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Android app crashing when control reaches findViewbyId() for recyclerview?

I intended to fetch data from ConnectionClass in background and then populate it into recyclerView.
Now, I have successfully fetched the data from url in json format, but my app is crashing when I am trying to display data using recyclerView.
Adapter Class for recyclerview
package com.example.mainapp;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import java.util.List;
import Model.PersonDetails;
public class PersonDetailsAdapter extends RecyclerView.Adapter<PersonDetailsAdapter.ViewHolder> {
private List<PersonDetails> personDetails;
PersonDetailsAdapter(List<PersonDetails>details)
{
personDetails = details;
}
#NonNull
#Override
public PersonDetailsAdapter.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
Log.d("create view " , personDetails.toString());
Context context = parent.getContext();
LayoutInflater inflater = LayoutInflater.from(context) ;
View personView = inflater.inflate(R.layout.person_details_view , parent , true) ;
ViewHolder view = new ViewHolder(personView) ;
return view;
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
PersonDetails details = personDetails.get(position);
holder.nameTextView.setText(details.getName());
holder.aliasTextView.setText(details.getAlias());
}
#Override
public int getItemCount() {
return personDetails.size();
}
public class ViewHolder extends RecyclerView.ViewHolder{
public TextView nameTextView;
public TextView aliasTextView;
public ViewHolder(#NonNull View itemView) {
super(itemView);
nameTextView = (TextView) itemView.findViewById(R.id.nameHolder);
aliasTextView = (TextView) itemView.findViewById(R.id.aliasHolder);
}
}
}
MainActivity.java
package com.example.mainapp;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import com.example.mainapp.Utility.ConnectionClass;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Text;
import java.net.MalformedURLException;
import java.util.List;
import Model.PersonDetails;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button getButton = findViewById(R.id.get);
Button postButton = findViewById(R.id.post);
Context context = this.getBaseContext();
getButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
ConnectionClass conn = null;
try {
conn = new ConnectionClass("URL", context);
conn.execute();
} catch (MalformedURLException e) {
System.out.println("connection not set ");
e.printStackTrace();
}
}
});
postButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
postRequest();
}
}
);
}
public void updateView( List<PersonDetails> personDetails ) {
Log.d("1" , "******************************************called fro");
RecyclerView rView = (RecyclerView)findViewById(R.id.recyclerViewPerson);
Log.d("2" , "******************************************iosdjdsa");
PersonDetailsAdapter adapter = new PersonDetailsAdapter(personDetails);
rView.setLayoutManager(new GridLayoutManager(this, 5));
rView.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
private void postRequest() {
}
}
ConnectionClass.java
package com.example.mainapp.Utility;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.Toast;
import com.example.mainapp.MainActivity;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import Model.PersonDetails;
public class ConnectionClass extends AsyncTask<Void, Void, Void> {
private URL url ;
private HttpURLConnection conn;
private String response ;
private Context context ;
public ConnectionClass() {
super();
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
Log.d("onPost", "*****************************************postexe");
Toast.makeText(context, "Records fetched",Toast.LENGTH_SHORT);
List<PersonDetails> details = new ArrayList<>();
try {
JSONArray arr = new JSONArray(response);
for( int i = 0; i < arr.length() ; ++i )
{
JSONObject jObject = arr.getJSONObject(i);
PersonDetails record = new PersonDetails(jObject.getString("name"),jObject.getString("alias") );
details.add(record);
}
} catch (JSONException e) {
Log.d("t","json exception");
e.printStackTrace();
}
Log.d( "detalis", "**************************************"+details.toString());
MainActivity activity = new MainActivity();
activity.updateView(details);
}
public ConnectionClass(String url, Context context) throws MalformedURLException {
this.url = new URL (url);
conn = null ;
this.context = context;
}
// public void sendRequest(){
// try {
// System.out.println("\n\n***************************************hello**********************\n\n");
// conn = (HttpURLConnection) url.openConnection();
// conn.setDoOutput(false);
// conn.setDoInput(true);
// conn.setUseCaches(false);
// conn.setRequestMethod("GET");
// conn.setRequestProperty("Content-Type", "application/json");
// conn.connect();
// // handle the response
// System.out.println("\n\n***************************************here**********************\n\n");
//
// int status = conn.getResponseCode();
// System.out.println(status);
//
// if (status != 200)
// throw new IOException("Request not completed");
// else
// {
// BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
// String inputLine ;
// StringBuilder builder = new StringBuilder() ;
// while((inputLine = in.readLine()) != null )
// builder.append(inputLine);
// in.close();
// response = builder.toString();
// }
//
// }
// catch (IOException e) {
// e.printStackTrace();
// }
// finally{
// if( conn != null )
// conn.disconnect();
// }
// }
public void setUrl(String url) throws MalformedURLException {
this.url = new URL(url);
}
public String getResponse() {
return response;
}
#Override
protected Void doInBackground(Void... voids) {
try {
conn = (HttpURLConnection) url.openConnection();
Log.d("conn", "***************************************************************************connectioon set " ) ;
} catch (IOException e) {
e.printStackTrace();
}
try {
conn.setRequestMethod("GET");
} catch (ProtocolException e) {
e.printStackTrace();
}
conn.setReadTimeout(10000 /* milliseconds */);
conn.setConnectTimeout(15000 /* milliseconds */);
conn.setDoOutput(true);
try {
conn.connect();
Log.d("conn " , "**********************************************************************connected ");
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader br = null;
StringBuilder sb = new StringBuilder();
try{
br =new BufferedReader(new InputStreamReader(url.openStream()));
char[] buffer = new char[1024];
String line;
while ((line = br.readLine()) != null) {
sb.append(line+"\n");
}
Log.d("sb" , String.valueOf(sb));
}
catch (IOException e)
{
e.printStackTrace();
}
finally{
Log.d("finally ", "*****************************************************************************************finally");
response = sb.toString();
System.out.println("JSON: " + response);
conn.disconnect();
}
return null ;
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_alignParentTop="true"
android:layout_marginTop="-3dp">
<TextView
android:id="#+id/nameText"
android:layout_width="141dp"
android:layout_height="45dp"/>
<TextView
android:id="#+id/aliasText"
android:layout_width="141dp"
android:layout_height="45dp"
android:layout_marginLeft="119dp"
android:layout_toRightOf="#+id/nameText" />
<Button
android:id="#+id/post"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentBottom="true"
android:layout_marginLeft="-11dp"
android:layout_marginBottom="2dp"
android:text="POST" />
<Button
android:id="#+id/get"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentBottom="true"
android:layout_marginRight="1dp"
android:layout_marginBottom="3dp"
android:text="GET" />
</RelativeLayout>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerViewPerson"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#972A2A" />
</RelativeLayout>
xml for RecyclerView content
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_margin="50dp"
android:padding="10dp">
<TextView
android:id="#+id/nameHolder"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp"
android:text="TextView" />
<TextView
android:id="#+id/aliasHolder"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp"
android:text="TextView" />
</LinearLayout>
Application is crashing when control reaches updateView()?

