为什么我的地图活动会导致我的应用崩溃？

Question

在我的主要活动中，我有一个按钮，按下按钮就会启动一个新的MapActivity。 目标是让MapActivity加载并在屏幕上显示一个地图，该地图在地图上的用户当前位置有一个指针。

当按下按钮时，应用程序崩溃，我已经尝试了很多次来解决这个问题但是4小时后我无处可去！

public class MapActivity extends AppCompatActivity implements         OnMapReadyCallback {
private LocationManager locationManager;
private String provider;
private Location location;
private GoogleMap mMap;
private int MY_PERMISSIONS_REQUEST_FINE_LOCATION= 1;

@Override
public void onMapReady(GoogleMap googleMap) {
    Toast.makeText(this, "Map is Ready", Toast.LENGTH_SHORT).show();
    mMap = googleMap;
}

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    location = getMyLocation();
    mMap.addMarker(new MarkerOptions().position(new LatLng(location.getLatitude(),location.getLongitude())).title("My location"));


}

public Location getMyLocation() {
    LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
    Criteria criteria = new Criteria();

    if (ContextCompat.checkSelfPermission(this,
            Manifest.permission.ACCESS_FINE_LOCATION)
            != PackageManager.PERMISSION_GRANTED) {
        // No explanation needed, we can request the permission.

        ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                MY_PERMISSIONS_REQUEST_FINE_LOCATION);

        // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
        // app-defined int constant. The callback method gets the
        // result of the request.
    }
    Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
    if (location != null)
    {
        mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
                new LatLng(location.getLatitude(), location.getLongitude()), 13));

        CameraPosition cameraPosition = new CameraPosition.Builder()
                .target(new LatLng(location.getLatitude(), location.getLongitude()))      // Sets the center of the map to location user
                .zoom(17)                   // Sets the zoom
                .bearing(90)                // Sets the orientation of the camera to east
                .tilt(40)                   // Sets the tilt of the camera to 30 degrees
                .build();                   // Creates a CameraPosition from the builder
        mMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));

    }

    return location;
}}

按下按钮时发生的崩溃日志：

05-21 01:07:24.379 30002-30002/com1032.cw2.jm01061.jm01061_assignmentv2 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com1032.cw2.jm01061.jm01061_assignmentv2, PID: 30002
java.lang.RuntimeException: Unable to start activity ComponentInfo{com1032.cw2.jm01061.jm01061_assignmentv2/com1032.cw2.jm01061.jm01061_assignmentv2.MapActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'double android.location.Location.getLatitude()' on a null object reference
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2596)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2678)
    at android.app.ActivityThread.-wrap11(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1494)
    at android.os.Handler.dispatchMessage(Handler.java:111)
    at android.os.Looper.loop(Looper.java:207)
    at android.app.ActivityThread.main(ActivityThread.java:5822)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:888)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:749)
 Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'double android.location.Location.getLatitude()' on a null object reference
    at com1032.cw2.jm01061.jm01061_assignmentv2.MapActivity.onCreate(MapActivity.java:50)
    at android.app.Activity.performCreate(Activity.java:6308)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1113)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2543)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2678)