Json (제이슨) 형식의 데이터 파싱하고 어댑터를 사용하기

 

 

activity_main.xml 작성하기

 

 

 

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <Button
            android:id="@+id/btnAdd"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_centerInParent="false"
            android:layout_marginLeft="10dp"
            android:layout_marginTop="10dp"
            android:layout_marginRight="10dp"
            android:layout_marginBottom="10dp"
            android:text="직원 추가"
            android:textSize="30sp" />

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_below="@id/btnAdd" />

        <ProgressBar
            android:id="@+id/progressBar2"
            style="?android:attr/progressBarStyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/btnAdd"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="316dp"
            android:visibility="visible" />

    </RelativeLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

 

 

 

 

 

JSON 데이터를 파싱하고 RecyclerView로 표시하는 과정

 

1. JSON 데이터 수신 및 파싱 : 서버에서 JSON 형식의 데이터를 수신, 파싱 라이브러리(Gson, Jackson 등)를 사용하여 JSON 데이터를 파싱하여        Java 객체로 변환
2. 어댑터 생성 : RecyclerView.Adapter를 확장하여 커스텀 어댑터를 만들고 어댑터 내에서 ViewHolder 클래스를 정의한 후, onBindViewHolder 메서드에서 데이터를 뷰에 바인딩
3. RecyclerView 설정 : RecyclerView에 레이아웃 매니저를 설정(예: LinearLayoutManager, GridLayoutManager 등) 후 RecyclerView에 어댑터를 설정

 

 

 

Json 데이터 파싱하고, 어댑터(adapter) 사용하여 RecyclerView로 만들기

 

 

JSON 데이터 파싱하기?

= 제이슨으로 받아온 데이터를 꺼내와 사용하는 것이다.  try 안에서 코드를 입력해야 한다.

 

 

RecyclerView는 Android에서 대량의 데이터를 효율적으로 표시하기 위한 뷰이다. RecyclerView는 스크롤 시 뷰를 재사용(recycle)하여 메모리 사용량을 줄이고, 성능을 향상시킨다. 또한 다양한 레이아웃 매니저를 통해 리스트, 그리드, 스태거드 레이아웃 등을 쉽게 구현할 수 있으며 애니메이션 지원 기능이 있다.

 

 

어댑터(Adapter)는 데이터 소스(예: JSON 데이터)와 RecyclerView를 연결하는 역할을 하며 데이터 항목을 개별 뷰 홀더(ViewHolder)와 바인딩하여 각 항목을 RecyclerView에 표시한다.

 

 

 

 

 

먼저 이 데이터를,

{"status":"success","data":[{"id":1,"employee_name":"Tiger Nixon","employee_salary":320800,"employee_age":61,"profile_image":""},{"id":2,"employee_name":"Garrett Winters","employee_salary":170750,"employee_age":63,"profile_image":""},{"id":3,"employee_name":"Ashton Cox","employee_salary":86000,"employee_age":66,"profile_image":""},{"id":4,"employee_name":"Cedric Kelly","employee_salary":433060,"employee_age":22,"profile_image":""},{"id":5,"employee_name":"Airi Satou","employee_salary":162700,"employee_age":33,"profile_image":""},{"id":6,"employee_name":"Brielle Williamson","employee_salary":372000,"employee_age":61,"profile_image":""},{"id":7,"employee_name":"Herrod Chandler","employee_salary":137500,"employee_age":59,"profile_image":""},{"id":8,"employee_name":"Rhona Davidson","employee_salary":327900,"employee_age":55,"profile_image":""},{"id":9,"employee_name":"Colleen Hurst","employee_salary":205500,"employee_age":39,"profile_image":""},{"id":10,"employee_name":"Sonya Frost","employee_salary":103600,"employee_age":23,"profile_image":""},{"id":11,"employee_name":"Jena Gaines","employee_salary":90560,"employee_age":30,"profile_image":""},{"id":12,"employee_name":"Quinn Flynn","employee_salary":342000,"employee_age":22,"profile_image":""},{"id":13,"employee_name":"Charde Marshall","employee_salary":470600,"employee_age":36,"profile_image":""},{"id":14,"employee_name":"Haley Kennedy","employee_salary":313500,"employee_age":43,"profile_image":""},{"id":15,"employee_name":"Tatyana Fitzpatrick","employee_salary":385750,"employee_age":19,"profile_image":""},{"id":16,"employee_name":"Michael Silva","employee_salary":198500,"employee_age":66,"profile_image":""},{"id":17,"employee_name":"Paul Byrd","employee_salary":725000,"employee_age":64,"profile_image":""},{"id":18,"employee_name":"Gloria Little","employee_salary":237500,"employee_age":59,"profile_image":""},{"id":19,"employee_name":"Bradley Greer","employee_salary":132000,"employee_age":41,"profile_image":""},{"id":20,"employee_name":"Dai Rios","employee_salary":217500,"employee_age":35,"profile_image":""},{"id":21,"employee_name":"Jenette Caldwell","employee_salary":345000,"employee_age":30,"profile_image":""},{"id":22,"employee_name":"Yuri Berry","employee_salary":675000,"employee_age":40,"profile_image":""},{"id":23,"employee_name":"Caesar Vance","employee_salary":106450,"employee_age":21,"profile_image":""},{"id":24,"employee_name":"Doris Wilder","employee_salary":85600,"employee_age":23,"profile_image":""}],"message":"Successfully! All records has been fetched."}

 

 

 

이 창을 열어 넣은 후, copy를 눌러준다.