Add your AsyncTask code at the bottom of your MainActivity and then update the recyclerview like this:
updateView(details);

Let me clarify #sdex answer:
When you create an instance of Activity - in your case MainActivity - it doesn't have a view, it is not visible to the user and it's not added to the Activity stack. You could say - this activity is "Dead"
In order to display the result to your currently running MainActivity, so it's displayed to the user, you need to pass the instance of it to the ConnectionClass class. For example - pass it to the constructor of the ConnectionClass.
By the way - please consider moving away from AsyncTask, it's been deprecated and could be a reason for the Context leaks, meaning - you'll have massive objects, that are no more visible to the user are retaining in the memory.
In order to avoid leaking the Activity reference, please store it as the "WeakReference"

MainActivity activity = new MainActivity();
activity.updateView(details);
You can't instantiate activity like this; if you want to call a method in the activity within the AsynkTask class ConnectionClass; you can pass a listener to it and implement this listener in the activity, and then invoke the callback of that listener when you want to call some functionality in the activity.
interface ConnectionClassListener {
void onPostExecuteFinished(List<PersonDetails> personDetails);
}
Pass the class to the AsyncTask constructor
public class ConnectionClass extends AsyncTask<Void, Void, Void> {
ConnectionClassListener mConnectionClassListener;
public ConnectionClass(String url, Context context, ConnectionClassListener listener) throws MalformedURLException {
this.url = new URL (url);
conn = null ;
this.context = context;
mConnectionClassListener = listener;
}
Implement the listener by the activity
public class MainActivity extends AppCompatActivity implements ConnectionClassListener {
#Override
void onPostExecuteFinished(List<PersonDetails> personDetails) {
// Do here what you want when the ConnectionClass calls `onPostExecuteFinished()`
updateView(personDetails);
}
}
add this when creating the AsynkTask class
conn = new ConnectionClass("URL", context, this);
And finally call onPostExecuteFinished() in your ConnectionClass
public class ConnectionClass extends AsyncTask<Void, Void, Void> {
// ...
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
// ...
mConnectionClassListener.onPostExecuteFinished(details);

MainActivity activity = new MainActivity();
You cannot just create the instance using the constructor. You should pass a reference of MainActivity to make it work. You need just to change a few lines of the code:
In ConnectionClass replace field private Context context; by private MainActivity activity; and change the constructor accordingly:
public ConnectionClass(String url, MainActivity activity) throws MalformedURLException {
this.url = new URL (url);
conn = null ;
this.activity = activity;
}
After that, you will be able to call activity.updateView(details);.
And don't forget to remove MainActivity activity = new MainActivity();
Further reading:
Proper use of AsyncTask
AsyncTask deprecation and alternatives

I am making activity that translate 1 language to another(eng-french).Everything is working fine except i have to click button many times to work

