Question

I created my lockscreen application that trigerred by a SMS.. i have ListenSMS class that always listen for incoming SMS. Here’s the code :

for (SmsMessage message : messages) {
    String tempMessage[] = message.getDisplayMessageBody().toString().split(" ");

    //checking command dan password                             
    if (tempMessage[0].toString().equalsIgnoreCase("andro-lock") && tempMessage[1].toString().equals(tempPassword.toString())) {
        //Toast.makeText(ListenSMSservice.this, "Menjalankan command andro-lock", Toast.LENGTH_LONG).show();
        openDatabase();
        updateStatusL();
        Intent myIntent = new Intent(ListenSMSservice.this,LockScreenForm.class);
        myIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        getApplication().startActivity(myIntent);
    }
    else if (tempMessage[0].toString().equalsIgnoreCase("andro-unlock") && tempMessage[1].toString().equals(tempPassword.toString())) {
        //Toast.makeText(ListenSMSservice.this, "Menjalankan command andro-unlock", Toast.LENGTH_LONG).show();
        openDatabase();
        updateStatusNL();                                                                   
        Intent myIntent = new Intent(ListenSMSservice.this,LockScreenForm.class);
        myIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        Bundle myKillerBundle = new Bundle();
        myKillerBundle.putString("kill","1");
        myIntent.putExtras(myKillerBundle);
        getApplication().startActivity(myIntent);
    }
}

If ListenSMS service has received an andro-lock command, it will go to the lockscreen.java and will go to the lockscreen.java with intent extra (putExtra) kill when it receive command andro-unclock. Here’s my lockscreen.java:

public class LockScreenForm extends Activity implements OnClickListener {
    /** Called when the activity is first created. */

    @Override
    public void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        setContentView(R.layout.lockscreen);             

        Bundle extra = getIntent().getExtras();
        if (extra == null) {
            return;
        }
        //Toast.makeText(this, extra.getString("kill"), 1).show();
        else if(this.getIntent().getExtras().getString("kill").equalsIgnoreCase("1")) {
            try {
                Toast.makeText(this, "extra accepted", 1).show();
                finish();
            } catch (Exception e) {
                // TODO: handle exception
                Toast.makeText(this, e.getMessage(), 1).show();
            }

        }

    }
}

I want to close my locksreen.java when my ListenSMS service has received “andro-unlock” command, so I put extra on intent “kill” and check it in lockscreen.java. This lockscreen.java can check the extra intent and can display a toast “extra accepted” but can close the lockscreen activity with finish().

My assumption is for now that Intent.FLAG_ACTIVITY_NEW_TASK is duplicating a locksreen activity. So it will create a double lockscreen activity and the finish method is closing another lockscreen.java that started by Intent.FLAG_ACTIVITY_NEW_TASK. That’s only assumption. Am i wrong? Please correct me.

Has anyone know how to solve my problem? I really want that “andro-unlock” command can close the lockscreen activity and need it works for my college final project. Please help.

Answer 1

From http://developer.android.com/reference/android/content/Intent.html#FLAG_ACTIVITY_NEW_TASK:

When using this flag, if a task is already running for the activity you are now starting, then a new activity will not be started; instead, the current task will simply be brought to the front of the screen with the state it was last in. See FLAG_ACTIVITY_MULTIPLE_TASK for a flag to disable this behavior. 

I expect your problem is somewhere else. I’d suggest having the lockscreen Activity register a BroadcastReceiver, and then when the unlock message is received send an Intent that the BroadcastReceiver will catch. The Activity can then cleanly exit.