XML : Can't see the map from the HelloWorld example ArcGIS android SDK

I tried the Hello World code from ArcGIS android SDK and followed all the steps but the map doesn't appear and instead I get a black mapview.

Here is the java code :

  package com.example.user.arcgismap;    import android.app.Activity;  import android.os.Bundle;  import com.esri.android.map.MapView;    public class MainActivity extends Activity {  MapView mMapView;    // Called when the activity is first created.  @Override  public void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      setContentView(R.layout.content_main);        // After the content of this Activity is set, the map can be accessed programmatically from the layout.      mMapView = (MapView) findViewById(R.id.map);  }    @Override  protected void onPause() {      super.onPause();        // Call MapView.pause to suspend map rendering while the activity is paused, which can save battery usage.      if (mMapView != null)      {          mMapView.pause();      }  }    @Override  protected void onResume() {      super.onResume();        // Call MapView.unpause to resume map rendering when the activity returns to the foreground.      if (mMapView != null)      {          mMapView.unpause();      }  }  }     

and here is the xml layout :

  <?xml version="1.0" encoding="utf-8"?>  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:app="http://schemas.android.com/apk/res-auto"  xmlns:tools="http://schemas.android.com/tools"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:paddingBottom="@dimen/activity_vertical_margin"  android:paddingLeft="@dimen/activity_horizontal_margin"  android:paddingRight="@dimen/activity_horizontal_margin"  android:paddingTop="@dimen/activity_vertical_margin"  app:layout_behavior="@string/appbar_scrolling_view_behavior"  tools:context="com.example.user.arcgismap.MainActivity"  tools:showIn="@layout/activity_main">    <com.esri.android.map.MapView  android:id="@+id/map"  android:layout_width="fill_parent"  android:layout_height="fill_parent"  mapoptions.MapType="streets"  mapoptions.center="34.056215, -117.195668,"  mapoptions.ZoomLevel="16">  </com.esri.android.map.MapView>  </RelativeLayout>    

can anyone help, what am I doing wrong ?