选择定期与服务器同步数据的方法android

Question

A有一个显示服务器数据的应用程序。我还需要定期从服务器获取数据（不同的暂停，但是）来缓存它，并在某些情况下发送通知。

通知可以非常重要，这样的情况时，我使用的服务，它就会被杀死因为某些原因和缓存时间将被跳过不应该出现（或者，如果它是不可能的，我应该尽量减少跳过时间）。此缓存过程应在系统引导（无论应用程序是否正在运行）后开始，并在设备开启时始终执行。

那么我应该使用什么方法？

Answer 1

在你的情况下，最合适的是使用Service不断更新数据源中的数据。至于它自己的数据，我认为在你的情况下，你最好创建一个SQLite数据库，以便在系统重启时保留你的数据。

Answer 2

我曾经服务这样

这可能会帮助你

public class MyService extends Service { 

int counter = 0; 
static final int UPDATE_INTERVAL = 60 * 1000; ///1000 = 1 second 
private Timer timer = new Timer(); 
JsonParsers jsonParser = new JsonParsers(); 
private static final String TAG_SUCCESS = "success"; 
private static String url_create_product = "http://ayyappagold.com/ayyappa/index.php"; 

@Override 
public IBinder onBind(Intent intent) { 
    // Not implemented...this sample is only for starting and stopping 
    // services. 
    // Service binding will be covered in another tutorial 
    return null; 
} 

@Override 
public int onStartCommand(Intent intent, int flags, int startId) { 

    // Announcement about starting 
    Toast.makeText(this, "Starting the Service", Toast.LENGTH_SHORT).show(); 
    // Start a Background thread 
    doSomethingRepeatedly(); 

    // We want this service to continue running until it is explicitly 
    // stopped, so return sticky. 
    return START_STICKY; 
} 

private void doSomethingRepeatedly() { 
    timer.scheduleAtFixedRate(new TimerTask() { 

     @Override 
     public void run() { 
      // TODO Auto-generated method stub 

      doIn(); 

      Calendar c = Calendar.getInstance(); 

      String month = String.valueOf(c.get(Calendar.MONTH) + 1); 
      String year = String.valueOf(c.get(Calendar.YEAR)); 
      String day = String.valueOf(c.get(Calendar.DAY_OF_MONTH)); 

      String months = null; 
      if (month.startsWith("0") || month.startsWith("1")) { 
       if (day.startsWith("0") || day.startsWith("1") 
         || day.startsWith("2") || day.startsWith("3")) { 
        months = year + "-" + month + "-" + day; 
       } 
      } else { 
       months = year + "-" + "0" + month + "-0" + day; 
      } 
      loadJewelDetails(months); 

     } 
    }, 0, UPDATE_INTERVAL); 

} 

@Override 
public void onDestroy() { 
    super.onDestroy(); 

    if (timer != null) { 
     timer.cancel(); 
    } 
    Toast.makeText(this, "Stopping the Service", Toast.LENGTH_SHORT).show(); 
} 

public void set_alarm(int year, int month, int day, String title, 
     String text, String billno) { 
    Calendar cal = Calendar.getInstance(); 

    cal.set(Calendar.MONTH, month - 1); 
    cal.set(Calendar.YEAR, year); 
    cal.set(Calendar.DAY_OF_MONTH, day); 

    cal.set(Calendar.HOUR_OF_DAY, 0); 
    cal.set(Calendar.MINUTE, 0); 

    Intent intent = new Intent(getApplicationContext(), AlarmActivity.class); 
    intent.putExtra("title", title); 
    intent.putExtra("text", text); 
    intent.putExtra("billno", billno); 

    PendingIntent pendingIntent = PendingIntent.getBroadcast(
      getApplicationContext(), 1234, intent, 
      PendingIntent.FLAG_UPDATE_CURRENT); 

