Why can’t I add a marker by clicking on the map?

Question

Why can’t I add a marker by clicking on the map?

Asked 6 years, 5 months ago

Viewed 199 times

0

I’m using this code:

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

import static com.marcadorfixo.R.id.map;

public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {
    GoogleMap googleMap;

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

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(map);
        mapFragment.getMapAsync(MainActivity.this);

        googleMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
            @Override
            public void onMapClick(LatLng position) {
                googleMap.addMarker(
                        new MarkerOptions().position(position)
                );
            }
        });
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        LatLng uaua = new LatLng(-9.840318, -39.480388);
        googleMap.addMarker(new MarkerOptions()
                .position(uaua)
                .title("Uauá"));
    }
}

Android Studio even compiles, but when trying to run the application it simply stops working.

2

What error presented by android studio?

– Antonio S. Junior

2018/01/23 at 21:10
Dude, he doesn’t accuse error, that’s what I don’t understand. For example: He compiles, no error, then when I run the app it stops working. Like, if he did, and when he clicked on the map, he would stop and I could look for the problem myself, but not even that... I’ve looked for some tutorials, but it’s scarce.

– Higor Cardoso

2018/01/24 at 00:49

1 answer

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by Guilherme Montanher • **461** points · Answer 1 · 2018-01-24T13:18:10+00:00

The problem is that you are adding the click on an object null that was not instantiated you can only add the click after receiving the object in the method onMapReady. Try the solution below:

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

import static com.marcadorfixo.R.id.map;

public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {
    //GoogleMap googleMap;

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

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(map);
        mapFragment.getMapAsync(MainActivity.this);
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        LatLng uaua = new LatLng(-9.840318, -39.480388);

        googleMap.addMarker(new MarkerOptions()
                .position(uaua)
                .title("Uauá"));

        googleMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
            @Override
            public void onMapClick(LatLng position) {
                googleMap.addMarker(
                        new MarkerOptions().position(position)
                );
            }
        });
    }
}