Develop Reference

Google Cloud Printing: read property 'o' of null

I facing to problem when use Google Cloud Printing when Print Button was clicked.
This's error show in debug mode
Uncaught TypeError: Cannot read property 'o' of null", source: https://www.google.com/cloudprint/client/2026774633-dialog_mobile__vi.js (295)
Does anyone has a solution for this problem?
Edit 1
This's my code for class PrintDialogActivity.java
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.ContentResolver;
import android.content.Intent;
import android.os.Bundle;
import android.util.Base64;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
#SuppressLint("SetJavaScriptEnabled")
public class PrintDialogActivity extends Activity {
private static final String PRINT_DIALOG_URL = "https://www.google.com/cloudprint/dialog.html";
private static final String JS_INTERFACE = "AndroidPrintDialog";
private static final String CONTENT_TRANSFER_ENCODING = "base64";
private static final String ZXING_URL = "http://zxing.appspot.com";
private static final int ZXING_SCAN_REQUEST = 65743;
/**
* Post message that is sent by Print Dialog web page when the printing dialog
* needs to be closed.
*/
private static final String CLOSE_POST_MESSAGE_NAME = "cp-dialog-on-close";
/**
* Web view element to show the printing dialog in.
*/
private WebView dialogWebView;
/**
* Intent that started the action.
*/
Intent cloudPrintIntent;
#SuppressLint("JavascriptInterface") #Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.print_dialog);
dialogWebView = (WebView) findViewById(R.id.webview);
cloudPrintIntent = this.getIntent();
WebSettings settings = dialogWebView.getSettings();
settings.setJavaScriptEnabled(true);
settings.setDomStorageEnabled(true);
dialogWebView.setWebViewClient(new PrintDialogWebClient());
dialogWebView.addJavascriptInterface(
new PrintDialogJavaScriptInterface(), JS_INTERFACE);
dialogWebView.loadUrl(PRINT_DIALOG_URL);
}
#Override
public void onActivityResult(int requestCode, int resultCode, Intent intent) {
if (requestCode == ZXING_SCAN_REQUEST && resultCode == RESULT_OK) {
dialogWebView.loadUrl(intent.getStringExtra("SCAN_RESULT"));
}
}
final class PrintDialogJavaScriptInterface {
public String getType() {
return cloudPrintIntent.getType();
}
public String getTitle() {
return cloudPrintIntent.getExtras().getString("title");
}
public String getContent() {
try {
ContentResolver contentResolver = getContentResolver();
InputStream is = contentResolver.openInputStream(cloudPrintIntent.getData());
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[4096];
int n = is.read(buffer);
while (n >= 0) {
baos.write(buffer, 0, n);
n = is.read(buffer);
}
is.close();
baos.flush();
return Base64.encodeToString(baos.toByteArray(), Base64.DEFAULT);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return "";
}
public String getEncoding() {
return CONTENT_TRANSFER_ENCODING;
}
public void onPostMessage(String message) {
if (message.startsWith(CLOSE_POST_MESSAGE_NAME)) {
finish();
}
}
}
private final class PrintDialogWebClient extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if (url.startsWith(ZXING_URL)) {
Intent intentScan = new Intent("com.google.zxing.client.android.SCAN");
intentScan.putExtra("SCAN_MODE", "QR_CODE_MODE");
try {
startActivityForResult(intentScan, ZXING_SCAN_REQUEST);
} catch (ActivityNotFoundException error) {
view.loadUrl(url);
}
} else {
view.loadUrl(url);
}
return false;
}
#Override
public void onPageFinished(WebView view, String url) {
if (PRINT_DIALOG_URL.equals(url)) {
// Submit print document.
view.loadUrl("javascript:printDialog.setPrintDocument(printDialog.createPrintDocument("
+ "window." + JS_INTERFACE + ".getType(),window." + JS_INTERFACE + ".getTitle(),"
+ "window." + JS_INTERFACE + ".getContent(),window." + JS_INTERFACE + ".getEncoding()))");
// Add post messages listener.
view.loadUrl("javascript:window.addEventListener('message',"
+ "function(evt){window." + JS_INTERFACE + ".onPostMessage(evt.data)}, false)");
}
}
}
}

