android - 如何使用异步任务获取位置？安卓

Question

我正在使用异步任务并搜索我的 gps 位置（使用网络提供商）我收到错误locManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locListener);

public class SimpleDirect extends MapActivity {
MapView mapView;

private ProgressDialog pDialog;
private LocationManager locManager;
private LocationListener locListener;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.simple_direct_main);
    mapView = (MapView)findViewById(R.id.mapView);
    initMap();
    new Activity().execute();
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (resultCode == 100) {
        Intent intent = getIntent();
        finish();
        startActivity(intent);
    }

}
class Activity extends AsyncTask<String, String, String> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(SimpleDirect.this);
        pDialog.setMessage("Mohon tunggu...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(false);
        pDialog.show();
    }
    protected String doInBackground(String... args) {
        initLocationManager();
        return null;
    }

    protected void onPostExecute(String file_url) {
        pDialog.dismiss();
    }
}

  private void initLocationManager(){
        locManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        locListener = new LocationListener() {
             public void onLocationChanged(Location newLocation) {
                tampilkanPosisikemap(newLocation);
            }
            public void onProviderDisabled(String arg0) {
            }

            public void onProviderEnabled(String arg0){
            }

            public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
            }
        };
        locManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locListener);
    }

    protected void tampilkanPosisikemap(Location newLocation) {
        List overlays = mapView.getOverlays();

        if(overlays.size() > 0) {
            for(Iterator iterator = overlays.iterator(); iterator.hasNext();) {
                iterator.next();
                iterator.remove();
            }
        }
                GeoPoint geopoint = new GeoPoint(
                        (int) (newLocation.getLatitude() * 1E6), (int) (newLocation
                                .getLongitude() * 1E6));

                Drawable icon = getResources().getDrawable(R.drawable.marker);
                icon.setBounds(0, 0, icon.getIntrinsicWidth(), icon
                        .getIntrinsicHeight());
                MyItemizedOverlay overlay = new MyItemizedOverlay(icon);
                OverlayItem item = new OverlayItem(geopoint, "My Location", null);
                overlay.addItem(item);
                mapView.getOverlays().add(overlay);
                mapView.getController().animateTo(geopoint);
                mapView.postInvalidate();
    }

private void initMap() {
    mapView = (MapView) findViewById(R.id.mapView);
    mapView.setBuiltInZoomControls(true);
    mapView.getController().setZoom(15);
}
@Override
protected boolean isRouteDisplayed(){
    return false;
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.simple_direct_main, menu);
    return true;
}
}

我的日志猫：

    04-22 20:48:26.763: E/AndroidRuntime(15676): FATAL EXCEPTION: AsyncTask #1
04-22 20:48:26.763: E/AndroidRuntime(15676): java.lang.RuntimeException: An error occured while executing doInBackground()
04-22 20:48:26.763: E/AndroidRuntime(15676):    at android.os.AsyncTask$3.done(AsyncTask.java:200)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at java.util.concurrent.FutureTask.run(FutureTask.java:137)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at java.lang.Thread.run(Thread.java:1096)
04-22 20:48:26.763: E/AndroidRuntime(15676): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
04-22 20:48:26.763: E/AndroidRuntime(15676):    at android.os.Handler.<init>(Handler.java:121)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at android.location.LocationManager$ListenerTransport$1.<init>(LocationManager.java:139)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at android.location.LocationManager$ListenerTransport.<init>(LocationManager.java:137)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at android.location.LocationManager._requestLocationUpdates(LocationManager.java:708)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at android.location.LocationManager.requestLocationUpdates(LocationManager.java:630)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at com.example.simpledirection.SimpleDirect.initLocationManager(SimpleDirect.java:128)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at com.example.simpledirection.SimpleDirect.access$2(SimpleDirect.java:107)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at com.example.simpledirection.SimpleDirect$Activity.doInBackground(SimpleDirect.java:93)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at com.example.simpledirection.SimpleDirect$Activity.doInBackground(SimpleDirect.java:1)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at android.os.AsyncTask$2.call(AsyncTask.java:185)
04-22 20:48:26.763: E/AndroidRuntime(15676):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
04-22 20:48:26.763: E/AndroidRuntime(15676):    ... 4 more
04-22 20:48:26.813: E/MapActivity(15676): Couldn't get connection factory client
04-22 20:48:27.623: E/WindowManager(15676): Activity com.example.simpledirection.SimpleDirect has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4a0aa048 that was originally added here
04-22 20:48:27.623: E/WindowManager(15676): android.view.WindowLeaked: Activity com.example.simpledirection.SimpleDirect has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4a0aa048 that was originally added here
04-22 20:48:27.623: E/WindowManager(15676):     at android.view.ViewRoot.<init>(ViewRoot.java:247)
04-22 20:48:27.623: E/WindowManager(15676):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
04-22 20:48:27.623: E/WindowManager(15676):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
04-22 20:48:27.623: E/WindowManager(15676):     at android.view.Window$LocalWindowManager.addView(Window.java:424)
04-22 20:48:27.623: E/WindowManager(15676):     at android.app.Dialog.show(Dialog.java:241)
04-22 20:48:27.623: E/WindowManager(15676):     at com.example.simpledirection.SimpleDirect$Activity.onPreExecute(SimpleDirect.java:88)
04-22 20:48:27.623: E/WindowManager(15676):     at android.os.AsyncTask.execute(AsyncTask.java:391)
04-22 20:48:27.623: E/WindowManager(15676):     at com.example.simpledirection.SimpleDirect.onCreate(SimpleDirect.java:59)
04-22 20:48:27.623: E/WindowManager(15676):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-22 20:48:27.623: E/WindowManager(15676):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2633)
04-22 20:48:27.623: E/WindowManager(15676):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2685)
04-22 20:48:27.623: E/WindowManager(15676):     at android.app.ActivityThread.access$2300(ActivityThread.java:126)
04-22 20:48:27.623: E/WindowManager(15676):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2038)
04-22 20:48:27.623: E/WindowManager(15676):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-22 20:48:27.623: E/WindowManager(15676):     at android.os.Looper.loop(Looper.java:123)
04-22 20:48:27.623: E/WindowManager(15676):     at android.app.ActivityThread.main(ActivityThread.java:4633)
04-22 20:48:27.623: E/WindowManager(15676):     at java.lang.reflect.Method.invokeNative(Native Method)
04-22 20:48:27.623: E/WindowManager(15676):     at java.lang.reflect.Method.invoke(Method.java:521)
04-22 20:48:27.623: E/WindowManager(15676):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
04-22 20:48:27.623: E/WindowManager(15676):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
04-22 20:48:27.623: E/WindowManager(15676):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

