OK: mJourneyInProgress = true; // Hide the toolbar to maximize the navigation UI. if (getActionBar() != null) { getActionBar().hide(); } // Register some listeners for navigation events. registerNavigationListeners(); // Display the time and distance to each waypoint. displayTimesAndDistances(); // Enable voice audio guidance (through the device speaker). mNavigator.setAudioGuidance(Navigator.AudioGuidance.VOICE_ALERTS_AND_GUIDANCE); // Simulate vehicle progress along the route for demo/debug builds. if (BuildConfig.DEBUG) { mNavigator .getSimulator() .simulateLocationsAlongExistingRoute( new SimulationOptions().speedMultiplier(5)); } // Start turn-by-turn guidance along the current route. mNavigator.startGuidance(); break; // Handle error conditions returned by the navigator. case NO_ROUTE_FOUND: displayMessage("Error starting navigation: No route found.", DISPLAY_BOTH); break; case NETWORK_ERROR: displayMessage("Error starting navigation: Network error.", DISPLAY_BOTH); break; case ROUTE_CANCELED: displayMessage("Error starting navigation: Route canceled.", DISPLAY_BOTH); break; default: displayMessage("Error starting navigation: " + String.valueOf(code), DISPLAY_BOTH); } } }); } /** * Creates a waypoint from a given place ID and title. * * @param placeId The ID of the place to be converted to a waypoint. * @param title A descriptive title for the waypoint. */ private void createWaypoint(String placeId, String title) { try { mWaypoints.add(Waypoint.builder().setPlaceIdString(placeId).setTitle(title).build()); } catch (Waypoint.UnsupportedPlaceIdException e) { displayMessage( "Error starting navigation: Place ID is not supported: " + placeId, DISPLAY_BOTH); } } /** Displays the calculated travel time and distance to each waypoint. */ private void displayTimesAndDistances() { List<TimeAndDistance> timesAndDistances = mNavigator.getTimeAndDistanceList(); int leg = 1; String message = "You're on your way!"; for (TimeAndDistance timeAndDistance : timesAndDistances) { message = message + "\nRoute leg: " + leg++ + ": Travel time (seconds): " + timeAndDistance.getSeconds() + ". Distance (meters): " + timeAndDistance.getMeters(); } displayMessage(message, DISPLAY_BOTH); } /** * Registers some event listeners to show a message and take other necessary steps when specific * navigation events occur. */ private void registerNavigationListeners() { mArrivalListener = new Navigator.ArrivalListener() { @Override public void onArrival(ArrivalEvent arrivalEvent) { displayMessage( "onArrival: You've arrived at a waypoint: " + mNavigator.getCurrentRouteSegment().getDestinationWaypoint().getTitle(), DISPLAY_BOTH); // Start turn-by-turn guidance for the next leg of the route. if (arrivalEvent.isFinalDestination()) { displayMessage("onArrival: You've arrived at the final destination.", DISPLAY_BOTH); } else { mNavigator.continueToNextDestination(); mNavigator.startGuidance(); } } }; // Listens for arrival at a waypoint. mNavigator.addArrivalListener(mArrivalListener); mRouteChangedListener = new Navigator.RouteChangedListener() { @Override public void onRouteChanged() { displayMessage( "onRouteChanged: The driver's