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:
- Implement
OnMapReadyCallback
inViewHolder
class. - In
onMapReady
, callMapsInitializer.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.
- Recycle map from
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(...);
... ...
}
}
}
Google says:
When using the API in fully interactive mode, users of the MapView class must forward all the activity life cycle methods to the corresponding methods in the MapView class. Examples of the life cycle methods include onCreate(), onDestroy(), onResume(), and onPause().
When using the MapView class in lite mode, forwarding lifecycle events is optional, except for the following situations:
It is mandatory to call onCreate(), otherwise no map will appear. If you wish to show the My Location dot on your lite mode map and use the default location source, you will need to call onResume() and onPause(), because the location source will only update between these calls. If you use your own location source, it's not necessary to call these two methods.
So on lite mode you don't have to worry about onDestroy(), onResume() and onPause()
Google map provides Lite Mode
The Maps SDK for Android can serve a bitmap image of a map, offering limited interactivity to the user. This is called a lite mode map.
Follow the LiteListDemoActivity
: Displaying maps efficiently in ListViews using lite mode
example.
You need to have a separate View Holder class. The RecyclerView Adapter class will just have onCreateViewHolder() and onBindViewHolder().
Your Layout file should look something similar to this:
<RelativeLayout 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"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MyActivity">
<view
<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>
And the onCreate(), onDestroy() will be called in the Activity class as usual.
Please follow this tutorial to get a complete overview.
I have removed this Override method because every time this gives empty map when testing and it works perfectly in my recyclerView.
@Override
public void onViewRecycled(ViewHolder holder)
{
// Cleanup MapView here?
if (holder.gMap != null)
{
holder.gMap.clear();
holder.gMap.setMapType(GoogleMap.MAP_TYPE_NONE);
}
}
You can try it if above code does not work in your case as well.
来源:https://stackoverflow.com/questions/28612782/google-maps-lite-mode-causes-jank-in-recyclerview