Use findViewById in Android Studio’s standard Mapsactivity

Question

I’m using the standard Maps template available on Android Studio, and in the activity_maps.xml added a EditText with the id towhere.

In the Mapsactivity class I just added a setOnFocusChangeListener:

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        if(mapFragment != null)
            mapFragment.getMapAsync(this);

        /* início da parte feita por mim */
        EditText towhere =  findViewById(R.id.towhere); //ERRO
        towhere.setOnFocusChangeListener(new View.OnFocusChangeListener() {
            @Override
            public void onFocusChange(View v, boolean hasFocus) {
                if(hasFocus) {
                    Intent findAddress = new Intent(MapsActivity.this, FindAddress.class);
                    startActivity(findAddress);
                }
            }
        });
        /* fim da parte feita por mim */
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
    }
}

I get the error:

java.lang.Nullpointerexception: Attempt to invoke virtual method 'void android.widget.Edittext.setOnFocusChangeListener(android.view.View$Onfocuschangelistener)' on a null Object Reference

The setContentView is set before the findViewById, but it doesn’t work.

Answer 1

The problem was in XML. As I am running the Nexus emulator, it is getting the folder component layout-v26 instead of layout, and the archives activity_maps.xml of these two folders were different, and so was giving Nullpointerexception to the requested id on findViewById(R.id.towhere)