Now, I found solution for my issue:
Maybe the problem come from the Android SDK version. You can see this link: https://developers.google.com/cloud-print/docs/android. (It's mean GCP only support for Android version 4.3 below).
Although, I tested on the emulator 4.2 but it still unlucky.
So that, I changed the direction to the Android Print Framework with a little difficult.
Firstly, I must install Cloud Print Services on emulator.
Secondly, I login Google Account Services for printing function enable and connect to my printer.
Thirdly, I use this code for exec print action
private void printDoc() {
PrintManager printManager = (PrintManager) this.getSystemService(Context.PRINT_SERVICE);
String jobName = mFileName;
Intent myIntent = getIntent();
Uri docUri = myIntent != null ? myIntent.getData() : null;
PrintDocumentAdapter pda = new PrintDocumentAdapter(){
#Override
public void onLayout(PrintAttributes oldAttributes, PrintAttributes newAttributes, CancellationSignal cancellationSignal, LayoutResultCallback callback, Bundle extras){
if (cancellationSignal.isCanceled()) {
callback.onLayoutCancelled();
//return;
}
// Compute the expected number of printed pages
int pages = computePageCount(newAttributes);
PrintDocumentInfo pdi = new PrintDocumentInfo.Builder(mFileName).setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT).setPageCount(pages).build();
callback.onLayoutFinished(pdi, true);
}
#Override
public void onWrite(PageRange[] pages, ParcelFileDescriptor destination, CancellationSignal cancellationSignal, WriteResultCallback callback){
InputStream input = null;
OutputStream output = null;
try {
input = new FileInputStream(docUri.toString());
output = new FileOutputStream(destination.getFileDescriptor());
byte[] buf = new byte[1024];
int bytesRead;
while ((bytesRead = input.read(buf)) > 0) {
output.write(buf, 0, bytesRead);
}
callback.onWriteFinished(pages);
} catch (FileNotFoundException ee){
//Catch exception
} catch (Exception e) {
//Catch exception
} finally {
try {
input.close();
output.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
};
printManager.print(jobName, pda, null);
}

ACRA 4.9.0 : How can I write ACRA report to file (in Application data folder)

