Creating an application that runs in the background

Question

Creating an application that runs in the background

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#1 by (12 votes)
#2 by (1 votes)

9

Some famous applications, among them Facebook, WhatsApp, Hangouts, use a service running in the background that does not end even with the device's power off.

My question is how to develop an application with this feature? Can anyone create a basic example that demonstrates this concept?

android

asked by anonymous 21.05.2014 / 18:04

2 answers

Difference from #! in the first line of a Python script Remove more than one item from an array

score 12 · Answer 1

This example shows how you can minimize your activity and start a service and resume your activity whenever necessary.

Create a new File New project and name the project for BackgroundAppExample .

Type the following in main.xml :

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:padding="@dimen/padding_medium"
    android:text="@string/hello_world"
    tools:context=".BackgroundAppExample" />

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_alignRight="@+id/textView1"
    android:layout_marginRight="49dp"
    android:layout_marginTop="74dp"
    android:text="Start Service" />

Type the following into the manifest file:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.backgroundappexample"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="15" />

<application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".BackgroundAppExample"
        android:label="@string/title_activity_background_app_example" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <service android:enabled="true" android:name=".BackgroundService" />
</application>

Create and write the following in src / BackgroundService.java :

package com.example.backgroundappexample;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.Bundle;
import android.os.IBinder;

public class BackgroundService extends Service {
    private NotificationManager mNM;
Bundle b;
Intent notificationIntent;
private final IBinder mBinder = new LocalBinder();
private String newtext;

public class LocalBinder extends Binder {
    BackgroundService getService() {
        return BackgroundService.this;
    }
}

@Override
public void onCreate() {
    mNM = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);

    newtext = "BackGroundApp Service Running";

    Notification notification = new Notification(R.drawable.ic_launcher, newtext,System.currentTimeMillis());
    PendingIntent contentIntent = PendingIntent.getActivity(BackgroundService.this, 0, new Intent(BackgroundService.this,   BackgroundAppExample.class), 0);
    notification.setLatestEventInfo(BackgroundService.this,"BackgroundAppExample", newtext, contentIntent);
    mNM.notify(R.string.local_service_started, notification);
    notificationIntent = new Intent(this, BackgroundAppExample.class);
    showNotification();     
}

public int onStartCommand(Intent intent, int flags, int startId) {
    return START_STICKY;
}
public void onDestroy() {
    mNM.cancel(R.string.local_service_started);
    stopSelf();
}
private void showNotification() {
    CharSequence text = getText(R.string.local_service_started);

    Notification notification = new Notification(R.drawable.ic_launcher, text, System.currentTimeMillis());
    PendingIntent contentIntent = PendingIntent.getActivity(this, 0,new Intent(this, BackgroundAppExample.class), 0);
    notification.setLatestEventInfo(this, "BackgroundAppExample",newtext, contentIntent);
    notification.flags = Notification.FLAG_ONGOING_EVENT | Notification.FLAG_NO_CLEAR;     
    notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);

    mNM.notify(R.string.local_service_started, notification);
}
@Override
public IBinder onBind(Intent intent) {
    return mBinder;
 }
}

Run!

Now follow these steps:

Create a project called BackgroundAppExample and set the information as indicated in the image.

 Build Target: Android 4.0
 Application Name: BackgroundAppExample
 Package Name: com. example. BackgroundAppExample
 Activity Name: BackgroundAppExample
 Min SDK Version: 8

OpentheBackgroundAppExample.javafileandtypethefollowingcodethere:

package com.example.backgroundappexample;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class BackgroundAppExample extends Activity {

public static boolean isService = false; 
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    Button startserviceButton = (Button) findViewById(R.id.button1);
    startserviceButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            startService(new Intent(BackgroundAppExample.this,BackgroundService.class));
            Intent startMain = new Intent(Intent.ACTION_MAIN);
            startMain.addCategory(Intent.CATEGORY_HOME);
            startMain.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(startMain);
            isService = true;
        }
    });
}

@Override
protected void onResume() {
    super.onResume();
    stopService(new Intent(BackgroundAppExample.this,
            BackgroundService.class));
    if(isService)
    {
        TextView tv = (TextView) findViewById(R.id.textView1);
        tv.setText("Service Resumed");
        isService = false;
    }
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
 }
}

Compile and execute.

Result:

This response was an adaptation of this tutorial ( written in English ).

score 1 · Answer 2

I was having the same problem and after a long time searching for the answer and testing I got using AlarmManager and BroadcastReceiver , what I needed:

I have a web system where someone registers notifications in the database, and an API that returns a json with the requests, I needed something to run with the app open or closed checking to see if it has new messages and notifying the user .

