为什么读不出数据

import android.app.Activity;
import android.content.ContentResolver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.Contacts;
import android.provider.Contacts.PeopleColumns;
import android.util.Log;public class query extends Activity {
    /** Called when the activity is first created. */    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        query1();
     }
    
private void query1() {
         ContentResolver cr=getContentResolver();
         Uri uri=Contacts.People.CONTENT_URI;
         String[] projection= {Contacts.PeopleColumns.NAME,
         Contacts.PeopleColumns.NOTES 
         };
         String selection=Contacts.PeopleColumns.NAME+ "=?";
         String[] selectionArgs={"Amaker"};
         String sortOrder=Contacts.PeopleColumns.NAME;
         Cursor c=cr.query(uri,projection,selection,selectionArgs,sortOrder);
        
         if(c.moveToFirst()){
         for(int i=0;i<c.getCount();i++){
         c.moveToPosition(i);
         int idx=c.getColumnIndexOrThrow(PeopleColumns.NAME);
         Log.i("Text",c.getString(idx));
         }
         }
      
    }
}