Removing Markers in android

问题:

I have a Global array Object like Marker marker_array[]; and later in Layout click I initialized it as marker_array = new Marker[8];. I want to add markers to map on that layout and remove on 2nd click so I created clickcount Global variable with zero value.

My proper code is here

final RelativeLayout layout = (RelativeLayout) findViewById(R.id.track_div);

        layout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                clickcount++;

                 point_new = new LatLng[8];
                point_new[0] = new LatLng(31.5301843, 74.3207487);
                point_new[1] = new LatLng(31.5214693,74.3236027);
                point_new[2] = new LatLng(31.5194393, 74.3257327);
                point_new[3] = new LatLng(31.4942166, 74.3004533);
                point_new[4] = new LatLng(31.4864646, 74.2911203);
                point_new[5] = new LatLng(31.4803596, 74.2787933);
                point_new[6] = new LatLng(31.4764716, 74.2638203);
                point_new[7] = new LatLng(31.4775236, 74.2628873);

//  initialize marker_array;
                marker_array = new Marker[8];

                Toast.makeText(getApplicationContext(), "count "+clickcount, Toast.LENGTH_SHORT).show();
//
                if (clickcount % 2 == 0) {
                    polyline.setVisible(false);


                    for (int i = 0; i < point_new.length; i++){

                        Toast.makeText(getApplicationContext(), "marker length ="+marker_array.length, Toast.LENGTH_SHORT).show();

                        marker_array[i].remove();

//                     marker_array.setVisible(false);

                    }
                } else {
                    polyline.setVisible(true);

 for (int i = 0; i < point_new.length; i++) {
                     //   marker_array = new Marker[point_new.length];
                    MarkerOptions markerOptions = new MarkerOptions()
                            .position(point_new[i]);

                         marker_array[i] = mMap.addMarker(markerOptions);
                        marker_array[i].setTitle("Points");
                    marker_array[i].setSnippet("Distance = 9.6 km, Time = 20 minute/s");
                    marker_array[i].setIcon(BitmapDescriptorFactory.fromResource(R.drawable.bus));


                    }
                }

The problem is that it creates all 8 markers But does not remove, Even if in if condition where I'm trying to remove markers Toast shows proper length 8. Butt when I remove any of the marker_array separately as marker_array[7] it removes it.

How can I remove all the markers in marker_array without map.clear(); method because I have some other things like polyline etc that I do not want to remove.

Any effort will be appreciated.

回答1:

Use this to add markers

As Global

List<Marker> mMarkers = new ArrayList<Marker>();

And In your for loop add markers to this list like

for (int i = 0; i < point_new.length; i++) {

                        MarkerOptions markerOptions = new MarkerOptions();

                            markerOptions.position(point_new[i]);

                        Marker marker = mMap.addMarker(markerOptions);
                               marker.setTitle("Point");
                        marker.setSnippet("this is snippet");
                        marker.setIcon(BitmapDescriptorFactory.fromResource(R.drawable.p));

                        mMarkers.add(marker); // <-- Like this
}

And to remove markers

private void removeMarkers() {
        for (Marker marker: mMarkers) {
            marker.remove();
        }
        mMarkers.clear();

    }

hope it will help.

回答2:

Try this,

private ArrayList<Marker> mMarkers;
...
private void removeMarkers() {
    for (Marker marker: mMarkers) {
          marker.remove();
     }
mMarkers.clear();

}

回答3:

The method signature for addMarker is:

public final Marker addMarker (MarkerOptions options)

So when you add a marker to a GoogleMap by specifying the options for the marker, you should save the Marker object that is returned (instead of the MarkerOptions object that you used to create it). This object allows you to change the marker state later on. When you are finished with the marker, you can call Marker.remove() to remove it from the map.

As an aside, if you only want to hide it temporarily, you can toggle the visibility of the marker by calling Marker.setVisible(boolean).

Similar to Remove a marker from a GoogleMap