public class MyService extends BackgroundService implements LocationListener {
private final static String TAG = MyService.class.getSimpleName();
private String mHelloTo = "World";
private LocationManager locationManager;
private String provider;
Context context;
String username;
CommentsDataSource datasource;
@Override
public void onCreate() {
context = getApplicationContext();
datasource = new CommentsDataSource(context);
datasource.open();
mHelloTo = datasource.getComment_1();
}
@Override
public void onDestroy() {
//datasource.close();
}
protected JSONObject doWork() {
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
int level=0;
provider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(provider);
Double latitude = location.getLatitude();
Double longitude = location.getLongitude();
if (location != null) {
Log.i("Provider", provider + " has been selected.");
onLocationChanged(location);
}
JSONObject result = new JSONObject();
try {
String msg = "Kasun " + mHelloTo + " - its currently "
+ "3.456789";
result.put("Message", msg);
Log.d(TAG, msg);
} catch (JSONException e) {
}
return result;
}
public void onLocationChanged(Location location) {
Double latitude = location.getLatitude();
Double longitude = location.getLongitude();
}
}
在这里，我创建了获取当前GPS位置并显示的后台服务。但是当我尝试上面的代码时，我得到以下错误。但是当我在Android选项卡上尝试它时，它工作正常但是我在Huwavi选项卡上尝试它给出了愚蠢的错误。
12-26 14:41:04.651: I/BackgroundService(5356): Exception occurred during doWork()
12-26 14:41:04.651: I/BackgroundService(5356): java.lang.NullPointerException
12-26 14:41:04.651: I/BackgroundService(5356): at org.apache.cordova.example.MyService.doWork(MyService.java:84)
12-26 14:41:04.651: I/BackgroundService(5356): at com.red_folder.phonegap.plugin.backgroundservice.BackgroundService.doWorkWrapper(BackgroundService.java:390)
答案 0 :(得分：0)
请使用此服务：
Gradle
implementation 'com.google.android.gms:play-services:12.0.1'
启动服务
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
ContextCompat.startForegroundService(MainActivity.this, new Intent(MainActivity.this, ServiceLocation.class));
} else {
startService(new Intent(MainActivity.this, ServiceLocation.class));
}
服务等级
public class ServiceLocation extends Service implements
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
private static final String NOTIFICATION_CHANNEL_ID = "my_notification_location";
private static final long TIME_INTERVAL_GET_LOCATION = 1000 * 5; // 1 Minute
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 7; // meters
private Handler handlerSendLocation;
private Context mContext;
private GoogleApiClient mGoogleApiClient;
private LocationRequest mLocationRequest;
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 5000;
Location locationData;
@Override
public void onCreate() {
super.onCreate();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
// Create the LocationRequest object
mLocationRequest = LocationRequest.create()
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
.setInterval(TIME_INTERVAL_GET_LOCATION) // 3 seconds, in milliseconds
.setFastestInterval(TIME_INTERVAL_GET_LOCATION); // 1 second, in milliseconds
mContext = this;
NotificationCompat.Builder builder = new NotificationCompat.Builder(this, NOTIFICATION_CHANNEL_ID)
.setOngoing(false)
.setSmallIcon(R.drawable.ic_notification)
.setColor(getResources().getColor(R.color.fontColorDarkGray))
.setPriority(Notification.PRIORITY_MIN);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID,
NOTIFICATION_CHANNEL_ID, NotificationManager.IMPORTANCE_LOW);
notificationChannel.setDescription(NOTIFICATION_CHANNEL_ID);
notificationChannel.setSound(null, null);
notificationManager.createNotificationChannel(notificationChannel);
startForeground(1, builder.build());
}
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.w("Service Update Location", "BGS > Started");
if (handlerSendLocation == null) {
handlerSendLocation = new Handler();
handlerSendLocation.post(runnableSendLocation);
Log.w("Service Send Location", "BGS > handlerSendLocation Initialized");
} else {
Log.w("Service Send Location", "BGS > handlerSendLocation Already Initialized");
}
return START_STICKY;
}
private Runnable runnableSendLocation = new Runnable() {
@Override
public void run() {
// You can get Location
//locationData
Log.w("==>UpdateLocation<==", "" + String.format("%.6f", locationData.getLatitude()) + "," +
String.format("%.6f", locationData.getLongitude()));
Log.w("Service Send Location", "BGS >> Location Updated");
if (handlerSendLocation != null && runnableSendLocation != null)
handlerSendLocation.postDelayed(runnableSendLocation, TIME_INTERVAL_GET_LOCATION);
}
};
@Override
public void onConnected(@Nullable Bundle bundle) {
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED &&
ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return;
}
Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
if (connectionResult.hasResolution() && mContext instanceof Activity) {
try {
Activity activity = (Activity) mContext;
connectionResult.startResolutionForResult(activity, CONNECTION_FAILURE_RESOLUTION_REQUEST);
} catch (Exception e) {
e.printStackTrace();
}
} else {
Log.i("", "Location services connection failed with code " + connectionResult.getErrorCode());
}
}
@Override
public void onLocationChanged(Location location) {
Log.w("==>UpdateLocation<==", "" + String.format("%.6f", location.getLatitude()) + "," + String.format("%.6f", location.getLongitude()));
locationData = location;
}
@Override
public void onDestroy() {
if (handlerSendLocation != null)
handlerSendLocation.removeCallbacks(runnableSendLocation);
Log.w("Service Update Info", "BGS > Stopped");
stopSelf();
super.onDestroy();
}
}
AndroidManifest.XML
<service
android:name=".ServiceLocation"
android:enabled="true"
android:exported="true" />