I tried to load Json Object to Listview with simple adapter, but i return the following error.
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
i've check the JSON object is valid.
here is the json object
{
"result": [
{
"nomor": "18",
"id_ortu": "020202",
"alasan_perizinan": "ada aja deh pokoknya",
"tgl_izin": "2019-07-10",
"lama_izin": "10",
"tgl_kembali": "2019-07-20"
},
{
"nomor": "17",
"id_ortu": "020202",
"alasan_perizinan": "ada aja",
"tgl_izin": "2019-07-10",
"lama_izin": "10",
"tgl_kembali": "2019-07-20"
},
{
"nomor": "16",
"id_ortu": "020202",
"alasan_perizinan": "ada dehhhhhhh",
"tgl_izin": "2019-07-10",
"lama_izin": "10",
"tgl_kembali": "2019-07-20"
},
{
"nomor": "14",
"id_ortu": "020202",
"alasan_perizinan": "hs",
"tgl_izin": "2019-07-10",
"lama_izin": "10",
"tgl_kembali": "2019-07-20"
}
]
}
here is my java
package com.budiluhur.almusyarrofahdigital;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.JsonReader;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class DaftarPermintaanIzin extends AppCompatActivity {
private String JSON_STRING;
ListView listView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
listView = findViewById(R.id.ListPermintaan);
getJSON();
}
private void showIzin() {
JSONObject jsonObject = null;
ArrayList<HashMap<String, String>> list = new ArrayList<>();
try {
jsonObject = new JSONObject(JSON_STRING);
JSONArray result = jsonObject.getJSONArray("result");
for (int i = 0; i < result.length(); i++) {
JSONObject jsonObject1 = result.getJSONObject(i);
String nomor = jsonObject1.getString("nomor");
String id_ortu = jsonObject1.getString("id_ortu");
String alasanPerizinan = jsonObject1.getString("alasan_perizinan");
String tglIzin = jsonObject1.getString("tgl_izin");
String lamaIzin = jsonObject1.getString("lama_izin");
String tglKembali = jsonObject1.getString("tgl_kembali");
HashMap<String, String> perizinan = new HashMap<>();
perizinan.put("nomor", nomor);
perizinan.put("id_ortu", id_ortu);
perizinan.put("alasan_perizinan", alasanPerizinan);
perizinan.put("tglIzin", tglIzin);
perizinan.put("lamaIzin", lamaIzin);
perizinan.put("tgl_kembali", tglKembali);
list.add(perizinan);
}
} catch (JSONException e) {
e.printStackTrace();
}
ListAdapter adapter = new SimpleAdapter(this, list, R.layout.list_izin, new String[]{"nomor", "id_ortu","alasan_perizinan","tglIzin","lamaIzin","tgl_kembali"}, new int[]{R.id.nomor1, R.id.id_ortu1,R.id.AlasanIzin1,R.id.TglIzin1,R.id.LamaIzin1,R.id.TglKembali1});
listView.setAdapter(adapter);
}
private void getJSON() {
class getJSON extends AsyncTask<Void, Void, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
Toast.makeText(DaftarPermintaanIzin.this,result, Toast.LENGTH_LONG).show();
JSON_STRING = result;
showIzin();
}
@Override
protected String doInBackground(Void... params) {
RequestHandler rh = new RequestHandler();
String s = rh.sendGetRequest("https://ohmybags.id/almus/getIzin.php");
return s;
}
}
getJSON getJSON = new getJSON();
getJSON.execute();
}
}
here is the xml file
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
>
<TextView
android:id="@+id/nomor1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Testing"
android:textSize="20dp"
android:layout_marginTop="20dp"
android:layout_marginBottom="20dp"/>
<TextView
android:id="@+id/id_ortu1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="testing"
android:textSize="20dp"
android:layout_marginTop="20dp"
android:layout_marginBottom="20dp"
/>
<TextView
android:id="@+id/AlasanIzin1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="testing"
android:textSize="20dp"
android:layout_marginTop="20dp"
android:layout_marginBottom="20dp"
/>
<TextView
android:id="@+id/TglIzin1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="testing"
android:textSize="20dp"
android:layout_marginTop="20dp"
android:layout_marginBottom="20dp"
/>
<TextView
android:id="@+id/LamaIzin1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="testing"
android:textSize="20dp"
android:layout_marginTop="20dp"
android:layout_marginBottom="20dp"
/>
<TextView
android:id="@+id/TglKembali1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="testing"
android:textSize="20dp"
android:layout_marginTop="20dp"
android:layout_marginBottom="20dp"
/>
</LinearLayout>
where did i go wrong?