route has changed. Current waypoint: " + mNavigator.getCurrentRouteSegment().getDestinationWaypoint().getTitle(), DISPLAY_LOG); } }; // Listens for changes in the route. mNavigator.addRouteChangedListener(mRouteChangedListener); // Listens for road-snapped location updates. mRoadSnappedLocationProvider = NavigationApi.getRoadSnappedLocationProvider(getApplication()); mLocationListener = new RoadSnappedLocationProvider.LocationListener() { @Override public void onLocationChanged(Location location) { displayMessage( "onLocationUpdated: Navigation engine has provided a new" + " road-snapped location: " + location.toString(), DISPLAY_LOG); } @Override public void onRawLocationUpdate(Location location) { displayMessage( "onLocationUpdated: Navigation engine has provided a new" + " raw location: " + location.toString(), DISPLAY_LOG); } }; if (mRoadSnappedLocationProvider != null) { mRoadSnappedLocationProvider.addLocationListener(mLocationListener); } else { displayMessage("ERROR: Failed to get a location provider", DISPLAY_LOG); } mRemainingTimeOrDistanceChangedListener = new Navigator.RemainingTimeOrDistanceChangedListener() { @Override public void onRemainingTimeOrDistanceChanged() { displayMessage( "onRemainingTimeOrDistanceChanged: Time or distance estimate" + " has changed.", DISPLAY_LOG); } }; // Listens for changes in time or distance. mNavigator.addRemainingTimeOrDistanceChangedListener( 60, 100, mRemainingTimeOrDistanceChangedListener); } /** Handles the result of the request for location permissions. */ @Override public void onRequestPermissionsResult( int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { mLocationPermissionGranted = false; switch (requestCode) { case PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION: { // If request is canceled, the result arrays are empty. if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { mLocationPermissionGranted = true; } } } } /** * Shows a message on screen and in the log. Used when something goes wrong. * * @param errorMessage The message to display. */ private void displayMessage(String errorMessage, String displayMedium) { if (displayMedium.equals(DISPLAY_BOTH) || displayMedium.equals(DISPLAY_TOAST)) { Toast.makeText(this, errorMessage, Toast.LENGTH_LONG).show(); } if (displayMedium.equals(DISPLAY_BOTH) || displayMedium.equals(DISPLAY_LOG)) { Log.d(TAG, errorMessage); } } }
检测到达目的地
在这里,“目的地”是指最终目的地或航路点。如需检测到达情况,请调用 Navigator.addArrivalListener()
,该函数会在设备到达目的地时注册回调。
到达目的地后,Navigation SDK for Android 会触发 onArrival()
回调并停止精细导航。您必须显式调用 Navigator.continueToNextDestination()
才能前往下一个航点,并调用 Navigator.startGuidance()
才能继续精细路线导航。
当您调用 continueToNextDestination()
时,导航器会舍弃与上一个目的地相关的所有信息。如果您想分析与上一段路线相关的信息,则必须先从导航器检索信息,然后再调用 continueToNextDestination()
。
为避免内存泄漏,您必须在不再需要监听器时调用 removeArrivalListener(listener)
。
mNavigator.addArrivalListener(new Navigator.ArrivalListener() {
@Override
public void onArrival(ArrivalEvent arrivalEvent) {
displayMessage("onArrival: You've arrived at a waypoint: "
+ mNavigator.getCurrentRouteSegment().getDestinationWaypoint().getTitle(),
DISPLAY_BOTH);
// Start turn-by-turn guidance for the next leg of the route.