In my activity, I want to take voice input when we click imageView and convert into text and display it in textfield and after we press button it converts it into french(currently it is fixed) and display it in textfield2.
I am using yandex translator.
My error::
When I click button for the first time nothing happens in textfield2 but in log, it display the correct translation.After my 2nd click,it changes the textfield2. But i want to show the translation after 1st click only.Why it is taking 2 click for working while my output is coming correct after 2nd click??
here is my XML file:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
android:layout_centerHorizontal="true"
android:layout_below="#+id/textView"
tools:layout_editor_absoluteX="131dp"
tools:layout_editor_absoluteY="202dp" />
<ImageView
android:id="#+id/imageView"
android:layout_centerHorizontal="true"
android:layout_width="267dp"
android:layout_height="244dp"
app:srcCompat="#android:drawable/ic_btn_speak_now" />
<TextView
android:id="#+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="30sp"
android:layout_below="#+id/imageView"
android:layout_centerHorizontal="true"
android:text="Text to be Translated" />
<TextView
android:id="#+id/textView2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#+id/button"
android:text="Translated Text"
android:textSize="30sp"
/>
</RelativeLayout>
Here is my MainActivty:
package com.example.translator;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.speech.RecognizerIntent;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Locale;
public class MainActivity extends AppCompatActivity {
final static int REQUEST_CODE_SPEECH=1000;
ImageView listen;
TextView ans,mresult;
Context context=this;
Button b;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listen=findViewById(R.id.imageView);
ans=findViewById(R.id.textView);
mresult=findViewById(R.id.textView2);
b=findViewById(R.id.button);
listen.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
speak();
}
});
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String textToBeTranslated = ans.getText().toString();
String languagePair = "en-fr"; //English to French ("<source_language>-<target_language>")
//Executing the translation function
Translate(textToBeTranslated,languagePair);
}
});
}
void Translate(String textToBeTranslated,String languagePair){
TranslatorBackgroundTask translatorBackgroundTask= new TranslatorBackgroundTask(context);
if(Build.VERSION.SDK_INT >=Build.VERSION_CODES.HONEYCOMB) {
translatorBackgroundTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR,textToBeTranslated,languagePair);
} else {
translatorBackgroundTask.execute(textToBeTranslated,languagePair);
}
Log.d("Translation Result:", translatorBackgroundTask.t); // Logs the result in Android Monitor
mresult.setText(translatorBackgroundTask.t);
}
void speak(){
Intent intent=new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE, Locale.getDefault());
intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "hi say something!!!");
try{
startActivityForResult(intent,REQUEST_CODE_SPEECH);
}
catch(Exception e) {
Toast.makeText(MainActivity.this, "" + e.getMessage(),Toast.LENGTH_LONG).show();
}
}
#Override
protected void onActivityResult(int requestCode, int resultCode, #Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch(requestCode){
case REQUEST_CODE_SPEECH:{
if(resultCode==RESULT_OK && data!=null) {
ArrayList<String>result=data.getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);
ans.setText(result.get(0));
}
break;
}
}
}
}
Here is my API File:
package com.example.translator;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class TranslatorBackgroundTask extends AsyncTask<String, Void, String> {
//Declare Context
Context ctx;
public static String t="";
//Set Context
TranslatorBackgroundTask(Context ctx){
this.ctx = ctx;
}
#Override
public String doInBackground(String... params) {
//String variables
String textToBeTranslated = params[0];
String languagePair = params[1];
String jsonString;
try {
//Set up the translation call URL
String yandexKey = "MY-API-KEY";
String yandexUrl = "https://translate.yandex.net/api/v1.5/tr.json/translate?key=" + yandexKey
+ "&text=" + textToBeTranslated + "&lang=" + languagePair;
URL yandexTranslateURL = new URL(yandexUrl);
//Set Http Conncection, Input Stream, and Buffered Reader
HttpURLConnection httpJsonConnection = (HttpURLConnection) yandexTranslateURL.openConnection();
InputStream inputStream = httpJsonConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
//Set string builder and insert retrieved JSON result into it
StringBuilder jsonStringBuilder = new StringBuilder();
while ((jsonString = bufferedReader.readLine()) != null) {
jsonStringBuilder.append(jsonString + "\n");
}
//Close and disconnect
bufferedReader.close();
inputStream.close();
httpJsonConnection.disconnect();
//Making result human readable
String resultString = jsonStringBuilder.toString().trim();
//Getting the characters between [ and ]
resultString = resultString.substring(resultString.indexOf('[')+1);
resultString = resultString.substring(0,resultString.indexOf("]"));
//Getting the characters between " and "
resultString = resultString.substring(resultString.indexOf("\"")+1);
resultString = resultString.substring(0,resultString.indexOf("\""));
Log.d("Translation Result:", resultString);
t=resultString;
return jsonStringBuilder.toString().trim();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected void onPostExecute(String result) {
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
}

I think it's this line:
mresult.setText(TranslatorBackgroundTask.t);
Shouldn't it be:
mresult.setText(translatorBackgroundTask.t);

Passing spinner data to other field

I have and xml activity, it contains a spinner item, I want to pass the value of spinner to other textView on the same activity. Attached tow files xml and java, and the spinner name is simpleSpinner and the textView that I want to have the spinner value is district_id please update the code and help me
package com.cp.comp;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.Toast;
import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.HashMap;