You should not be calling locManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locListener); inside AsyncTask but rather code inside public void onLocationChanged(Location newLocation) { should be called on a separate thread.

requestLocationUpdates is asynchornous non-blocking call and doesn't require you to add threads. Your AsyncTask ends immediately.

Apart from that I would suggest not to have a code structure like this. Notice that every time a location is found, you will start an AsyncTask. You will end up having many started at the same time and memory leaks will also come if you rotate device or finish this Activity.

Answer 2

答案就在那里，David Olsson 已经提到过。你在mapView.postInvalidate();做doInBackground。doInBackground 不允许 UI 工作。对于 UI 工作，您需要使用 onPre，或者在您的情况下使用 onPost。

例外只是说

原因：java.lang.RuntimeException：无法在未调用 Looper.prepare() 的线程内创建处理程序

Answer 3

此代码适用于我您可以异步获取位置

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        mw = new Mywidgets(getApplicationContext());
        progressDialog = new ProgressDialog(MapsActivity.this);

        try
        {
            progressDialog.setMessage("Loading Please wait");
            Load_task load_task = new Load_task();
            load_task.execute();

        }catch (Exception e){
            mw.app_log(e.getMessage());
        }



    }

 public class Load_task extends AsyncTask<Void,Void,Void>{

        @Override
        protected Void doInBackground(Void... voids) {
            Bundle bun = getIntent().getExtras();
            final String location = bun.getString("location");
            location_arr = location.split(",");

            Geocoder gc = new Geocoder(getApplicationContext());
            List<Address> addresses = new LinkedList<>();
            int c = 0;
            for (String loc : location_arr) {
                //  mw.app_log(loc);
                List<Address> each_addr = null;
                try {
                    each_addr = gc.getFromLocationName(loc, 1);

                } catch (IOException e) {
                    mw.app_log("cant get location");
                    e.printStackTrace();
                }
                addresses.add(each_addr.get(0));
            }

            lat_long = new ArrayList<LatLng>(addresses.size()); // A list to save the coordinates if they are available
            for (Address a : addresses) {
                if (a.hasLatitude() && a.hasLongitude()) {
                    lat_long.add(new LatLng(a.getLatitude(), a.getLongitude()));
                    mw.app_log("added "+lat_long.toString());
                }else{
                    mw.app_log("not added");
                }
            }


            return null;
        }

        @Override
        protected void onPreExecute() {
            progressDialog.show();
            super.onPreExecute();
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            progressDialog.hide();
            mw.app_log(lat_long.toString());
            set_map();

            super.onPostExecute(aVoid);
        }
    }


public void set_map(){

 // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

}

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        if (Geocoder.isPresent()) {

            try {
                progressDialog.hide();


                //addresses.remove(0);


                // Add a marker in Sydney and move the camera
                int n = 0;
                for (LatLng lat : lat_long) {

                    MarkerOptions marker = new MarkerOptions().position(lat).title(location_arr[n++]);

                    marker.icon(BitmapDescriptorFactory.fromResource(R.mipmap.eauction_car_icon_map)).position(lat).snippet(location_arr[n - 1]);
                    mMap.addMarker(marker);
                }

                mMap.moveCamera(CameraUpdateFactory.newLatLng(lat_long.get(2)));
                ;
                mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(lat_long.get(0), 12.0f));
                mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
                    @Override
                    public boolean onMarkerClick(Marker marker) {
                        Intent prop_intent = new Intent(getApplicationContext(), Property_view.class);
                        int pos = Integer.parseInt(marker.getId().substring(1));
                        //prop_intent.putExtra("location",location[pos]);

                        mw.toast(location_arr[pos]);
                        // startActivity(prop_intent);

                        return false;
                    }
                });
                //mMap.setOnCameraIdleListener(mClusterManager);

            } catch (Exception e) {
                Log.d("json_obj", e.getMessage());
            }
        }

    }