在后台连续获取当前位置

Posted 2023-04-14

【中文标题】在后台连续获取当前位置

【英文标题】：Getting current location continuously in background

【发布时间】：2015-02-17 07:40:00

【问题描述】：

在我的项目中，我使用了一项服务来在后台连续检索位置。我的LocationService如下：

public class LocationService extends Service


    private static final int TWO_MINUTES = 1000 * 60 * 2;
    public LocationManager locationManager;
    public MyLocationListener listener;
    public Location previousBestLocation = null;

    Intent i;


    @Override
    public void onCreate()
    
        super.onCreate();
    i = new Intent("LOCATION_CHANGED");

    

    @Override
    public int onStartCommand(Intent intent,int flags, int startId)
    
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        listener = new MyLocationListener();
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 4000, 0, listener);
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 4000, 0, listener);
        return super.onStartCommand(intent, flags, startId);

    

    @Override
    public IBinder onBind(Intent intent)
    
        return null;
    

    protected boolean isBetterLocation(Location location, Location currentBestLocation) 
        if (currentBestLocation == null) 
            // A new location is always better than no location
            return true;

        

        // Check whether the new location fix is newer or older
        long timeDelta = location.getTime() - currentBestLocation.getTime();
        boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;
        boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;
        boolean isNewer = timeDelta > 0;

        // If it's been more than two minutes since the current location, use the new location
        // because the user has likely moved
        if (isSignificantlyNewer) 
            return true;
            // If the new location is more than two minutes older, it must be worse
         else if (isSignificantlyOlder) 
            return false;
        

        // Check whether the new location fix is more or less accurate
        int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation.getAccuracy());
        boolean isLessAccurate = accuracyDelta > 0;
        boolean isMoreAccurate = accuracyDelta < 0;
        boolean isSignificantlyLessAccurate = accuracyDelta > 200;

        // Check if the old and new location are from the same provider
        boolean isFromSameProvider = isSameProvider(location.getProvider(),
                currentBestLocation.getProvider());

        // Determine location quality using a combination of timeliness and accuracy
        if (isMoreAccurate) 
            return true;
         else if (isNewer && !isLessAccurate) 
            return true;
         else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) 
            return true;
        
        return false;
    



    /** Checks whether two providers are the same */
    private boolean isSameProvider(String provider1, String provider2) 
        if (provider1 == null) 
            return provider2 == null;
        
        return provider1.equals(provider2);
    



    @Override
    public void onDestroy() 
        // handler.removeCallbacks(sendUpdatesToUI);
        super.onDestroy();
        Log.v("STOP_SERVICE", "DONE");
        locationManager.removeUpdates(listener);
    

    public static Thread performOnBackgroundThread(final Runnable runnable) 
        final Thread t = new Thread() 
            @Override
            public void run() 
                try 
                    runnable.run();
                 catch(Exception e) 
System.out.print(e);
                
            
        ;
        t.start();
        return t;
    




    public class MyLocationListener implements LocationListener
    

        public void onLocationChanged(final Location loc)
        
            Log.i("**************************************", "Location changed");
            if(isBetterLocation(loc, previousBestLocation)) 
                String newLocation = "Lat: " + loc.getLatitude() + " and Long: " + loc.getLongitude();
               i = new Intent("LOCATION_CHANGED");
                i.putExtra("location", newLocation);
                sendBroadcast(i);



            
        

        public void onProviderDisabled(String provider)
        
            Toast.makeText( getApplicationContext(), "Gps Disabled", Toast.LENGTH_SHORT ).show();
        


        public void onProviderEnabled(String provider)
        
            Toast.makeText(getApplicationContext(), "Gps Enabled", Toast.LENGTH_SHORT).show();
        


        public void onStatusChanged(String provider, int status, Bundle extras)
        

        

    

我在MainActivity 收到了广播意图，如下：

public class MainActivity extends Activity 


    TextView txt_location;



    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        txt_location = (TextView)findViewById(R.id.current_location);


        if (savedInstanceState == null) 
            getFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment()).commit();


        