I want to write the crash report in text file using latest Acra 4.9.0.
I can,t example for this latest version.
I tried using available documentation.
Acra is enabled
but it,s not writing in the file.
myApp
package com.myApp;
import org.acra.ACRA;
import android.app.AlertDialog;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.KeyEvent;
import android.view.View;
import com.myApp.Application.AppLauncher;
import com.myApp.interfaces.AppEvents;
import com.myApp.R;
import com.utils.Config;
import com.utils.Constants;
import com.utils.DeviceValidator;
public class myApp extends FragmentActivity
{
private AppLauncher appLauncher = null;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
if(!ACRA.isACRASenderServiceProcess())
{
setContentView(R.layout.activity_myApp);
appLauncher = new AppLauncher();
appLauncher.registerEventListener(appEventsListener);
appLauncher.initApp(this);
}
}
#Override
public void onPause() {
super.onPause();
if(!DeviceValidator.isDeviceValid())
{
return;
}
appLauncher.activityOnPause();
}
#Override
protected void onRestart() {
super.onRestart();
}
#Override
protected void onStart()
{
super.onStart();
}
#Override
public void onResume()
{
super.onResume();
appLauncher.activityOnResume();
}
}
AcraApplication
package com.myAPP;
import org.acra.ACRA;
import org.acra.ReportField;
import org.acra.ReportingInteractionMode;
import org.acra.annotation.ReportsCrashes;
import org.acra.sender.HttpSender.Method;
import android.app.Application;
#ReportsCrashes(
formUri = "http://staging.jemtv.com/variable_dump/index.php",
customReportContent = { ReportField.REPORT_ID, ReportField.DEVICE_ID, ReportField.APP_VERSION_NAME, ReportField.ANDROID_VERSION, ReportField.STACK_TRACE, ReportField.CUSTOM_DATA, ReportField.LOGCAT },
httpMethod = Method.POST,
reportSenderFactoryClasses = org.acra.util.MyOwnSenderFactory.class,
mode = ReportingInteractionMode.SILENT
)
public class AcraApplication extends Application
{
public AcraApplication()
{
super();
}
#Override
public void onCreate() {
super.onCreate();
ACRA.init(this);
}
}
MyOwnSender
package org.acra.util;
import java.io.File;
import java.io.FileOutputStream;
import org.acra.ReportField;
import org.acra.collector.CrashReportData;
import org.acra.config.ACRAConfiguration;
import org.acra.sender.ReportSender;
import org.acra.sender.ReportSenderException;
import android.content.Context;
import android.support.annotation.NonNull;
import android.util.Log;
public class MyOwnSender implements ReportSender {
private static final String FILE_NAME = "AcraReport.txt";
//private final Map<ReportField, String> mMapping = new HashMap<ReportField, String>();
//private FileWriter crashReport = null;
MyOwnSender(Context context, #NonNull ACRAConfiguration config)
{
Log.d("testAcra", "MyOwnSender created");
/* File logFile = new File(context.getFilesDir().getPath() + "/" + FILE_NAME, FILE_NAME);
try {
crashReport = new FileWriter(logFile, true);
} catch (IOException e) {
e.printStackTrace();
}*/
}
#Override
public void send(Context context, CrashReportData report) throws ReportSenderException
{
// Iterate over the CrashReportData instance and do whatever
// you need with each pair of ReportField key / String value
String finalReport = createCrashReport(report);
String tempFile = context.getFilesDir().getPath() + "/" + FILE_NAME;
try
{
File detailedFile = new File(tempFile);
if(!detailedFile.exists())
detailedFile.createNewFile();
FileOutputStream stream = new FileOutputStream(detailedFile, true);
stream.write(finalReport.getBytes());
Log.d("testAcra","adding to file: "+stream);
stream.close();
}
catch (Exception e)
{
e.printStackTrace();
}
/*final Map<String, String> finalReport = remap(report);
try {
BufferedWriter buf = new BufferedWriter(crashReport);
Set<Entry<String, String>> set = reportBody.entrySet();
Iterator<Entry<String, String>> i = set.iterator();
while (i.hasNext()) {
Map.Entry<String, String> me = (Entry<String, String>) i.next();
buf.append("[" + me.getKey() + "]=" + me.getValue());
}
buf.flush();
buf.close();
} catch (IOException e) {
Log.e("TAG", "IO ERROR", e);
}*/
}
private String createCrashReport(CrashReportData crashReportData){
StringBuilder body = new StringBuilder();
body.append("ReportID : " + crashReportData.getProperty(ReportField.REPORT_ID))
.append("\n")
.append("DeviceID : " + crashReportData.getProperty(ReportField.DEVICE_ID))
.append("\n")
.append("AppVersionName : " + crashReportData.getProperty(ReportField.APP_VERSION_NAME))
.append("\n")
.append("Android Version : " + crashReportData.getProperty(ReportField.ANDROID_VERSION))
.append("\n")
.append("CustomData : " + crashReportData.getProperty(ReportField.CUSTOM_DATA))
.append("\n")
.append("STACK TRACE : \n" + crashReportData.getProperty(ReportField.STACK_TRACE))
.append("\n")
.append("LogCAT : \n" + crashReportData.getProperty(ReportField.LOGCAT));
return body.toString();
}
/* private Map<String, String> remap(Map<ReportField, String> report) {
Set<ReportField>fields = ACRA.getConfig().getReportFields();
final Map<String, String> finalReport = new HashMap<String, String>(report.size());
for (ReportField field : fields)
{
if (mMapping == null || mMapping.get(field) == null)
finalReport.put(field.toString(), report.get(field));
else
finalReport.put(mMapping.get(field), report.get(field));
}
return finalReport;
}*/
}
MyOwnSenderFactory
package org.acra.util;
import org.acra.config.ACRAConfiguration;
import org.acra.sender.ReportSender;
import org.acra.sender.ReportSenderFactory;
import android.content.Context;
import android.support.annotation.NonNull;
public class MyOwnSenderFactory implements ReportSenderFactory {
// NB requires a no arg constructor.
/*MyOwnSenderFactory()
{
Log.e("testAcra", "MyOwnSenderFactory created");
}*/
#Override
#NonNull
public ReportSender create(#NonNull Context context, #NonNull ACRAConfiguration config) {
// TODO Auto-generated method stub
return new MyOwnSender(context, config);
}
}

