java - onLocationChanged 不起作用？

Question

在 LocationChanged 监听器上不起作用。

import android.app.Activity;
import android.content.Context;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.Toast;

public class SimpleLocation extends Activity implements LocationListener {
    private LocationManager locationManager;
    private String provider;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // setContentView(R.layout.main);
        // Get the location manager
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        // Define the criteria how to select the locatioin provider -> use
        // default
        Criteria criteria = new Criteria();
        provider = locationManager.getBestProvider(criteria, false);
        Location location = locationManager.getLastKnownLocation(provider);

        // Initialize the location fields
        if (location != null) {
            System.out.println("Provider " + provider + " has been selected.");
            int lat = (int) (location.getLatitude());
            int lng = (int) (location.getLongitude());
            Toast.makeText(getApplicationContext(),
                    "Lat:" + lat + " Lng:" + lng, Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(getApplicationContext(), "No Value",
                    Toast.LENGTH_LONG).show();
        }
    }

    /* Request updates at startup */
    @Override
    protected void onResume() {
        super.onResume();
        locationManager.requestLocationUpdates(provider, 400, 1,
                (LocationListener) this);
    }

    /* Remove the locationlistener updates when Activity is paused */
    @Override
    protected void onPause() {
        super.onPause();
        locationManager.removeUpdates((LocationListener) this);
    }

    public void onLocationChanged(Location location) {
        int lat = (int) (location.getLatitude());
        int lng = (int) (location.getLongitude());
        Toast.makeText(getApplicationContext(),
                "onLocationChanged Lat:" + lat + " Lng:" + lng,
                Toast.LENGTH_LONG).show();
    }

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

    }

    public void onProviderEnabled(String provider) {
        Toast.makeText(this, "Enabled new provider " + provider,
                Toast.LENGTH_SHORT).show();

    }

    public void onProviderDisabled(String provider) {
        Toast.makeText(this, "Disabled provider " + provider,
                Toast.LENGTH_SHORT).show();
    }

}

Answer 1

locationManager.requestLocationUpdates(provider, 400, 1,
            (LocationListener) this);

其格式为:

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

代码中的这一行指定仅当移动距离最小为“1”时才会在应用程序中注册位置更改。将其设置为 0 并尝试再次运行您的代码。或者将 minTime 和 minDistance 都设置为 0 并尝试。