Google地图无法使用API​​级别19

Question

我正在开发一个Android应用程序，我正在使用谷歌地图。这是我的代码：

import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.DialogInterface.OnClickListener;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.Toast;
import java.io.UnsupportedEncodingException;
import java.util.Properties;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;

public class ContactUs extends Activity 
{

     private GoogleMap googleMap;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_contact_us);

            try {
                // Loading map
                initilizeMap();

            } catch (Exception e) {
                e.printStackTrace();
            }

        }

        /**
         * function to load map. If map is not created it will create it for you
         * */
        @SuppressLint("NewApi")
        private void initilizeMap() {
            if (googleMap == null) {
                googleMap = ((MapFragment)getFragmentManager().findFragmentById(R.id.map)).getMap();

                // check if map is created successfully or not
                if (googleMap == null) {
                    Toast.makeText(getApplicationContext(),
                            "Sorry! unable to create maps", Toast.LENGTH_SHORT).show();
                }
            }
        }

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

---

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:padding="10dip"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content">

<ScrollView
    android:layout_width="wrap_content"
    android:layout_height="match_parent" >

    <LinearLayout 
         android:orientation="vertical"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content">
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dip"
        android:text="@string/address1"
        android:textStyle="bold"
        android:textSize="18sp"
        android:layout_marginBottom="5dp" />

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="5dp"
        android:layout_marginTop="5dp"
        android:text="@string/address2"
        android:textSize="12sp" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/address3" 
        android:textSize="12sp" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:textStyle="bold"
        android:text="@string/get" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:textStyle="bold"
        android:text="@string/central" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/address4" />

        </LinearLayout>  
    </ScrollView>
    <RelativeLayout 
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" >

    <fragment
        android:id="@+id/map"
        android:name="com.google.android.gms.maps.MapFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
    </RelativeLayout>
</LinearLayout>

当我运行这个应用程序时，它说不幸的是应用程序已停止。 请给我解决我出错的地方...... !!!