Develop Reference

android 4.3 - BufferedReader shows Please Wait message

I have the following function to allow my android app to communicate with a web server. However the app shows a 'Please Wait' message when I call this code and only disappears if a new activity loads in or if I press the back button. Where is the Please wait coming from and how can I avoid it appearing? Thanks
package util.sapa.sapacontainermanager5;
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;
public class SimpleWebCalls {
public String executeHttpGet(String serverIP, String nvp) {
String lines="";
serverIP="???????????";
URL url = null;
try {
url = new URL("http://" + serverIP + "/WCF.aspx?" + nvp);
HttpURLConnection conn = null;
try {
conn = (HttpURLConnection) url.openConnection();
try {
conn.setRequestMethod("GET");
BufferedReader in = null;
try {
in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuffer sb = new StringBuffer("");
String line = "";
String NL = System.getProperty("line.separator");
while ((line = in.readLine()) != null) {
sb.append(line + NL);
lines+=line;
}
in.close();
return lines;
} catch (IOException e) {
e.printStackTrace();
}
} catch (ProtocolException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
} catch (MalformedURLException e) {
e.printStackTrace();
}
return "";
}
}
the above class is called from:
public String GetDataFromServer(String serverIP,String nvp) {
SimpleWebCalls tWebCall = new SimpleWebCalls();
String sReturn="";
sReturn= tWebCall.executeHttpGet(serverIP,nvp);
return sReturn;
}
the above function is called from:
String data="";
data="doAction=location&u=" + sess.getUserName()+
"&p=" + sess.getPwd() +
"&uid=" + sess.getUserID() +
"&lf=" + sess.encodeStr(editScannedCode.getText().toString());
result = sess.GetDataFromServer(serverIP,data);

follow this tutorial link it might be helpful to you.
add GetDataFromServer() method in to your doInBackground() method.

Android InputStream reads garbage ServerSocket running in a Thread. How should ServerSocket read from client socket?

I have a an application which communicates between two android devices through socket. It seems like they do connect, but when data from the client socket is read by ServerSocket (using InputStream), it doesnot return the desired result (it is supposed to return somrthing like "21.24891706//95.23659845//ff8iuj67898n47fu" ).Instead I'm getting " [B#416b9488" as the message.
My client runs an AsyncTask and server runs a Thread.
Can you please help me solve this problem? Any help will is appreciated. Thanks in advance.
Here is Server.java which runs on the server:
import android.content.Context;
import android.widget.Toast;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.Enumeration;
public class Server {
Context context;
ServerSocket serverSocket;
String message = "";
static final int socketServerPORT = 8080;
ShowConnectedStudents activity;
public Server(ShowConnectedStudents callingActivity) {
activity = callingActivity;
Thread socketServerThread = new Thread(new SocketServerThread());
socketServerThread.start();
}
public int getPort() {
return socketServerPORT;
}
public void onDestroy() {
if (serverSocket != null) {
try {
serverSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private class SocketServerThread extends Thread {
int count = 0;
byte buffer[] = new byte[1024];
int bytesRead;
String message;
#Override
public void run() {
try {
// create ServerSocket using specified port
serverSocket=new ServerSocket();
serverSocket.setReuseAddress(true);
serverSocket.bind(new InetSocketAddress(socketServerPORT));
while (true) {
// block the call until connection is created and return
// Socket object
Socket socket = serverSocket.accept();
message = "";
InputStream input = socket.getInputStream();
BufferedInputStream br= new BufferedInputStream(input);
while ((bytesRead = br.read(buffer)) != -1 ) {
message += " " + buffer.toString();
}
message += socket.isConnected();
message+=":"+socket.isClosed();
input.close();
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
activity.status.setText("Message is: " + message);
}
});
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
Here is Client.java which runs on the client:
import android.os.AsyncTask;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.Socket;
import java.net.UnknownHostException;
public class Client extends AsyncTask<Void, Void, Void> {
String dstAddress;
int dstPort;
String status = "";
double Lat,Long;
String deviceId;
Socket socket = null;
ConnectToDevice activity;
byte buffer[] = new byte[1024];
int bytesRead;
Client(String addr, int port,double latitude,double longitude,String deviceIdentification,ConnectToDevice callingActivity) {
dstAddress = addr;
dstPort = port;
Lat=latitude;
Long=longitude;
deviceId=deviceIdentification;
activity=callingActivity;
if(dstAddress.charAt(0)=='/'){
dstAddress=dstAddress.substring(1);
}
}
#Override
protected Void doInBackground(Void... arg0) {
while(socket==null){
try {
socket = new Socket(dstAddress, dstPort);
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
OutputStream outputStream = socket.getOutputStream();
PrintStream printStream = new PrintStream(outputStream,true);
printStream.print(Lat + "//" + Long+"//"+deviceId);
printStream.flush();
} catch (UnknownHostException e) {
e.printStackTrace();
status = "UnknownHostException: " + e.toString();
} catch (IOException e) {
e.printStackTrace();
status = "IOException: " + e.toString();
} finally {
}
return null;
}
#Override
protected void onPostExecute(Void result) {
activity.statusText.setText(Lat+ "//" + Long+"//"+deviceId);
super.onPostExecute(result);
}
}

