How can I parse a local JSON file from assets folder into a ListView

Question

I m currently developing a physics app that is supposed to show a list of formulas and even solve some of them  the only problem is the ListView   This is my main layout       lt LinearLayout xmlns android  http   schemas android com apk res android      xmlns tools  http   schemas android com tools      android layout width  fill parent      android layout height  wrap content      android measureWithLargestChild  false      android orientation  vertical      tools context   CatList   gt         lt RelativeLayout         android layout width  match parent          android layout height  wrap content          android background   drawable titlebar   gt            lt TextView             android id    id Title1              android layout width  wrap content              android layout height  wrap content              android layout centerHorizontal  true              android layout centerVertical  true              android text   string app name              android textAppearance   android attr textAppearanceLarge              android textColor   ff1c00              android textIsSelectable  false    gt        lt  RelativeLayout gt        lt ListView         android id    id listFormulas          android layout width  match parent          android layout height  wrap content   gt        lt  ListView gt    lt  LinearLayout gt    And this is my main activity  package com wildsushii quickphysics   import java io IOException  import java io InputStream  import java util ArrayList  import java util HashMap   import org json JSONException  import org json JSONObject   import android os Bundle  import android app Activity  import android content Context  import android content res AssetManager  import android view Menu  import android widget ListView   public class CatList extends Activity          public static String AssetJSONFile  String filename  Context context  throws IOException           AssetManager manager   context getAssets            InputStream file   manager open filename           byte   formArray   new byte file available             file read formArray           file close             return new String formArray                Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity cat list           ListView categoriesL    ListView findViewById R id listFormulas            ArrayList lt HashMap lt String  String gt  gt  formList   new ArrayList lt HashMap lt String  String gt  gt             Context context   null          try               String jsonLocation   AssetJSONFile  formules json   context               JSONObject formArray    new JSONObject    getJSONObject  formules                String formule   formArray getString  formule                String url   formArray getString  url              catch  IOException e                e printStackTrace              catch  JSONException e                e printStackTrace                         My problem is here                Override     public boolean onCreateOptionsMenu Menu menu               Inflate the menu  this adds items to the action bar if it is present          getMenuInflater   inflate R menu cat list  menu           return true            I actually know I can make this without using JSON but I need more practice parsing JSON  By the way  this is the JSON             formules                  formule    Linear Motion          url    qp1                      formule    Constant Acceleration Motion          url    qp2                      formule    Projectile Motion          url    qp3                      formule    Force          url    qp4                      formule    Work  Power  Energy          url    qp5                      formule    Rotary Motion          url    qp6                      formule    Harmonic Motion          url    qp7                      formule    Gravity          url    qp8                      formule    Lateral and Longitudinal Waves          url    qp9                      formule    Sound Waves          url    qp10                      formule    Electrostatics          url    qp11                      formule    Direct Current          url    qp12                      formule    Magnetic Field          url    qp13                      formule    Alternating Current          url    qp14                      formule    Thermodynamics          url    qp15                      formule    Hydrogen Atom          url    qp16                      formule    Optics          url    qp17                      formule    Modern Physics          url    qp18                      formule    Hydrostatics          url    qp19                      formule    Astronomy          url    qp20                I have tried a lot of things and even delete the entire project to make a new one

User · Answer

json object node      formules        json array formules          json object         formule    Linear Motion      string        url    qp1          What you are doing    Context context   null     context is null      try           String jsonLocation   AssetJSONFile  formules json   context     So change to     try           String jsonLocation   AssetJSONFile  formules json   CatList this     To parse     I believe you get the string from the assests folder   try   String jsonLocation   AssetJSONFile  formules json   context   JSONObject jsonobject   new JSONObject jsonLocation   JSONArray jarray    JSONArray  jsonobject getJSONArray  formules    for int i 0 i lt jarray length   i      JSONObject jb   JSONObject  jarray get i   String formula   jb getString  formule    String url   jb getString  url        catch  IOException e            e printStackTrace      catch  JSONException e            e printStackTrace

