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How do I get my app to give me message "Net not connected" instead of crashing [closed]

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My app crashes, and I am unable to find the error.
I would like it to give me a message saying the network is not connected.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
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.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
public class SimpleForm extends Activity {
private EditText editTextUserName;
private EditText editTextPassword;
//public static final String USER_NAME = "USERNAME";
String username;
String password;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_registeration);
editTextUserName = (EditText) findViewById(R.id.et_username_ID);
editTextPassword = (EditText) findViewById(R.id.et_pass_ID);
}
public void invokeLogin(View view){
username = editTextUserName.getText().toString();
password = editTextPassword.getText().toString();
login(username,password);
}
private void login(final String username, String password) {
class LoginAsync extends AsyncTask<String, Void, String>{
private Dialog loadingDialog;
#Override
protected void onPreExecute() {
super.onPreExecute();
loadingDialog = ProgressDialog.show(SimpleForm .this, "Please wait", "Loading...");
}
#Override
protected String doInBackground(String... params) {
//String uname = params[0];
// String pass = params[1];
JSONObject jsonObject = new JSONObject();
try {
jsonObject.accumulate("username", params[0]);
} catch (JSONException e4) {
// TODO Auto-generated catch block
e4.printStackTrace();
}
try {
jsonObject.accumulate("password", params[1]);
} catch (JSONException e3) {
// TODO Auto-generated catch block
e3.printStackTrace();
}
try {
jsonObject.accumulate("deviceToken", "2324h5gj345gj3h4g5j");
} catch (JSONException e5) {
// TODO Auto-generated catch block
e5.printStackTrace();
}
try {
jsonObject.accumulate("os", "android");
} catch (JSONException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
try {
jsonObject.accumulate("key", "MEu07MgiuWgXwJOo7Oe1aHL0yM8P");
} catch (JSONException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
// 4. convert JSONObject to JSON to String
String dataString = jsonObject.toString();
//String dataString = {"username":"apitest","password":"123456","deviceToken":"2324h5gj345gj3h4g5j34g","os":"andriod","key":"MEu07MgiuWgXwJOo7Oe1aHL0yM8VvP"}
InputStream is = null;
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
nameValuePairs.add(new BasicNameValuePair("data", dataString));
//nameValuePairs.add(new BasicNameValuePair("password", pass));
String result = null;
try{
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(
"http://mobile.betfan.com/api/?action=login");
//http://mobile.betfan.com/api/?action=login
//http://192.168.1.10/mobiletest/process.php
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpClient.execute(httpPost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
}
result = sb.toString();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
protected void onPostExecute(String result){
String s = result.trim();
loadingDialog.dismiss();
JSONObject respObject;
try {
respObject = new JSONObject(s);
String active = respObject.getString("status_message");
if(active.equalsIgnoreCase("success")){
Toast.makeText(getApplicationContext(), s+"Login successfull", Toast.LENGTH_LONG).show();
Intent intent=new Intent(SimpleForm.this,Welcome.class);
startActivity(intent);
// Intent intent = new Intent(MainActivity.this, UserProfile.class);
//intent.putExtra(USER_NAME, username);
// finish();
//startActivity(intent);
}else {
Toast.makeText(getApplicationContext(), "Login Fail", Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
LoginAsync la = new LoginAsync();
la.execute(username, password);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}

Before you use any code that requires network connectivity, you can call a method like this to check for connectivity:
private boolean isConnected() {
ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
return networkInfo != null && networkInfo.isConnectedOrConnecting();
}

How to print the entire JSON output?

Please have a look at the following code
package com.example.jsontest;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
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 android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity {
private EditText editText;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
StrictMode.ThreadPolicy policy = new StrictMode.
ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
setContentView(R.layout.activity_main);
editText = (EditText)findViewById(R.id.edit_text);
//Call The JSon
try {
JSONObject jObject = new JSONObject(getJson());
int code = jObject.getInt("code");
editText.append("Code: "+code+"\n");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private String getJson()
{
DefaultHttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("https://bigml.io/andromeda/source/5277b1bd035d074e940056e0?username=xxx;api_key=xxxxxxxxxxxxxxx");
// Depends on your web service
httppost.setHeader("Content-type", "application/json");
InputStream inputStream = null;
String result = null;
try {
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
inputStream = entity.getContent();
// json is UTF-8 by default
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
}
result = sb.toString();
} catch (Exception e) {
// Oops
}
finally {
try{if(inputStream != null)inputStream.close();}catch(Exception squish){}
}
return result;
}
}
In here, what I need to do is, print the "entire" result I retrieved. I wish to print the entire thing, I don't need to get separate values. How can I do this? Here is the link to the BigML retrieve documentation.

Just use JSONObject.toString() ?

