获得联系人显示于ListView中，并实现单击联系人拨号

import android.app.Activity;
import android.app.PendingIntent;
import android.content.ContentUris;
import android.content.Intent;
import android.database.Cursor;
import android.database.CursorWrapper;
import android.graphics.Color;
import android.net.Uri;
import android.os.Bundle;
import android.provider.Contacts.People;
import android.telephony.PhoneNumberUtils;
import android.telephony.gsm.SmsManager;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.LinearLayout;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.Toast;

public class App extends Activity {
 private static final String TAG="App";
 ListView listView;
 ListAdapter adapter; //声明一个适配器名称
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
       // setContentView(R.layout.main);
        LinearLayout linearLayout=new LinearLayout(this);//实例化linearLayout，获得其对象
        linearLayout.setOrientation(LinearLayout.VERTICAL);//设置布局方式，这里面是垂直分布
        linearLayout.setBackgroundColor(Color.BLACK);//设置背景颜色
        LinearLayout.LayoutParams param  =
        new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT);//配置layout的长和宽  链接显示LayoutParams的用法
        
        listView=new ListView(this);
        listView.setBackgroundColor(Color.BLACK);
        
        linearLayout.addView(listView,param);//动态添加View
        
        this.setContentView(linearLayout);
        
        //从数据库获取联系人姓名和电话号码
        Cursor cur=this.getContentResolver().query(People.CONTENT_URI,null, null,null,null);
        adapter=new SimpleCursorAdapter(this,android.R.layout.simple_list_item_2,cur,new String[]{People.NAME,People.NUMBER},new int[]{android.R.id.text1,android.R.id.text2});
        //SimpleCursorAdapter(Context context, int layout, Cursor c, String[] from, int[] to) 构造函数参数
        this.startManagingCursor(cur);
        listView.setAdapter(adapter);
        //listView.setEmptyView(findViewById(R.id.empty));
        
        listView.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener(){
   public void onItemSelected(AdapterView<?> arg0, View arg1,
     int arg2, long arg3) {
    // TODO Auto-generated method stub
    //openToast("滚动到："+arg0.getSelectedItemId());
    //短信发送
    // PendingIntent pi = PendingIntent.getActivity(App.this,0,new Intent(App.this,App.class),0);
    // SmsManager sms = SmsManager.getDefault();  
   //  sms.sendTextMessage("5554", null, "message", pi, null); 
   }
   public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub
    
   }
         
        });
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener(){
   public void onItemClick(AdapterView<?> arg0, View arg1, int position,
     long arg3) {
    // TODO Auto-generated method stub
//    String[] names=((CursorWrapper)listView.getItemAtPosition(position)).getColumnNames();
    //从指针的封装类中获得选中项的电话号码并拨号
    CursorWrapper wrapper=(CursorWrapper)listView.getItemAtPosition(position);//返回值是Object类需要向下转型成CursorWrapper类型
    int columnIndex=wrapper.getColumnIndex(People.NUMBER);//返回从0开始的索引，如果列名不存在将返回-1
    if(!wrapper.isNull(columnIndex)){
     String number=wrapper.getString(columnIndex);
     Log.d(TAG,"number="+number);
 //    //判断电话号码的有效性
     if(PhoneNumberUtils.isGlobalPhoneNumber(number)){
      Intent intent = new Intent(Intent.ACTION_DIAL,Uri.parse("tel://"+ number));
      startActivity(intent);
     }
    }
   }
        });
    }
    private void openToast(String str){
     Toast.makeText(this,str,Toast.LENGTH_SHORT).show();
    }
}