Generate and use Json data instances in Android

1. Production of Json

package com.example.usingjson2;  

  

import org.json.JSONException;  

import org.json.JSONObject;  

  

import android.os.Bundle;  

import android.app.Activity;  

  

public class MainActivity extends Activity {  

  

    @Override  

    protected void onCreate(Bundle savedInstanceState) {  

        super.onCreate(savedInstanceState);  

        setContentView(R.layout.activity_main);  

          

        System.out.println("\"Hello World\"");  

        JSONObject object = new JSONObject();  

          

        try {  

            object.put("one", "yu");  

            object.put("two", "xi");  

            object.put("three", "kuo");  

            object.put("four", "hi");  

            System.out.println(object);  

              

        } catch (JSONException e) {  

            // TODO Auto-generated catch block  

            e.printStackTrace();  

        }  

          

    }  

}

2. Use of Json

(1) First create a new class in the current package

package com.example.useingjson;
public class Data {

 

 public static final String jsonStr = "{'arr':[1,2,3,4],'dat':[yu,xi,kuo]}";

}

(2) Called in Activity

package com.example.useingjson;
import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;
import android.os.Bundle;

import android.app.Activity;
public class MainActivity extends Activity {
 @Override

 protected void onCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

  setContentView(R.layout.activity_main);

  

  System.out.println(Data.jsonStr);

  

  try {

   JSONObject jsonObject = new JSONObject(Data.jsonStr);

   JSONArray jsonArray = jsonObject.getJSONArray("arr");

   System.out.println(jsonArray);

   

   for(int i = 0; i < jsonArray.length(); i++)

   {

    System.out.println(jsonArray.get(i));

   }

   

   JSONArray jsonArray2 = jsonObject.getJSONArray("dat");

   System.out.println(jsonArray2);

   for(int j = 0; j < jsonArray2.length(); j++)

   {

    System.out.println(jsonArray2.get(j));

   }

   

  } catch (JSONException e) {

   // TODO Auto-generated catch block

   e.printStackTrace();

  } 

 }

}

3, pay attention to

The production and use of Json are two projects respectively. As I am new to Android, the code is relatively simple and the emphasis is on understanding the principle.