import java.util.Map;
public class add_comp extends AppCompatActivity implements AdapterView.OnItemSelectedListener{
String[] bankNames={"جنين","2","طولكرم","نابلس","قلقيلية","سلفيت","رام الله","اريحا","بيت لحم","القدس","الخليل"};
private EditText shop_name, complainant_name, complainant_id, mobile;
private EditText district_id, address_detail, comp_type, comp_detail;
private ProgressBar loading;
private static String URL_ADDCOMP = "http://172.23.50.55/CP/add_comp.php";
private Button btn_add_comp;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_comp);
btn_add_comp = findViewById(R.id.btn_add_comp);
loading = findViewById(R.id.loading);
shop_name = findViewById(R.id.shop_name);
complainant_name = findViewById(R.id.complainant_name);
complainant_id = findViewById(R.id.complainant_id);
mobile = findViewById(R.id.mobile);
district_id = findViewById(R.id.district_id);
address_detail = findViewById(R.id.address_detail);
comp_type = findViewById(R.id.comp_type);
comp_detail = findViewById(R.id.comp_detail);
Spinner spin = (Spinner) findViewById(R.id.district_id);
spin.setOnItemSelectedListener(this);
//Creating the ArrayAdapter instance having the bank name list
ArrayAdapter aa = new ArrayAdapter(this,android.R.layout.simple_spinner_item,bankNames);
aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spin.setAdapter(aa);
btn_add_comp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Add_comp();
}
});
private void Add_comp() {
loading.setVisibility(View.VISIBLE);
btn_add_comp.setVisibility(View.GONE);
final String shop_name = this.shop_name.getText().toString().trim();
final String complainant_name = this.complainant_name.getText().toString().trim();
final String complainant_id = this.complainant_id.getText().toString().trim();
final String mobile = this.mobile.getText().toString().trim();
final String district_id = this.district_id.getText().toString().trim();
final String address_detail = this.address_detail.getText().toString().trim();
final String comp_type = this.comp_type.getText().toString().trim();
final String comp_detail = this.comp_detail.getText().toString().trim();
System.out.println("ya abed almoty " + comp_detail);
StringRequest stringRequest = new StringRequest(Request.Method.POST, URL_ADDCOMP,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try{
JSONObject jsonObject = new JSONObject(response);
String success = jsonObject.getString("success");
System.out.println("ya habibi");
if (success.equals("1")) {
Toast.makeText(add_comp.this, "تم إرسال الشكوى بنجاح!", Toast.LENGTH_SHORT).show();
System.out.println("ya belal");
}
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(add_comp.this, "ارسال خاطئ! " + e.toString(), Toast.LENGTH_SHORT).show();
loading.setVisibility(View.GONE);
btn_add_comp.setVisibility(View.VISIBLE);
System.out.println("ya jehad");
}
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(add_comp.this, "ارسال خاطئ! " + error.toString(), Toast.LENGTH_SHORT).show();
loading.setVisibility(View.GONE);
btn_add_comp.setVisibility(View.VISIBLE);
System.out.println("ya morad");
}
})
{
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<>();
params.put("shop_name", shop_name);
params.put("complainant_name", complainant_name);
params.put("complainant_id", complainant_id);
params.put("mobile", mobile);
params.put("district_id", district_id);
params.put("address_detail", address_detail);
params.put("comp_type", comp_type);
params.put("comp_detail", comp_detail);
System.out.println("ya fahed" + params.put("comp_type", comp_type));
System.out.println("ya vvvvvvvvv" + bankNames.toString().trim());
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(stringRequest);
}
#Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int position,long id) {
Toast.makeText(getApplicationContext(), bankNames[position], Toast.LENGTH_LONG).show();
String district_id = bankNames[position];
System.out.println("bobobo " + district_id);
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
}}
and the xml file is :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingLeft="30dp"
android:paddingTop="80dp"
android:paddingRight="30dp"
tools:context="com.cp.comp.add_comp">
<EditText
android:id="#+id/shop_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="اسم المحل"
android:inputType="textPersonName"
android:textColor="#color/colorText" />
<EditText
android:id="#+id/complainant_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:hint="اسم المشتكي"
android:inputType="textPersonName"
android:textColor="#color/colorText" />
<EditText
android:id="#+id/complainant_id"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="هوية المشتكي"
android:inputType="textPersonName"
android:textColor="#color/colorText" />
<EditText
android:id="#+id/mobile"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:hint="موبايل المشتكي"
android:inputType="textPersonName"
android:textColor="#color/colorText" />
<EditText
android:id="#+id/address_detail"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:hint="عنوان المحل التفصيلي"
android:inputType="textPersonName"
android:textColor="#color/colorText" />
<EditText
android:id="#+id/comp_type"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="طبيعة الشكوى"
android:inputType="textPersonName"
android:textColor="#color/colorText" />
<EditText
android:id="#+id/comp_detail"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:hint="تفصيل الشكوى"
android:inputType="textPersonName"
android:textColor="#color/colorText" />
<ProgressBar
android:id="#+id/loading"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="30dp"
android:visibility="gone" />
<EditText
android:id="#+id/district_id"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="المحافظة"
android:inputType="textPersonName"
android:textColor="#color/colorText" />
<Spinner
android:id="#+id/simpleSpinner"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_marginTop="10dp" />
<Button
android:id="#+id/btn_add_comp"
android:layout_width="match_parent"
android:layout_height="55dp"
android:layout_marginTop="30dp"
android:backgroundTint="#color/colorPrimaryDark2"
android:text="ارسال"
android:textColor="#android:color/white" />
</LinearLayout>

