android - 在 Android 后台运行应用程序或方法，即使应用程序关闭

Question

我创建的应用程序每 1 分钟给我一次纬度和经度。我必须每 1 分钟将此位置信息更新到服务器。计时器运行完美。但是，当我关闭该应用程序或从我最近打开的应用程序中终止该应用程序时，计时器不起作用。

即使我关闭应用程序，如何在后台执行此操作？

GpsTracket.java

public class GPSTracker extends Service implements LocationListener {

private final Context mContext;
private final Handler _handler = new Handler();
private static int DATA_INTERVAL = 1 * 60 * 1000;
public static final long NOTIFY_INTERVAL =1 * 60 * 1000; // 60 seconds

// run on another Thread to avoid crash
private Handler mHandler = new Handler();
// timer handling
private Timer mTimer = null;

// flag for GPS status
boolean isGPSEnabled = false;

// flag for network status
boolean isNetworkEnabled = false;

// flag for GPS status
boolean canGetLocation = false;

Location location; // location
double latitude; // latitude
double longitude; // longitude

// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters

// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute

// Declaring a Location Manager
protected LocationManager locationManager;
private Handler handler = new Handler();
private long initial_time;
long timeInMilliseconds = 0L;
private Intent intent;
public static final String BROADCAST_ACTION = "com.example.gpstracking.AndroidGPSTrackingActivity";

@Override
public void onCreate() {
    super.onCreate();
    startService(new Intent(this, AndroidGPSTrackingActivity.class));
    initial_time = SystemClock.uptimeMillis();
    intent = new Intent(BROADCAST_ACTION);
    handler.removeCallbacks(sendUpdatesToUI);
    handler.postDelayed(sendUpdatesToUI, 1000);


    if(mTimer != null) {
        mTimer.cancel();
    } else {
        // recreate new
        mTimer = new Timer();
    }
    // schedule task
    mTimer.scheduleAtFixedRate(new TimeDisplayTimerTask(), 0, NOTIFY_INTERVAL);// 1 second

}



private Runnable sendUpdatesToUI = new Runnable() {
    public void run() {
        getLocation();
        handler.postDelayed(this, 1000); // 1 seconds
    }
};
public GPSTracker(Context context) {
    this.mContext = context;
    getLocation();
}

public Location getLocation() {
    try {
        locationManager = (LocationManager) mContext
                .getSystemService(LOCATION_SERVICE);

        // getting GPS status
        isGPSEnabled = locationManager
                .isProviderEnabled(LocationManager.GPS_PROVIDER);

        // getting network status
        isNetworkEnabled = locationManager
                .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        if (!isGPSEnabled && !isNetworkEnabled) {
            // no network provider is enabled
        } else {
            this.canGetLocation = true;
            if (isNetworkEnabled) {
                locationManager.requestLocationUpdates(
                        LocationManager.NETWORK_PROVIDER,
                        MIN_TIME_BW_UPDATES,
                        MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                Log.d("Network", "Network");
                if (locationManager != null) {
                    location = locationManager
                            .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                    if (location != null) {
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                    }
                }
            }
            // if GPS Enabled get lat/long using GPS Services
            if (isGPSEnabled) {
                if (location == null) {
                    locationManager.requestLocationUpdates(
                            LocationManager.GPS_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    Log.d("GPS Enabled", "GPS Enabled");
                    if (locationManager != null) {
                        location = locationManager
                                .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        if (location != null) {
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
                        }
                    }
                }
            }
        }

    } catch (Exception e) {
        e.printStackTrace();
    }

    return location;
}

/**
 * Stop using GPS listener
 * Calling this function will stop using GPS in your app
 * */
public void stopUsingGPS(){
    if(locationManager != null){
        locationManager.removeUpdates(GPSTracker.this);
    }       
}

/**
 * Function to get latitude
 * */
public double getLatitude(){
    if(location != null){
        latitude = location.getLatitude();
    }