You should never connect to network on main thread. Best and the most simple option is to use AsyncTask<...>.
something like this:
private class DownloadProductsTask extends AsyncTask<Void, Void, String> {
#Override
protected String doInBackground(Void... params) {
try {
return new PublicDataDBManager().retriveJsonData(mCode, mUserMail);
} catch (Exception e) {
}
return null;
}
#Override
protected void onPostExecute(String result){
buildData(result);// here you update mathod in your main thread
}
}
Here is simple example: http://androide-examples.blogspot.com/2013/11/android-retrieve-json-data-from-url.html

So I ran your code, and it crashed. I also see that you are bypassing security and doing network operations in onCreate, in the main thread. This isn't a good idea in Android. Network operations should go in a background thread.
I refactored it very quickly to use a thread and it worked. Here is the code:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText = (EditText)findViewById(R.id.edit_text);
}
#Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
new Thread(new Runnable() {
#Override
public void run() {
JSONObject jObject;
try {
jObject = new JSONObject(getJson());
// I am logging the raw value that was returned here
Log.i("JSON Body", jObject.toString());
int code = jObject.getInt("code");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}).start();
}
If you want to update the main thread (MainActivity) within the thread, create a Handler and pass a reference to that into the thread, and use that for updates.

async task fails when i try to use params

guys. I have this code:
package com.example.httpprogress;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
public class MyPicGetTask extends AsyncTask<URL , Void, Bitmap>{
InputStream is = null;
BufferedInputStream bis = null;
Bitmap bmp = null;
#Override
protected Bitmap doInBackground(URL... urls) {
// TODO Auto-generated method stub
URL url = urls[0];
try {
URLConnection conn = url .openConnection();
conn.connect();
is = conn.getInputStream();
bis = new BufferedInputStream( is );
bmp = BitmapFactory.decodeStream( bis );
} catch (MalformedURLException e) {
} catch (IOException e) {
} finally {
try {
is.close();
bis.close();
} catch (IOException e) {
}
}
return bmp;
}
}
it fails, but if i use AsyncTask and describe this class as inner in my activity - it's ok . I can not say the reason because i can not debug, i can see that debug tab opens when it fails but it is not informative for me. Any ideas? Sorry for my noob question
that's my Activity:
package com.example.httpprogress;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import android.app.Activity;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;
public class PicActivity extends Activity implements OnClickListener{
InputStream is = null;
BufferedInputStream bis = null;
Bitmap bmp = null;
private URL url;
//"http://192.168.0.30/03.jpg";
/*
private class getPicTask extends AsyncTask<Void, Void, Void>{
#Override
protected Void doInBackground(Void... s) {
// TODO Auto-generated method stub
try {
url = new URL("http://192.168.0.93/image.php");
} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
URLConnection conn = url .openConnection();
conn.connect();
is = conn.getInputStream();
bis = new BufferedInputStream( is );
bmp = BitmapFactory.decodeStream( bis );
} catch (MalformedURLException e) {
} catch (IOException e) {
} finally {
try {
is.close();
bis.close();
} catch (IOException e) {
}
}
return null;
}
};
*/
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pic);
final ImageView image = (ImageView) findViewById(R.id.imageView1);
image.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
///////////
try {
url = new URL("http://192.168.0.30/03.jpg");
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
new MyPicGetTask().execute(url);
image.setImageBitmap(bmp);
}
});
////////////////
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.pic, menu);
////////////////
return true;
}
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
Log.d("httpProgress", "Onclick()");
}
}

Add Log.d() code to doInBackground(...) to print out all exceptions that occur. That should tell you what's going wrong, e.g.
try {
URLConnection conn = url .openConnection();
conn.connect();
is = conn.getInputStream();
bis = new BufferedInputStream( is );
bmp = BitmapFactory.decodeStream( bis );
} catch (Exception e) {
Log.d("Async","EXCEPTION",e);
} finally {
try {
is.close();
bis.close();
} catch (IOException e) {
Log.d("Close","EXCEPTION",e);
}
}

When the MyPicGetTask is an inner class it has access to the bmp field. When you pulled it out of your activity it lost access to the bmp class field.
I would suggest reading Google's documentation and following their examples for AsyncTasks.

The bitmap you return from doInBackground should then be used to update your UI in onPostExecute.
protected void onPostExecute(Bitmap bitmap) {
image.setImageBitmap(bitmap);
}
Your asyncTask subclass needs access to image in order to update the UI, so having it as a inner class is one way to make sure it can do this.

Your AsyncTask if you're using it as a public class outside the activity in which you are calling it needs to recieve the context of that activity. There are a number of posts here, here and here that explain how to set this up.