To change a TextViews text you need to simply do it:
myTextView.setText(district_id);

package com.cp.comp;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.Spinner;
import android.widget.Toast;
import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
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.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
public class add_comp extends AppCompatActivity implements AdapterView.OnItemSelectedListener{
private EditText shop_name, complainant_name, complainant_id, mobile;
private EditText district_id, address_detail, comp_type, comp_detail;
private EditText myTextView;
private ProgressBar loading;
private static String URL_ADDCOMP = "http://172.23.50.55/CP/add_comp.php";
private Button btn_add_comp;
ArrayList<String> listItems=new ArrayList<>();
ArrayAdapter<String> adapter;
Spinner sp;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_comp);
sp=(Spinner)findViewById(R.id.spinner);
adapter=new ArrayAdapter<String>(this,R.layout.spinner_layout,R.id.txt,listItems);
System.out.println("frfrfrfr " + adapter);
sp.setAdapter(adapter);
btn_add_comp = findViewById(R.id.btn_add_comp);
loading = findViewById(R.id.loading);
shop_name = findViewById(R.id.shop_name);
complainant_name = findViewById(R.id.complainant_name);
complainant_id = findViewById(R.id.complainant_id);
mobile = findViewById(R.id.mobile);
district_id = findViewById(R.id.district_id);
address_detail = findViewById(R.id.address_detail);
comp_type = findViewById(R.id.comp_type);
comp_detail = findViewById(R.id.comp_detail);
btn_add_comp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Add_comp();
}
});
}
private void Add_comp() {
loading.setVisibility(View.VISIBLE);
btn_add_comp.setVisibility(View.GONE);
final String shop_name = this.shop_name.getText().toString().trim();
final String complainant_name = this.complainant_name.getText().toString().trim();
final String complainant_id = this.complainant_id.getText().toString().trim();
final String mobile = this.mobile.getText().toString().trim();
final String district_id = this.district_id.getText().toString().trim();
final String address_detail = this.address_detail.getText().toString().trim();
final String comp_type = this.comp_type.getText().toString().trim();
final String comp_detail = this.comp_detail.getText().toString().trim();
System.out.println("ya abed almoty");
StringRequest stringRequest = new StringRequest(Request.Method.POST, URL_ADDCOMP,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try{
JSONObject jsonObject = new JSONObject(response);
String success = jsonObject.getString("success");
System.out.println("ya habibi");
if (success.equals("1")) {
Toast.makeText(add_comp.this, "تم إرسال الشكوى بنجاح!", Toast.LENGTH_SHORT).show();
System.out.println("ya belal");
}
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(add_comp.this, "ارسال خاطئ! " + e.toString(), Toast.LENGTH_SHORT).show();
loading.setVisibility(View.GONE);
btn_add_comp.setVisibility(View.VISIBLE);
System.out.println("ya jehad");
}
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(add_comp.this, "ارسال خاطئ! " + error.toString(), Toast.LENGTH_SHORT).show();
loading.setVisibility(View.GONE);
btn_add_comp.setVisibility(View.VISIBLE);
System.out.println("ya morad");
}
})
{
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<>();
params.put("shop_name", shop_name);
params.put("complainant_name", complainant_name);
params.put("complainant_id", complainant_id);
params.put("mobile", mobile);
params.put("district_id", district_id);
params.put("address_detail", address_detail);
params.put("comp_type", comp_type);
params.put("comp_detail", comp_detail);
System.out.println("ya fahed" + params.put("comp_type", comp_type));
System.out.println("ya mymymymym" + myTextView);
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(stringRequest);
}
public void onStart(){
super.onStart();
add_comp.BackTask bt=new add_comp.BackTask();
bt.execute();
}
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(getApplicationContext(),parent.getItemAtPosition(position).toString(), Toast.LENGTH_LONG).show();
parent.getItemAtPosition(position).toString();
System.out.println("mrmrmr " + parent.getItemAtPosition(position).toString());
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
private class BackTask extends AsyncTask<Void,Void,Void> {
ArrayList<String> list;
protected void onPreExecute(){
super.onPreExecute();
list=new ArrayList<>();
}
protected Void doInBackground(Void...params){
InputStream is=null;
String result="";
try{
HttpClient httpclient=new DefaultHttpClient();
HttpPost httppost= new HttpPost("http://172.23.50.55/CP/select_district_name.php");
HttpResponse response=httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
// Get our response as a String.
is = entity.getContent();
}catch(IOException e){
e.printStackTrace();
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"utf-8"));
String line = null;
while ((line = reader.readLine()) != null) {
result+=line;
}
is.close();
//result=sb.toString();
}catch(Exception e){
e.printStackTrace();
}
// parse json data
try{
JSONArray jArray =new JSONArray(result);
for(int i=0;i<jArray.length();i++){
JSONObject jsonObject=jArray.getJSONObject(i);
// add interviewee name to arraylist
list.add(jsonObject.getString("dis_name"));
System.out.println("txt_txt" + result);
}
}
catch(JSONException e){
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Void result){
listItems.addAll(list);
adapter.notifyDataSetChanged();
}
}
}
the dis_name is the value that I want to pass to district_id

