Android Java; Comment analyser un fichier JSON local du dossier assets dans un ListView
Je développe actuellement une application de physique censée afficher une liste de formules et même en résoudre certaines (le seul problème est le ListView)
Ceci est ma mise en page principale
<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" >
<RelativeLayout
Android:layout_width="match_parent"
Android:layout_height="wrap_content"
Android:background="@drawable/titlebar" >
<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" />
</RelativeLayout>
<ListView
Android:id="@+id/listFormulas"
Android:layout_width="match_parent"
Android:layout_height="wrap_content" >
</ListView>
</LinearLayout>
Et ceci est mon activité principale
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<HashMap<String, String>> formList = new ArrayList<HashMap<String, String>>();
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;
}
}
En fait, je sais que je peux le faire sans utiliser JSON, mais j'ai besoin de davantage de pratique pour analyser JSON. Au fait, c'est le 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"
}
]
}
J'ai essayé beaucoup de choses et j'ai même supprimé tout le projet pour en créer un nouveau :(
Comme décrit par Faizan dans leur réponse ici :
Tout d’abord, lisez le fichier Json de votre fichier assests en utilisant le code ci-dessous.
et alors vous pouvez simplement lire ce retour chaîne par cette fonction
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;
}
et utiliser cette méthode comme ça
try {
JSONObject obj = new JSONObject(loadJSONFromAsset());
JSONArray m_jArry = obj.getJSONArray("formules");
ArrayList<HashMap<String, String>> formList = new ArrayList<HashMap<String, String>>();
HashMap<String, String> m_li;
for (int i = 0; i < m_jArry.length(); i++) {
JSONObject jo_inside = m_jArry.getJSONObject(i);
Log.d("Details-->", 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<String, String>();
m_li.put("formule", formula_value);
m_li.put("url", url_value);
formList.add(m_li);
}
} catch (JSONException e) {
e.printStackTrace();
}
Pour plus de détails concernant JSON Lire ICI
{ // json object node
"formules": [ // json array formules
{ // json object
"formule": "Linear Motion", // string
"url": "qp1"
}
Que fais tu
Context context = null; // context is null
try {
String jsonLocation = AssetJSONFile("formules.json", context);
Alors changez pour
try {
String jsonLocation = AssetJSONFile("formules.json", CatList.this);
Analyser
Je crois que vous obtenez la chaîne du dossier assests.
try
{
String jsonLocation = AssetJSONFile("formules.json", context);
JSONObject jsonobject = new JSONObject(jsonLocation);
JSONArray jarray = (JSONArray) jsonobject.getJSONArray("formules");
for(int i=0;i<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();
}
Méthode permettant de lire le fichier JSON à partir du dossier Assets et de le renvoyer sous la forme d'un objet chaîne.
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;
}
Maintenant, pour analyser les données de votre activité: -
String data = getAssetJsonData(getApplicationContext());
Type type = new TypeToken<Your Data model>() {
}.getType();
<Your Data model> modelObject = new Gson().fromJson(data, type);
Avec Kotlin, cette fonction d’extension permet de lire le retour de fichier sous forme de chaîne.
fun AssetManager.readAssetsFile(fileName : String): String = open(fileName).bufferedReader().use{it.readText()}
Analyser la chaîne de sortie en utilisant n'importe quel analyseur JSON.
Utiliser OKIO
public static String readFileFromAssets(Context context, String fileName) {
try {
InputStream input = context.getAssets().open(fileName);
BufferedSource source = Okio.buffer(Okio.source(input));
return source.readByteString().string(Charset.forName("utf-8"));
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
puis...
String data = readFileFromAssets(context, "json/some.json"); //here is my file inside the folder assets/json/some.json
Type reviewType = new TypeToken<List<Object>>() {
}.getType();
Object object = new Gson().fromJson(data, reviewType);
Code source Comment extraire un fichier Json local du dossier Assets
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 -->" + responseCode);
Log.e("keshav", "responseMessage -->" + responseMessage);
Log.e("keshav", "responseTime -->" + 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 -->" + jsonArray.length());
for (int i = 0; i < 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();
}
}