Android StudioでGoogle Mapを利用したアプリのエラー

やりたいこと

Map上に、緯度経度、ズームレベルを表示する。

MapsActivity
1import androidx.fragment.app.FragmentActivity;
2
3import android.os.Bundle;
4import android.widget.TextView;
5
6import com.google.android.gms.maps.CameraUpdateFactory;
7import com.google.android.gms.maps.GoogleMap;
8import com.google.android.gms.maps.OnMapReadyCallback;
9import com.google.android.gms.maps.SupportMapFragment;
10import com.google.android.gms.maps.model.CameraPosition;
11import com.google.android.gms.maps.model.LatLng;
12import com.google.android.gms.maps.model.MarkerOptions;
13
14public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
15
16    private GoogleMap mMap;
17    private TextView centerLocationText;
18
19    @Override
20    protected void onCreate(Bundle savedInstanceState) {
21        super.onCreate(savedInstanceState);
22        setUpMap();
23        setContentView(R.layout.activity_maps);
24        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
25        //SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
26           //     .findFragmentById(R.id.map);
27        //mapFragment.getMapAsync(this);
28
29        centerLocationText=(TextView)findViewById(R.id.center_location_textView);
30
31    }
32
33    //Override
34    /*public void onMapReady(GoogleMap googleMap) {
35        mMap = googleMap;
36
37        // Add a marker in Sydney and move the camera
38        LatLng sydney = new LatLng(-34, 151);
39        mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
40        mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
41        mMap.setMyLocationEnabled(true);
42    }*/
43
44   private void setUpMap(){
45        mMap.addMarker(new MarkerOptions().position(new LatLng(0,0)).title("Maker"));
46        mMap.setMyLocationEnabled(true);
47        mMap.setTrafficEnabled(false);
48        mMap.setOnCameraChangeListener(new GoogleMap.OnCameraChangeListener() {
49            @Override
50            public void onCameraChange(CameraPosition cameraPosition) {
51                double zoomLevel=cameraPosition.zoom;
52                double latitude=cameraPosition.target.latitude;
53                double longitude=cameraPosition.target.longitude;
54
55                String centerText="zoom level"+zoomLevel+"\n"
56
57                        +"latitude"+latitude+"\n"
58
59                        +"longitude"+longitude;
60                centerLocationText.setText(centerText);
61
62            }
63        });
64
65
66}
67
68}

エラー

ビルドを完了し、デバッグすると以下のエラーが出ます。
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.regu1.maptest1/com.regu1.maptest1.MapsActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.model.Marker com.google.android.gms.maps.GoogleMap.addMarker(com.google.android.gms.maps.model.MarkerOptions)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2827)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2902)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1603)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:169)
at android.app.ActivityThread.main(ActivityThread.java:6578)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.model.Marker com.google.android.gms.maps.GoogleMap.addMarker(com.google.android.gms.maps.model.MarkerOptions)' on a null object reference
at com.regu1.maptest1.MapsActivity.setUpMap(MapsActivity.java:47)
at com.regu1.maptest1.MapsActivity.onCreate(MapsActivity.java:24)
at android.app.Activity.performCreate(Activity.java:7016)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2780)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2902)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1603)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:169)
at android.app.ActivityThread.main(ActivityThread.java:6578)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)