package com.cp.comp;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.Spinner;
import android.widget.Toast;
import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
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.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
public class add_comp extends AppCompatActivity {
private EditText shop_name, complainant_name, complainant_id, mobile;
private EditText district_id, address_detail, comp_type, comp_detail;
private ProgressBar loading;
private static String URL_ADDCOMP = "http://172.23.50.55/CP/add_comp.php";
private Button btn_add_comp;
ArrayList<String> listItems=new ArrayList<>();
ArrayAdapter<String> adapter;
Spinner sp;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_comp);
btn_add_comp = findViewById(R.id.btn_add_comp);
loading = findViewById(R.id.loading);
shop_name = findViewById(R.id.shop_name);
complainant_name = findViewById(R.id.complainant_name);
complainant_id = findViewById(R.id.complainant_id);
mobile = findViewById(R.id.mobile);
district_id = findViewById(R.id.district_id);
address_detail = findViewById(R.id.address_detail);
comp_type = findViewById(R.id.comp_type);
comp_detail = findViewById(R.id.comp_detail);
sp=(Spinner)findViewById(R.id.spinner);
adapter=new ArrayAdapter<String>(this,R.layout.spinner_layout,R.id.txt,listItems);
sp.setAdapter(adapter);
btn_add_comp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Add_comp();
}
});
}
private void Add_comp() {
loading.setVisibility(View.VISIBLE);
btn_add_comp.setVisibility(View.GONE);
final String shop_name = this.shop_name.getText().toString().trim();
final String complainant_name = this.complainant_name.getText().toString().trim();
final String complainant_id = this.complainant_id.getText().toString().trim();
final String mobile = this.mobile.getText().toString().trim();
final String district_id = this.district_id.getText().toString().trim();
final String address_detail = this.address_detail.getText().toString().trim();
final String comp_type = this.comp_type.getText().toString().trim();
final String comp_detail = this.comp_detail.getText().toString().trim();
System.out.println("ya abed almoty");
StringRequest stringRequest = new StringRequest(Request.Method.POST, URL_ADDCOMP,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try{
JSONObject jsonObject = new JSONObject(response);
String success = jsonObject.getString("success");
System.out.println("ya habibi");
if (success.equals("1")) {
Toast.makeText(add_comp.this, "تم إرسال الشكوى بنجاح!", Toast.LENGTH_SHORT).show();
System.out.println("ya belal");
}
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(add_comp.this, "ارسال خاطئ! " + e.toString(), Toast.LENGTH_SHORT).show();
loading.setVisibility(View.GONE);
btn_add_comp.setVisibility(View.VISIBLE);
System.out.println("ya jehad");
}
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(add_comp.this, "ارسال خاطئ! " + error.toString(), Toast.LENGTH_SHORT).show();
loading.setVisibility(View.GONE);
btn_add_comp.setVisibility(View.VISIBLE);
System.out.println("ya morad");
}
})
{
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<>();
params.put("shop_name", shop_name);
params.put("complainant_name", complainant_name);
params.put("complainant_id", complainant_id);
params.put("mobile", mobile);
params.put("district_id", district_id);
params.put("address_detail", address_detail);
params.put("comp_type", comp_type);
params.put("comp_detail", comp_detail);
System.out.println("ya fahed" + params.put("comp_type", comp_type));
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(stringRequest);
}
public void onStart(){
super.onStart();
add_comp.BackTask bt=new add_comp.BackTask();
bt.execute();
}
private class BackTask extends AsyncTask<Void,Void,Void> {
ArrayList<String> list;
protected void onPreExecute(){
super.onPreExecute();
list=new ArrayList<>();
}
protected Void doInBackground(Void...params){
InputStream is=null;
String result="";
try{
HttpClient httpclient=new DefaultHttpClient();
HttpPost httppost= new HttpPost("http://172.23.50.55/CP/select_district_name.php");
HttpResponse response=httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
// Get our response as a String.
is = entity.getContent();
}catch(IOException e){
e.printStackTrace();
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"utf-8"));
String line = null;
while ((line = reader.readLine()) != null) {
result+=line;
}
is.close();
//result=sb.toString();
}catch(Exception e){
e.printStackTrace();
}
// parse json data
try{
JSONArray jArray =new JSONArray(result);
for(int i=0;i<jArray.length();i++){
JSONObject jsonObject=jArray.getJSONObject(i);
// add interviewee name to arraylist
list.add(jsonObject.getString("dis_name"));
}
}
catch(JSONException e){
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Void result){
listItems.addAll(list);
adapter.notifyDataSetChanged();
}
}
}
the dis_name is the value that I want to pass to district_id

