关于android gps获取当前位置问题，希望高手帮忙

悬赏园豆：20 [待解决问题]

话就不多说了，直接上代码吧，希望高手帮忙

import android.app.Activity;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        String serviceString = Context.LOCATION_SERVICE;
        LocationManager locationManager = (LocationManager)getSystemService(serviceString);
           String provider = LocationManager.GPS_PROVIDER;
           Location location = locationManager.getLastKnownLocation(provider);
           getLocationInfo(location);
           locationManager.requestLocationUpdates(provider, 2000, 0, locationListener);
       }
       
       private void getLocationInfo(Location location){
           String latLongInfo;
           TextView locationText = (TextView)findViewById(R.id.tv1);
           if (location != null){
               double lat = location.getLatitude();
               double lng = location.getLongitude();
               latLongInfo = "Lat: " + lat + "\nLong: " + lng;
           }
           else{
               latLongInfo = "No location found";
           }
           locationText.setText("Your Current Position is:\n" + latLongInfo);
       }
    
       private final LocationListener locationListener = new LocationListener(){
           @Override
           
           public void onLocationChanged(Location location) {
               getLocationInfo(location);
           }

           @Override
           public void onProviderDisabled(String provider) {
               // TODO Auto-generated method stub
               
           }

           @Override
           public void onProviderEnabled(String provider) {
               // TODO Auto-generated method stub
               
           }

           @Override
           public void onStatusChanged(String provider, int status, Bundle extras) {
               // TODO Auto-generated method stub
               
           }


   };
       
   }

下面是main.xml中的内容

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    android:id="@+id/tv1"
    />
</LinearLayout>

下面是AndroidManifest.xml中的代码

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="android.bzu.hzp"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="3" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".MainActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
   <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    </application>
</manifest>