toString() on a byte[] is not what you want, you're getting basically the memory address of the byte array
instead convert to a string, something like this
while ((bytesRead = br.read(buffer)) != -1 ) {
message += " " + new String(buffer, 0, bytesRead);
}

I have figured out another way, before reading this accepted answer. I'm posting it in case if it benefit anyone.
My data is text-only. So I wrapped the socket's input stream inside a Scanner.
InputStream input = socket.getInputStream();
Scanner scanner= new Scanner(input);
while(scanner.hasNextLine()){
message+=scanner.nextLine();
}

Unable to read data (send by server) at Client Side

I am trying to develop an app in which
1.client sends request to server for connection(IP address+PORT no.)+sends data using "PrintStream"+Tries to read the data from Server(Using Inputstream)
2.Client creates the socket.
3.Server reads the data send by Client
4.SERVER writes the data using "PrintStream" at same time point no 3.
Problem is at point 4 Data written by SERVER is not Read by "INPUTSTREAM" of client(Point 1)
I dont know these Simultaneous operation are possible or not.If possible then how.If not then what is the alternate way?
Server Code
package com.example.loneranger.ser;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.Enumeration;
public class MainActivity extends Activity {
TextView ip;
TextView msg;
String data = "";
ServerSocket httpServerSocket;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ip = (TextView) findViewById(R.id.infoip);
msg = (TextView) findViewById(R.id.msg);
ip.setText(getIpAddress() + ":"
+ 8080 + "\n");
Server server = new Server();
server.start();
}
#Override
protected void onDestroy() {
super.onDestroy();
if (httpServerSocket != null) {
try {
httpServerSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
private String getIpAddress() {
String ip = "";
try {
Enumeration<NetworkInterface> enumNetworkInterfaces = NetworkInterface
.getNetworkInterfaces();
while (enumNetworkInterfaces.hasMoreElements()) {
NetworkInterface networkInterface = enumNetworkInterfaces
.nextElement();
Enumeration<InetAddress> enumInetAddress = networkInterface
.getInetAddresses();
while (enumInetAddress.hasMoreElements()) {
InetAddress inetAddress = enumInetAddress.nextElement();
if (inetAddress.isSiteLocalAddress()) {
ip += "IP: "
+ inetAddress.getHostAddress() + "\n";
}
}
}
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
ip += "Something Wrong! " + e.toString() + "\n";
}
return ip;
}
private class Server extends Thread {
#Override
public void run() {
Socket socket = null;
try {
httpServerSocket = new ServerSocket(8888);
while(true){
socket = httpServerSocket.accept();
HttpResponseThread httpResponseThread =
new HttpResponseThread(
socket);
httpResponseThread.start();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private class HttpResponseThread extends Thread {
Socket socket;
HttpResponseThread(Socket socket){
this.socket = socket;
}
#Override
public void run() {
BufferedReader BReader;
PrintWriter printer;
String request;
try { InputStream inputStream = socket.getInputStream();
BReader = new BufferedReader(new InputStreamReader(inputStream));
request = BReader.readLine();
Thread.sleep(500);
printer = new PrintWriter(socket.getOutputStream(), true);
printer.print("hello laundu");
printer.flush();
String ip123=socket.getInetAddress().toString();
printer.close();
BReader.close();
socket.close();
data += "Request of " + request
+ " from "+ ip123 + "\n";
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
msg.setText(data);
}
});
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
return;
}
}
}
Client Code
mport android.os.AsyncTask;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.net.Socket;
import java.net.UnknownHostException;
public class Client extends AsyncTask<Void, Void, Void> {
String dstAddress;
int dstPort;
String response = "";
TextView textResponse;
MainActivity activity;
OutputStream outputStream;
BufferedReader BReader;
String request;
Client(String addr, int port, TextView textResponse) {
dstAddress = addr;
dstPort = port;
this.textResponse=textResponse;
this.activity=activity;
}
#Override
protected Void doInBackground(Void... arg0) {
Socket socket = null;
try {
socket = new Socket(dstAddress, dstPort);
Server server = new Server(socket);
server.start();
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())),
true);
out.print("futfujb");
out.flush();
/*
* notice: inputStream.read() will block if no data return
*/
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
response = "UnknownHostException: " + e.toString();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
response = "IOException: " + e.toString();
} /*finally {
if (socket != null) {
try {
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}*/
return null;
}
#Override
protected void onPostExecute(Void result) {
textResponse.setText(response);
super.onPostExecute(result);
}
private class Server extends Thread {
Socket socket;
Server(Socket socket)
{
this.socket=socket;
}
#Override
public void run() {
try { //Thread.sleep(500);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(
1024);
byte[] buffer = new byte[1024];
int bytesRead;
InputStream inputStream = socket.getInputStream();
if(inputStream.available()>0)
{
while ((bytesRead = inputStream.read(buffer)) != -1) {
byteArrayOutputStream.write(buffer, 0, bytesRead);
response += byteArrayOutputStream.toString("UTF-8");
}
}
inputStream.close();
socket.close();
}
catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

