MainActivity.java

package ngvl.android.aulasummerjob;

import android.content.Intent;
import android.location.Location;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptor;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;

public class MainActivity extends AppCompatActivity
        implements
            GoogleApiClient.ConnectionCallbacks,
            GoogleApiClient.OnConnectionFailedListener,
            LocationListener {

    GoogleApiClient mGoogleApiClient;
    GoogleMap mMap;
    Marker mMarkerAtual;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final EditText edtNome = (EditText)findViewById(R.id.edtNome);

        Button btn = (Button)findViewById(R.id.button);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this,
                        "Mensagem! "+ edtNome.getText().toString(),
                        Toast.LENGTH_SHORT).show();

                Intent it = new Intent(MainActivity.this, Tela2Activity.class);
                startActivity(it);
            }
        });

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();

        SupportMapFragment mapFragment = (SupportMapFragment)
                getSupportFragmentManager().findFragmentById(R.id.map);
        mMap = mapFragment.getMap();


    }

    @Override
    protected void onResume() {
        super.onResume();
        mGoogleApiClient.connect();
    }

    @Override
    protected void onPause() {
        super.onPause();
        mGoogleApiClient.disconnect();
    }

    protected void createLocationRequest() {
        LocationRequest mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(1000);
        mLocationRequest.setFastestInterval(500);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);

        Location lastKnownLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
        BitmapDescriptor icon = BitmapDescriptorFactory.fromResource(R.mipmap.ic_launcher);
        mMarkerAtual = mMap.addMarker(
                new MarkerOptions().title("Local atual").icon(icon).position(
                        new LatLng(lastKnownLocation.getLatitude(),lastKnownLocation.getLongitude()))
        );

        LocationServices.FusedLocationApi.requestLocationUpdates(
                mGoogleApiClient, mLocationRequest, this);
    }

    @Override
    public void onConnected(@Nullable Bundle bundle) {
        createLocationRequest();
    }

    @Override
    public void onConnectionSuspended(int i) {

    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {

    }

    @Override
    public void onLocationChanged(Location location) {
        TextView txt = (TextView)findViewById(R.id.textView);
        txt.setText("LAT:"+ location.getLatitude() +
            "LONG:"+ location.getLongitude());

        LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
        mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 17));
        mMarkerAtual.setPosition(latLng);
    }
}