服务中的 Android 位置更新

Question

我想做这样的事情：

• 当我的应用程序启动时，我想启动一个服务来检查我的位置

• 当应用程序进入后台时，我想停止服务

我有两个主要问题：

1. 如何检测我的应用程序进入后台？我有几个活动，我在 MainActivity 中尝试了覆盖 onPause，但是当我开始其他活动时也会调用 onPause。

2. 这个问题更重要：我的服务应该如何检查我的位置？我尝试了几种方法，但都没有成功。

我的服务看起来像这样，但它不起作用。我应该改变什么才能让它工作？

package com.pivoscore.service;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;

public class LocationService extends Service {

    private LocationListener locationListener;

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

    @Override
    public int onStartCommand(final Intent intent, final int flags, final int startId) {
        super.onStartCommand(intent, flags, startId);
        return Service.START_STICKY;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        final LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
        this.locationListener = new MyLocationListener();
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 100, 0, this.locationListener);
    }

    private static class MyLocationListener implements LocationListener {

        @Override
        public void onLocationChanged(final Location location) {
        }

        @Override
        public void onProviderDisabled(final String provider) {
        }

        @Override
        public void onProviderEnabled(final String provider) {
        }

        @Override
        public void onStatusChanged(final String provider, final int status, final Bundle extras) {
        }

    }

}

Answer 1

这将帮助您确定您的要求是什么 但不要忘记添加我在评论中添加的权限 并且不要忘记在清单文件中添加服务标签 代码片段正在关注

public class LocationService extends Service {
public static final String BROADCAST_ACTION = "Hello World";
private static final int TWO_MINUTES = 1000 * 60 * 2;
public LocationManager locationManager;
public MyLocationListener listener;
public Location previousBestLocation = null;

Intent intent;
int counter = 0;

@Override
public void onCreate() {
    super.onCreate();
    intent = new Intent(BROADCAST_ACTION);      
}

@Override
public void onStart(Intent intent, int startId) {      
    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    listener = new MyLocationListener();        
    locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, listener);
    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, listener);
}

@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();
            } finally {

            }
        }
    };
    t.start();
    return t;
}


public class MyLocationListener implements LocationListener
{

    public void onLocationChanged(final Location loc)
    {
        Log.i("**************************************", "Location changed");
        if(isBetterLocation(loc, previousBestLocation)) {
            loc.getLatitude();
            loc.getLongitude();             
            intent.putExtra("Latitude", loc.getLatitude());
            intent.putExtra("Longitude", loc.getLongitude());     
            intent.putExtra("Provider", loc.getProvider());                 
            sendBroadcast(intent);          
            /*final Geocoder geocoder = new Geocoder(getApplicationContext(), Locale.getDefault());         
            String Text = "";
            try {
                List<Address> addresses = geocoder.getFromLocation(loc.getLatitude(), loc.getLongitude(), 1);                
                Text = "My current location is: "+addresses.get(0).getAddressLine(0); 

            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                Text = "My current location is: " +"Latitude = " + loc.getLatitude() + ", Longitude = " + loc.getLongitude();  
            }
            */
            //Toast.makeText( getApplicationContext(), "Location polled to server", Toast.LENGTH_SHORT).show();
        }                               
    }

    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)
    {

    }

}

Answer 2

1. 应用程序不是 Android 中的可视组件。它分为活动，每个活动在可见时运行，在其他情况下暂停和销毁。因此，没有整个 Application 进入后台的概念，Activity 根据其各自的可见性暂停和恢复，并且在此问题上完全独立于其他 Activity。

2. 您的服务应在其onCreate() 中向位置管理器注册，并在其onDestroy() 中取消注册。在其onBind() 中，它应该返回一个Messenger 对象。而且，在onLocationChanged() 中，它应该通过其共享的Messenger 发送消息。无需使用START_STICKY，因为您不希望 Service 一直运行。

3. Activity（可以是App中的任何Activity）只需要在它的onStart()中调用bindService()，如果还没有启动服务，Activity就会从服务中得到一个Messenger。此外，Activity 应该从其onStop() 调用unbindService()。当没有任何绑定时，服务将自动停止。

4. 如果您需要在应用程序（任务）级别执行第 3 点中的内容，请实现 Application 类，并使用其 onCreate() 和 onTerminate()。应用程序类不会像 Activity 那样暂停或停止。

Answer 3

建议你使用google提供的最新位置api（也兼容2.2版本）。

这里有一个例子展示了如何使用它： https://github.com/chenjishi/android_location_demo

当您的应用运行到后台时，您可以调用 disconnect 来停止位置更新。

Answer 4

试试这个代码.. 通过使用这个你可以找到你的应用程序是在前台还是后台。希望这会帮助你。

try {
    foreground = new ForegroundCheckTask().execute(ctx).get();
}

======================================


class ForegroundCheckTask extends AsyncTask<Context, Void, Boolean> {

@Override
protected Boolean doInBackground(Context... params) {
    final Context context = params[0].getApplicationContext();
    return isAppOnForeground(context);
}

private boolean isAppOnForeground(Context context) {
    ActivityManager activityManager = (ActivityManager) context
            .getSystemService(Context.ACTIVITY_SERVICE);
    List<RunningAppProcessInfo> appProcesses = activityManager
            .getRunningAppProcesses();
    if (appProcesses == null) {
        return false;
    }
    final String packageName = context.getPackageName();


    String activePackageName = activityManager.getRunningTasks(1).get(0).topActivity.getPackageName();
    if (activePackageName.equals(packageName)) {
        return true;
    }
    else{
        return false;
    }


}

}