arcgis andriod 点击后变色

<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">

    <com.esri.android.map.MapView
        android:id="@+id/map"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        url="http://www.arcgis.com/home/webmap/viewer.html?webmap=fab9925c7c974a0aa47ea0f463535367" >
    </com.esri.android.map.MapView>
</RelativeLayout>

package yanlei.example.com.querydata;

import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.esri.android.map.GraphicsLayer;
import com.esri.android.map.MapView;
import com.esri.android.map.event.OnSingleTapListener;
import com.esri.android.map.event.OnStatusChangedListener;
import com.esri.core.geometry.Point;
import com.esri.core.geometry.SpatialReference;
import com.esri.core.map.Feature;
import com.esri.core.map.FeatureResult;
import com.esri.core.map.Graphic;
import com.esri.core.renderer.SimpleRenderer;
import com.esri.core.symbol.SimpleFillSymbol;
import com.esri.core.tasks.query.QueryParameters;
import com.esri.core.tasks.query.QueryTask;

public class MainActivity extends AppCompatActivity {

    MapView mMapView;
    GraphicsLayer graphicsLayer;
    Graphic fillGraphic;
    String queryLayer;
    boolean boolQuery = true;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mMapView = (MapView) findViewById(R.id.map);
        queryLayer = "http://services.arcgisonline.com/ArcGIS/rest/services/Demographics/USA_Average_Household_Size/MapServer/3";
        mMapView.setOnStatusChangedListener(new OnStatusChangedListener() {

            private static final long serialVersionUID = 1L;

            @Override
            public void onStatusChanged(Object source, STATUS status) {
                // TODO Auto-generated method stub
                if (source == mMapView && status == STATUS.INITIALIZED) {
                    graphicsLayer = new GraphicsLayer();
                    SimpleRenderer sr = new SimpleRenderer(
                            new SimpleFillSymbol(Color.RED));
                    graphicsLayer.setRenderer(sr);
                    mMapView.addLayer(graphicsLayer);
                }
            }
        });
        mMapView.setOnSingleTapListener(new OnSingleTapListener() {

            private static final long serialVersionUID = 1L;

            @Override
            public void onSingleTap(float x, float y) {
                // TODO Auto-generated method stub

                AsyncQueryTask ayncQuery = new AsyncQueryTask();
                ayncQuery.execute(x, y);

            }
        });
    }

    private class AsyncQueryTask extends AsyncTask<Float, Void, FeatureResult> {

        @Override
        protected FeatureResult doInBackground(Float... queryArray) {
            // TODO Auto-generated method stub
            if (queryArray == null || queryArray.length <= 1)
                return null;
            float x = queryArray[0];
            float y = queryArray[1];
            Point point = mMapView.toMapPoint(x, y);
            QueryParameters qParameters = new QueryParameters();
            SpatialReference sr = SpatialReference.create(102100);
            qParameters.setGeometry(point);
            qParameters.setOutSpatialReference(sr);
            qParameters.setReturnGeometry(true);

            QueryTask qTask = new QueryTask(queryLayer);
            try {
                FeatureResult results = qTask.execute(qParameters);
                return results;
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(FeatureResult results) {

            if (results != null) {
                for (Object element : results) {
                    if (element instanceof Feature) {
                        Feature feature = (Feature) element;
                        // turn feature into graphic
                        Graphic graphic = new Graphic(feature.getGeometry(),
                                feature.getSymbol(), feature.getAttributes());
                        // add graphic to layer
                        graphicsLayer.removeAll();
                        graphicsLayer.addGraphic(graphic);
                    }
                }
            }
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        mMapView.pause();
    }

    @Override
    protected void onResume() {
        super.onResume();
        mMapView.unpause();
    }

}