android 服务完全在后台运行，没有 UI

Question

我们如何才能在没有任何主要 Activity 的情况下完全在后台运行 android 服务？如果是，那么如何，我尝试了广播接收器，但它无法正常工作，非常感谢任何帮助和建议...

Answer 1

@SuppressWarnings("deprecation")
public class LocationService extends Service {




    DBAdapter mDbAdapter;
    double distance;
    double longitude,latitude;
    String to;
    String txt_msg;
    @Override
    public void onCreate() {
        Log.i("Background service ", "calls");

        recurscall_location_alert();


    }




    public static double distFrom(double lat1, double lng1, double lat2,
            double lng2) {
        double earthRadius = 3958.75;
        double dLat = Math.toRadians(lat2 - lat1);
        double dLng = Math.toRadians(lng2 - lng1);
        double sindLat = Math.sin(dLat / 2);
        double sindLng = Math.sin(dLng / 2);
        double a = Math.pow(sindLat, 2) + Math.pow(sindLng, 2)
                * Math.cos(Math.toRadians(lat1))
                * Math.cos(Math.toRadians(lat2));
        double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
        double dist = earthRadius * c;

        return dist;
    }

    private void recurscall_location_alert() {
    // TODO Auto-generated method stub
    new Timer().scheduleAtFixedRate(new TimerTask() {

        @SuppressWarnings("deprecation")
        @Override
        public void run() 
        {
            c = Calendar.getInstance();
            mYear = c.get(Calendar.YEAR);
            mMonth = c.get(Calendar.MONTH) + 1;
            mDay = c.get(Calendar.DAY_OF_MONTH);
            mHour = c.get(Calendar.HOUR_OF_DAY);
            mMin = c.get(Calendar.MINUTE);
            mSec = c.get(Calendar.SECOND);

            ConnectionDetector detect_conn=new ConnectionDetector(getApplicationContext());
            boolean connect=detect_conn.isConnectingToInternet();
            if(connect)
            {
                Criteria criteria = new Criteria();
                LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
                String provider = locationManager.NETWORK_PROVIDER;
                Location location = locationManager.getLastKnownLocation(provider);
                if(location==null)
                {

                }else
                {
                    longitude = location.getLongitude();
                    latitude = location.getLatitude();
                    Log.i("Latitude : ", String.valueOf(latitude));
                    Log.i("longitude : ", String.valueOf(longitude));
                }

            }

            get_latlong();

            get_contacts();
            Log.d("Location  Alert", "Call location Alert");
            /* for (int i = 0; i < Tasks.size(); i++)
            {

                String[] stringdstime = Start_Time.get(i).split(":");
                String[] stringsdate = Task_date.get(i).split("-");

                int dshour = Integer.parseInt(stringdstime[0]);
                int dsmin = Integer.parseInt(stringdstime[1]);
                int day = Integer.parseInt(stringsdate[0]);
                int month = Integer.parseInt(stringsdate[1]);
                double year1 = Double.parseDouble(stringsdate[2]);

                Log.i("Entered : ",
                        String.valueOf(dsmin) + " "
                                + String.valueOf(dshour) + " "
                                + String.valueOf(day) + " "
                                + String.valueOf(month) + " "
                                + String.valueOf(year1));
                Log.i("Calendar : ",
                        String.valueOf(mMin) + " "
                                + String.valueOf(mHour) + " "
                                + String.valueOf(mDay) + " "
                                + String.valueOf(mMonth));
                if(year1 == mYear && month == mMonth && day == mDay
                        && ( (mHour > dshour)||((mHour == dshour) &&(mMin >= (dsmin)))))
                {

                    Log.i("Date Time: ", "Time Match");

                    Log.d("ID MATCH=", ids.get(i) + "=="+alertid.get(i));

                    if(ids.get(i).equals(alertid.get(i)))
                    {
                        if(type.get(i).toString().equalsIgnoreCase("EMAIL"))
                        {
                            String response = new String();

                            JSONParser parser = new JSONParser();

                            Pattern emailPattern = Patterns.EMAIL_ADDRESS;
                            Account[] accounts = AccountManager.get(getBaseContext())
                                    .getAccounts();
                            String possibleEmail = "";
                            to=phone_email.get(i).toString();
                            txt_msg=content.get(i).toString();
                        //  Account account = accounts[0];
                            for (Account account : accounts) {
                            if (emailPattern.matcher(account.name).matches()) {
                                possibleEmail = account.name.toString();
                            }
                            }
                            Log.d("Email Address ::", possibleEmail);

                            if (possibleEmail.trim().length() != 0) {

                                ConnectionDetector detect=new ConnectionDetector(getApplicationContext());
                                boolean conn=detect.isConnectingToInternet();
                                Log.i("Conn", String.valueOf(conn));
                                if(conn)
                                {
                                    try{
                                    String temp = "http://122.170.105.226/projects/apps/zealalert/email.php?to="+to+"&from="+possibleEmail+"&message="+txt_msg+"";
                                    temp = temp.replaceAll(" ", "%20");
                                    response = parser.getJSONFromUrlbyGEt(temp);
                                    System.out.println("Response Zeal Alert" + response);
                                    }
                                    catch(Exception e)
                                    {

