Android mapview with fragments can't be added twice?

Question

I am using the android compatibility class with the hack for using mapviews in a fragment found here: https://github.com/petedoyle/android-support-v4-googlemaps

Unfortunately, what I am finding is that if the mapfragment gets removed from the activity, and then readded, I get the "You are only allowed to have a single MapView in a MapActivity" error."

I understand the principle behind the error, and tried destroying the mapview in the fragments onPause method. Unfortunately I can't seem to destroy the mapview completely, since I am still getting it. My Code looks like this:

private RelativeLayout layout; 
private MapView mp;

public void onResume(){
    super.onResume();
    Bundle args = getArguments();
    if(mp == null)
    {
        mp = new MapView(getActivity(), this.getString(R.string.map_api_key)); 
        mp.setClickable(true);
    }

    String request = args.getString("requestId");
    layout = (RelativeLayout) getView().findViewById(R.id.mapholder);
    layout.addView(mp);
    //TextView txt = (TextView) getView().findViewById(R.id.arguments);
    //txt.setText(request);
}

public void onPause(){
    super.onPause();
    layout.removeView(mp);
    mp = null;
}

Does anyone have any thoughts on what the reference I am neglecting to destroy here?

Answer 1

I encountered the same issue. Here is how I solved it :

• As it should be only one instance of the mapView in the activity, I initialize it in onCreate method in Activity :

  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      // initialize MapView programmatically to be used in Fragment :
      this.mActivityMapView = new MapView(MainActivity.this, getString(R.string.debug_mapview_apikey));
  
      setContentView(R.layout.activity_main);
  }
  

• Then I recover it in the fragment onCreateView method :

  public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
      this.mMapView = ((MainActivity) getActivity()).getMapView();
      return this.mMapView;
  }
  

• And I destroy it in the fragment onDestroy method :

  public void onDestroy() {
      NoSaveStateFrameLayout parentView = (NoSaveStateFrameLayout) this.mMapView.getParent();
      parentView.removeView(this.mMapView);
      super.onDestroy();
  }
  

Answer 2

You might want to remove the map view in the onPause method (instead of the onDestroy method)

public void onPause() {
    NoSaveStateFrameLayout parentView = (NoSaveStateFrameLayout) this.mMapView.getParent();
    parentView.removeView(this.mMapView);
    super.onPause();}

This way, you can add a MapFragment to the backstack. (FragmentTransaction.addToBackStack prevents a fragment from being destroyed)

Answer 3

Max and Bleeker's answers work well but you need to take special care if you want to support screen orientation changes, as I do. It turns out when you rotate the screen, it will call OnCreateView again without calling the onPause method, thus adding the mapview twice. To fix it, inside OnCreateView I did the following:

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
    this.mMapView = ((MyGameActivity) getActivity()).getMapView();
    if (this.mMapView.getParent()!=null)
    {
        NoSaveStateFrameLayout parentView = (NoSaveStateFrameLayout) this.mMapView.getParent();
        parentView.removeView(this.mMapView);
    }
    return this.mMapView;
}

Answer 4

I tried to get a simple solution to this problem. On the class that handles my View details (a RelativeLayout extension), I declared a private static MapView myMapView;.

Then, override onFinishInflate() method like the following code snippet:

    @Override
protected void onFinishInflate() {  
    super.onFinishInflate();

    //myMapView = (MapView) findViewById(R.id.map_view);
    if (myMapView==null) 
        myMapView = new MapView(context, getResources().getString(R.string.map_view_api_key));  
    if (myMapView.getParent() != null)
        ((ViewGroup)myMapView.getParent()).removeView(myMapView);

    myMapView.setClickable(true);
    myMapView.setEnabled(true);
    RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
    myMapView.setLayoutParams(lp);          
    this.addView(myMapView);

}

This way you have only one instance of MapView.

Answer 5

Here is how i solved this issue in case of Fragment.

Create the Layout

 <LinearLayout
        android:id="@+id/ll_mapcontainer"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" />

You can place this like layout anywhere in your XML File where you want to display the map

Now the Code will be Like this.

package com.yuviii.sample;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.yuviii.sample.R;

/**
 * Created by yubraj Poudel on 12/20/15.
 */
public class ContactUsFragment extends Fragment  {
    static final LatLng PRACTICAL_ANSWER_LOCATION = new LatLng(53.558, 9.927);
    private SupportMapFragment fragment;
    private GoogleMap map;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
       View v = inflater.inflate(R.layout.page_contactus, container, false);
        return v;
    }



    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
                    initializeMap();
    }

    private void initializeMap() {

        FragmentManager fm = getChildFragmentManager();
        fragment = (SupportMapFragment) fm.findFragmentById(R.id.ll_mapcontainer);
        if (fragment == null) {
            fragment = SupportMapFragment.newInstance();
            fm.beginTransaction().replace(R.id.ll_mapcontainer, fragment).commit();
        }

    }
    @Override
    public void onResume() {
        super.onResume();
        if (map == null) {
            map = fragment.getMap();
            map.addMarker(new MarkerOptions().position(PRACTICAL_ANSWER_LOCATION));
        }
    }   
}

This works for me. Enjoy !!!