moveCamera with CameraUpdateFactory.newLatLngBound

Question

I'm making use of the new Android Google Maps API.

I create an activity which includes a MapFragment. In the activity onResume I set the markers into the GoogleMap object and then define a bounding box for the map which includes all of the markers.

This is using the following pseudo code:

LatLngBounds.Builder builder = new LatLngBounds.Builder();
while(data) {
   LatLng latlng = getPosition();
   builder.include(latlng);
}
CameraUpdate cameraUpdate = CameraUpdateFactory
   .newLatLngBounds(builder.build(), 10);
map.moveCamera(cameraUpdate);

The call to map.moveCamera() causes my application to crash with the following stack:

Caused by: java.lang.IllegalStateException: 
    Map size should not be 0. Most likely, layout has not yet 

    at maps.am.r.b(Unknown Source)
    at maps.y.q.a(Unknown Source)
    at maps.y.au.a(Unknown Source)
    at maps.y.ae.moveCamera(Unknown Source)
    at com.google.android.gms.maps.internal.IGoogleMapDelegate$Stub
        .onTransact(IGoogleMapDelegate.java:83)
    at android.os.Binder.transact(Binder.java:310)
    at com.google.android.gms.maps.internal.IGoogleMapDelegate$a$a
        .moveCamera(Unknown Source)
    at com.google.android.gms.maps.GoogleMap.moveCamera(Unknown Source)
    at ShowMapActivity.drawMapMarkers(ShowMapActivity.java:91)
    at ShowMapActivity.onResume(ShowMapActivity.java:58)
    at android.app.Instrumentation
        .callActivityOnResume(Instrumentation.java:1185)
    at android.app.Activity.performResume(Activity.java:5182)
    at android.app.ActivityThread
        .performResumeActivity(ActivityThread.java:2732)

If - instead of the newLatLngBounds() factory method I use newLatLngZoom() method then the same trap does not occur.

Is the onResume the best place to draw the markers onto the GoogleMap object or should I be drawing the markers and setting the camera position somewhere else?

Answer 1

The solution is simpler than that....

// Pan to see all markers in view.
try {
    this.gmap.moveCamera(CameraUpdateFactory.newLatLngBounds(bounds, 50));
} catch (IllegalStateException e) {
    // layout not yet initialized
    final View mapView = getFragmentManager()
       .findFragmentById(R.id.map).getView();
    if (mapView.getViewTreeObserver().isAlive()) {
        mapView.getViewTreeObserver().addOnGlobalLayoutListener(
        new OnGlobalLayoutListener() {
            @SuppressWarnings("deprecation")
            @SuppressLint("NewApi")
            // We check which build version we are using.
            @Override
            public void onGlobalLayout() {
                if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
                    mapView.getViewTreeObserver()
                        .removeGlobalOnLayoutListener(this);
                } else {
                    mapView.getViewTreeObserver()
                        .removeOnGlobalLayoutListener(this);
                }
                gmap.moveCamera(CameraUpdateFactory.newLatLngBounds(bounds, 50));
            }
        });
    }
}

Catch IllegalStateException and use the global listener on the view instead. Setting the bound size in advance (pre-layout) using the other methods means you have to compute the size of THE VIEW, not the screen device. They only match if you go full screen with your map and do not use fragments.

Answer 2

In very rare cases, MapView layout is finished, but GoogleMap layout is not finished, ViewTreeObserver.OnGlobalLayoutListener itself can't stop the crash. I saw the crash with Google Play services package version 5084032. This rare case may be caused by the dynamic change of the visibility of my MapView.

To solve this problem, I embedded GoogleMap.OnMapLoadedCallback in onGlobalLayout(),

if (mapView.getViewTreeObserver().isAlive()) {
    mapView.getViewTreeObserver().addOnGlobalLayoutListener(
    new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        @SuppressWarnings("deprecation")
        public void onGlobalLayout() {
            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
                mapView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
            } else {
                mapView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
            }
            try {
                map.moveCamera(CameraUpdateFactory.newLatLngBounds(bounds, 5));
            } catch (IllegalStateException e) {
                map.setOnMapLoadedCallback(new GoogleMap.OnMapLoadedCallback() {
                    @Override
                    public void onMapLoaded() {
                        Log.d(LOG_TAG, "move map camera OnMapLoadedCallback");
                        map.moveCamera(CameraUpdateFactory
                            .newLatLngBounds(bounds, 5));
                    }
                });
            }
        }
    });
}

