5-5-1 JSON 이해하기 / 5-5-1 Gson 사용하기

MainActivity

package com.example.boostcoursepractice;
 
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
 
import com.android.volley.AuthFailureError;
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.StringRequest;
import com.android.volley.toolbox.Volley;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.snackbar.Snackbar;
 
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
 
import androidx.annotation.NonNull;
import androidx.core.view.GravityCompat;
import androidx.appcompat.app.ActionBarDrawerToggle;
 
import android.view.MenuItem;
 
import com.google.android.material.navigation.NavigationView;
import com.google.gson.Gson;
 
import androidx.drawerlayout.widget.DrawerLayout;
 
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.fragment.app.Fragment;
 
import android.view.Menu;
import android.widget.Button;
import android.widget.EditText;
import android.widget.FrameLayout;
import android.widget.TextView;
import android.widget.Toast;
 
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.HttpURLConnection;
import java.net.Socket;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
 
public class MainActivity extends AppCompatActivity {
 
    TextView textView;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        textView = (TextView) findViewById(R.id.textView);
        Button button = (Button) findViewById(R.id.button);
 
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                sendRequest();
            }
        });
 
        if(AppHelper.requestQueue == null) AppHelper.requestQueue = Volley.newRequestQueue(getApplicationContext());
 
    }
 
    public void sendRequest()
    {
        //String url = "http://www.google.co.kr";
        String url = "http://www.kobis.or.kr/kobisopenapi/webservice/rest/boxoffice/searchDailyBoxOfficeList.json?key=430156241533f1d058c603178cc3ca0e&targetDt=20120101";
        StringRequest request = new StringRequest(
                Request.Method.GET,
                url,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        //println("응답 -> " + response);
 
                        processResponse(response) ;
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        println("에러 -> " + error.getMessage());
                    }
                }
        ){
            @Override
            protected Map<String, String> getParams() throws AuthFailureError {////Post방식으로 파라미터를 전달해주고싶을 때
                Map<String, String> params = new HashMap<String, String>() ;
 
                return params ;
            }
        };
 
        request.setShouldCache(false);
        AppHelper.requestQueue.add(request);
        println("응답 보냄");
    }
 
    public void processResponse(String response)
    {
        Gson gson = new Gson();
        MovieList movieList = gson.fromJson(response, MovieList.class) ;
 
        if(movieList != null)
        {
            int cnt = movieList.boxOfficeResult.dailyBoxOfficeList.size();
            for(int i=0; i<cnt ; i++)
            {
                println(movieList.boxOfficeResult.dailyBoxOfficeList.get(i).movieNm);
            }
        }
    }
 
 
    public void println(String data) {
        textView.append(data + "\n");
    }
 
}

 

AppHelper

package com.example.boostcoursepractice;
 
import com.android.volley.RequestQueue;
 
public class AppHelper
{
    public static RequestQueue requestQueue;
 
}
 

 

MovieList

package com.example.boostcoursepractice;
 
public class MovieList {
    MovieListResult boxOfficeResult ;
}
 

 

MovieListResutlt

package com.example.boostcoursepractice;
 
import java.util.ArrayList;
 
public class MovieListResult {
    String boxofficeType ;
    String showRange;
 
    ArrayList<Movie> dailyBoxOfficeList = new ArrayList<Movie>();
}
 

 

Movie

package com.example.boostcoursepractice;
 
public class Movie {
    String rnum;
    String rank;
    String rankInten;
    String rankOldAndNew;
    String movieCd;
    String movieNm;
    String openD;
    String salesAmt;
    String salesShare;
    String salesInten;
    String salesChange;
    String salesAcc;
    String audiCnt;
    String audiInten;
    String audiChange;
    String audiAcc;
    String scrnCnt;
    String showCnt;
}
 

 

activity_main_xml

<?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:layout_height="match_parent"
    android:orientation="vertical">
 
    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="요청하기" />
 
    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/holo_orange_light">
 
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">
 
            <TextView
                android:id="@+id/textView"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textSize="18dp" />
        </LinearLayout>
    </ScrollView>
 
</LinearLayout>
 

 

우선 JSON 형식을 자바의 객체로 만들기 위해서는 GSON이라는 외부라이브러리를 써야 한다. 그러기 위하여 gradle에 implementation 'com.google.code.gson:gson:2.8.2' 을 추가해야만 한다. 이렇게 하고 우선 JSON형식에 맞게 클래스를 만들어 주어야한다. 여기서는 영화진흥위원회의 예제 JSON을 썼고 그에 맞게 MovieList, MovieListResult, Movie 이렇게 3개의 클래스를 만들어 주었다. 마지막으로 아래의 코드처럼

 

Gson gson = new Gson();

        MovieList movieList = gson.fromJson(response, MovieList.class) ;

 

이렇게 해주면 우리가 만든 클래스에 gson을 이용하여 json데이터를 객체로 만들어 준다. 그것을 이용하면 된다.

 

 

 

결과화면