As I commented above, there is nothing in this code that corresponds to either of these steps:
2.Server gets the request creates new SOCKET connection.
(a) There is no request, and (b) the server does not create a new connection. The client creates it. The server accepts it.
3.Server reads the data send by Client.
The client doesn't send any data.
There are two problems here (at least):
The server is blocking in readLine() waiting for a message that the client never sends. So it never gets to its own send, so nothing is received by the client. Have the client send a request, as per the comments.
The client is incorrectly using available(). Remove this test and let the client fall through into the read loop. It will exit that when the peer (the server) closes the connection.

NetworkOnMainThreadException android activity [duplicate]

This question already has answers here:
How can I fix 'android.os.NetworkOnMainThreadException'?
(66 answers)
Closed 6 years ago.
I am using this code to retrieve website data inside android activity.It is throwing android.os.networkonmainthreadexception
try
{
URL url = new URL("https://enigmatic-woodland-35608.herokuapp.com/pager.json");
URLConnection tc = url.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(
tc.getInputStream()));
String line, newl = " ";
while ((line = in.readLine()) != null) {
newl += line.trim();
}
System.out.println("newl" + newl.trim());
} catch (Exception e) {
Log.e("exception", e.toString());
}
Please give me a possible solution..

Network oprations/call cannot be done in main thread. You need to run it from another thread , asynchronous task or an intent service
Note : All UI opration shoud be done onPostExecute,onPreExecute
The below code may help you to solve.
Call AsyncTask where you want
new PagerAsyncTask().execute();
class PagerAsyncTask extends AsyncTask<String,Void,String>{
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... params) {
StringBuilder sb=null;
BufferedReader reader=null;
String serverResponse=null;
try {
URL url = new URL(""https://enigmatic-woodland-35608.herokuapp.com/pager.json"");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
connection.setConnectTimeout(5000);
connection.setRequestMethod("GET");
connection.connect();
int statusCode = connection.getResponseCode();
//Log.e("statusCode", "" + statusCode);
if (statusCode == 200) {
sb = new StringBuilder();
reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
}
connection.disconnect();
if (sb!=null)
serverResponse=sb.toString();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
return serverResponse;
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
//All your UI operation can be performed here
//Response string can be converted to JSONObject/JSONArray like
JSONObject response=new JSONObject(s);
System.out.println(s);
}
}

Network operations can involve unpredictable delays. To prevent this
from causing a poor user experience, always perform network operations
on a separate thread from the UI.
Please check the doc.