My AndroidManifest.xml

<receiver
        android:name=".Servico.BootReciever"
        android:enabled="true"
        android:exported="true">
        <intent-filter>
            <action android:name="ALARME_DISPARADO2"/>
            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </receiver>

In my% of Activity

boolean alarmeativo = (PendingIntent.getBroadcast( this, 0, new Intent( "ALARME_DISPARADO2" ), PendingIntent.FLAG_NO_CREATE ) == null);

        if(alarmeativo) {
            Intent intent = new Intent( "ALARME_DISPARADO2" );
            PendingIntent p = PendingIntent.getBroadcast( this, 0, intent, 0 );
            Calendar c = Calendar.getInstance();
            c.setTimeInMillis( System.currentTimeMillis() );
            c.add( Calendar.SECOND, 3 );

            AlarmManager alarm = (AlarmManager) getSystemService( ALARM_SERVICE );
            alarm.set( AlarmManager.RTC_WAKEUP, c.getTimeInMillis(), p );
        }

I check if the alarm is already created, I assign the onCreate that will be executed referring to my Intent , I assign a time to start and set the BroadcastReceiver alarm to execute even with the device blogged, done in the % with_% start a Task , since I need to post a page on the web, using recursion to continue running.

My RTC_WAKEUP

public class BootReciever extends BroadcastReceiver {
public static Usuario us;
public static Notifi not;
public static NotifiSetor notSet;
public static Agenda notAg;

public static boolean Iniciar = true;
public static boolean saida;

int x = 0;

@Override
public void onReceive(Context context, Intent intent) {

        Iniciar = false;
        Usuario u = new Usuario( context );
        u.Select();
        us = u;

        Notifi n = new Notifi( context );
        not = n;

        NotifiSetor ns = new NotifiSetor(context );
        notSet = ns;

        Agenda ag = new Agenda( context );
        notAg = ag;

        NotificationTask us = new NotificationTask();
        us.execute(context);
}

public boolean isOnline(Context context) {
    boolean conectado;
    try {
        ConnectivityManager conectivtyManager = (ConnectivityManager) context.getSystemService( Context.CONNECTIVITY_SERVICE );
        if (conectivtyManager.getActiveNetworkInfo() != null
                && conectivtyManager.getActiveNetworkInfo().isAvailable()
                && conectivtyManager.getActiveNetworkInfo().isConnected()) {
            conectado = true;
        } else {
            conectado = false;
        }
    } catch (Exception e) {
        conectado = false;
    }
    return conectado;
}

private class NotificationTask extends AsyncTask<Context, Void, Context> {
    @Override
    protected Context doInBackground(Context... ct) {


        saida = false;
        try {
            Agenda a = new Agenda(notAg.getCt());
            List<Agenda> list = a.SelectExibir();
            if(list != null) {
                for (int x = 0; x < list.size(); x++) {
                    long date1 = System.currentTimeMillis();
                    SimpleDateFormat sdf = new SimpleDateFormat("HH:mm");
                    String dateString = sdf.format(date1);
                    if(list.get(x).getExibir().equals(dateString)) {
                        Calendar cal = Calendar.getInstance( TimeZone.getTimeZone("GMT"));
                        Date currentLocalTime = cal.getTime();
                        DateFormat date = new SimpleDateFormat("dd-MM-yyyy");
                        date.setTimeZone(TimeZone.getTimeZone("GMT"));
                        String localTime = date.format(currentLocalTime);

                        NewMessageNotification.notify(ct[0], list.get(x).getTitulo(), list.get(x).getMensagem(), list.get(x).getID());
                        a.setID(list.get(x).getID());
                        a.setUltimo_Exib(localTime);
                        a.UpdateExibir();
                    }
                }
            }
        } catch (Exception e) {
        }

        if(isOnline(ct[0])) {
            //Log.d("",String.valueOf( x++ ));
            // notificaçoes agendadas
            try {
                //buscar na api
                // buscar no webservice
                String json = "json a ser enviando para API";
                HttpService servi = new HttpService();
                String retorno = servi.post(json);

                try {
                    JSONObject jsonObj = new JSONObject(retorno);
                    JSONArray array = jsonObj.getJSONArray("Res");
                    if (jsonObj.getBoolean("Response")) {

                        for (int i = 0; i < array.length(); i++) {
                            // notificacao
                            notAg.setID(array.getJSONObject(i).getInt("ID"));
                            if (!notAg.ValidaId()) {
                                Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
                                //cal.add(Calendar.DAY_OF_MONTH, -1);
                                Date currentLocalTime = cal.getTime();
                                DateFormat date = new SimpleDateFormat("dd-MM-yyyy");
                                date.setTimeZone(TimeZone.getTimeZone("GMT"));
                                String localTime = date.format(currentLocalTime);