Exchange messages between android apps with bluetooth

I have followed the below urls for the sample program.It us used to send a message to a paired blutooth device via an android app.
https://stackoverflow.com/a/22899728/1559331
IOException: read failed, socket might closed - Bluetooth on Android 4.3
What the code is trying to do is
1)Connect to paired device and writes data to it outputstream . The data to write is taken from edittext
2)The code also displays the data in the inputstream in an edittext
On testing it on a device , I could see that I am able to connect and write data to outputstream , but not able to read it.Even the Read button onclick is not working
main_activity_xml -- xml for UI used
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content" android:orientation="horizontal"
android:layout_width="fill_parent">
<EditText
android:id="#+id/editText"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_width="fill_parent"
android:inputType="number"
/>
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Submit"/>
<EditText
android:id="#+id/editText2"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_width="fill_parent"
/>
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Read"
/>
</LinearLayout>
MainActivity.java - Main activity class
package com.example.dileep.blutooth_messenger;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.EmbossMaskFilter;
import android.graphics.PointF;
import android.os.ParcelUuid;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.InputFilter;
import android.text.format.DateUtils;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TimePicker;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.util.Scanner;
import java.util.Set;
import java.util.UUID;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final BluetoothSocketWrapper bluetoothSocketWrapper=new BluetoothSocketWrapper(getApplicationContext());
et = (EditText) findViewById(R.id.editText);
et.setFilters(new InputFilter[]{ new InputFilterMinMax("1", "100")});
final Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (bluetoothSocketWrapper.getSocket() != null) {
if (!bluetoothSocketWrapper.isConnected()) {
bluetoothSocketWrapper.init();
}
try {
bluetoothSocketWrapper.getOutputStream().write(et.getText().toString().getBytes());
} catch (Exception e) {
Toast.makeText(getApplicationContext(), "Exception while writing to output stream-->" + e.getMessage(), Toast.LENGTH_SHORT).show();
}
finally {
try { bluetoothSocketWrapper.getOutputStream().close();}
catch (Exception e) {
Toast.makeText(getApplicationContext(), "Exception whileclosing output stream-->" + e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
Toast.makeText(getApplicationContext(), "Writing completed", Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(getApplicationContext(), "Not able to connect", Toast.LENGTH_SHORT).show();
}
}
});
et2 = (EditText) findViewById(R.id.editText2);
final Button button2 = (Button) findViewById(R.id.button2);
Toast.makeText(getApplicationContext(), "just beofre 2 nd listner", Toast.LENGTH_SHORT).show();
button2.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Toast.makeText(getApplicationContext(), "second listener", Toast.LENGTH_SHORT).show();
if(bluetoothSocketWrapper.getSocket()!=null){
if(!bluetoothSocketWrapper.isConnected()) {
bluetoothSocketWrapper.init();
}
StringBuilder builder=new StringBuilder();
Scanner s = null;//.useDelimiter("\n");
try {
s = new Scanner(bluetoothSocketWrapper.getInputStream());
while(s.hasNext()){
builder.append(s.next());
}
Toast.makeText(getApplicationContext(), builder.toString(), Toast.LENGTH_SHORT).show();
et2.setText(builder.toString());
Toast.makeText(getApplicationContext(), "reading completed", Toast.LENGTH_SHORT).show();
} catch (IOException e) {
e.printStackTrace();
}
finally {
try { bluetoothSocketWrapper.getInputStream().close();}
catch (Exception e) {
Toast.makeText(getApplicationContext(), "Exception while closing input stream-->" + e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
}
else{
Toast.makeText(getApplicationContext(), "Not able to connect", Toast.LENGTH_SHORT).show();
}
}});
}
private OutputStream outputStream;
private InputStream inStream;
private EditText et;
private EditText et2;
}
BluetoothSocketWrapper class -->Used as a wrapper to bluetooth socket
package com.example.dileep.blutooth_messenger;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.os.ParcelUuid;
import android.util.Log;
import android.widget.Toast;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.net.Socket;
import java.util.Set;
import java.util.UUID;
public class BluetoothSocketWrapper {
private BluetoothSocket socket = null;
private OutputStream outputStream;
private InputStream inStream;
private Context context = null;
public BluetoothSocketWrapper(Context context) {
this.context = context;
init();
}
public void init() {
BluetoothAdapter blueAdapter = BluetoothAdapter.getDefaultAdapter();
if (blueAdapter == null) {
Toast.makeText(context, "Device doesnt Support Bluetooth", Toast.LENGTH_SHORT).show();
}
if (blueAdapter != null) {
if (blueAdapter.isEnabled()) {
Set<BluetoothDevice> bondedDevices = blueAdapter.getBondedDevices();
if (bondedDevices.size() > 0) {
Object[] devices = (Object[]) bondedDevices.toArray();
BluetoothDevice device = (BluetoothDevice) devices[0];
ParcelUuid[] uuids = device.getUuids();
// Toast.makeText(context,uuids[0].getUuid().toString(),Toast.LENGTH_LONG).show();
// BluetoothSocket socket=null;
try {
//socket = device.createRfcommSocketToServiceRecord(uuids[0].getUuid());
UUID SERIAL_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
socket = device.createRfcommSocketToServiceRecord(SERIAL_UUID);
} catch (Exception e) {
Toast.makeText(context, "exc with 1st conn", Toast.LENGTH_LONG).show();
}
try {
socket.connect();
} catch (Exception e) {
Log.e("", e.getMessage());
try {
Toast.makeText(context, "tryiing fallback", Toast.LENGTH_LONG).show();
Class<?> clazz = socket.getRemoteDevice().getClass();
Class<?>[] paramTypes = new Class<?>[]{Integer.TYPE};
Method m = clazz.getMethod("createRfcommSocket", paramTypes);
Object[] params = new Object[]{Integer.valueOf(2)};
socket = (BluetoothSocket) m.invoke(socket.getRemoteDevice(), params);
socket.connect();
Toast.makeText(context, "Connected", Toast.LENGTH_LONG).show();
} catch (Exception e2) {
Toast.makeText(context, "Couldn't establish Bluetooth connection -->" + e2.getMessage(), Toast.LENGTH_LONG).show();
}
}
}
Log.e("error", "No appropriate paired devices.");
} else {
Log.e("error", "Bluetooth is disabled.");
}
}
}
public boolean isConnected(){
return this.socket.isConnected();
}
public OutputStream getOutputStream() throws IOException {
return this.socket.getOutputStream();
}
public InputStream getInputStream() throws IOException {
return this.socket.getInputStream();
}
public void close() throws IOException {
this.socket.close();
}
public BluetoothSocket getSocket(){
return socket;
}
}
InputFilter class used for edittext
package com.example.dileep.blutooth_messenger;
import android.text.InputFilter;
import android.text.Spanned;
public class InputFilterMinMax implements InputFilter {
private int min, max;
public InputFilterMinMax(int min, int max) {
this.min = min;
this.max = max;
}
public InputFilterMinMax(String min, String max) {
this.min = Integer.parseInt(min);
this.max = Integer.parseInt(max);
}
#Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
try {
int input = Integer.parseInt(dest.toString() + source.toString());
if (isInRange(min, max, input))
return null;
} catch (NumberFormatException nfe) { }
return "";
}
private boolean isInRange(int a, int b, int c) {
return b > a ? c >= a && c <= b : c >= b && c <= a;
}
}
Can somebody please explain why the app and device getting hanged .Also please suggest the changes needed

