I have a RecyclerView
which is a vertical scrolling list of items. Each list item contains a Google Maps V2 MapView in Lite Mode. I'm taking advantage of this new feature which returns bitmaps instead of a full-blown map as a replacement to the Google Static Maps API
.
MapView requires that you call onCreate()
, onResume()
, onPause()
, onDestroy()
etc. from the parent Activity/Fragment's corresponding method. Where is the proper place to call these from the RecyclerView.Adapter
and/or RecyclerView.ViewHolder
?
How can I clean up recycled MapViews so that memory doesn't leak, while keeping the list jank free?
Google says Lite Mode can be used in lists:
... ‘lite mode’ map option, ideal for situations where you want to provide a number of smaller maps, or a map that is so small that meaningful interaction is impractical, such as a thumbnail in a list.
ListItem.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<com.google.android.gms.maps.MapView
android:id="@+id/mapImageView"
xmlns:map="http://schemas.android.com/apk/res-auto"
android:layout_width="80dp"
android:layout_height="100dp"
map:liteMode="true"
map:mapType="normal"
map:cameraZoom="15"/>
<!-- ... -->
</RelativeLayout>
RecyclerView.Adapter and ViewHolder
public class NearbyStopsAdapter extends RecyclerView.Adapter<NearbyStopsAdapter.ViewHolder> {
private final Context mContext;
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
MapView map;
public ViewHolder(View view) {
super(view);
map = (MapView) view.findViewById(R.id.mapImageView);
// Should this be created here?
map.onCreate(null);
map.onResume();
}
}
public NearbyStopsAdapter(Context c) {
this.mContext = c;
}
@Override public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int position) {
View itemView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.list_item_nearby_stop, viewGroup, false);
return new ViewHolder(itemView);
}
@Override public void onBindViewHolder(ViewHolder holder, int position) {
//Call Async Map here?
holder.map.getMapAsync(this);
}
@Override public void onViewRecycled(ViewHolder holder) {
// Cleanup MapView here?
// if (holder.map != null) {
// holder.map.onPause();
// holder.map.onDestroy();
// }
}
@Override public void onViewAttachedToWindow(ViewHolder holder) {
// Setup MapView here?
// holder.map.onCreate(null);
// holder.map.onResume();
}
@Override public void onViewDetachedFromWindow(ViewHolder holder) {
// Cleanup MapView here?
// if (holder.map != null) {
// holder.map.onPause();
// holder.map.onDestroy();
// }
}
// ...
}
Logcat:
I/Google Maps Android API﹕ Google Play services package version: 659943
W/Google Maps Android API﹕ Map Loaded callback is not supported in Lite Mode
W/Google Maps Android API﹕ Buildings are not supported in Lite Mode
W/Google Maps Android API﹕ Indoor is not supported in Lite Mode
W/Google Maps Android API﹕ Toggling gestures is not supported in Lite Mode
W/Google Maps Android API﹕ Toggling gestures is not supported in Lite Mode
W/Google Maps Android API﹕ Toggling gestures is not supported in Lite Mode
W/Google Maps Android API﹕ Toggling gestures is not supported in Lite Mode
Update: (Jun 8, 2018) Google has released a code sample for using Lite Maps in a ListView. See here
Solution as following:
OnMapReadyCallback
in ViewHolder
class.onMapReady
, call MapsInitializer.initialize
, to gaurantee features can to be used before obtaining a map.Use this class to initialize the Google Maps Android API if features need to be used before obtaining a map. It must be called because some classes such as BitmapDescriptorFactory and CameraUpdateFactory need to be initialized.
onViewRecycled
.
public class NearbyStopsAdapter extends RecyclerView.Adapter<NearbyStopsAdapter.ViewHolder> {
@Override
public void onBindViewHolder(ViewHolder holder, int position)
{
//get 'location' by 'position' from data list
//get GoogleMap
GoogleMap thisMap = holder.gMap;
//then move map to 'location'
if(thisMap != null)
//move map to the 'location'
thisMap.moveCamera(...);
}
//Recycling GoogleMap for list item
@Override
public void onViewRecycled(ViewHolder holder)
{
// Cleanup MapView here?
if (holder.gMap != null)
{
holder.gMap.clear();
holder.gMap.setMapType(GoogleMap.MAP_TYPE_NONE);
}
}
public class ViewHolder extends RecyclerView.ViewHolder implements OnMapReadyCallback {
GoogleMap gMap;
MapView map;
... ...
public ViewHolder(View view) {
super(view);
map = (MapView) view.findViewById(R.id.mapImageView);
if (map != null)
{
map.onCreate(null);
map.onResume();
map.getMapAsync(this);
}
}
@Override
public void onMapReady(GoogleMap googleMap) {
//initialize the Google Maps Android API if features need to be used before obtaining a map
MapsInitializer.initialize(getApplicationContext());
gMap = googleMap;
//you can move map here to item specific 'location'
int pos = getPosition();
//get 'location' by 'pos' from data list
//then move to 'location'
gMap.moveCamera(...);
... ...
}
}
}