    // return latitude
    return latitude;
}

/**
 * Function to get longitude
 * */
public double getLongitude(){
    if(location != null){
        longitude = location.getLongitude();
    }

    // return longitude
    return longitude;
}


/**
 * Function to check GPS/wifi enabled
 * @return boolean
 * */
public boolean canGetLocation() {
    return this.canGetLocation;
}

/**
 * Function to show settings alert dialog
 * On pressing Settings button will lauch Settings Options
 * */
public void showSettingsAlert(){
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

    // Setting Dialog Title
    alertDialog.setTitle("GPS is settings");

    // Setting Dialog Message
    alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");

    // On pressing Settings button
    alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog,int which) {
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            mContext.startActivity(intent);
        }
    });

    // on pressing cancel button
    alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int which) {
        dialog.cancel();
        }
    });

    // Showing Alert Message
    alertDialog.show();
}

@Override
public void onLocationChanged(Location location) {




}
public void notifyUser() {
    NotificationManager notificationManager = (NotificationManager)this.getSystemService(Context.NOTIFICATION_SERVICE);

    Intent intent = new Intent(GPSTracker.this, AndroidGPSTrackingActivity.class);

    //use the flag FLAG_UPDATE_CURRENT to override any notification already there
    PendingIntent contentIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);

    Notification notification = new Notification(R.drawable.ic_launcher, "Some Text", System.currentTimeMillis());
    notification.flags = Notification.FLAG_AUTO_CANCEL | Notification.DEFAULT_LIGHTS | Notification.DEFAULT_SOUND;

    notification.setLatestEventInfo(this, "", "", contentIntent);
    //10 is a random number I chose to act as the id for this notification
    notificationManager.notify(10, notification);
}

@Override
public void onDestroy() {
    super.onDestroy();
    handler.removeCallbacks(sendUpdatesToUI);

}

class TimeDisplayTimerTask extends TimerTask {

    @Override
    public void run() {
        // run on another thread
        handler.post(new Runnable() {

            @Override
            public void run() {
                // display toast
                Toast.makeText(getApplicationContext(), getDateTime(),
                        Toast.LENGTH_SHORT).show();
            }

        });
    }

    private String getDateTime() {
        // get date time in custom format
        SimpleDateFormat sdf = new SimpleDateFormat("[yyyy/MM/dd - HH:mm:ss]");
        return sdf.format(new Date());
    }
}

    @Override
public void onProviderDisabled(String provider) {
}

@Override
public void onProviderEnabled(String provider) {
}

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

@Override
public IBinder onBind(Intent arg0) {
    return null;
}

}

AndroidGPSTrackingActivity.java

public class AndroidGPSTrackingActivity extends Activity {

Button btnShowLocation;

Geocoder geocoder;
List<Address> addresses;
private final Handler _handler = new Handler();
private static int DATA_INTERVAL = 1 * 60 * 1000;
// GPSTracker class
GPSTracker gps;
double longitude;
double latitude;
Calendar c;
SimpleDateFormat sdf;
String strDate;
Intent intent;
private Timer mTimer = null;

protected LocationManager locationManager;
private Handler handler = new Handler();
private long initial_time;
public static final long NOTIFY_INTERVAL = 60 * 1000;
public static final String BROADCAST_ACTION = "com.example.gpstracking.GPSTrackers";
String address,city,state,country,postalCode,knownName,city2;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    geocoder = new Geocoder(this, Locale.getDefault());
    initial_time = SystemClock.uptimeMillis();
    intent = new Intent(BROADCAST_ACTION);
    handler.removeCallbacks(sendUpdatesToUI);
    handler.postDelayed(sendUpdatesToUI, 1000 * 70);


    if(mTimer != null) {
        mTimer.cancel();
    } else {
        // recreate new
        mTimer = new Timer();
    }
    // schedule task
    mTimer.scheduleAtFixedRate(new TimeDisplayTimerTask(), 0, NOTIFY_INTERVAL);// 1 second


    location();
    btnShowLocation = (Button) findViewById(R.id.btnShowLocation);

