I keep getting the following error in my logcat whenever i try to click on "login" or "signup" on my virtual device
2021-01-27 19:08:14.703 11914-11964/com.kate.CapstoneProject
E/Buffer?Error: Error converting result java.lang.NullPointerException
2021-01-27 19:08:14.704 11914-11964/com.kate.CapstoneProject
E/JSON?Parser: Error parsing data org.json.JSONException: End of input
at character 0 of
help please!
Here is my main java code(MainActivity.java):
package com.kate.CapstoneProject;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.os.AsyncTask;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
EditText editEmail, editPassword, editName;
Button btnSignIn, btnRegister;
String URL= "https://192.168.1.68/test_android/index.php";
JSONParser jsonParser=new JSONParser();
int i=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editEmail=(EditText)findViewById(R.id.editEmail);
editName=(EditText)findViewById(R.id.editName);
editPassword=(EditText)findViewById(R.id.editPassword);
btnSignIn=(Button)findViewById(R.id.btnSignIn);
btnRegister=(Button)findViewById(R.id.btnRegister);
btnSignIn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
AttemptLogin attemptLogin= new AttemptLogin();
attemptLogin.execute(editName.getText().toString(),editPassword.getText().toString(),"");
}
});
btnRegister.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(i==0)
{
i=1;
editEmail.setVisibility(View.VISIBLE);
btnSignIn.setVisibility(View.GONE);
btnRegister.setText("CREATE ACCOUNT");
}
else{
btnRegister.setText("REGISTER");
editEmail.setVisibility(View.GONE);
btnSignIn.setVisibility(View.VISIBLE);
i=0;
AttemptLogin attemptLogin= new AttemptLogin();
attemptLogin.execute(editName.getText().toString(),editPassword.getText().toString(),editEmail.getText().toString());
}
}
});
}
private class AttemptLogin extends AsyncTask<String, String, JSONObject> {
private String[] args;
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected JSONObject doInBackground(String... args) {
this.args = args;
String email = args[2];
String password = args[1];
String name= args[0];
ArrayList params = new ArrayList();
params.add(new BasicNameValuePair("username", name));
params.add(new BasicNameValuePair("password", password));
if(email.length()>0)
params.add(new BasicNameValuePair("email",email));
JSONObject json = jsonParser.makeHttpRequest(URL, "POST", params);
return json;
}
protected void onPostExecute(JSONObject result) {
// dismiss the dialog once product deleted
//Toast.makeText(getApplicationContext(),result,Toast.LENGTH_LONG).show();
try {
if (result != null) {
Toast.makeText(getApplicationContext(),result.getString("message"),Toast.LENGTH_LONG).show();
// login to activity
Intent intent = new Intent(getApplicationContext(),Homepage.class);
startActivity(intent);
}
else {
Toast.makeText(getApplicationContext(), "Unable to retrieve any data from server", Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
here is my JSONparser.java
package com.kate.CapstoneProject;
import android.util.Log;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static JSONArray jArr = null;
static String json = "";
static String error = "";
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET mehtod
public JSONObject makeHttpRequest(String url, String method,ArrayList params) {
// Making HTTP request
try {
// check for request method
if(method.equals("POST")){
// request method is POST
// defaultHttpClient
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
try {
Log.e("API123", " " +convertStreamToString(httpPost.getEntity().getContent()));
Log.e("API123",httpPost.getURI().toString());
} catch (Exception e) {
e.printStackTrace();
}
HttpResponse httpResponse = httpClient.execute(httpPost);
Log.e("API123",""+httpResponse.getStatusLine().getStatusCode());
error= String.valueOf(httpResponse.getStatusLine().getStatusCode());
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method.equals("GET")){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, StandardCharsets.ISO_8859_1), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "
");
}
is.close();
json = sb.toString();
Log.d("API123",json);
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try to parse the string to a JSON object
try {
jObj = new JSONObject(json);
jObj.put("error_code",error);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
private String convertStreamToString(InputStream is) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line);
}
is.close();
return sb.toString();
}
}
here is my android manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.kate.CapstoneProject">
<application
android:allowBackup="true"
android:usesCleartextTraffic="true"
android:icon="@mipmap/ic_launcher"
android:label="CapstoneProject"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<uses-library
android:name="org.apache.http.legacy"
android:required="false" />
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.GET_ACCOUNTS"/>
</manifest>
question from:
https://stackoverflow.com/questions/65930525/error-converting-result-java-lang-nullpointerexception-and-json-parser-error-pa 