Because i was using jar file instead of aar
in my manifest i was missing
<service
android:name="org.acra.sender.SenderService"
android:exported="false"
android:process=":acra" />
enter code here
That,s why SendeService used in Acra was not starting.

I want to write in application data folder
That is called internal data
I have created my own saver class to handle all of those savings:
import android.content.Context;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.math.BigDecimal;
import java.math.BigInteger;
public class Saver {
static FileOutputStream fos;
static FileInputStream fis;
public static void save(String filename, String data, Context c){
try {
fos = c.openFileOutput(filename, Context.MODE_PRIVATE);
fos.write(data.getBytes());
fos.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
String file;
public String getFile(){return file;}
public void setFile(String loc){
file = loc;
}
String result;
private static String mainLoad(String fn, Context c){
String collected = null;
try{
fis = c.openFileInput(fn);
byte[] dataArray = new byte[fis.available()];
while(fis.read(dataArray) != -1){
collected = new String(dataArray);
}
}catch(Exception e){
e.printStackTrace();
return null;
}finally{
try {
fis.close();
return collected;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
}
}
public static int loadInt(String fn, Context c){
if(mainLoad(fn,c) == null) return 0;
else return Integer.parseInt(mainLoad(fn,c));
}
public static double loadDouble(String fn, Context c){
if(mainLoad(fn,c) == null) return 0;
else return Double.parseDouble(mainLoad(fn,c));
}
public static float loadFloat(String fn, Context c){
return Float.parseFloat(mainLoad(fn,c));
}
public static String loadString(String fn, Context c){
return mainLoad(fn, c);
}
public static Boolean loadBoolean(String fn, Context c){
if(mainLoad(fn,c) == null) return false;
else return Boolean.parseBoolean(mainLoad(fn,c));
}
public static BigInteger loadBigInteger(String fn, Context c){
return new BigInteger(mainLoad(fn,c));
}
public static BigDecimal loadBigDecimal(String fn, Context c){
return new BigDecimal(mainLoad(fn,c));
}
}
I want to write the crash report in text file using latest Acra 4.9.0. I can,t example for this latest version.
If you want to write to a .txt file on server, try this backend. Uses the default sender:
<?php
// Outputs all POST parameters to a text file. The file name is the date_time of the report reception
$fileName = date('Y-m-d_H-i-s').'.txt';
$file = fopen($fileName,'w') or die('Could not create report file: ' . $fileName);
foreach($_POST as $key => $value) {
$reportLine = $key." = ".$value."\n";
fwrite($file, $reportLine) or die ('Could not write to report file ' . $reportLine);
}
fclose($file);
?>
If you only want to write locally, then the point of ACRA disappears as you cannot get the files.
If you create .txt files to transmit them, it is actually better to use the backend I linked. It transmits the raw data, and you can get all your fields in a .txt file

How to connect android app to node server?