 

https://jsoneditoronline.org/#left=local.tusimo&right=local.qofoce

JSON Editor Online: edit JSON, format JSON, query JSON

 

 

 

 

중괄호 {} 는 object 데이터 타입이다.

대괄호 []는 array 데이터 타입이다.

 

 

 

Adapter.java 클래스

 

(EmployeeAdapter.java로 만들어주었다.)

package com.~.employee.adapter;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.~.employee.R;
import com.~.employee.model.Employer;

import java.text.DecimalFormat;
import java.util.ArrayList;

public class EmployerAdapter extends RecyclerView.Adapter<EmployerAdapter.ViewHolder> {

    Context context;
    ArrayList<Employer> employerArrayList;

    public EmployerAdapter(Context context, ArrayList<Employer> employerArrayList) {
        this.context = context;
        this.employerArrayList = employerArrayList;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.employer_row, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        Employer employer = employerArrayList.get(position);
        holder.txtName.setText(employer.name);
        holder.txtAge.setText(String.valueOf("나이 : "+employer.age+"세"));

        DecimalFormat formatter = new DecimalFormat("#,###");
        String strSalary = formatter.format(employer.salary);
        holder.txtSalary.setText(String.valueOf("연봉 : $"+strSalary));
    }

    @Override
    public int getItemCount() {
        return employerArrayList.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {

        TextView txtName;
        TextView txtAge;
        TextView txtSalary;
        ImageView imgDelete;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            txtName = itemView.findViewById(R.id.txtName);
            txtAge = itemView.findViewById(R.id.txtAge);
            txtSalary = itemView.findViewById(R.id.txtSalary);
            imgDelete = itemView.findViewById(R.id.imgDelete);
        }
    }
}

 

 

 

 

MainActivity.java 클래스 (파싱하기)

package com.~.employee;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import com.yujinoh.employee.adapter.EmployerAdapter;
import com.yujinoh.employee.model.Employer;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    Button btnAdd;
    ProgressBar progressBar;
    EmployerAdapter adapter;

    //리사이클러뷰는 관련된 멤버변수 2개 더 작성해야 한다
    RecyclerView recyclerView;
    ArrayList<Employer> employerArrayList = new ArrayList<>();


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //다음 코드는 쌍으로 무조건 같이 작성
        recyclerView = findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));

        btnAdd = findViewById(R.id.btnAdd);
        progressBar = findViewById(R.id.progressBar2);
        recyclerView = findViewById(R.id.recyclerView);

        btnAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // AddActivity를 띄운다
                Intent intent = new Intent(MainActivity.this, AddActivity.class);
                startActivity(intent);
            }
        });

        // 네트워크로부터 데이터를 받아온다
        // Volley 라이브러리를 이용한 네트워크 통신

        // 1. request queue 를 만든다
        RequestQueue queue = Volley.newRequestQueue(MainActivity.this);

        // 2. request(요청)을 만든다.
        // 데이터 타입은, 응답의 json 형식을 보고 결정한다.
        JsonObjectRequest request = new JsonObjectRequest(
                Request.Method.GET,
                "https://block1-image-test.s3.ap-northeast-2.amazonaws.com/employees.json",
                null,
                new Response.Listener<JSONObject>() {
                    @Override
                    public void onResponse(JSONObject response) {
                        // 프로그레스 바를 유저의 눈에서 사라지게 하는 코드
                        progressBar.setVisibility(View.GONE);

                        Log.i("EMPLOYEE MAIN", response.toString());

                        try {
                            String status = response.getString("status");
                            if(status.equals("success") == false){
                                Toast.makeText(MainActivity.this,
                                        "네트워크 에러",
                                        Toast.LENGTH_SHORT).show();
                                return;
                            }

                            JSONArray data = response.getJSONArray("data");

                            for(int i = 0 ; i < data.length() ; i++){
                                JSONObject row = data.getJSONObject(i);
                                int id = row.getInt("id");
                                String name = row.getString("employee_name");
                                int salary = row.getInt("employee_salary");
                                int age = row.getInt("employee_age");

                                Employer employer= new Employer(id, name, salary, age);
                                employerArrayList.add(employer);
                            }

                            // 어댑터를 만들고
                            adapter = new EmployerAdapter(MainActivity.this, employerArrayList);
                            // 리사이클러뷰에 어댑터를 적용하면 화면에 나온다
                            recyclerView.setAdapter(adapter);

                        } catch (JSONException e) {
                            Toast.makeText(MainActivity.this,
                                    "파싱 에러",
                                    Toast.LENGTH_SHORT).show();
                            return;
                        }
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        // 프로그레스 바를 유저의 눈에서 사라지게 하는 코드
                        progressBar.setVisibility(View.GONE);

                        Toast.makeText(MainActivity.this,
                                "네트워크 통신 에러",
                                Toast.LENGTH_SHORT).show();
                        Log.i("EMPLOYEE MAIN", error.toString());
                    }
                }
        );

        // 3. 네트워크로 보낸다.
        queue.add(request);

    }
}

 

 

 

Employer.java 클래스

package com.~.employee.model;

public class Employer {

    public int id;
    public String name;
    public int salary;
    public int age;

    public Employer(){

    }

    public Employer(int id, String name, int salary, int age) {
        this.id = id;
        this.name = name;
        this.salary = salary;
        this.age = age;
    }
}