User · Answer

If you are using Kotlin in android then you can create Extension function  Extension Functions are defined outside of any class - yet they reference the class name and can use this  In our case we use applicationContext  So in Utility class you can define all extension functions     Utility kt  fun Context loadJSONFromAssets fileName  String   String       return applicationContext assets open fileName  bufferedReader   use   reader - gt          reader readText               MainActivity kt  You can define private function for load JSON data from assert like this    lateinit var facilityModelList  ArrayList lt FacilityModel gt   private fun bindJSONDataInFacilityList         facilityModelList   ArrayList lt FacilityModel gt        val facilityJsonArray   JSONArray loadJSONFromAsserts  NDoH facility list json       Extension Function call here     for  i in 0 until facilityJsonArray length             val facilityModel   FacilityModel           val facilityJSONObject   facilityJsonArray getJSONObject i          facilityModel Facility   facilityJSONObject getString  Facility           facilityModel District   facilityJSONObject getString  District           facilityModel Province   facilityJSONObject getString  Province           facilityModel Subdistrict   facilityJSONObject getString  Facility           facilityModel code   facilityJSONObject getInt  code           facilityModel gps latitude   facilityJSONObject getDouble  gps latitude           facilityModel gps longitude   facilityJSONObject getDouble  gps longitude            facilityModelList add facilityModel            You have to pass facilityModelList in your ListView    FacilityModel kt  class FacilityModel  Serializable       var District  String          var Facility  String          var Province  String          var Subdistrict  String          var code  Int   0     var gps latitude  Double  0 0     var gps longitude  Double  0 0       In my case JSON response start with JSONArray             code   875933       Province    Eastern Cape        District    Amathole DM        Subdistrict    Amahlathi LM        Facility    Amabele Clinic        gps latitude   -32 6634       gps longitude   27 5239                code   455242       Province    Eastern Cape        District    Amathole DM        Subdistrict    Amahlathi LM        Facility    Burnshill Clinic        gps latitude   -32 7686       gps longitude   27 055

User · Answer

Method to read JSON file from Assets folder and return as a string object   public static String getAssetJsonData Context context                String json   null              try                   InputStream is   context getAssets   open  myJson json                    int size   is available                    byte   buffer   new byte size                   is read buffer                   is close                    json   new String buffer   UTF-8                  catch  IOException ex                    ex printStackTrace                    return null                             Log e  data   json               return json               Now for parsing data in your activity -  String data   getAssetJsonData getApplicationContext             Type type   new TypeToken lt Your Data model gt                getType       lt Your Data model gt  modelObject   new Gson   fromJson data  type

User · Answer

Just summarising  libing s answer with a sample that worked for me     val gson   Gson   val todoItem  TodoItem   gson fromJson this assets readAssetsFile  versus json    TodoItem  class java    private fun AssetManager readAssetsFile fileName   String   String   open fileName  bufferedReader   use it readText     Without this extension function the same can be achieved by using BufferedReader and InputStreamReader this way   val i  InputStream   this assets open  versus json   val br   BufferedReader InputStreamReader i   val todoItem  TodoItem   gson fromJson br  TodoItem  class java

User · Answer

With Kotlin have this extension function to read the file return as string   fun AssetManager readAssetsFile fileName   String   String   open fileName  bufferedReader   use it readText     Parse the output string using any JSON parser