    // show location button click event
    btnShowLocation.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // create class object

            location();
        }
    });
}
class TimeDisplayTimerTask extends TimerTask {

    @Override
    public void run() {
        // run on another thread
        handler.post(new Runnable() {

            @Override
            public void run() {
                // display toast
                location();
            }

        });
    }
}

public void location(){

    gps = new GPSTracker(AndroidGPSTrackingActivity.this);

    // check if GPS enabled
    if(gps.canGetLocation()){

        latitude = gps.getLatitude();
        longitude = gps.getLongitude();
        try {
            addresses = geocoder.getFromLocation(latitude, longitude, 1);
            Log.d("adddd", String.valueOf(addresses));
            address = addresses.get(0).getAddressLine(0);
            city = addresses.get(0).getAddressLine(1);
            state = addresses.get(0).getAddressLine(2);
            c = Calendar.getInstance();
             sdf= new SimpleDateFormat("dd/MM/yyyy hh:mm a ");
             strDate = sdf.format(c.getTime());


        } catch (IOException e) {
            e.printStackTrace();
        }
        // \n is for new line
        Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude + address + "\n"
                +city +" "+ state + "\n" + strDate
                , Toast.LENGTH_LONG).show();
        _handler.postDelayed(getData, DATA_INTERVAL);
    }else{
        // can't get location
        // GPS or Network is not enabled
        // Ask user to enable GPS/network in settings
        gps.showSettingsAlert();
    }
}
private Runnable sendUpdatesToUI = new Runnable() {
    public void run() {

        handler.postDelayed(this, 1000 * 60); // 1 seconds
    }
};
public void notifyUser() {
    NotificationManager notificationManager = (NotificationManager)this.getSystemService(Context.NOTIFICATION_SERVICE);

    Intent intent = new Intent(AndroidGPSTrackingActivity.this, AndroidGPSTrackingActivity.class);

    //use the flag FLAG_UPDATE_CURRENT to override any notification already there
    PendingIntent contentIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);

    Notification notification = new Notification(R.drawable.ic_launcher, "Some Text", System.currentTimeMillis());
    notification.flags = Notification.FLAG_AUTO_CANCEL | Notification.DEFAULT_LIGHTS | Notification.DEFAULT_SOUND;

    notification.setLatestEventInfo(this, city, state, contentIntent);
    //10 is a random number I chose to act as the id for this notification
    notificationManager.notify(10, notification);
}

@Override
public void onStop() {
    super.onStop();
    _handler.postDelayed(getData, DATA_INTERVAL);
    //write your code here to start your service
}
@Override
public void onDestroy() {
    startService(new Intent(this, Service.class));
    super.onDestroy();

}

@Override
public void onPause() {
    super.onPause();
    startService(new Intent(this, GPSTracker.class));
    location();
    //write your code here to start your service
}
private final Runnable getData = new Runnable()
{
    @Override
    public void run()
    {

        location();
        notifyUser();
    }
};
}

请帮助。

Answer 1

您必须创建扩展 IntentService 的后台服务，它每 1 分钟提供一次纬度和经度。

您可以在服务中使用 Timer 或 ScheduledExecutorService 每 1 分钟获取一次位置。

您已经在 AndroidGPSTrackingActivity 类中创建了您的计时器，而不是创建新服务并将所有与计时器相关的代码移动到后台服务的 onStartCommand 方法。

在您的 AndroidGPSTrackingActivity 中启动您的后台服务。要自动重启服务，您必须在服务的 onStartCommand 方法中返回 START_STICKY。

要创建 Intent 服务，请参阅 https://developer.android.com/training/run-background-service/create-service.html

希望对您有所帮助!