I am trying out the WebSockets with Fallbacks transports for Android, Node.js and Atmosphere example. I get an the following error:
/home/mofa/NetBeansProjects/App/src/com/jullio/advisor/wAsyncChat.java:87: error: cannot access JsonParseException
return mapper.readValue(data, Message.class);
class file for org.codehaus.jackson.JsonParseException not found
/home/mofa/NetBeansProjects/App/src/com/jullio/advisor/wAsyncChat.java:68: error: cannot access ObjectCodec
return mapper.writeValueAsString(data);
class file for org.codehaus.jackson.ObjectCodec not found
Here is the androidchat code:
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.StrictMode;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import org.atmosphere.wasync.ClientFactory;
import org.atmosphere.wasync.Decoder;
import org.atmosphere.wasync.Encoder;
import org.atmosphere.wasync.Event;
import org.atmosphere.wasync.Function;
import org.atmosphere.wasync.Request;
import org.atmosphere.wasync.RequestBuilder;
import org.atmosphere.wasync.impl.AtmosphereClient;
import org.codehaus.jackson.map.ObjectMapper;
import java.io.IOException;
import java.util.Date;
public class wAsyncChat extends Activity {
private Button bt;
private TextView tv;
private String serverIpAddress = "http://10.0.2.2:8080";
private final static ObjectMapper mapper = new ObjectMapper();
private final Handler uiHandler = new Handler();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
setContentView(R.layout.main);
bt = (Button) findViewById(R.id.myButton);
tv = (TextView) findViewById(R.id.myTextView);
try {
AtmosphereClient client = ClientFactory.getDefault().newClient(AtmosphereClient.class);
RequestBuilder request = client.newRequestBuilder()
.method(Request.METHOD.GET)
.uri(serverIpAddress + "/chat")
.trackMessageLength(true)
.encoder(new Encoder<Message, String>() {
#Override
public String encode(Message data) {
try {
return mapper.writeValueAsString(data);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
})
.decoder(new Decoder<String, Message>() {
#Override
public Message decode(Event type, String data) {
data = data.trim();
// Padding
if (data.length() == 0) {
return null;
}
if (type.equals(Event.MESSAGE)) {
try {
return mapper.readValue(data, Message.class);
} catch (IOException e) {
e.printStackTrace();
return null;
}
} else {
return null;
}
}
})
.transport(Request.TRANSPORT.WEBSOCKET);
final org.atmosphere.wasync.Socket socket = client.create();
socket.on("message", new Function<Message>() {
#Override
public void on(final Message t) {
uiHandler.post(new Runnable() {
#Override
public void run() {
Date d = new Date(t.getTime());
tv.append("Author " + t.getAuthor() + "# " + d.getHours() + ":" + d.getMinutes() + ": " + t.getMessage() + "\n");
}
});
}
}).on(new Function<Throwable>() {
#Override
public void on(Throwable t) {
tv.setText("ERROR 3: " + t.getMessage());
t.printStackTrace();
}
}).open(request.build());
bt.setOnClickListener(new OnClickListener() {
String name = null;
public void onClick(View v) {
try {
EditText et = (EditText) findViewById(R.id.EditText01);
String str = et.getText().toString();
if (name == null) {
name = str;
}
socket.fire(new Message(name, str));
et.setText("");
Log.d("Client", "Client sent message");
} catch (Throwable e) {
tv.setText("ERROR 3: " + e.getMessage());
e.printStackTrace();
}
}
});
} catch (Throwable e) {
tv.setText("Unable to connect: " + e.getMessage());
e.printStackTrace();
}
}
}

I have the library for nodeserver connection. You can use it from git
SocketIO socketio = new SocketIO() {
#Override
public void onConnect() {
}
#Override
public void onDisconnect() {
}
#Override
public void onMessage(String message) {
Log.d("===Server Answer====",message);
}
};
socketio.Connect("192.168.0.1", 9000);
after onConnect() send the message:
socketio.send("Your message to socket");
it work with latest socketIO, and use RFC 6455 websocket protocol

