这个项目实现了从通讯录中获取联系人信息，也实现了将数据储存在数据库中，并对数据进行增删改查的操作

项目结构如图

 

 在进行获取通讯录信息之前要在AndroidManifest.xml文件中添加如下代码：

<uses-permission android:name="android.permission.READ_CONTACTS"/>
主活动布局如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:orientation="vertical"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <EditText
        android:id="@+id/ed_name"
        android:layout_width="match_parent"
        android:hint="姓名"
        android:layout_marginTop="25dp"
        android:layout_height="wrap_content"/>
    <EditText
        android:id="@+id/ed_phone"
        android:layout_width="match_parent"
        android:hint="电话"
        android:layout_marginTop="25dp"
        android:layout_height="wrap_content"/>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="25dp"
        android:orientation="horizontal">
        <Button
            android:id="@+id/btn_add"
            android:layout_marginRight="5dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="添加"/>
        <Button
            android:id="@+id/btn_query"
            android:layout_width="wrap_content"
            android:layout_marginRight="5dp"
            android:layout_height="wrap_content"
            android:text="查询"/>
        <Button
            android:id="@+id/btn_update"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginRight="5dp"
            android:text="修改"/>
        <Button
            android:id="@+id/btn_delete"
            android:layout_width="wrap_content"
            android:layout_marginRight="5dp"
            android:layout_height="wrap_content"
            android:text="删除"/>
    </LinearLayout>
    <Button
        android:id="@+id/btn_Contact"
        android:layout_width="wrap_content"
        android:layout_gravity="center"
        android:layout_height="wrap_content"
        android:text="获取通讯录联系人信息"/>
    <TextView
        android:id="@+id/tv_show"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>


</LinearLayout>

MainActivity.java：

package cn.itcast.tongxunludemo;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.Context;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private EditText edName;
private EditText edPhone;
private TextView tvShow;
private Button btnAdd;
private Button btnQuery;
private Button btnUpdate;
private Button btnDelete;
private Button btnContact;
MyHelper myHelper;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        edName=findViewById(R.id.ed_name);
        edPhone=findViewById(R.id.ed_phone);
        tvShow=findViewById(R.id.tv_show);
        btnAdd=findViewById(R.id.btn_add);
        btnQuery=findViewById(R.id.btn_query);
        btnUpdate=findViewById(R.id.btn_update);
        btnDelete=findViewById(R.id.btn_delete);
        btnContact=findViewById(R.id.btn_Contact);

        myHelper=new MyHelper(this);

        btnAdd.setOnClickListener((View.OnClickListener) MainActivity.this);
        btnQuery.setOnClickListener((View.OnClickListener) MainActivity.this);
        btnUpdate.setOnClickListener((View.OnClickListener) MainActivity.this);
        btnDelete.setOnClickListener((View.OnClickListener) MainActivity.this);
        btnContact.setOnClickListener((View.OnClickListener) MainActivity.this);
    }

    @Override
    public void onClick(View v) {
        String name,phone;
        SQLiteDatabase db;
        ContentValues values;
        switch (v.getId()){
            case R.id.btn_add:
                name=edName.getText().toString();
                phone=edPhone.getText().toString();
                db=myHelper.getWritableDatabase();
                String sqlSave="insert into information (name,phone) values(?,?)";
                db.execSQL(sqlSave,new String[]{name,phone});
                Toast.makeText(this,"信息已经添加",Toast.LENGTH_SHORT).show();
                db.close();
                break;
            case R.id.btn_query:
                db=myHelper.getReadableDatabase();
                Cursor cursor=db.rawQuery("select * from information",null);
                if(cursor.getCount()==0){
                    tvShow.setText("");
                    Toast.makeText(this,"没有数据",Toast.LENGTH_SHORT).show();
                }else {
                    cursor.moveToFirst();
                    tvShow.setText("Name:"+cursor.getString(1)+";Tel:"+cursor.getString(2));
                }
                while (cursor.moveToNext()){
                    tvShow.append("\n"+"Name:"+cursor.getString(1)+";Tel:"+cursor.getString(2));
                }
                cursor.close();
                db.close();
                break;
            case R.id.btn_update:
                String nerName=edName.getText().toString();
                String newPhoto=edPhone.getText().toString();
                db=myHelper.getWritableDatabase();
                String sqlUpdata="update information set phone=? where name=?";
                db.execSQL(sqlUpdata,new String[]{newPhoto,nerName});
                Toast.makeText(this,"信息已经修改",Toast.LENGTH_SHORT).show();
                db.close();
                break;
            case R.id.btn_delete:
                db=myHelper.getWritableDatabase();
                db.execSQL("delete from information");
                Toast.makeText(this,"信息已经删除",Toast.LENGTH_SHORT).show();
                tvShow.setText("");
                db.close();
                break;
            case R.id.btn_Contact:
                if(Build.VERSION.SDK_INT<23){
                    //获取联系人信息
                    getContacts();
                }else {
                    if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_CONTACTS)!= PackageManager.PERMISSION_GRANTED){
                        //发起动态权限申请
                        ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.READ_CONTACTS},1);
                    }else {
                        //获取联系人
                        getContacts();
                    }
                }
                break;
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if(requestCode==1 && permissions[0].equals(Manifest.permission.READ_CONTACTS)&& grantResults[0]==PackageManager.PERMISSION_GRANTED){
            //获取联系人信息
            getContacts();
        }else {
            Toast.makeText(MainActivity.this,"您拒绝了相关权限，无法获取联系人信息！",Toast.LENGTH_SHORT).show();
        }
    }

    private void getContacts(){
        tvShow.setText("");
        Uri uri= ContactsContract.CommonDataKinds.Phone.CONTENT_URI;
        ContentResolver resolver=getContentResolver();
        Cursor cursor=resolver.query(uri,null,null,null,null);
        if(cursor !=null){
            while (cursor.moveToNext()){
                String name=cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
                String phone=cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                tvShow.append("\n姓名："+name+".电话："+phone);
            }
        }
    }

    class MyHelper extends SQLiteOpenHelper{
        public MyHelper(Context context){
            super(context,"itcast.db",null,1);
        }
        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL("create table information(_id integer primary key autoincrement,name varchar(20),phone varchar(20))");
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        }
    }
}

这样这个项目就完成了