My connection between php and android by json not working

I developed an app to connect my android app to remote server and display data in listview.
I did everything but the data doesn't show up in the listview.
These are the files I used to accomplish that, please help me:
MediaActivity.java
package com.shadatv.shada;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Locale;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.net.ParseException;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
public class MediaActivity extends OptionsMenu {
Locale locale;
// boolean mybooks;
Configuration config = new Configuration();
static SharedPreferences sharedPreferenceid;
static SharedPreferences.Editor editorid;
public static final String Myid = "Myid";
String myid = "";
InputStream is = null;
StringBuilder sb = null;
String resultt = "";
JSONArray jArray;
String result = null;
public DAOCanticles cantDatabase = null;
int numberofrowssss;
int responseCode;
String targetcover, targetbname, targetauthname;
public String caNameField = "", caLinkField = "", caImgField = "";
// ///////////////////ONLINE BESTSALED//////////////////////
String caNameJson, caLinkJson, caImgJson;
public ArrayList<String> caNameHolder = new ArrayList<String>();
public ArrayList<String> caLinkHolder = new ArrayList<String>();
public ArrayList<String> caImgHolder = new ArrayList<String>();
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.media);
cantDatabase = new DAOCanticles(this);
new LoadData().execute();
}
// =============================================================================
public void onClickPrograms(View view) {
startActivity(new Intent("com.shadatv.ProgramsActivity"));
}
// =============================================================================
public void onClickCanticles(View view) {
startActivity(new Intent("com.shadatv.CanticlesActivity"));
}
// =============================================================================
public void onClickDocumentaries(View view) {
startActivity(new Intent("com.shadatv.DocumentariesActivity"));
}
// =============================================================================
private class LoadData extends AsyncTask<Void, Void, Void> {
public ProgressDialog progressDialog1;
#Override
protected Void doInBackground(Void... params) {
cantDatabase.deletetable();
getCanticlesByJSON();
addCanticles();
return null;
}
#Override
// can use UI thread here
protected void onPreExecute() {
CharSequence contentTitle = getString(R.string.loading);
this.progressDialog1 = ProgressDialog.show(MediaActivity.this, "",
contentTitle);
}
// -------------------------------------------//
#Override
protected void onPostExecute(final Void unused) {
this.progressDialog1.dismiss();
}
}
// =============================================================================
public void getCanticlesByJSON() {
try {
HttpClient httpclient = new DefaultHttpClient();
try {
} catch (Exception e) {
Log.e("my_log_tag", e.toString());
}
// buffered reader
try {
HttpPost httppost = new HttpPost(
"http://dt-works.com/ags/shadatv/canticles/android_data");
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
BufferedReader reader = new BufferedReader(
new InputStreamReader(is, "UTF-8"), 80);
sb = new StringBuilder();
sb.append(reader.readLine() + "\n");
String line = "0";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = EntityUtils.toString(entity);
//result = sb.toString();
} catch (Exception e) {
Log.e("my_log_tag", e.toString());
}
try {
result = result.substring(1);
jArray = new JSONArray(result);
JSONObject json_data = null;
for (int i = 0; i < jArray.length(); i++) {
json_data = jArray.getJSONObject(i);
caNameJson = json_data.getString("ca_name");
caLinkJson = json_data.getString("ca_link");
caImgJson = json_data.getString("ca_link");
caNameHolder.add(caNameJson);
caLinkHolder.add(caLinkJson);
caImgHolder.add(caImgJson);
}
} catch (JSONException e) {
Log.e("my_log_tag", e.toString());
}
} catch (ParseException e) {
Log.e("my_log_tag", e.toString());
} catch (Exception e) {
Log.e("my_log_tag", e.toString());
}
}
// =============================================================================
public void addCanticles() {
try {
for (int i = 0; i < caNameHolder.size(); i++) {
caNameField = caNameHolder.get(i);
caLinkField = caLinkHolder.get(i);
caImgField = caImgHolder.get(i);
cantDatabase.createCanticle(caNameField, caLinkField,
caImgField);
}
} catch (Exception e) {
Log.e("my_log_tag", "notfilled yet");
}
}
}
CanticlesActivity.java
package com.shadatv.shada;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.zip.ZipInputStream;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;
import android.content.SharedPreferences;
import android.database.Cursor;
public class CanticlesActivity extends Activity {
int read;
boolean flage;
final Context context = this;
String picpath="http://img.youtube.com/vi/";
ArrayList<String> getCaName = new ArrayList<String>();
ArrayList<String> getCaLink = new ArrayList<String>();
ArrayList<String> getCaImg = new ArrayList<String>();
String targetCaName;
String targetCaLink;
String targetCaImg;
File sdcard = Environment.getExternalStorageDirectory();
File shadaRoot = new File (sdcard.getAbsolutePath() + "/Shada_Folder");
BitmapFactory.Options options = new BitmapFactory.Options();
Bitmap bm ;
ImageView img ;
public DAOCanticles cantDatabase =null;
byte[] encoded;
String value;
String useriddd;
//=============================================================================
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.canticles);
cantDatabase = new DAOCanticles(this);
new LoadData().execute();
}
//=============================================================================
private class LoadData extends AsyncTask<Void, Void, Void> {
private ProgressDialog progressDialog;
#Override
// can use UI thread here
protected void onPreExecute() {
CharSequence contentTitle = getString(R.string.loading);
this.progressDialog = ProgressDialog.show(CanticlesActivity.this,"",contentTitle);
}
//-------------------------------------------//
#Override
protected void onPostExecute(final Void unused) {
this.progressDialog.dismiss();
showCanticles();
}
//-------------------------------------------//
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
// HTTP post
getCanticles();
return null;
}
}
//=============================================================================
public void getCanticles() {
try{
Cursor canticles = cantDatabase.getCanticlesList();
do{
getCaName.add(canticles.getString(0));
getCaLink.add(canticles.getString(1));
getCaImg.add(canticles.getString(2));
}
while(canticles.moveToNext());
}catch(Exception e){
}
}
//=============================================================================
public void Downloadimage(String imgURL) {
try {
String finlpth="";
finlpth=picpath + imgURL + "/2.jpg";
shadaRoot.mkdirs();
URL u = new URL(finlpth);
HttpURLConnection c = (HttpURLConnection) u.openConnection();
c.setRequestMethod("GET");
c.setDoOutput(true);
c.connect();
File DownloadedFile=new File(shadaRoot, imgURL + ".jpg");
// if(!outfile.exists())
FileOutputStream f = new FileOutputStream(DownloadedFile);
InputStream in = c.getInputStream();
byte[] buffer = new byte[1024];
int len1 = 0;
while ((len1 = in.read(buffer)) > 0) {
f.write(buffer, 0, len1);
}
f.close();
} catch (Exception e) {
Log.d("Downloader", e.getMessage());
}
}
//=============================================================================
public void showCanticles()
{
final ListView listview = (ListView) findViewById(R.id.listView1);
for(int i=0; i < getCaName.size(); i++)
{
String caName=getCaName.get(i);
String caLink=getCaLink.get(i);
String caImg=getCaImg.get(i);
Toast.makeText(getBaseContext(), caName, Toast.LENGTH_SHORT).show();
if(!caImg.equalsIgnoreCase("0"))
{
Downloadimage(caLink);
}
}
listview.setOnItemClickListener(new ListView.OnItemClickListener(){
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
long selectedItemId = listview.getSelectedItemId();
ListAdapter adapterr = listview.getAdapter();
String selectedValue = (adapterr.getItem(position)).toString();
String selectedCaName=getCaName.get(position);
String selectedCaLink=getCaLink.get(position);
// // custom dialog
final Dialog dialog = new Dialog(context);
dialog.setContentView(R.layout.customdialogue);
dialog.setTitle(selectedCaName);
// set the custom dialog components - text, image and button
String selectedbookcover=getCaImg.get(position);
String test= shadaRoot+"/"+ selectedCaName;
String myJpgPath = test+".jpg";
TextView caLink = (TextView) dialog.findViewById(R.id.ca_link);
caLink.setText(selectedCaLink);
options.inSampleSize = 6;
Button dialogButton = (Button) dialog.findViewById(R.id.dialogButtonOK);
// if button is clicked, close the custom dialog
dialogButton.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
dialog.dismiss();
}
});
dialog.show();
dialog.getWindow().setLayout(350,350);
}
});
listview.setAdapter(new DataAdapter(
CanticlesActivity.this,
getCaName.toArray(new String[getCaName.size()]),
getCaLink.toArray(new String[getCaLink.size()]),
getCaImg.toArray(new String[getCaImg.size()])));
}
}
canticles.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/LinearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#drawable/bg1"
android:orientation="vertical" >
<ListView
android:id="#+id/listView1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:divider="#b5b5b5"
android:dividerHeight="1dp"
android:listSelector="#drawable/list_selector" >
</ListView>
</LinearLayout>
custom_grid.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#drawable/list_selector"
android:gravity="left"
android:orientation="horizontal"
android:padding="10dip" >
<!-- ListRow Left sied Thumbnail image -->
<ImageView
android:id="#+id/caImgView"
android:layout_width="57dip"
android:layout_height="84dip"
android:layout_alignLeft="#+id/linearLayout1"
android:layout_alignTop="#+id/linearLayout1"
android:paddingLeft="0dip"
android:scaleType="fitXY"
android:src="#drawable/noimage" />
<LinearLayout
android:id="#+id/linearLayout2"
android:layout_width="170dip"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/targetmonth1"
android:layout_alignTop="#+id/targetmonth1"
android:layout_marginLeft="16dp"
android:layout_toRightOf="#+id/targetmonth1"
android:orientation="vertical"
android:padding="0dip" >
<TextView
android:id="#+id/caNameView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/linearLayout1"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal"
android:text="dddddddd"
android:textColor="#040404"
android:textSize="13dip"
android:textStyle="bold"
android:typeface="sans" />
<TextView
android:id="#+id/caLinkView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/caNameView"
android:layout_alignRight="#+id/caNameView"
android:layout_below="#+id/caNameView"
android:layout_gravity="center_horizontal"
android:text="author"
android:textColor="#343434"
android:textSize="9dip"
android:typeface="sans" />
</LinearLayout>
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:src="#drawable/arrow" />
</RelativeLayout>

use this
public List< String> caNameHolder = new ArrayList< String>();
instead of
public ArrayList< String> caNameHolder = new ArrayList< String>();