User · Answer

Source code How to fetch Local Json from Assets folder  https   drive google com open id 1NG1amTVWPNViim caBr8eeB4zczTDK2p                 responseCode    200            responseMessage    Recode Fetch Successfully             responseTime    10 22            employeesList                                    empId    1                    empName    Keshav                    empFatherName    Mr Ramesh Chand Gera                    empSalary    9654267338                    empDesignation    Sr  Java Developer                    leaveBalance    3                    pfBalance    60 000                    pfAccountNo     12345678                                                empId    2                    empName    Ram                    empFatherName    Mr Dasrath ji                    empSalary    9999999999                    empDesignation    Sr  Java Developer                    leaveBalance    3                    pfBalance    60 000                    pfAccountNo     12345678                                                empId    3                    empName    Manisha                    empFatherName    Mr Ramesh Chand Gera                    empSalary    8826420999                    empDesignation    BusinessMan                    leaveBalance    3                    pfBalance    60 000                    pfAccountNo     12345678                                                empId    4                    empName    Happy                    empFatherName    Mr Ramesh Chand Gera                    empSalary    9582401701                    empDesignation    Two Wheeler                    leaveBalance    3                    pfBalance    60 000                    pfAccountNo     12345678                                                empId    5                    empName    Ritu                    empFatherName    Mr Keshav Gera                    empSalary    8888888888                    empDesignation    Sararat Vibhag                    leaveBalance    3                    pfBalance    60 000                    pfAccountNo     12345678                                    Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity employee             emp recycler view    RecyclerView  findViewById R id emp recycler view            emp recycler view setLayoutManager new LinearLayoutManager EmployeeActivity this           LinearLayoutManager VERTICAL  false            emp recycler view setItemAnimator new DefaultItemAnimator              employeeAdapter   new EmployeeAdapter EmployeeActivity this   employeeModelArrayList            emp recycler view setAdapter employeeAdapter            getJsonFileFromLocally                 public String loadJSONFromAsset             String json   null          try               InputStream is   EmployeeActivity this getAssets   open  employees json            TODO Json File  name from assets folder             int size   is available                byte   buffer   new byte size               is read buffer               is close                json   new String buffer   UTF-8              catch  IOException ex                ex printStackTrace                return null                    return json             private void getJsonFileFromLocally             try                JSONObject jsonObject   new JSONObject loadJSONFromAsset                 String responseCode   jsonObject getString  responseCode                String responseMessage   jsonObject getString  responseMessage                String responseTime   jsonObject getString  responseTime                 Log e  keshav    responseCode -- gt     responseCode               Log e  keshav    responseMessage -- gt     responseMessage               Log e  keshav    responseTime -- gt     responseTime                 if responseCode equals  200                   else                  Toast makeText this   No Receord Found    Toast LENGTH SHORT  show                               JSONArray jsonArray   jsonObject getJSONArray  employeesList                       TODO pass array object name             Log e  keshav    m jArry -- gt     jsonArray length                   for  int i   0  i  lt  jsonArray length    i                                  EmployeeModel employeeModel   new EmployeeModel                     JSONObject jsonObjectEmployee   jsonArray getJSONObject i                     String empId   jsonObjectEmployee getString  empId                    String empName   jsonObjectEmployee getString  empName                    String empDesignation   jsonObjectEmployee getString  empDesignation                    String empSalary   jsonObjectEmployee getString  empSalary                    String empFatherName   jsonObjectEmployee getString  empFatherName                     employeeModel setEmpId    empId                   employeeModel setEmpName    empName                   employeeModel setEmpDesignation    empDesignation                   employeeModel setEmpSalary    empSalary                   employeeModel setEmpFatherNamer    empFatherName                    employeeModelArrayList add employeeModel                           for              if employeeModelArrayList  null                    employeeAdapter dataChanged employeeModelArrayList                           catch  JSONException e                e printStackTrace

User · Answer

Using OKIO public static String readJsonFromAssets Context context  String filePath                 try               InputStream input   context getAssets   open filePath               BufferedSource source   Okio buffer Okio source input                return source readByteString   string Charset forName  quot utf-8 quot               catch  IOException e                e printStackTrace                           return null     and then    String data   readJsonFromAssets context   quot json some json quot      here is my file inside the folder assets json some json  Type reviewType   new TypeToken lt List lt Object gt  gt       getType     if  data    null        Object object   new Gson   fromJson data  reviewType

User · Answer

As Faizan describes in their answer here   First of all read the Json  File from your assests file using below code   and then you can simply read this string return by this function as  public String loadJSONFromAsset         String json   null      try           InputStream is   getActivity   getAssets   open  yourfilename json            int size   is available            byte   buffer   new byte size           is read buffer           is close            json   new String buffer   UTF-8          catch  IOException ex            ex printStackTrace            return null            return json      and use this method like that      try           JSONObject obj   new JSONObject loadJSONFromAsset             JSONArray m jArry   obj getJSONArray  formules            ArrayList lt HashMap lt String  String gt  gt  formList   new ArrayList lt HashMap lt String  String gt  gt             HashMap lt String  String gt  m li           for  int i   0  i  lt  m jArry length    i                  JSONObject jo inside   m jArry getJSONObject i               Log d  Details-- gt    jo inside getString  formule                 String formula value   jo inside getString  formule                String url value   jo inside getString  url                   Add your values in your  ArrayList  as below              m li   new HashMap lt String  String gt                 m li put  formule   formula value               m li put  url   url value                formList add m li                   catch  JSONException e            e printStackTrace            For further details regarding JSON Read HERE

[java] How can I parse a local JSON file from assets folder into a ListView?

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