Applications crashes in 3.0 but works fine in 2.3.3

Hi guys im trying to create a application that uses a socket connection i was going across some examples, the piece of code below works fine when i run it on 2.3.3 and the same crashes in 3.0.
package com.simple.client;
import android.app.Activity;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.net.UnknownHostException;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.os.Bundle;
public class SimpleClientActivity extends Activity {
EditText textOut;
TextView textIn;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
textOut = (EditText)findViewById(R.id.textout);
Button buttonSend = (Button)findViewById(R.id.send);
textIn = (TextView)findViewById(R.id.textin);
buttonSend.setOnClickListener(buttonSendOnClickListener);
}
Button.OnClickListener buttonSendOnClickListener
= new Button.OnClickListener(){
public void onClick(View arg0) {
// TODO Auto-generated method stub
Socket socket = null;
DataOutputStream dataOutputStream = null;
DataInputStream dataInputStream = null;
try {
socket = new Socket("172.16.2.172", 8899);
dataOutputStream = new DataOutputStream(socket.getOutputStream());
dataInputStream = new DataInputStream(socket.getInputStream());
dataOutputStream.writeUTF(textOut.getText().toString());
textIn.setText(dataInputStream.readUTF());
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
e.printStackTrace();
}
finally{
if (socket != null){
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (dataOutputStream != null){
try {
dataOutputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (dataInputStream != null){
try {
dataInputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}};
}
I have tried all but not able to figure out what is happening,

My guess is, the error caused by StrictMode.ThreadPolicy. In android 3.0, you can't access network in the same UI thread.

Do you have multiple resource folders for your layouts? if yes, maybe you do not have its related layout.

How can i parse the last 3 tweets instead of the last 1 with json

i got this code working and it to return the last tweet from my brother, i would like to it to return the last 3 tweets can somebody help me? im not really good in java or xml i just followed a few tutorials from mybringback, please ignore my bad English.
i think the problem is in the line: JSONObject last = timeline.getJSONObject(0); this makes it return the first tweet so how do i alter this so it returns the first 3? (0, 1 ,2) isn't allowed :(
package net.thinkbin;
import java.io.IOException;
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.methods.HttpGet;
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.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class menu extends Activity {
TextView httpStuff;
HttpClient client;
JSONObject json;
final static String URL = "http://api.twitter.com/1/statuses/user_timeline.json?screen_name=";
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
httpStuff = (TextView) findViewById(R.id.tvHttp1);
client = new DefaultHttpClient();
new Read().execute("Title");
Button view = (Button) findViewById(R.id.button1);
view.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
startActivity(new Intent("net.thinkbin.TUTORIAL1"));
finish();
}
});
Button share = (Button) findViewById(R.id.button2);
share.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
startActivity(new Intent("net.thinkbin.SHARE"));
finish();
}
});
}
public JSONObject lastTweet(String username)
throws ClientProtocolException, IOException, JSONException{
StringBuilder url = new StringBuilder(URL);
url.append(username);
System.out.println(url.toString());
HttpGet get = new HttpGet(url.toString());
HttpResponse r = client.execute(get);
int status = r.getStatusLine().getStatusCode();
if (status == 200){
HttpEntity e = r.getEntity();
String data = EntityUtils.toString(e);
JSONArray timeline = new JSONArray(data);
JSONObject last = timeline.getJSONObject(0);
return last;
}else{
Toast.makeText(menu.this, "error", Toast.LENGTH_SHORT);
return null;
}
}
public class Read extends AsyncTask<String, Integer, String>{
#Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
try {
json = lastTweet("koen*****");
return json.getString("params[0]");
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
httpStuff.setText(result);
}
}
}

https://api.twitter.com/1/statuses/user_timeline.xml?screen_name=username&count=3
use this url instead of your url
Just a minor change in your url is append "&count=3"

use DilSe url and try this code.
public JSONArray lastTweet(String username)
throws ClientProtocolException, IOException, JSONException{
StringBuilder url = new StringBuilder(URL);
url.append(username);
System.out.println(url.toString());
HttpGet get = new HttpGet(url.toString());
HttpResponse r = client.execute(get);
int status = r.getStatusLine().getStatusCode();
if (status == 200){
HttpEntity e = r.getEntity();
String data = EntityUtils.toString(e);
return new JSONArray(data);
}else{
Toast.makeText(menu.this, "error", Toast.LENGTH_SHORT);
return null;
}
}
public class Read extends AsyncTask<String, Integer, String>{
#Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
try {
JSONArray timeline = lastTweet("koen*****");
return timeline.getJSONObject(0).getString("params[0]")+" : "
+timeline.getJSONObject(1).getString("params[0]")+" : "
+timeline.getJSONObject(2).getString("params[0]");
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
httpStuff.setText(result);
}