I am using a NetworkOps util in my projects. Try it:
import android.content.Context;
import android.net.Uri;
import android.util.Log;
import com.csehelper.variables.Constants;
import com.csehelper.variables.Keys;
import com.csehelper.variables.Url;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.ProtocolException;
import java.net.SocketTimeoutException;
import java.net.URL;
import java.util.ArrayList;
public class NetworkOps {
public final String EXCEPTION = "~Exception~";
/****************************
* Method to Grab Source
****************************/
public static String GrabSource(String URL) {
return PostData(URL, null);
}
/**
* *****************************************
* Method to Grab Source code from URL
* Posting Data
* *****************************************
*/
private static String PostData(String url, Uri.Builder uribuilder) {
String Source;
HttpURLConnection.setFollowRedirects(false);
HttpURLConnection urlConnection = null;
try {
urlConnection = (HttpURLConnection) new URL(url).openConnection();
urlConnection.setDoOutput(true);
urlConnection.setConnectTimeout(10000);
if(uribuilder != null) {
String query = uribuilder.build().getEncodedQuery();
OutputStream os = urlConnection.getOutputStream();
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(os, "UTF-8"));
writer.write(query);
writer.flush();
writer.close();
os.close();
}
urlConnection.connect();
if (urlConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
String line;
StringBuilder builder = new StringBuilder();
InputStreamReader isr = new InputStreamReader(
urlConnection.getInputStream());
BufferedReader reader = new BufferedReader(isr);
while ((line = reader.readLine()) != null) {
builder.append(line);
}
Source = builder.toString();
} else {
Source = EXCEPTION + "Server unreachable. Check network connection.";
}
} catch (SocketTimeoutException e) {
Source = EXCEPTION + "Connection timed out.";
} catch (java.net.UnknownHostException e) {
Source = EXCEPTION + Constants.EXCEPTION_NO_NET;
} catch (ArrayIndexOutOfBoundsException e) {
Source = EXCEPTION + "Server error";
} catch (ProtocolException e) {
Source = EXCEPTION + "Protocol error";
} catch (IOException e) {
Source = EXCEPTION + "Server unreachable. Check network connection.";
} catch (Exception e) {
Source = EXCEPTION + "Error:" + e.toString() + " - "
+ e.getMessage();
e.printStackTrace();
} finally {
if (urlConnection != null) urlConnection.disconnect();
}
return Source;
}
}
Call these Static Functions from AsyncTask:
/*********************************
* AsyncTask to GrabSource
********************************/
class AsyncTask_GrabSource extends AsyncTask<Void, Void, Void> {
String Source = null;
String url = "https://enigmatic-woodland-35608.herokuapp.com/pager.json";
#Override
protected void onPreExecute() {
//Runs on Main Thread. You can access your UI elements here.
}
#Override
protected Void doInBackground(Void... params) {
// Don't access any UI elements from this function
Source = NetworkOps.GrabSource(this.url);
return null;
}
#Override
protected void onPostExecute(Void result) {
if (Source != null) {
if (!Source.contains(EXCEPTION)) {
//Show Error Message or do whatever you want
} else {
//Do Whatever with your Grabbed Sourcecode.
// This function runs on UI Thread, so you can update UI elements here
}
}
}
You can also post data with the function PostData. In method doInBackground, add this:
Uri.Builder builder = new Uri.Builder()
.appendQueryParameter("key", "value")
.appendQueryParameter("key2", "value2");
Source = NetworkOps.PostData(getApplicationContext(), url, builder);

Basic android http get

I'm a android noob on programming, but with some help of a few programms I can learn the basics. I would like to do a basic http get request to an arduino ethernetshield.
For this I've found some code, but I can't get it to work.
I'm allways stuck on the getResponse part with the code I've tried from several pages.
I've found the following page which gave me readable code:
How to work with an image using url in android?
Now I've created the following:
Press on a button and do a get to an url:
package adhttpget.test;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.URL;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
public class AdhttpgetActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void pushbutton1(View view) {
Toast.makeText(getBaseContext(), "button press", Toast.LENGTH_SHORT).show();
Log.e("button", "pressed");
URL connectURL = new URL("http://192.168.0.48/?out=13&status=2");
HttpURLConnection conn = (HttpURLConnection)connectURL.openConnection();
// do some setup
conn.setDoInput(true);
conn.setDoOutput(true);
conn.setUseCaches(false);
conn.setRequestMethod("GET");
// connect and flush the request out
conn.connect();
conn.getOutputStream().flush();
// now fetch the results
String response = getResponse(conn); // <-- THIS IS MY PROBLEM
}
private String getResponseOrig(HttpURLConnection conn)
{
InputStream is = null;
try
{
is = conn.getInputStream();
// scoop up the reply from the server
int ch;
StringBuffer sb = new StringBuffer();
while( ( ch = is.read() ) != -1 ) {
sb.append( (char)ch );
}
return sb.toString();
}
catch(Exception e)
{
Log.e("http", "biffed it getting HTTPResponse");
}
finally
{
try {
if (is != null)
is.close();
} catch (Exception e) {}
}
return "";
}
}
Where can I find information to learn how to write the code correctly?
Or do you happen to have the answer in some kind of hint so I can learn from it?

You must create a BufferedReader passing the InputStream, then you can read strings
private static String convertStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
Then I recommend you make the connection (or read/write file) with a separeted thread from the Thread UI (use Thread, AsyncTask, Handler, etc) because that will improve your app.
http://developer.android.com/intl/es/guide/components/processes-and-threads.html