SQLiteDatabase 数据库 （第六章内容）

ContentResolver的基本用法

读取系统联系人

import android.Manifest;

import android.annotation.TargetApi;

import android.content.pm.PackageManager;

import android.database.Cursor;

import android.os.Build;

import android.os.Bundle;

import android.provider.ContactsContract;

import android.support.annotation.NonNull;

import android.support.v4.app.ActivityCompat;

import android.support.v4.content.ContextCompat;

import android.support.v7.app.AppCompatActivity;

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 SystemContactActivityextends AppCompatActivity {

ArrayAdapteradapter;

    ListcontactsList =new ArrayList<>();

    @Override

    protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_system_contact);

        ListView contactsView = findViewById(R.id.lv_contact);

        adapter =new ArrayAdapter(this, android.R.layout.simple_list_item_1, contactsList);

        contactsView.setAdapter(adapter);

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) {

ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_CONTACTS}, 1000);

        }else {

readContact();

        }

}

@TargetApi(Build.VERSION_CODES.O)

private void readContact() {

Cursor cursor =null;

        try {

//查询联系人数据

            cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null);

            if (cursor !=null) {

while (cursor.moveToNext()) {

//获取联系人姓名

                    String displayName = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));

                    //获取联系人手机号

                    String number = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

                    contactsList.add(displayName +"\n" + number);

                    Log.e("weng", displayName +"\n" + number);

                }

adapter.notifyDataSetChanged();

            }else {

Toast.makeText(this, "cursor为空", Toast.LENGTH_SHORT).show();

            }

}catch (Exception e) {

e.printStackTrace();

        }finally {

if (cursor !=null) {

cursor.close();

            }

}

}

@Override

    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {

super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        switch (requestCode) {

case 1000:

if (grantResults.length >0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

readContact();

                }else {

Toast.makeText(this, "You denied the permission", Toast.LENGTH_SHORT).show();

                }

break;

        }

}

}