Android之JSON解析

编写项目，包含一个Activity。Activity页面效果如下图所示。点击按钮“解析文件1”后解析Json文件json_single并将结果显示在红色框体中，点击按钮“解析文件2”后解析Json文件json_multiple并将结果显示在红色框体中（有多条数据，建议使用列表控件ListView进行信息展示）。

 先写xml布局文件

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

    <Button
        android:id="@+id/button50"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"

        android:text="解析文件1" />
    <Button
        android:id="@+id/button51"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="解析文件2" />
    <ListView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/LS"/>
</LinearLayout>

将我们的JSON文件导入到res的raw下，如果没有raw，右键Andrriod Resource Directory在Resource type中输入raw,ok

json_single.json :

{
    "name":"王小二",
    "age":25,
    "birthday":"1990-01-01",
    "school":"师大",
    "car":"比亚迪",
    "house":"宿舍",
}

json_multiple.json :

[{
    "name":"王小二",
    "age":25,
    "birthday":"1990-01-01",
    "school":"师大",
    "car":"比亚迪",
    "house":"宿舍",
},
{
    "name":"李三",
    "age":30,
    "birthday":"1987-04-13",
    "school":"清华",
    "car":"大众速腾",
    "house":"公寓",
},
{
    "name":"张盼盼",
    "age":17,
    "birthday":"1995-07-02",
    "school":"北大",
    "car":"宝马7系",
    "house":"别墅",
}]

思路很简单，就是读取到json文件然后解析最后显示出来。

Mainactiviyt ： 

package com.example.app;

import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;

import android.Manifest;
import android.annotation.SuppressLint;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.LayoutInflater;

import android.widget.*;
import org.json.*;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.security.Permission;
import java.security.Permissions;
import java.io.UnsupportedEncodingException;


public class MainActivity extends AppCompatActivity {

    private static String[] Json; //用来存储的数组
    private ListView LS;
    private Button B1;
    private Button B2;
    private int a = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.homework_8_2);

        B1 = (Button) findViewById(R.id.button50);
        B2 = (Button) findViewById(R.id.button51);
        LS = (ListView) findViewById(R.id.LS); //实例化按钮B1,B2,和listview
        B1.setOnClickListener(new View.OnClickListener() {//监听B1
            @Override
            public void onClick(View v) {
                //Json = new String[100];
                JsonDataToString1(); //读取json文件
            }
        });
        B2.setOnClickListener(new View.OnClickListener() {//监听B2
            @Override
            public void onClick(View v) {
                //Json = new String[100];
                a = 0; //当B2被点击，变量a就会重置为0
                JsonDataToString2(); //读取json文件
            }
        });
    }
    @SuppressLint("ResourceType")
    private void JsonDataToString1(){

        InputStreamReader inputStreamReader = null;
        String jsonData = "";
        try {
            inputStreamReader = new InputStreamReader(getResources().openRawResource(R.raw.json_single),"UTF-8");//读取
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            String line;
            StringBuilder srt = new StringBuilder();
            while((line = bufferedReader.readLine()) != null){
                srt.append(line);
            }
            inputStreamReader.close();
            bufferedReader.close();
            jsonData = srt.toString(); //以上就是读取json文件，转化成string
        }catch (UnsupportedOperationException e){
            e.printStackTrace();
        }catch (IOException e){
            e.printStackTrace();
        }

        if (jsonData != ""){
            getDataFromData1(jsonData); //进一步分析字符串，获取json内容
        }else {
            Toast.makeText(MainActivity.this,"error",Toast.LENGTH_SHORT).show();
        }
        }

        private void getDataFromData1(String jsonData){
        try{

            JSONObject jsonObject = new JSONObject(jsonData);
            String name = jsonObject.getString("name");
            String age = jsonObject.getString("age");
            String birthday = jsonObject.getString("birthday");
            String school = jsonObject.getString("school");
            String car = jsonObject.getString("car");
            String house = jsonObject.getString("house"); //获取json内容
            Json = new String[]{
                    "name:"+name,"age:"+age,"birthday:"+birthday,"school:"+school,"car:"+car,"house:"+house
            };//将json内容存进数组中
            ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,R.id.LS);//新建并配置ArrayAapeter
            MyBaseAdapter mAdapter = new MyBaseAdapter();
            LS.setAdapter(mAdapter);
        }catch (JSONException e){
            e.printStackTrace();
        }
        }

