安卓通过OkHttp获取json数据

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <Button
        android:id="@+id/send_request"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Send Request"
        />

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        >
        <TextView
            android:id="@+id/response_text"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            />
    </ScrollView>

</LinearLayout>

package demo.jq.com.networktest;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.io.BufferedReader;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import okhttp3.FormBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

/**
 * @author jim
 */

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    TextView responseText;


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

        Button sendRequest = (Button) findViewById(R.id.send_request);
        responseText = (TextView) findViewById(R.id.response_text);
        sendRequest.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.send_request) {
            sendRequestWithOkHttp();
        }
    }

    private void sendRequestWithOkHttp() {
        // 开启线程来发起网络请求
        new Thread(new Runnable() {
            @Override
            public void run() {
                HttpURLConnection connection = null;
                BufferedReader reader = null;
                try {
                    OkHttpClient client = new OkHttpClient();


                    // post请求
                    RequestBody requestBody = new FormBody.Builder()
                            .add("type","1")
                            .build();


                    Request request = new Request.Builder()
                            .url("http://devmg.yunlutong.com/api/test/testApi")
                            .post(requestBody)
                            .build();

                    Response response = client.newCall(request).execute();
                    String responseData = response.body().string();
                    showResponse(responseData);
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (reader != null) {
                        try {
                            reader.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }

                    if (connection != null) {
                        connection.disconnect();
                    }
                }
            }
        }).start();
    }

    private void showResponse(final String response) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                responseText.setText(response);
            }
        });

    }
}