Java 第一次执行服务时，如何获取最后一个已知位置？

问题是，我正在模拟器上尝试，它可以工作，但只有在我按下模拟器上的“发送位置到设备”之后，我才有机会获取位置……我如何第一次使用此服务获取位置？。我现在还没有真正的设备，模拟器是我目前唯一的测试方法……我一开始试着发送一个0,0，看看这是否会触发位置更新，但它不起作用……有什么想法吗

@SuppressWarnings("MissingPermission")
public class GPSService extends Service {

    private LocationListener listener;
    private LocationManager locationManager;
    private String lastKnownLatitude;
    private String lastKnownLongitude;
    private Boolean isFirstTime=true;

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {

        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();



        broadcastLocation("0","0");


        listener= new LocationListener() {
            @Override
             public void onLocationChanged(Location location) {

                //To transfer the data to the main activity I use broadcast receiver in the main activity, using an intent filter location_update
                 Intent intentSendLocationMainActivity = new Intent("location_update");
                lastKnownLatitude=""+location.getLatitude();
                lastKnownLongitude=""+location.getLongitude();
                Log.d("LOCATION-UPDATE",lastKnownLatitude+" long:"+lastKnownLongitude);
                broadcastLocation(lastKnownLatitude,lastKnownLongitude);
            }

            @Override
            public void onStatusChanged(String s, int i, Bundle bundle) {
                Log.d("GPS-Stat-Changed",s);
            }

            @Override
            public void onProviderEnabled(String s) {
                Log.d("GPS-Provider-Enabled",s);
            }

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

            }
        };

        locationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
        //noinspection MissingPermission, listen for updates every 3 seconds
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,5000,0,listener);
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.d("ClearFromRecentService", "Service Started");
        Log.d("LAST_LAT_AND_LONG",lastKnownLatitude+" "+lastKnownLongitude);

        return START_STICKY;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.d("ClearFromRecentService", "Service Destroyed, Removing update location listener");
        //unregistering the listener
        /*if(locationManager != null){
            locationManager.removeUpdates(listener);
        }*/

    }

    public void onTaskRemoved(Intent rootIntent) {
        Log.e("ClearFromRecentService", "END");
        //here you can call a background network request to post you location to server when app is killed
        Toast.makeText(getApplicationContext(), "I'm still getting user coordinates", Toast.LENGTH_LONG).show();
        //stopSelf(); //call this method to stop the service
    }

    public void broadcastLocation(String latitude,String longitude){
        Intent intentSendLocationMainActivity = new Intent("location_update");
        intentSendLocationMainActivity.putExtra("latitude",latitude);
        intentSendLocationMainActivity.putExtra("longitude",longitude);
        //I need to differentiate here if the app is killed or not to send the location to main activity or to a server
        sendBroadcast(intentSendLocationMainActivity);
    }
}

编辑：这是完整的服务工作。这是它第一次使用getLastKnownLocation（）获取坐标，并使用侦听器onLocationChanged（）成功获取坐标

@SuppressWarnings（“MissingPermission”）
公共类GPSService扩展服务{
私密地点监听；
私人场所经理场所经理；
私有字符串lastnownlatitude；
私有字符串lastnownlongude；
私有布尔值isFirstTime=true；
@可空
@凌驾
公共IBinder onBind（意向）{
返回null；
}
@凌驾
public void onCreate（）{
super.onCreate（）；
listener=新位置listener（）{
@凌驾
已更改位置上的公共无效（位置）{
//为了将数据传输到主活动，我在主活动中使用广播接收器，并使用意图过滤器位置更新
意向意向转让意向活动=新意向（“位置更新”）；
lastKnownLatitude=”“+位置。getLatitude（）；
lastKnownLongitude=”“+位置。getLongitude（）；
Log.d（“位置更新”，lastKnownLatitude+“长：”+lastKnownLatitude）；
广播位置（lastKnownLatitude、LastKnownLongude）；
}
@凌驾
状态已更改的公共void（字符串s、int i、Bundle）{
Log.d（“GPS状态改变”，s）；
}
@凌驾
已提供已启用的公共void（字符串s）{
Log.d（“GPS提供程序已启用”，s）；
}
@凌驾
公共无效onProviderDisabled（字符串s）{
Intent activateGPSIntent=新意图（设置、操作位置、源设置）；
activateGPSIntent.setFlags（Intent.FLAG\u ACTIVITY\u NEW\u TASK）；
起始触觉（激活EGPSINTENT）；
}
};
locationManager=（locationManager）getApplicationContext（）.getSystemService（Context.LOCATION\u服务）；
//noinspection Missing权限，每3秒侦听一次更新
locationManager.RequestLocationUpdate（locationManager.GPS_提供程序，5000,0，侦听器）；
地图坐标=getLastKnownLocation（locationManager）；
广播位置（坐标.get（“纬度”）、坐标.get（“经度”）；
}
@凌驾
公共int onStartCommand（Intent Intent、int标志、int startId）{
Log.d（“ClearFromRecentService”，“服务已启动”）；
Log.d（“最后一次和最后一次”，lastKnownLatitude+“”+lastKnownLatitude）；
返回开始时间；
}
@凌驾
公共空间{
super.ondestory（）；
Log.d（“ClearFromRecentService”，“服务已销毁，删除更新位置侦听器”）；
//注销侦听器
/*如果（locationManager！=null）{
locationManager.RemoveUpdate（侦听器）；
}*/
}
公共void onTaskRemoved（Intent rootIntent）{
Log.e（“ClearFromRecentService”、“END”）；
//在这里，当应用程序被终止时，您可以调用后台网络请求将您的位置发布到服务器
Toast.makeText（getApplicationContext（），“我仍在获取用户坐标”，Toast.LENGTH\u LONG.show（）；
//stopSelf（）；//调用此方法停止服务
}
私有位置（字符串纬度、字符串经度）{
意向意向转让意向活动=新意向（“位置更新”）；
intentSendLocationMainActivity.putExtra（“纬度”，纬度）；
intentSendLocationMainActivity.putExtra（“经度”，经度）；
//我需要在这里区分应用程序是否被终止，是否将位置发送到主活动或服务器
发送广播（IntentSendLocationMain活动）；
}
私有地图getLastKnownLocation（LocationManager lm）{
Location lastKnownLocation=lm.getLastKnownLocation（LocationManager.GPS\U提供程序）；
字符串ll=”“+lastKnownLocation.getLatitude（）；
地图坐标=新的HashMap（）；
//每次检查此值时，它可能为空
if（lastKnownLocation！=null）{
坐标.put（“纬度”，“lastKnownLocation.getLatitude（））；
坐标.put（“经度”，“lastKnownLocation.getLongitude（））；
}否则{
坐标。放置（“纬度”，“0”）；
坐标。放置（“经度”，“0”）；
}
返回坐标；
}
}