   



    public class LocationBroadcast extends BroadcastReceiver 
        @Override
        public void onReceive(Context ctx, Intent intent) 

            txt_location.setText(intent.getExtras().getString("location"));
        

    



       public static class PlaceholderFragment extends Fragment 


        public PlaceholderFragment() 

        

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) 


            return inflater.inflate(R.layout.fragment_main, container,
                    false);

        
    

我要做的就是在txt_location 上设置位置的纬度和经度。此代码不起作用并按原样显示txt_location：

如您所见，它没有显示任何位置更新...Logcat 没有显示任何错误..谁能指导我是什么错误？

【问题讨论】：

使用 AndoridHive 教程：androidhive.info/2012/07/android-gps-location-manager-tutorial

@TusharPandey 它用于在某些按钮单击时检索位置。我说我想在后台连续获取位置（使用服务或任何其他方法）

为它创建一个服务，或者无限时间使用后台线程并在位置变化时生成本地广播消息。

@TusharPandey 我已经做了服务..LocationService 类扩展了服务

无限时间使用后台线程并生成

【参考方案1】：

将此类用作服务。但在此之前在清单中定义服务类

<service android:name="com.example.androidservice.beckend.EndlessService" />

在活动类中使用

startService(new Intent ( this , EndlessService.class)) ;

import android.app.Service;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.os.Process;
import android.util.Log;
import android.widget.Toast;

public class EndlessService extends Service 
    private Looper mServiceLooper;
    private ServiceHandler mServiceHandler;

    // Handler that receives messages from the thread
    private final class ServiceHandler extends Handler 
        public ServiceHandler(Looper looper) 
            super(looper);
        

        @Override
        public void handleMessage(Message msg) 
        
            new HitToTheInternet().execute("");
        
    

    @Override
    public void onCreate() 
        // Start up the thread running the service. Note that we create a
        // separate thread because the service normally runs in the process's
        // main thread, which we don't want to block. We also make it
        // background priority so CPU-intensive work will not disrupt our UI.
        HandlerThread thread = new HandlerThread("ServiceStartArguments",Process.THREAD_PRIORITY_BACKGROUND);
        thread.start();

        // Get the HandlerThread's Looper and use it for our Handler
        mServiceLooper = thread.getLooper();
        mServiceHandler = new ServiceHandler(mServiceLooper);
    

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) 
        Toast.makeText(this, "service starting", Toast.LENGTH_SHORT).show();

        // For each start request, send a message to start a job and deliver the
        // start ID so we know which request we're stopping when we finish the
        // job
        Message msg = mServiceHandler.obtainMessage();
        msg.arg1 = startId;
        mServiceHandler.sendMessage(msg);

        if ( intent == null )
        
            Log.e("intentStatus", "intent is null");
        

        // If we get killed, after returning from here, restart
        return START_STICKY;
    

    @Override
    public IBinder onBind(Intent intent) 
        // We don't provide binding, so return null
        return null;
    

    @Override
    public void onDestroy() 
        Toast.makeText(this, "service done", Toast.LENGTH_SHORT).show();
    

    class HitToTheInternet extends AsyncTask<String, String, String>
    

        @Override
        protected String doInBackground(String... params) 
            // TODO Auto-generated method stub

            Log.e("doInBackground", "Running") ;

            return null;
        

        @Override
        protected void onPostExecute(String result) 
            // TODO Auto-generated method stub
            super.onPostExecute(result);

            new Handler().postDelayed(new Runnable() 
                public void run() 
                    Message msg = mServiceHandler.obtainMessage();
                    mServiceHandler.sendMessage(msg);
                
            , 10000);
        
    

【参考方案2】：

在 5 秒后开始服务说：

AlarmManager alarm =(AlarmManager)context.getSystemService(context.ALARM_SERVICE);
        PendingIntent pi = PendingIntent.getService(context, 0, new Intent(context,MonitorService.class), 0);
        alarm.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime(), 5*1000, pi);

停止报警：

AlarmManager mgr =(AlarmManager)getSystemService(ALARM_SERVICE);
        PendingIntent pi = PendingIntent.getService(context, 0, new Intent(this,MonitorService.class), 0);
        mgr.cancel(pi);
        pi.cancel();