Answer 3

This is my fix, just wait untill the map is loaded in that case.

final int padding = getResources().getDimensionPixelSize(R.dimen.spacing);    

try {
    mMap.animateCamera(CameraUpdateFactory.newLatLngBounds(pCameraBounds, padding));
} catch (IllegalStateException ise) {

    mMap.setOnMapLoadedCallback(new GoogleMap.OnMapLoadedCallback() {

        @Override
        public void onMapLoaded() {
            mMap.animateCamera(CameraUpdateFactory.newLatLngBounds(pCameraBounds, padding));
        }
    });
}

Answer 4

I've created a way to combine the two callbacks: onMapReady and onGlobalLayout into one single observable which will emit only when both the events have been triggered.

https://gist.github.com/abhaysood/e275b3d0937f297980d14b439a8e0d4a

Answer 5

Why not just use something like this:

CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngBounds(builder.build(), padding);
try {
    map.moveCamera(cameraUpdate);
} catch (Exception e) {
    int width = getResources().getDisplayMetrics().widthPixels;
    int height = getResources().getDisplayMetrics().heightPixels;
    cameraUpdate = CameraUpdateFactory.newLatLngBounds(builder.build(), width, height, padding);
    map.moveCamera(cameraUpdate);
}

Answer 6

There is a helper class in the Google Maps repo that you can leverage - it waits for both the layout and map to be ready before notifying a callback with the GoogleMap:

The original source is here:

https://github.com/googlemaps/android-samples/blob/7ee737b8fd6d39c77f8b3716ba948e1ce3730e61/ApiDemos/java/app/src/main/java/com/example/mapdemo/OnMapAndViewReadyListener.java

There is a Kotlin implementation too:

https://github.com/googlemaps/android-samples/blob/master/ApiDemos/kotlin/app/src/main/java/com/example/kotlindemos/OnMapAndViewReadyListener.kt

public class OnMapAndViewReadyListener implements OnGlobalLayoutListener, OnMapReadyCallback {

/** A listener that needs to wait for both the GoogleMap and the View to be initialized. */
public interface OnGlobalLayoutAndMapReadyListener {
    void onMapReady(GoogleMap googleMap);
}

private final SupportMapFragment mapFragment;
private final View mapView;
private final OnGlobalLayoutAndMapReadyListener devCallback;

private boolean isViewReady;
private boolean isMapReady;
private GoogleMap googleMap;

public OnMapAndViewReadyListener(
        SupportMapFragment mapFragment, OnGlobalLayoutAndMapReadyListener devCallback) {
    this.mapFragment = mapFragment;
    mapView = mapFragment.getView();
    this.devCallback = devCallback;
    isViewReady = false;
    isMapReady = false;
    googleMap = null;

    registerListeners();
}

private void registerListeners() {
    // View layout.
    if ((mapView.getWidth() != 0) && (mapView.getHeight() != 0)) {
        // View has already completed layout.
        isViewReady = true;
    } else {
        // Map has not undergone layout, register a View observer.
        mapView.getViewTreeObserver().addOnGlobalLayoutListener(this);
    }

    // GoogleMap. Note if the GoogleMap is already ready it will still fire the callback later.
    mapFragment.getMapAsync(this);
}

@Override
public void onMapReady(GoogleMap googleMap) {
    // NOTE: The GoogleMap API specifies the listener is removed just prior to invocation.
    this.googleMap = googleMap;
    isMapReady = true;
    fireCallbackIfReady();
}

@SuppressWarnings("deprecation")  // We use the new method when supported
@SuppressLint("NewApi")  // We check which build version we are using.
@Override
public void onGlobalLayout() {
    // Remove our listener.
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
        mapView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
    } else {
        mapView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
    }
    isViewReady = true;
    fireCallbackIfReady();
}

private void fireCallbackIfReady() {
    if (isViewReady && isMapReady) {
        devCallback.onMapReady(googleMap);
    }
}
}