                                notAg.setTitulo(array.getJSONObject(i).getString("TITULO"));
                                notAg.setMensagem(array.getJSONObject(i).getString("MENSAGEM"));
                                notAg.setCadastro(array.getJSONObject(i).getString("DATA_CAD"));
                                notAg.setExibir(array.getJSONObject(i).getString("REPETIR"));
                                notAg.setUltimo_Exib(localTime);
                                notAg.setStatus(array.getJSONObject(i).getInt("STATUS"));
                                notAg.Insert();
                            } else {
                                notAg.setTitulo(array.getJSONObject(i).getString("TITULO"));
                                notAg.setMensagem(array.getJSONObject(i).getString("MENSAGEM"));
                                notAg.setCadastro(array.getJSONObject(i).getString("DATA_CAD"));
                                notAg.setExibir(array.getJSONObject(i).getString("REPETIR"));
                                notAg.setStatus(array.getJSONObject(i).getInt("STATUS"));
                                notAg.Update();
                            }
                        }
                    }
                } catch (Exception e) {
                }
            } catch (Exception e) {
                // Restore interrupt status.
                //Thread.currentThread().interrupt();
            }

            // notificaçoes geral equipe
            try {
                //buscar na api
                // buscar no webservice
                String json = "json a ser enviando para API";
                HttpService servi = new HttpService();
                String retorno = servi.post(json);

                try {
                    JSONObject jsonObj = new JSONObject(retorno);
                    JSONArray array = jsonObj.getJSONArray("Res");
                    if (jsonObj.getBoolean("Response")) {

                        for (int i = 0; i < array.length(); i++) {
                            // notificacao
                            not.setID(array.getJSONObject(i).getInt("ID"));
                            if (!not.ValidaId()) {
                                not.setTitulo(array.getJSONObject(i).getString("TITULO"));
                                not.setMensagem(array.getJSONObject(i).getString("MENSAGEM"));
                                not.setData(array.getJSONObject(i).getString("DATA_CAD"));
                                not.setStatus(array.getJSONObject(i).getInt("STATUS"));
                                not.Insert();
                                NewMessageNotification.notify(ct[0], not.getTitulo(), not.getMensagem(), not.getID());
                            }
                        }
                    }
                } catch (Exception e) {
                }
            } catch (Exception e) {
                // Restore interrupt status.
                //Thread.currentThread().interrupt();
            }

            // notificaçoes geral setor
            try {
                //buscar na api
                // buscar no webservice
                String json = "json a ser enviando para API";
                HttpService servi = new HttpService();
                String retorno = servi.post(json);

                try {
                    JSONObject jsonObj = new JSONObject(retorno);
                    JSONArray array = jsonObj.getJSONArray("Res");
                    if (jsonObj.getBoolean("Response")) {

                        for (int i = 0; i < array.length(); i++) {
                            // notificacao
                            notSet.setID(array.getJSONObject(i).getInt("ID"));
                            if (!notSet.ValidaId()) {
                                notSet.setTitulo(array.getJSONObject(i).getString("TITULO"));
                                notSet.setMensagem(array.getJSONObject(i).getString("MENSAGEM"));
                                notSet.setData(array.getJSONObject(i).getString("DATA_CAD"));
                                notSet.setStatus(array.getJSONObject(i).getInt("STATUS"));
                                notSet.Insert();
                                NewMessageNotification.notify(ct[0], notSet.getTitulo(), notSet.getMensagem(), notSet.getID());
                            }
                        }
                    }
                } catch (Exception e) {
                }
                // exibir
            } catch (Exception e) {
                // Restore interrupt status.
                //Thread.currentThread().interrupt();
            }
        }
        try { 
            // recursividade para continuar executando
            doInBackground( ct[0] );
        } catch(Exception e) {

        }
        return ct[0];
    }

    @Override
    protected void onPostExecute(Context result) {
        // Após a inserção da nota, vamos mostrar um Toast ao usuário
        saida = true;
        Iniciar = true;
        doInBackground(result);
    }
}

}

Result

I/art: Increasing code cache capacity to 128KB
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I/art: Background sticky concurrent mark sweep GC freed 3085(212KB) AllocSpace objects, 2(40KB) LOS objects, 1% free, 28MB/28MB, paused 5.805ms total 16.525ms
D/14:47:50: -> Iniciado
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Application terminated.

And testing on my cell phone has worked properly and with little delay to display notifications with the application closed and open, you can also call a Service or < in> IntetService in BroadcastReceiver .