Why my ContentObserver is not being called when I

问题:

I am trying to detect when a SMS is sent. I have searched on the web and on StackOverflow and all seems to be the same solution. I have a simple Activity that starts a Service and in the service I am trying to detect when a SMS is sent:

MainActivity.java

import android.os.Bundle;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.util.Log;
import android.view.Menu;

public class MainActivity extends Activity {

    Intent serviceIntent;
    private static MyReceiver mServiceReceiver; 

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    @Override
    protected void onPause() {
        Log.i("Status","Pause");
        unregisterReceiver(mServiceReceiver);
        super.onPause();
    }

    @Override
    protected void onResume() {
        Log.i("Status","Resume");

        // Inicio el Servicio
        serviceIntent = new Intent(MainActivity.this, TrackerService.class);
        startService(serviceIntent);
        // Registro el broadcast del Service para obtener los datos
        mServiceReceiver = new MyReceiver();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(TrackerService.mAction);
        registerReceiver(mServiceReceiver, intentFilter);

        super.onResume();
    }

    /**
     * Receiver del Service, aqui se obtienen los datos que envia el Service
     */
    private class MyReceiver extends BroadcastReceiver{
        @Override
        public void onReceive(Context arg0, Intent arg1) {
            Log.i("ServiceReceiver", "onReceive()");
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

TrackerService.java

import android.app.Service;
import android.content.ContentResolver;
import android.content.Intent;
import android.database.ContentObserver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Handler;
import android.os.IBinder;
import android.util.Log;

public class TrackerService extends Service{

    // Nombre del service
    public static final String mAction = "SMSTracker";
    ContentResolver content;
    ContentResolver contentResolver;

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i("Status","Service Start");

        // ContentResolver para obtener los SMS salientes
        contentResolver = this.getContentResolver();
        contentResolver.registerContentObserver(Uri.parse("content://sms/out"), true, new mObserver(new Handler()));

        return super.onStartCommand(intent, flags, startId);
    }

    /**
     * Observer que obtiene los SMS salientes
     */
    class mObserver extends ContentObserver {

        public mObserver(Handler handler) {
            super(handler);
        }

        @Override
        public void onChange(boolean selfChange) {
            super.onChange(selfChange);
            Log.i("Status","onChange");

            Uri uriSMS = Uri.parse("content://sms/out");
            Cursor cur = contentResolver.query(uriSMS, null, null, null, null);
            Log.i("SMS", "Columns: " + cur.getColumnNames());

            cur.moveToNext();
            String smsText = cur.getString(cur.getColumnIndex("body"));

            Log.i("SMS", "SMS Lenght: " + smsText.length());

        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.i("Status","Service Destroy");
    }

    @Override
    public IBinder onBind(Intent intent) {
        Log.i("Status","Service Bind");
        return null;
    }

}

Manifest

<uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="15" />
    <uses-permission android:name="android.permission.RECEIVE_SMS"></uses-permission>
    <uses-permission android:name="android.permission.READ_SMS"></uses-permission>

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

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    <service android:name=".TrackerService" />

</application>

According to my LogCat the service is started and I can see it in running services in my Android phone onChange() method inside my service is never called when I send an sms. Is something I am missing ?

回答1:

If you replace content://sms/out by content://sms/, you'll see that the ContentObserver is not called when the SMS is sent but when one is received. Here is the code of my observer. It only enters onChange(boolean) when receiving a SMS. The protocol is "0" at that time.

So, I am struck at the same point as you :(

class SmsProviderObserver extends ContentObserver {

    public SmsProviderObserver(Handler handler) {
        super(handler);
    }

    @Override
    public void onChange(boolean selfChange) {
        super.onChange(selfChange);

        Uri uriSms = Uri.parse("content://sms/");

        ContentResolver cr = getContentResolver();
        Cursor cur = cr.query(uriSms, null, null, null, null);
        // this will make it point to the first record, which is the last
        // SMS sent
        if (!cur.moveToNext()) {
            return; // weird!
        }

        String protocol = cur.getString(cur.getColumnIndex("protocol"));
        if (protocol == null) {
            // send
            Log.i("SMS", "SMS SEND");
            int threadId = cur.getInt(cur.getColumnIndex("thread_id"));

            Log.i("SMS", "SMS SEND ID = " + threadId);
            Cursor c = cr.query(
                    Uri.parse("content://sms/outbox/" + threadId), null,
                    null, null, null);
            c.moveToNext();
            int p = cur.getInt(cur.getColumnIndex("person"));
            Log.i("SMS", "SMS SEND person= " + p);
            // getContentResolver().delete(Uri.parse("content://sms/conversations/"
            // + threadId), null, null);

        } else {
            // receive
            Log.i("SMS", "SMS RECIEVE");
            int threadIdIn = cur.getInt(cur.getColumnIndex("thread_id"));

            cr.delete(
                    Uri.parse("content://sms/conversations/" + threadIdIn),
                    null, null);
        }
    }
}

And the code registering the observer:

ContentResolver contentResolver = getContentResolver();
mSmsObserverHandler = new Handler();
mSmsProviderObserver = new SmsProviderObserver(mSmsObserverHandler);
contentResolver.registerContentObserver(Uri.parse("content://sms/"), true, mSmsProviderObserver);

回答2:

Ok, seems there is no way, don´t know if it is my error on an Android bug but I got it working:

        if( (type == 2 || type == 1) && (!lastID.contentEquals(cur.getString(cur.getColumnIndex("_id")))) ){
            String protocol = cur.getString(cur.getColumnIndex("protocol"));
            lastID = cur.getString(cur.getColumnIndex("_id"));
            // Mensaje enviado
            if(protocol == null){
                Log.i("SMSStatus", "SMS Sent");
            }
            // Mensaje recibido
            else{
                Log.i("SMSStatus", "SMS received");
            }
        }

When an SMS is received it is type = 1, when send an SMS and its type 6, 4 and finally when it is sent is type = 2. Be carefull because sometimes the onChange method is called lots of times no matters if it is only one SMS so you should detect if it is the same SMS by checking the _id parameter.