AlertDialog from within BroadcastReceiver?? Can it be done?

Question

AlertDialog from within BroadcastReceiver? Can it be done? I am working on a app that will pop up a Dialog box if I get SMS message. I am trying to code this within a BroadcaseReceiver. But I cant use this line of code AlertDialog.Builder builder = new AlertDialog.Builder(this);. Can someone please help me with a hint!

public class SMSPopUpReceiver extends BroadcastReceiver {

    private static final String LOG_TAG = "SMSReceiver";
    public static final int NOTIFICATION_ID_RECEIVED = 0x1221;
    static final String ACTION = "android.provider.Telephony.SMS_RECEIVED";

    public void onReceive(Context context, Intent intent) {
        Log.i(LOG_TAG, "onReceive");

        if (intent.getAction().equals(SMSPopUpReceiver.ACTION)) {
            StringBuilder sb = new StringBuilder();
            Bundle bundle = intent.getExtras();
            if (bundle != null) {
            Object[] pdus = (Object[]) bundle.get("pdus");

            for (Object pdu : pdus){
                    SmsMessage messages =
            SmsMessage.createFromPdu((byte[]) pdu);

            sb.append("Received SMS\nFrom: ");
            sb.append(messages.getDisplayOriginatingAddress());
            sb.append("\n----Message----\n");
            sb.append( messages.getDisplayMessageBody());
            }
            }
            Log.i(SMSPopUpReceiver.LOG_TAG,
            "[SMSApp] onReceiveIntent: " + sb);
            Toast.makeText
            (context, sb.toString(), Toast.LENGTH_LONG).show();
            }

        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setMessage("Are you sure you want to exit?")
               .setCancelable(false)
               .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                       dialog.cancel();
                   }
               })
               .setNegativeButton("No", new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                        dialog.cancel();
                   }
               });
        AlertDialog alert = builder.create();
    }

}

Answer 1

Principal issue: try to avoid placing time consuming functionalities into BroadcastReceiver. It should just receive and initiate further processing in bound Activity/Service.

UPDATE:

Please check following sources that might be helpful:

Similar questions on StackOverflow:

How to send data from BroadcastReceiver to an Activity in android?

Android SMS receiver not working

Android SDK demo example:

android-sdk-windows\samples\android-8\ApiDemos\src\com\example\android\apis\os\SmsMessagingDemo.java

And of course standard Android API documentation: http://developer.android.com/reference/android/content/BroadcastReceiver.html

UPDATE2:

Added app skeleton as it should look. Please note that no content view is defined. It is because your app will have transparent screen. To achieve that

@android:style/Theme.Translucent

is entered under Theme tag for this activity in AndroidManifest.xml.

public class NotifySMSReceived extends Activity 
{
    private static final String LOG_TAG = "SMSReceiver";
    public static final int NOTIFICATION_ID_RECEIVED = 0x1221;
    static final String ACTION = "android.provider.Telephony.SMS_RECEIVED";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        IntentFilter filter = new IntentFilter(ACTION);
        this.registerReceiver(mReceivedSMSReceiver, filter);
    }

    private void displayAlert()
    {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setMessage("Are you sure you want to exit?").setCancelable(
                false).setPositiveButton("Yes",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        dialog.cancel();
                    }
                }).setNegativeButton("No",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        dialog.cancel();
                    }
                });
        AlertDialog alert = builder.create();
        alert.show();
    }

    private final BroadcastReceiver mReceivedSMSReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();

            if (ACTION.equals(action)) 
            {
                //your SMS processing code
                displayAlert();
            }
        }
    };    
}

Answer 2

I've been looking into it and the documentation of the BroadcastReceiver actually says:

public abstract void onReceive (Context context, Intent intent)

Since: API Level 1 This method is called when the BroadcastReceiver is receiving an Intent broadcast. During this time you can use the other methods on BroadcastReceiver to view/modify the current result values. The function is normally called within the main thread of its process, so you should never perform long-running operations in it (there is a timeout of 10 seconds that the system allows before considering the receiver to be blocked and a candidate to be killed). You cannot launch a popup dialog in your implementation of onReceive().

You cannot launch a popup dialog in your implementation of onReceive()

So it seems it is not possible