MainActivity

package com.example.contextprovider;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.text.TextUtils;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        List<String> contactsList = new ArrayList<String>();
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        List<String> list = new ArrayList<String>();
        Cursor cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null, null);
        String phoneNumber;
        String phoneName;
        //while(cursor.moveToNext()){}这两种遍历方式一样
        for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {
            String displayName = cursor.getString(cursor.getColumnIndex(
                    ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
            String number = cursor.getString(cursor.getColumnIndex(
                    ContactsContract.CommonDataKinds.Phone.NUMBER));

            System.out.println("phoneNumber:" + number + "phoneName:" + displayName);
            contactsList.add(displayName + "\n" + number);


            ListView listview = (ListView) findViewById(R.id.lst1);
            ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, contactsList);
            listview.setAdapter(adapter);

        }

    }


}