Android Chat App crashes

Me and some friends wrote a chat-program in Java and now we wanted to make an Android-App of it. I started today with just the basic functions. When I tried to run it, it crashes
"Unfortunately Your App crashed" or something like that.
Main.java
package com.Linkr.linkrandroid;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.ArrayList;
import static com.Linkr.linkrandroid.R.*;
public class Chat extends Activity {
String username;
Socket sock;
BufferedReader reader;
PrintWriter writer;
ArrayList<String> userList = new ArrayList();
//Boolean isConnected = false;
TextView chatTextArea = (TextView) findViewById(R.id.chatTextArea);
TextView inputTextArea = (TextView) findViewById(id.inputTextArea);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(layout.activity_chat);
this.setTitle("Linkr");
}
public class IncomingReader implements Runnable{
public void run() {
String[] data;
String stream, done = "Done", connect = "Connect", disconnect = "Disconnect", chat = "Chat";
try {
while ((stream = reader.readLine()) != null) {
data = stream.split(":");
if (data[2].equals(chat)) {
chatTextArea.append(data[0] + ": " + data[1] + "\n");
//chatTextArea.setCaretPosition(chatTextArea.getDocument().getLength());
} else if (data[2].equals(connect)){
//chatTextArea.removeAll();
//userAdd(data[0]);
} else if (data[2].equals(disconnect)) {
//userRemove(data[0]);
} else if (data[2].equals(done)) {
/*usersList.setText("");
writeUsers();
userList.clear();
*/
}
}
}catch(Exception ex) {
}
}
}
public void ListenThread() {
Thread IncomingReader = new Thread(new IncomingReader());
IncomingReader.start();
}
public void userAdd(String data) {
userList.add(data);
}
public void userRemove(String data) {
chatTextArea.append(data + " has disconnected.\n");
}
public void writeUsers() {
String[] tempList = new String[(userList.size())];
userList.toArray(tempList);
/*for (String token:tempList) {
usersList.append(token + "\n");
}
*/
}
public void sendDisconnect() {
String bye = (username + ": :Disconnect");
try{
writer.println(bye); // Sends server the disconnect signal.
writer.flush(); // flushes the buffer
} catch (Exception e) {
chatTextArea.append("Could not send Disconnect message.\n");
}
}
public void Disconnect() {
try {
chatTextArea.append("Disconnected.\n");
sock.close();
} catch(Exception ex) {
chatTextArea.append("Failed to disconnect. \n");
}
isConnected = false;
//usersList.setText("");
}
private void onClickButton(View view) {
String nothing = "";
if ((inputTextArea.getText()).equals(nothing)) {
inputTextArea.setText("");
inputTextArea.requestFocus();
} else {
try {
writer.println(username + ":" + inputTextArea.getText() + ":" + "Chat");
writer.flush(); // flushes the buffer
} catch (Exception ex) {
chatTextArea.append("Message was not sent. \n");
}
inputTextArea.setText("");
inputTextArea.requestFocus();
}
inputTextArea.setText("");
inputTextArea.requestFocus();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.chat, menu);
return true;
}
}
acitivity_chat.xml
<RelativeLayout 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:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context=".Chat">
android:text = "Linkr"
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/inputTextArea"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_toLeftOf="#+id/onClickButton"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Send"
android:id="#+id/onClickButton"
android:layout_below="#+id/chatTextArea"
android:layout_alignRight="#+id/chatTextArea"/>
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textMultiLine"
android:ems="10"
android:id="#+id/chatTextArea"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_above="#+id/inputTextArea"
android:layout_alignParentRight="true"/>
Thank you for helping me!
<3

These lines are your culprits
TextView chatTextArea = (TextView) findViewById(R.id.chatTextArea);
TextView inputTextArea = (TextView) findViewById(id.inputTextArea);
they can't be initialized before setContentView() or they will return null giving you a NPE when you try to call a method on them like setText()
Try changing it like so
TextView chatTextArea;
TextView inputTextArea;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(layout.activity_chat);
chatTextArea; = (TextView) findViewById(R.id.chatTextArea);
inputTextArea; = (TextView) findViewById(id.inputTextArea);
this.setTitle("Linkr");
Also, it looks like you are trying to update UI elements on a background thread here
chatTextArea.append
You can only update the UI on the UI Thread. I suggest looking into AsyncTask. With AsyncTask you can do all of your network stuff in doInBackground() then update your UI in any of its other methods. Read through the documentation carefully. It can be tricky but once you get a handle on it life is much easier.
Also, when posting on SO, if your app crashes post the logcat because that will generally make it easier for people to help.

How to get gmail user's contacts?

I need to retrieve the email addresses that the user has stored in his gmail account. In my app, the user can now decide to invite a friend of him. I want that the application (if the user tell me "ok") presents a list of the user's contacts email addresses stored in gmail, among which he can choose one or more...
I know that exists Authentication and Authorization for Google APIs". Is it the right way? And, how to use them in Android?

