Oreo - 在前台启动服务

Question

我创建了一项服务，可在设备移动时跟踪设备的位置。该服务由绑定到它的 Activity 启动，并且在此 Activity 中有一个“开始跟踪”按钮。当按下此按钮时，我需要服务在前台启动，以便它存储设备移动到的位置，即使绑定到它的 Activity 已关闭，或者应用程序已最小化。

我了解，要使服务处于前台，必须显示通知。我已尝试这样做，但是当活动被销毁时，我无法显示通知或服务在前台工作。

由于通知渠道的原因，Oreo 中的通知似乎发生了变化，但我无法弄清楚需要做些什么不同的事情。我正在测试的设备是 8.0.0。

这是我的服务：

public class LocationTrackerService extends Service {

    private LocationListener locationListener;
    private LocationManager locationManager;
    private IBinder binder = new LocalBinder();
    private boolean isTracking;
    private ArrayList<Location> trackedWaypoints;
    private String bestProvider;
    private Timer timer;
    private Distance distance;

    @SuppressLint("MissingPermission")
    @Override
    public void onCreate() {
        super.onCreate();

        locationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
        Criteria criteria = new Criteria();
        bestProvider = locationManager.getBestProvider(criteria, true);

        isTracking = false;

        locationListener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                Intent intent = new Intent("location_update");
                intent.putExtra("latitude", location.getLatitude());
                intent.putExtra("longitude", location.getLongitude());
                sendBroadcast(intent);
                if (isTracking) {
                    if (trackedWaypoints.size() > 1) {
                        distance.add(trackedWaypoints.get(trackedWaypoints.size() - 1).distanceTo(location));
                    }
                    trackedWaypoints.add(location);
                }
            }

            @Override
            public void onStatusChanged(String s, int i, Bundle bundle) { }

            @Override
            public void onProviderEnabled(String s) { }

            @Override
            public void onProviderDisabled(String s) {
                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                startActivity(intent);
            }
        };

        locationManager.requestLocationUpdates(bestProvider, 0, 0, locationListener);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (locationManager != null) {
            locationManager.removeUpdates(locationListener);
        }
    }

    public void startTracking() {
        trackedWaypoints = new ArrayList<Location>();
        timer = new Timer();
        distance = new Distance();
        timer.start();
        isTracking = true;
        startInForeground();
    }

    private void startInForeground() {
        Intent notificationIntent = new Intent(this, WorkoutActivity.class);
        PendingIntent pendingIntent =
                PendingIntent.getActivity(this, 0, notificationIntent, 0);

        Notification notification =
                new Notification.Builder(this)
                        .setContentTitle("TEST")
                        .setContentText("HELLO")
                        .setSmallIcon(R.drawable.ic_directions_run_black_24dp)
                        .setContentIntent(pendingIntent)
                        .setTicker("TICKER")
                        .build();

        startForeground(101, notification);
    }

    public void stopTracking() {
        isTracking = false;
        stopForeground(true);
    }

    public boolean isTracking() {
        return isTracking;
    }

    public ArrayList<Location> getTrackedWaypoints() {
        return trackedWaypoints;
    }

    public Timer getTime() {
        timer.update();
        return timer;
    }

    public Distance getDistance() {
        return distance;
    }

    public int getSteps() {
        return 0;
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return binder;
    }

    public class LocalBinder extends Binder {
        public LocationTrackerService getLocationTrackerInstance() {
            return LocationTrackerService.this;
        }
    }
}

Answer 1

尝试使用以下代码更改您的 startInForeground() 方法：

private void startInForeground() {
        Intent notificationIntent = new Intent(this, WorkoutActivity.class);
        PendingIntent pendingIntent=PendingIntent.getActivity(this,0,notificationIntent,0);
        NotificationCompat.Builder builder = new NotificationCompat.Builder(this,NOTIFICATION_CHANNEL_ID)
                .setSmallIcon(R.drawable.shsl_notification)
                .setContentTitle("TEST")
                .setContentText("HELLO")
                .setTicker("TICKER") 
                .setContentIntent(pendingIntent);
        Notification notification=builder.build();
        if(Build.VERSION.SDK_INT>=26) {
            NotificationChannel channel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, NOTIFICATION_CHANNEL_NAME, NotificationManager.IMPORTANCE_DEFAULT);
            channel.setDescription(NOTIFICATION_CHANNEL_DESC);
            NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            notificationManager.createNotificationChannel(channel);
        }
        startForeground(NOTIFICATION_ID, notification);
}

因此，当您的 Android 版本为 Oreo（或更高版本）时，将创建通知通道，否则不会。

Answer 2

在显示通知之前，您必须创建通知渠道：

private void createNotificationChannel() {
    if (Build.VERSION_CODES.O <= Build.VERSION.SDK_INT) {
        NotificationChannel notificationChannel =
                new NotificationChannel(PRIMARY_CHANNEL_ID, CHANNEL_NAME, NotificationManager.IMPORTANCE_DEFAULT);
        notificationManager.createNotificationChannel(notificationChannel);
    }
}

然后更改创建通知生成器

new Notification.Builder(context, PRIMARY_CHANNEL_ID)