andriod 读取通讯录

package com.example.yanlei.wifi;

import android.content.ContentResolver;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.provider.ContactsContract.PhoneLookup;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private ListView lvContacts=null;
    private Cursor cursor=null;
    private Button btnRead=null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        TextView tv = new TextView(this);
        String str = "";
// 得到contentresolver对象
        ContentResolver cr = getContentResolver();
// 取得电话本中开始一项的光标，必须先moveToNext()
        Cursor cursor = cr.query(ContactsContract.Contacts.CONTENT_URI, null,
                null, null, null);
        while (cursor.moveToNext())
        {
//取得联系人的名字索引
            int nameIndex = cursor.getColumnIndex(PhoneLookup.DISPLAY_NAME);
            String contact = cursor.getString(nameIndex);
            str += (contact + ":" + "\n");
//取得联系人的ID索引值
            String contactId = cursor.getString(cursor
                    .getColumnIndex(ContactsContract.Contacts._ID));
            Cursor phone = cr.query(
                    ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,
                    ContactsContract.CommonDataKinds.Phone.CONTACT_ID + "="
                            + contactId, null, null);

//一个人可能有几个号码
            while (phone.moveToNext())
            {
                String strPhoneNumber = phone
                        .getString(phone
                                .getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                str += (strPhoneNumber + "\n");
                Log.i("TAG","phoneNumber:"+strPhoneNumber+"contact"+contact);
            }
            phone.close();
        }
        cursor.close();
        tv.setText(str);
        setContentView(tv);

    }

}