当用户按下后退按钮或有新的意图时，停止位置侦听器活动

Question

每当用户的位置发生变化时，该应用程序都会发出嘟嘟声。问题是，即使用户离开应用程序并处于后台，应用程序也会继续监控用户的位置。

一旦应用程序进入后台，我该如何停止位置侦听器？

我想我必须在OnPause（）中添加一些内容，但我无法使其工作。

package com.example.locationbeeper;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.media.AudioManager;
import android.media.ToneGenerator;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
public class MainActivity extends FragmentActivity implements LocationListener {
    LocationManager locationManager;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // set up location manager
        locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
        Criteria criteria = new Criteria();
        String bestProvider = locationManager.getBestProvider(criteria, true);
        Location location = locationManager.getLastKnownLocation(bestProvider);
        if (location != null) {
            onLocationChanged(location);
        }
        locationManager.requestLocationUpdates(bestProvider, 200, 5, this);  // time in miliseconds, distance in meters (Distance drains battry life) originally set to 20000 and 0
    }
    @Override
    public void onLocationChanged(Location location) {
        // beep when location changed
        final ToneGenerator tg = new ToneGenerator(AudioManager.STREAM_NOTIFICATION, 100);
        tg.startTone(ToneGenerator.TONE_PROP_BEEP);
    }
    @Override
    public void onSaveInstanceState(Bundle outState) {
    }
    @Override
    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub
    }
    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub
    }
    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub
    }
    @Override
    public void onPause(){
        super.onPause();
        
        locationManager = null;
    }
}

Answer 1

根据您的需求，您可以在活动的onPause()或onStop()回调方法中添加以下行。

if(locationManager !=null)
      locationManager.removeUpdates(this);

Answer 2

当"活动"停止时，使用LocationManager.removeUpdates停止接收来自LocationManager的更新：

@Override
public void onStop(){
    super.onStop();
    if(locationManager !=null)
      locationManager.removeUpdates(this);
}