android 获取手机中的联系人

import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.provider.ContactsContract.PhoneLookup;
import android.util.Log;

public class ContactsActivity extends Activity {
    private static final String TAG = "ContactsActivity";
	/** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Cursor c = null;
        c = getContentResolver().query(ContactsContract.Contacts.CONTENT_URI, 
        		null, null, null, null);
        StringBuilder sb = new StringBuilder("所有联系人:").append("\n");
        while(c.moveToNext()){
        	int index = c.getColumnIndex(PhoneLookup.DISPLAY_NAME);
        	String name = c.getString(index);
        	sb.append("name="+name);
        	String id = c.getString(c.getColumnIndex(ContactsContract.Contacts._ID));
        	Cursor phone = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
        			null, ContactsContract.CommonDataKinds.Phone.CONTACT_ID+" = "+id, null,null);
        	sb.append("phone number:\n");
        	while(phone.moveToNext()){
        		String number = phone.getString(phone.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
        		sb.append(number).append("\n");
        	}
        	phone.close();
        	
        }
        c.close();
        
        Log.i(TAG,sb.toString());
        setContentView(R.layout.main);
        
    }
    
}