Android, mapFragment.getMapAsync errors occur with null object reference

Question

I tried to use google map at here by fragment. I used SupportMapFragment, and get that Fragment by R.id.map. And finally I used mapFragment.GetMapAsync(this).

But, It's keep making errors. I don't know why...... Plz, someone give me help over here.

// MainActivity.java
package com.example.fleago;

import androidx.annotation.NonNull;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.fragment.app.FragmentTransaction;

import android.Manifest;
import android.app.Activity;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;

import com.daimajia.swipe.SwipeLayout;
import com.daimajia.swipe.util.Attributes;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
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 com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import com.sothree.slidinguppanel.SlidingUpPanelLayout;

import net.daum.android.map.MapView;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

import adapter.ListViewAdapter;

import static com.example.fleago.ARActivity.REQUEST_LOCATION_PERMISSIONS_CODE;

public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {
    private GoogleMap mMap;
    private static final String TAG = "MarketListView";

    private SlidingUpPanelLayout mLayout;
    private ListViewAdapter mAdapter;
    private ArrayList<Market> list;

    private Location currentLocation;
    private LocationManager locationManager;
    boolean isGPSEnabled;
    boolean isNetworkEnabled;
    boolean locationServiceAvailable;
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1; // 10 meters
    private static final long MIN_TIME_BW_UPDATES = 100;//1000 * 60 * 1; // 1 minute
    private static final int MAX_DISTANCE = Integer.MAX_VALUE;

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

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        LatLng SEOUL = new LatLng(37.56, 126.97);

        MarkerOptions markerOptions = new MarkerOptions();
        markerOptions.position(SEOUL);
        markerOptions.title("Seoul");
        markerOptions.snippet("Korea's Center");
        mMap.addMarker(markerOptions);

        mMap.moveCamera(CameraUpdateFactory.newLatLng(SEOUL));
        mMap.animateCamera(CameraUpdateFactory.zoomTo(10));
    }
}

This is XML layout code

//activity_main.xml
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:sothree="http://schemas.android.com/apk/res-auto"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    android:orientation="vertical">

    <com.sothree.slidinguppanel.SlidingUpPanelLayout
        android:id="@+id/sliding_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="bottom"

        sothree:umanoDragView="@+id/btn_handle"
        sothree:umanoPanelHeight="@dimen/default_small_list_height"
        sothree:umanoShadowHeight="0dp"
        sothree:umanoParallaxOffset="100dp">

        <!-- MAIN CONTENT -->
        <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
            xmlns:tools="http://schemas.android.com/tools"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:context=".MainActivity" >

            <fragment
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:id="@+id/map"
                tools:context=".MapsActivity"
                android:name="com.google.android.gms.maps.SupportMapFragment" />

        </LinearLayout>
        <!-- SLIDING LAYOUT -->
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="@dimen/default_full_list_height"
            android:background="@color/seoul_default_light"
            android:orientation="vertical"
            android:focusable="false"
            android:clickable="false">

            <!--- 손잡이 -->
            <Button
                android:id="@+id/btn_handle"
                android:background="#00ff0000"
                android:layout_width="match_parent"
                android:layout_height="40dp"
                android:layout_gravity="right"
                android:layout_marginRight="10dp"
                android:clickable="true"    >
            </Button>

            <ListView
                android:id="@+id/marketList"
                android:layout_width="match_parent"
                android:layout_height="match_parent" >
            </ListView>
        </LinearLayout>
    </com.sothree.slidinguppanel.SlidingUpPanelLayout>
</LinearLayout>

and this is error coming from Logcat

2019-09-28 17:35:13.911 18564-18564/com.example.fleago E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.fleago, PID: 18564
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.fleago/com.example.fleago.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.SupportMapFragment.getMapAsync(com.google.android.gms.maps.OnMapReadyCallback)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3114)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3257)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1948)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7050)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.SupportMapFragment.getMapAsync(com.google.android.gms.maps.OnMapReadyCallback)' on a null object reference
        at com.example.fleago.MainActivity.onCreate(MainActivity.java:74)
        at android.app.Activity.performCreate(Activity.java:7327)
        at android.app.Activity.performCreate(Activity.java:7318)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3094)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3257) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1948) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:214) 
        at android.app.ActivityThread.main(ActivityThread.java:7050) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)

I can't understand why getMapAsync(this) is null at here Plz anybody can tell me why this things happen?

I hope this'll help you : https://stackoverflow.com/questions/27420945/java-lang-nullpointerexception-attempt-to-invoke-virtual-method-on-a-null-objec — Viral Patel, Sep 28 '19 at 09:15

score 0 · Accepted Answer · answered Sep 28 '19 at 09:10

0

Set supportfragment like this

<fragment android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/map" tools:context=".MapsActivity" class="com.google.android.gms.maps.SupportMapFragment" />

answered Sep 28 '19 at 09:10

Chintan

394
2
7

score 0 · Answer 2 · answered Sep 28 '19 at 10:11

What I have observed from your issue, is that you might be facing naming convention of your Activity class.

You might have declared it MapsActivity in your manifest file. Whereas, you are using MainActivity name above in your given code. Change that to MapsActivity and check your Manifest file that it is also not showing any error.

If it showing error then change the name same to the name which you are using for Activity class.

Android, mapFragment.getMapAsync errors occur with null object reference

2 Answers2