                                    }
                                }
                            }
                            mDbAdapter=new DBAdapter(getApplicationContext());
                            mDbAdapter.open();
                            mDbAdapter.updateDeletedTask(ids.get(i), "1");



                        }
                        else if(type.get(i).toString().equalsIgnoreCase("SMS"))
                        {

                                to=phone_email.get(i).toString();
                                txt_msg=content.get(i).toString();
                                try{

                                SmsManager manager=SmsManager.getDefault();
                                manager.sendTextMessage(to, null, txt_msg, null, null);
                                }catch(Exception e)
                                {

                                }
                                mDbAdapter=new DBAdapter(getApplicationContext());
                                mDbAdapter.open();
                                mDbAdapter.updateDeletedTask(ids.get(i), "1");

                        }
                        else
                        {
                            mDbAdapter=new DBAdapter(getApplicationContext());
                            mDbAdapter.open();
                            mDbAdapter.updateDeletedTask(ids.get(i), "1");
                        }

                    }


                }

            }*/


            isOutside = new boolean[Tasks.size()];
            StringBuilder sb=new StringBuilder();
            boolean isTimeAlert=false;
            int j=0;

            for (int i = j; i < Tasks.size(); i++) {
                Log.i("Length : ", String.valueOf(Tasks.size()));
                distance = distFrom(latitude, longitude, lat_array.get(i),
                        long_array.get(i));

                double km = distance / 0.62137;
                Log.d("KM", String.valueOf(km));

                String[] stringdstime = Start_Time.get(i).split(":");
                String[] stringsdate = Task_date.get(i).split("-");

                int dshour = Integer.parseInt(stringdstime[0]);
                int dsmin = Integer.parseInt(stringdstime[1]);
                int day = Integer.parseInt(stringsdate[0]);
                int month = Integer.parseInt(stringsdate[1]);
                double year1 = Double.parseDouble(stringsdate[2]);


                Log.i("Entered : ",
                        String.valueOf(dsmin) + " "
                                + String.valueOf(dshour) + " "
                                + String.valueOf(day) + " "
                                + String.valueOf(month) + " "
                                + String.valueOf(year1));
                Log.i("Calendar : ",
                        String.valueOf(mMin) + " "
                                + String.valueOf(mHour) + " "
                                + String.valueOf(mDay) + " "
                                + String.valueOf(mMonth));
                if (dsmin < 10){
                    dsmin += 60;
                    dshour-=1;}

                if (radius_array.get(i) >= km) {

                    Log.i("Alert : ", "You are in Range...." + ids.get(i));

                    isOutside[i]=true;
                     Intent intent = new Intent(LocationService.this,LocationAlert.class);
                     intent.putExtra("idloc", ids.get(i));
                     intent.putExtra("taskname", Tasks.get(i).toString());
                     intent.putExtra("distance", String.valueOf(km));
                     intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                    // stopService(intent);
                     startActivity(intent);
                     if(j == Tasks.size()-1)
                     {
                         j=0;
                     }
                     else
                     {
                         j++;
                     }

                } 

            }

        }
    }, 3000, 180 * 1000);

}

void get_latlong() {

    mDbAdapter = new DBAdapter(getApplicationContext());
    mDbAdapter.read_open();

    Cursor cr = mDbAdapter.fetchAllTasks();
    cr.moveToFirst();
    ids.clear();
    Tasks.clear();
    Priority.clear();
    lat_array.clear();
    long_array.clear();
    radius_array.clear();
    Start_Time.clear();
    Task_date.clear();
    Desc.clear();
    while (!cr.isAfterLast()) {

        ids.add(Integer.parseInt(cr.getString(0)));
        Tasks.add(cr.getString(1));
        Priority.add(cr.getString(2));
        Task_date.add(cr.getString(3));
        Start_Time.add(cr.getString(5));
        lat_array.add(Double.valueOf(cr.getString(6)));
        long_array.add(Double.valueOf(cr.getString(7)));
        radius_array.add(Double.parseDouble(cr.getString(8)));
        cr.moveToNext();

    }
    cr.close();

    mDbAdapter.close();
    Log.d("LatLongs::", "Lattitude:" + String.valueOf(lat_array)
            + "long_array:" + String.valueOf(long_array));

    //get_contacts();

}

public void get_contacts() {
    mDbAdapter = new DBAdapter(getApplicationContext());
    mDbAdapter.read_open();
    Cursor cr2 = mDbAdapter.fetchAllTaskContacts();
    cr2.moveToFirst();
    alertid.clear();
    phone_email.clear();
    type.clear();
    content.clear();

    while (!cr2.isAfterLast()) {

        alertid.add(Integer.parseInt(cr2.getString(0)));
        phone_email.add(cr2.getString(2));
        type.add(cr2.getString(3));
        content.add(cr2.getString(4));
        cr2.moveToNext();

    }
    cr2.close();
    mDbAdapter.close();
    Log.d("Contacts", String.valueOf(alertid) + phone_email + type
            + content);

}

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



}