if (arrivalEvent.isFinalDestination()) {
displayMessage("onArrival: You've arrived at the final destination.",
DISPLAY_BOTH);
} else {
mNavigator.continueToNextDestination();
mNavigator.startGuidance();
}
}
});
接收位置信息更新
从 NavigationApi
获取 RoadSnappedLocationProvider
,然后调用 RoadSnappedLocationProvider.addLocationListener()
以在设备的位置或航向发生变化时注册回调。请注意,此位置已与道路对齐,因此可能与 Google Play 服务地理位置 API 中的一体化位置信息提供程序返回的位置不同。
Navigation SDK 会尽可能频繁地提供位置信息更新。当有位置信息更新可用时,Navigation SDK 会触发 onLocationChanged()
回调。
基于道路的定位更新与导航无关,即使导航已停止,也能继续更新。如果您让位置信息更新在后台运行,订阅位置信息更新可能会导致电池电量耗尽、内存泄露或意外收集设备位置数据。当您不再需要监听器时,请调用 RoadSnappedLocationProvider.removeLocationListener
。
mRoadSnappedLocationProvider =
NavigationApi.getRoadSnappedLocationProvider(getApplication());
if (mRoadSnappedLocationProvider != null) {
mRoadSnappedLocationProvider.addLocationListener(
new RoadSnappedLocationProvider.LocationListener() {
@Override
public void onLocationChanged(Location location) {
displayMessage("onLocationUpdated: Navigation engine has provided a new"
+ " road-snapped location: "
+ location.toString(),
DISPLAY_LOG);
}
});
} else {
displayMessage("ERROR: Failed to get a location provider", DISPLAY_LOG);
}
接收时间和距离更新
调用 Navigator.addRemainingTimeOrDistanceChangedListener()
以在剩余时间(秒)或距离(米)的变化超过给定阈值时注册回调。
当时间或距离的变化超过指定量时,Navigation SDK 会触发 onRemainingTimeOrDistanceChanged()
回调。
如需查找剩余时间和距离,请调用 Navigator.getTimeAndDistanceList()
。请注意,列表中的时间和距离是累计的:它们显示的是从当前位置到每个航点的时间和距离,而不是从一个航点到另一个航点的时间和距离。TimeAndDistance
对象现在也会返回 delaySeverity
。此枚举将为“重”“中”“轻”或“未知”。这与您在地图界面中看到的 ETA 颜色相对应(严重 = 红色、中等 = 黄色、轻微 = 绿色)。如果您需要创建自己的 ETA 页脚,这将非常有用。
为了避免内存泄漏,您必须在不再需要监听器时调用 Navigator.removeRemainingTimeOrDistanceChangedListener(listener)
。
如果剩余时间变化超过 60 秒或剩余距离变化超过 100 米,以下示例会请求回调。
mNavigator.addRemainingTimeOrDistanceChangedListener(60, 100,
new Navigator.RemainingTimeOrDistanceChangedListener() {
@Override
public void onRemainingTimeOrDistanceChanged() {
displayMessage("onRemainingTimeOrDistanceChanged: Time or distance estimate"
+ " has changed.",
DISPLAY_LOG);
}
});
您可以使用 setEtaCardEnabled()
方法并传递值为 TRUE
的参数,通过内置显示屏显示剩余时间和距离信息。如需禁止显示时间和距离,请将此值设置为 FALSE
。
您还可以使用 getTimeAndDistanceList()
方法公开多个航点的预计到达时间。
接收路线更新
调用 Navigator.addRouteChangedListener()
以在路线发生变化时注册回调。
当路线发生变化时,Navigation SDK 会触发 onRouteChanged()
回调。您可以调用 Navigator.getRouteSegments
和 Navigator.getCurrentRouteSegment()
来查找新路线。
为了避免内存泄漏,您必须在不再需要监听器时调用 removeRouteChangedListener(listener)
。
mNavigator.addRouteChangedListener(new Navigator.RouteChangedListener() {
@Override
public void onRouteChanged() {
displayMessage("onRouteChanged: The driver's route has changed. Current waypoint: "
+ mNavigator.getCurrentRouteSegment().getDestinationWaypoint().getTitle(),
DISPLAY_LOG);
}
});
检测夜间模式的变化
调用 NavigationView.addOnNightModeChangedListener
或 SupportNavigationFragment.addOnNightModeChangedListener
以在夜间模式发生变化时注册回调。
以下示例展示了如何监听导航 fragment 上的夜间模式更改。
mNavFragment.addOnNightModeChangedListener(new NavigationView.OnNightModeChangedListener() {
@Override
public void onNightModeChanged(NightModeChangedEvent nightModeChangedEvent) {
displayMessage("Night mode is active: " + nightModeChangedEvent.inNightMode(),
DISPLAY_LOG);
}
});
您还可以通过程序化方式设置夜间模式。如需了解详情,请参阅设置夜间模式。