如何在非活动文件中调用 SupportMapFragment，即 RecyclerView Adapter

Question

I want to create Iterative Map view. For which Im using RecyclerView.

I tried calling the activity method getSupportFragmentManager() using context that I initialised in constructor of my adapter. But it's not working.

template.xml

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

<android.support.v7.widget.CardView
    android:layout_margin="8dp"
    app:cardElevation="20dp"
    android:layout_width="match_parent"
    android:layout_height="256dp">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:text="29-18-2019 5:30"
            android:textSize="18dp"
            android:padding="8dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

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

    </LinearLayout>

</android.support.v7.widget.CardView>

RecyclerViewAdapter.java

public class HistoryAdapter extends RecyclerView.Adapter<HistoryAdapter.ViewHolder> {

Context mContext;
ArrayList<HistoryModel> dataList;

public HistoryAdapter(Context mContext, ArrayList<HistoryModel> dataList) {
    this.mContext = mContext;
    this.dataList = dataList;
}

@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
    LayoutInflater layoutInflater = LayoutInflater.from(mContext);
    View view = layoutInflater.inflate(R.layout.history_single, viewGroup, false);
    final ViewHolder viewHolder = new ViewHolder(view);
    return viewHolder;
}

@Override
public void onBindViewHolder(@NonNull ViewHolder viewHolder, int i) {

}

@Override
public int getItemCount() {
    return dataList.size();
}

class ViewHolder extends RecyclerView.ViewHolder implements OnMapReadyCallback {

    SupportMapFragment mMapFragment;

    public ViewHolder(@NonNull View itemView) {
        super(itemView);

    }

    @Override
    public void onMapReady(GoogleMap googleMap) {

    }
}
}

I want to know how to initialise google maps in non activity java files. As in above case.

Answer 1

For RecyclerView Adapter is better to use MapView in Lite Mode as in that Official example of using MapView inside RecyclerView :

 /** * Holder for Views used in the {@link LiteListDemoActivity.MapAdapter}. * Once the the <code>map</code> field is set, otherwise it is null. * When the {@link #onMapReady(com.google.android.gms.maps.GoogleMap)} callback is received and * the {@link com.google.android.gms.maps.GoogleMap} is ready, it stored in the {@link #map} * field. The map is then initialised with the NamedLocation that is stored as the tag of the * MapView. This ensures that the map is initialised with the latest data that it should * display. */ class ViewHolder extends RecyclerView.ViewHolder implements OnMapReadyCallback { MapView mapView; TextView title; GoogleMap map; View layout; private ViewHolder(View itemView) { super(itemView); layout = itemView; mapView = layout.findViewById(R.id.lite_listrow_map); title = layout.findViewById(R.id.lite_listrow_text); if (mapView != null) { // Initialise the MapView mapView.onCreate(null); // Set the map ready callback to receive the GoogleMap object mapView.getMapAsync(this); } } @Override public void onMapReady(GoogleMap googleMap) { MapsInitializer.initialize(getApplicationContext()); map = googleMap; setMapLocation(); } /** * Displays a {@link LiteListDemoActivity.NamedLocation} on a * {@link com.google.android.gms.maps.GoogleMap}. * Adds a marker and centers the camera on the NamedLocation with the normal map type. */ private void setMapLocation() { if (map == null) return; NamedLocation data = (NamedLocation) mapView.getTag(); if (data == null) return; // Add a marker for this item and set the camera map.moveCamera(CameraUpdateFactory.newLatLngZoom(data.location, 13f)); map.addMarker(new MarkerOptions().position(data.location)); // Set the map type back to normal. map.setMapType(GoogleMap.MAP_TYPE_NORMAL); } private void bindView(int pos) { NamedLocation item = namedLocations[pos]; // Store a reference of the ViewHolder object in the layout. layout.setTag(this); // Store a reference to the item in the mapView's tag. We use it to get the // coordinate of a location, when setting the map location. mapView.setTag(item); setMapLocation(); title.setText(item.name); } }

Here you can find MapView layout settings for that case:

 <!-- MapView in lite mode. Note that it needs to be initialised programmatically before it can be used. --> <com.google.android.gms.maps.MapView android:id="@+id/lite_listrow_map" android:layout_width="match_parent" android:layout_height="150dp" map:liteMode="true" map:mapType="none" />