Question

I’m pretty new to Android/java, and have come up against my first head-scratcher.

I’m trying to conditionally change the starting view based on if a user is logged in (I’ve set is_logged_in already, here, to more simply illustrate the problem).

Many thanks.

public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        boolean is_logged_in = false;

        if(is_logged_in) {
            setContentView(R.layout.activity_main);
        } else {
            menu_sign_up(); // How would I pass the View?
        }
    }

    // Doesn't work, at least when called inside of MainActivity's onCreate
    public void menu_sign_up(/* View view */) {
        Intent intent = new Intent(this, SignUp.class);
        startActivity(intent);
    }

    // Example of a working method, at least when called from android:onClick in XML
    public void menu_sign_in(View view) {
        Intent intent = new Intent(this, SignIn.class);
        startActivity(intent);
        overridePendingTransition(0,0);
    }
}

public class SignUp extends MainActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sign_up);
    }

    // ...
}

***** Truncated Stack Trace Below ******* (adb logcat *:W)

W/ActivityManager(19583): Activity idle timeout for HistoryRecord{40953fd8 com.example.digitalkarmaeclipse/.SignUp}
W/ActivityManager(): Activity idle timeout for HistoryRecord{}
W/ActivityManager(21900): Launch timeout has expired, giving up wake lock!
W/ActivityManager(21900): Activity idle timeout for HistoryRecord{40a23580 com.example.digitalkarmaeclipse/.MainActivity}
W/ActivityManager(21900): Activity idle timeout for HistoryRecord{40a2c6f8 com.example.digitalkarmaeclipse/.SignUp}
W/ActivityManager(21900): Activity idle timeout for HistoryRecord{40a30100 com.example.digitalkarmaeclipse/.SignUp}
W/ActivityManager(21900): Activity idle timeout for HistoryRecord{40a338e8 com.example.digitalkarmaeclipse/.SignUp}
W/ActivityManager(21900): Activity idle timeout for HistoryRecord{40a376e0 com.example.digitalkarmaeclipse/.SignUp}

Answer 1

Your current app structure doesn’t make a lot of sense. Does SignUp have to be an Activity as well? You could use an AlertDialog to do something similar. If it does need to be an Activity then have it extend Activity, it doesn’t make much sense to extend HomeActivity in this context.

I also don’t like the idea of putting setContentView() in a logical statement. onCreate() is only called when the Activity is created. So if you start your SignUp Activity and then press the back button, there won’t be a layout for your HomeActivity.

edit: And like Shark said it doesn’t look like you have a way to pass the data from SignUp back to HomeActivity. You should try to use startActivityForResult() and then use setResult() in SignUp to say whether it was successful or not.