    @SuppressLint("ResourceType")
    private void JsonDataToString2(){

        InputStreamReader inputStreamReader = null;
        String jsonData = "";
        try {
            inputStreamReader = new InputStreamReader(getResources().openRawResource(R.raw.json_multiple),"UTF-8");//读取
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            String line;
            StringBuilder srt = new StringBuilder();
            while((line = bufferedReader.readLine()) != null){
                srt.append(line);
            }
            inputStreamReader.close();
            bufferedReader.close();
            jsonData = srt.toString();//以上就是读取json文件，转化成string
        }catch (UnsupportedOperationException e){
            e.printStackTrace();
        }catch (IOException e){
            e.printStackTrace();
        }

        if (jsonData != ""){
            getDataFromData2(jsonData); //进一步分析字符串，获取json内容
        }else {
            Toast.makeText(MainActivity.this,"error",Toast.LENGTH_SHORT).show();
        }
    }

    private void getDataFromData2(String jsonData){
        try{
            Json = new String[100]; //这里必须初始化Json数组，否则点击完解析一后Json数组的length只有6，会因空间不足而程序崩溃
            JSONArray jsonArray = new JSONArray(jsonData);
            //String[] bbk = new String[]{};
            for (int i=0;i<jsonArray.length();i++){ //会循环三次
                JSONObject jsonObject = jsonArray.getJSONObject(i);
                String name = jsonObject.getString("name");
                String age = jsonObject.getString("age");
                String birthday = jsonObject.getString("birthday");
                String school = jsonObject.getString("school");
                String car = jsonObject.getString("car");
                String house = jsonObject.getString("house");//解析出json的内容
                Json[a] = "name:"+name;  //为了将数据循环存储进Json数组中，用了一个变量a来控制
                Json[a+1] = "age:"+age;
                Json[a+2] = "birthday:"+birthday;
                Json[a+3] = "school:"+school;
                Json[a+4] = "car:"+car;
                Json[a+5] = "house:"+house; //因为发现数据有六项且key值都一样，就正好用一个变量a来表示数组的下标
                a = a+6;  //如果a不重置为0,那么a会不停的往上加，直到超出数组下标溢出，导致程序崩溃
            }
            ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,R.id.LS);//新建并配置ArrayAapeter
            MyBaseAdapter mAdapter = new MyBaseAdapter();
            LS.setAdapter(mAdapter);
        }catch (JSONException e){
            e.printStackTrace();
        }
    }

    class MyBaseAdapter extends BaseAdapter{ //这里不解释

        @Override
        public int getCount() {
            return Json.length;
        }
        @Override
        public Object getItem(int position) {
            return null;
        }
        @Override
        public long getItemId(int position) {
            return 0;
        }
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder holder;
            if(convertView == null){
                convertView = LayoutInflater.from(getApplicationContext()).inflate(R.layout.homework_five_2,parent,false);
                holder = new ViewHolder();
                holder.mTextView = (TextView) convertView.findViewById(R.id.tv);
                convertView.setTag(holder);
            }else {
                holder = (ViewHolder) convertView.getTag();
            }
            holder.mTextView.setText(Json[position]);
            return convertView;
        }
        class ViewHolder {
            TextView mTextView;
        }
    }

}

我们的布局文件用的listview,所以我们需要再写一个布局文件提供格式

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/tv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</LinearLayout>

结果如图

最后，赶时间写出来的，写的很烂，等过几天精简一下代码，等待更新哦!