在onCreate中，您可以使用

getLastKnownLocation（LocationManager.GPS\U PROVIDER）我用调试器尝试了这一点，它在我调用getLastKnownLocation…..的线路上崩溃了<代码>@Override public void onCreate（）{super.onCreate（）；Location lastnownlocation=locationManager.getlastnownlocation（locationManager.GPS_提供程序）

你能提供一个关于你建议的代码片段吗？。谢谢！事实上，只要移动这一行

Location-lastnownlocation=locationManager.getlastnownlocation（locationManager.GPS\u PROVIDER）；

就在

locationManager.requestLocationUpdates（locationManager.GPS\u PROVIDER，5000,0，listener）之后

工作得很好…我把它放在了onCreate的边缘。它看起来像getLastKnownLocation需要在requestLocationUpdates方法之后运行。非常感谢先生！我用最后的代码更新了我的帖子，以供将来参考。非常感谢！！

@SuppressWarnings("MissingPermission")
public class GPSService extends Service {

    private LocationListener listener;
    private LocationManager locationManager;
    private String lastKnownLatitude;
    private String lastKnownLongitude;
    private Boolean isFirstTime=true;

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {

        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();

        listener= new LocationListener() {
            @Override
             public void onLocationChanged(Location location) {

                //To transfer the data to the main activity I use broadcast receiver in the main activity, using an intent filter location_update
                 Intent intentSendLocationMainActivity = new Intent("location_update");
                lastKnownLatitude=""+location.getLatitude();
                lastKnownLongitude=""+location.getLongitude();
                Log.d("LOCATION-UPDATE",lastKnownLatitude+" long:"+lastKnownLongitude);
                broadcastLocation(lastKnownLatitude,lastKnownLongitude);
            }

            @Override
            public void onStatusChanged(String s, int i, Bundle bundle) {
                Log.d("GPS-Stat-Changed",s);
            }

            @Override
            public void onProviderEnabled(String s) {
                Log.d("GPS-Provider-Enabled",s);
            }

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

            }
        };

        locationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
        //noinspection MissingPermission, listen for updates every 3 seconds
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,5000,0,listener);


        Map<String, String> coordinates=getLastKnownLocation(locationManager);
        broadcastLocation(coordinates.get("latitude"),coordinates.get("longitude"));
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.d("ClearFromRecentService", "Service Started");
        Log.d("LAST_LAT_AND_LONG",lastKnownLatitude+" "+lastKnownLongitude);

        return START_STICKY;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.d("ClearFromRecentService", "Service Destroyed, Removing update location listener");
        //unregistering the listener
        /*if(locationManager != null){
            locationManager.removeUpdates(listener);
        }*/

    }

    public void onTaskRemoved(Intent rootIntent) {
        Log.e("ClearFromRecentService", "END");
        //here you can call a background network request to post you location to server when app is killed
        Toast.makeText(getApplicationContext(), "I'm still getting user coordinates", Toast.LENGTH_LONG).show();
        //stopSelf(); //call this method to stop the service
    }

    private void broadcastLocation(String latitude,String longitude){
        Intent intentSendLocationMainActivity = new Intent("location_update");
        intentSendLocationMainActivity.putExtra("latitude",latitude);
        intentSendLocationMainActivity.putExtra("longitude",longitude);
        //I need to differentiate here if the app is killed or not to send the location to main activity or to a server
        sendBroadcast(intentSendLocationMainActivity);
    }

    private Map<String, String> getLastKnownLocation(LocationManager lm){

        Location lastKnownLocation=lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        String ll=""+lastKnownLocation.getLatitude();
        Map<String, String> coordinates = new HashMap<String, String>();


        // Check everytime this value, it may be null
        if(lastKnownLocation != null){
            coordinates.put("latitude",""+lastKnownLocation.getLatitude());
            coordinates.put("longitude",""+lastKnownLocation.getLongitude());

        }else{
            coordinates.put("latitude","0");
            coordinates.put("longitude","0");
        }

        return coordinates;
    }
}

@Override
public void onCreate() {
    super.onCreate();

    locationManager = (LocationManager) getApplicationContext()
        .getSystemService(Context.LOCATION_SERVICE);

    Location lastKnownLocation = locationManager
        .getLastKnownLocation(Locat‌​ionManager.GPS_PROVI‌​DER); 

    // Check everytime this value, it may be null
    if(lastKnownLocation != null){
        double latitude = lastKnownLocation.getLatitude();
        double longitude = lastKnownLocation.getLongitude();
        // Use values as you wish
    }

    broadcastLocation("0","0");


    ....
}