    @SuppressWarnings("static-access") 
    AlarmManager alarmManager = (AlarmManager) getApplicationContext() 
      .getSystemService(getApplicationContext().ALARM_SERVICE); 

    alarmManager.cancel(pendingIntent); // cancel any existing alarms 

    alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, 
      cal.getTimeInMillis(), AlarmManager.INTERVAL_DAY, 

      pendingIntent); 

    Database db = new Database(getApplicationContext()); 
    db.insertFlg(1, billno); 
} 

public void loadJewelDetails(String month) { 

    try { 

     Cursor cursor = null; 

     Database db = new Database(getApplicationContext()); 

     cursor = db.getGoldPush(month); 
     if (cursor.getCount() != 0) { 
      if (cursor.moveToFirst()) { 
       do { 
        String billno = cursor.getString(cursor 
          .getColumnIndex("id")); 
        String title = "Ayyappa Gold"; 
        String name = cursor.getString(cursor 
          .getColumnIndex("items")); 

        String dates = cursor.getString(cursor 
          .getColumnIndex("date")); 

        String yr = dates.substring(0, 4); 
        int year = Integer.parseInt(yr); 
        String mon = dates.substring(5); 
        String mo = mon.substring(0, 2); 
        int months = Integer.parseInt(mo); 
        String da = dates.substring(9); 
        int day = Integer.parseInt(da); 

        String tex = name.replace("*", "\n"); 

        String text = tex; 

        // Ask our service to set an alarm for that date, 
        // this 
        // activity talks to the client that talks to the 
        // service 
        int flg = getFlag(billno); 
        if (flg == 0) { 
         set_alarm(year, months, day, title, text, billno); 
        } 
        System.out.println(dates); 

       } while (cursor.moveToNext()); 

      } 

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

    // looping through All Contacts 

} 

public int getFlag(String bill) { 
    int flag = 0; 
    try { 

     Cursor cursor = null; 

     Database db = new Database(getApplicationContext()); 

     cursor = db.getFlag(bill); 
     if (cursor.getCount() != 0) { 
      if (cursor.moveToFirst()) { 
       do { 

        flag = Integer.parseInt(cursor.getString(cursor 
          .getColumnIndex("flag"))); 

       } while (cursor.moveToNext()); 

      } 

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

    // looping through All Contacts 
    return flag; 
} 

public void doIn() { 

    // Building Parameters 
    int id = getId(); 
    String name = String.valueOf(id); 
    Database db = new Database(getApplicationContext()); 
    System.out.println("read the Gold and Silver rate details"); 

    JSONArray jsonarr = null; 

    List<NameValuePair> params = new ArrayList<NameValuePair>(); 
    params.add(new BasicNameValuePair("start", name)); 

    // getting JSON Object 
    // Note that create product url accepts POST method 
    JSONObject json = jsonParser.makeHttpRequest(url_create_product, 
      "POST", params); 

    // check log cat fro response 
    Log.d("Create Response", json.toString()); 

    // check for success tag 
    try { 
     int success = json.getInt(TAG_SUCCESS); 

     if (success == 1) { 
      // Getting Array of Contacts 
      jsonarr = json.getJSONArray("ayyappagolddetails"); 

      for (int i = 0; i < jsonarr.length(); i++) { 
       JSONObject c = jsonarr.getJSONObject(i); 

       String billno = c.getString("id"); 
       String item = c.getString("items"); 
       String date = c.getString("date"); 
       String time = c.getString("time"); 
       db.addGoldItemDetails(billno, item, date, time); 

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

} 

public int getId() { 
    int id = 0; 
    try { 
     System.out.println("read the id value"); 
     Cursor cursor = null; 

     Database db = new Database(getApplicationContext()); 

     cursor = db.getId(); 
     if (cursor.getCount() != 0) { 
      if (cursor.moveToFirst()) { 
       do { 

        id = Integer.parseInt(cursor.getString(cursor 
          .getColumnIndex("id"))); 

       } while (cursor.moveToNext()); 

      } 

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

    // looping through All Contacts 
    System.out.println("last id value is" + id); 
    return id; 
} 

}