I hope this will help for someone like me, because I have searched a lot for this and finally done with the below.
I have used GData java client library for Google Contacts API v3.
package com.example.cand;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.MalformedURLException;
import java.net.URL;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import com.google.gdata.client.Query;
import com.google.gdata.client.Service;
import com.google.gdata.client.contacts.ContactsService;
import com.google.gdata.data.Link;
import com.google.gdata.data.contacts.ContactEntry;
import com.google.gdata.data.contacts.ContactFeed;
import com.google.gdata.util.AuthenticationException;
import com.google.gdata.util.NoLongerAvailableException;
import com.google.gdata.util.ServiceException;
public class MainActivity extends Activity {
private URL feedUrl;
private static final String username="yourUsername";
private static final String pwd="yourPassword";
private ContactsService service;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String url = "https://www.google.com/m8/feeds/contacts/default/full";
try {
this.feedUrl = new URL(url);
} catch (MalformedURLException e) {
e.printStackTrace();
}
new GetTask().execute();
}
#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;
}
private class GetTask extends AsyncTask<Void, Void, Void>{
#Override
protected Void doInBackground(Void... params) {
service = new ContactsService("ContactsSample");
try {
service.setUserCredentials(username, pwd);
} catch (AuthenticationException e) {
e.printStackTrace();
}
try {
queryEntries();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
private void queryEntries() throws IOException, ServiceException{
Query myQuery = new Query(feedUrl);
myQuery.setMaxResults(50);
myQuery.setStartIndex(1);
myQuery.setStringCustomParameter("showdeleted", "false");
myQuery.setStringCustomParameter("requirealldeleted", "false");
// myQuery.setStringCustomParameter("sortorder", "ascending");
// myQuery.setStringCustomParameter("orderby", "");
try{
ContactFeed resultFeed = (ContactFeed)this.service.query(myQuery, ContactFeed.class);
for (ContactEntry entry : resultFeed.getEntries()) {
printContact(entry);
}
System.err.println("Total: " + resultFeed.getEntries().size() + " entries found");
}
catch (NoLongerAvailableException ex) {
System.err.println("Not all placehorders of deleted entries are available");
}
}
private void printContact(ContactEntry contact) throws IOException, ServiceException{
System.err.println("Id: " + contact.getId());
if (contact.getTitle() != null)
System.err.println("Contact name: " + contact.getTitle().getPlainText());
else {
System.err.println("Contact has no name");
}
System.err.println("Last updated: " + contact.getUpdated().toUiString());
if (contact.hasDeleted()) {
System.err.println("Deleted:");
}
// ElementHelper.printContact(System.err, contact);
Link photoLink = contact.getLink("http://schemas.google.com/contacts/2008/rel#photo", "image/*");
if (photoLink.getEtag() != null) {
Service.GDataRequest request = service.createLinkQueryRequest(photoLink);
request.execute();
InputStream in = request.getResponseStream();
ByteArrayOutputStream out = new ByteArrayOutputStream();
RandomAccessFile file = new RandomAccessFile("/tmp/" + contact.getSelfLink().getHref().substring(contact.getSelfLink().getHref().lastIndexOf('/') + 1), "rw");
byte[] buffer = new byte[4096];
for (int read = 0; (read = in.read(buffer)) != -1; )
out.write(buffer, 0, read);
file.write(out.toByteArray());
file.close();
in.close();
request.end();
}
System.err.println("Photo link: " + photoLink.getHref());
String photoEtag = photoLink.getEtag();
System.err.println(" Photo ETag: " + (photoEtag != null ? photoEtag : "(No contact photo uploaded)"));
System.err.println("Self link: " + contact.getSelfLink().getHref());
System.err.println("Edit link: " + contact.getEditLink().getHref());
System.err.println("ETag: " + contact.getEtag());
System.err.println("-------------------------------------------\n");
}
}
Required library files: you can get these jars from here
gdata-client-1.0.jar
gdata-client-meta-1.0.jar
gdata-contacts-3.0.jar
gdata-contacts-meta-3.0.jar
gdata-core-1.0.jar
guava-11.0.2.jar
Note: Add internet permission in AndroidManifest file.
<uses-permission android:name="android.permission.INTERNET"/>