如何打印整个 JSON 输出？

Question

请看下面的代码

package com.example.jsontest;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

    private EditText editText;

/** Called when the activity is first created. */

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    StrictMode.ThreadPolicy policy = new StrictMode.
    ThreadPolicy.Builder().permitAll().build();
    StrictMode.setThreadPolicy(policy); 

    setContentView(R.layout.activity_main);

    editText = (EditText)findViewById(R.id.edit_text);

    //Call The JSon
    try {
        JSONObject jObject = new JSONObject(getJson());


        int code = jObject.getInt("code");

        editText.append("Code: "+code+"\n");

    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace(); 
    }

  }

  private String getJson()
  {
      DefaultHttpClient   httpclient = new DefaultHttpClient();
      HttpPost httppost = new HttpPost("https://bigml.io/andromeda/source/5277b1bd035d074e940056e0?username=xxx;api_key=xxxxxxxxxxxxxxx");
      // Depends on your web service
      httppost.setHeader("Content-type", "application/json");

      InputStream inputStream = null;
      String result = null;
      try {
          HttpResponse response = httpclient.execute(httppost);           
          HttpEntity entity = response.getEntity();

          inputStream = entity.getContent();
          // json is UTF-8 by default
          BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"), 8);
          StringBuilder sb = new StringBuilder();

          String line = null;
          while ((line = reader.readLine()) != null)
          {
              sb.append(line + "\n");
          }
          result = sb.toString();
      } catch (Exception e) { 
          // Oops
      }
      finally {
          try{if(inputStream != null)inputStream.close();}catch(Exception squish){}
      }

      return result;
  }
} 

在这里，我需要做的是，打印我检索到的“整个”结果。我希望打印整个东西，我不需要单独的值。我怎样才能做到这一点？ Here 是 BigML 检索文档的链接。

Answer 1

只需使用JSONObject.toString() 吗？

Answer 2

你不应该在主线程上连接到网络。最好和最简单的选择是使用AsyncTask<...>。

类似这样的：

private class DownloadProductsTask extends AsyncTask<Void, Void, String> {

    @Override
    protected String doInBackground(Void... params) {
        try {
            return new PublicDataDBManager().retriveJsonData(mCode, mUserMail);
        } catch (Exception e) {
        }
        return null;
    }

    @Override
    protected void onPostExecute(String result){
        buildData(result);// here you update mathod in your main thread
    }
}

这是一个简单的例子：http://androide-examples.blogspot.com/2013/11/android-retrieve-json-data-from-url.html

Answer 3

所以我运行了你的代码，但它崩溃了。我还看到您在主线程中绕过安全性并在onCreate 中执行网络操作。这在 Android 中不是一个好主意。网络操作应该在后台线程中进行。

我很快重构了它以使用一个线程并且它起作用了。代码如下：

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    editText = (EditText)findViewById(R.id.edit_text);
  }

  @Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();

    new Thread(new Runnable() {

        @Override
        public void run() {
            JSONObject jObject;
            try {
                jObject = new JSONObject(getJson());
                // I am logging the raw value that was returned here
                Log.i("JSON Body", jObject.toString());
                int code = jObject.getInt("code");
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    }).start();
}

如果您想更新线程内的主线程 (MainActivity)，请创建一个 Handler 并将对它的引用传递到线程中，并将其用于更新。