Question

我试图每隔几秒就获得一次GPS值，而我却错过了一些技巧。以下是我尝试过的内容：

public class Locn extends ActionBarActivity 
{
    private LocationManager locationManager;
    private String provider;
    private Location loc = null;
    private Criteria criteria;
    ... local variables ...

    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        ...

        // Get the location manager
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        LocationManager service = (LocationManager) getSystemService(LOCATION_SERVICE);
        boolean enabled = service.isProviderEnabled(LocationManager.GPS_PROVIDER);

        // Check if enabled. If not send user to the GPS settings
        if (!enabled) 
        {
            Toast.makeText(this, "Please enable GPS location service",  
                      Toast.LENGTH_SHORT).show();
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            startActivity(intent);
        }
        else 
        {
        Toast.makeText(this, "GPS location service is enabled", 
                      Toast.LENGTH_SHORT).show();
        }
        // Define the criteria to select the location provider -> use default
        criteria = new Criteria();
        criteria.setAccuracy(Criteria.ACCURACY_FINE);
        criteria.setPowerRequirement(Criteria.NO_REQUIREMENT);

        // Let Android select the best location provider based on criteria
        provider = locationManager.getBestProvider(criteria, true);

        ...
    }

    //--------------------------------------
    // Set up timer handlers
    Handler timerHandler = new Handler();
    Runnable timerRunnable = new Runnable() 
    {
        @Override
        public void run() 
        {
            provider = locationManager.getBestProvider(criteria, true);
            loc = locationManager.getLastKnownLocation(provider);

            milli = System.currentTimeMillis();
        longitude = loc.getLongitude();
        latitude = loc.getLatitude();
        count++;

            timerHandler.postDelayed(this, 2000);
        }    
    };

计数和毫秒每两秒更换一次，但纬度和经度根本不会改变。（是的，我改变了位置 - 最多2英里）

我在这里缺少什么？在再次调用getLastKnownLocation之前是否必须清除loc？

谢谢，沃尔特

Answer 1

    Timer tm =new Timer();
    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates( LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
    boolean enabled = service.isProviderEnabled(LocationManager.GPS_PROVIDER);
    tm.schedule(new task(),10,10000);//this execute task every 10 seconds

//在主要活动中使用计时器任务

class task extends TimerTask {
         public void run() {
             Home.this.runOnUiThread(new Runnable() {
                 public void run() {
                           longitude = loc.getLongitude();
                           latitude = loc.getLatitude();

             });
         }
     };

Answer 2

你不需要定时器。只需使用LocationManager.requestLocationUpdates()

即可

来自Android文档：

requestLocationUpdates(String provider, long minTime, float minDistance, LocationListener listener)

见：Android LocationManager

只需使用如下：

public class MainActivity extends Activity implements LocationListener {

    private String provider;
    private LocationManager lm;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_activity);

        lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
        Criteria criteria = new Criteria();       
        provider = lm.getBestProvider(criteria, false);

        Location location = lm.getLastKnownLocation(provider);

        if (location != null) {
            onLocationChanged(location);
            }
    }

    @Override   
    protected void onResume() {  
        super.onResume();  
        lm.requestLocationUpdates(provider, 1000, 10, this); 
    }
    @Override   
    protected void onPause() {    
        super.onPause();
        lm.removeUpdates(this); 
    }

    @Override
    protected boolean isRouteDisplayed() {
        return false;
    }

    public void onLocationChanged(Location location) {
        double lat = location.getLatitude();
        double lng = location.getLongitude();
        }

    public void onProviderDisabled(String provider) {

    }

    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub

    }

    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub

    }

    }

运行GPS值

2 个答案: