I have this android code:
private class myTask extends AsyncTask<String, String, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... params) {
try {
client = new Socket("192.168.1.2", 4444);
oos = new ObjectOutputStream(client.getOutputStream());
ois = new ObjectInputStream(client.getInputStream());
oos.writeUTF("LOGIN");
oos.flush();
String emailText = email.getText().toString();
oos.writeUTF(emailText);
oos.flush();
String passwordText = password.getText().toString();
oos.writeUTF(passwordText);
oos.flush();
string = ois.readUTF();
}catch (ConnectException e){
return "Host not found";
}catch (IOException e) {
return "Exception Caught";
}
return null;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if ("Host not found".equalsIgnoreCase(result)){
Toast.makeText(getApplicationContext(), "Host not found" ,Toast.LENGTH_LONG).show();
}else if("Exception Caught".equalsIgnoreCase(result)){
Toast.makeText(getApplicationContext(), "Connection error" ,Toast.LENGTH_LONG).show();
}else{
Toast.makeText(getApplicationContext(), "Connection established" ,Toast.LENGTH_LONG).show();
}
Toast.makeText(getApplicationContext(), string ,Toast.LENGTH_LONG).show();
if(string.equals("Login successfully Done!")){
startActivity(new Intent(Login.this, User.class));
}
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
register = (TextView)findViewById(R.id.register);
login = (Button)findViewById(R.id.login);
email = (EditText)findViewById(R.id.email);
password = (EditText)findViewById(R.id.password);
connection = (TextView)findViewById(R.id.connection);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
register.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View arg0) {
startActivity(new Intent(Login.this, Register.class));
}
});
login.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
new myTask().execute();
}
});
}
but my connection create everytime i click on login button. I want my app connect to server at start and then when i press login button it sends request to server..How i need to change my code?
thanks
I think the easiest way to do that would be to move away from AsyncTasks and move to Threads. Create a new Thread in your onCreate function that creates the socket and connects it, then have it wait for a notification from the UI thread (easiest way to do this is to wait on a semaphore or message queue). Then have the onClick of the button notify the socket thread that it needs to login. With this design, you'll have it connect at startup but not login until you request it.
Your biggest worry here is if your server times out your connection for inactivity. But I assume you have control of the server to prevent that.
The problem here is that you're creating the socket in your doInBackground() method. This means that every time you execute an instance of AsyncTask that socket will be recreated. What you probably want to do is subclass Application or some sort of singleton and initialize your socket in there. Then make your AsyncTask do something like:
doInBackground(Object... params) {
// do stuff
Socket socket = Application.getSocket();
// do stuff with the socket
}
This introduces a bit of complexity as you need to handle properly opening/closing your socket at the proper points in your application lifecycle, but it is the cleanest solution that comes to mind.
Related
I have network operation inside a thread which in oncreate() based on network response I need to process the next step but the thread is running after the activity life cycle.
I called networkRequest() in oncreate() in activity
private void networkRequest() {
final String[] resp = new String[1];
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
try {
resp[0] = AttemptingUploadCheckList.getJsonObj(url);
JSONObject response = new JSONObject(resp[0]);
if (response != null) {
version_code = response.getInt("version_code");
recommended_update = response.getBoolean("recommended_update");
forced_update = response.getBoolean("forced_update");
}
if (recommended_update) {
recomendUpadate();
} else if (forced_update)
onUpdateNeeded(url);
else {
Intent intent = new Intent(SplashActivity.this, LoginActivity.class);
startActivity(intent);
finish();
}
} catch (Exception e) {
e.printStackTrace();
}
}
});
thread.start();
}
Thread is not bound with the activity. It's not running with the main thread.
Android said if you want to perform any long running tasks like api call, data from database then you need to use the AsyncTask or the Service.
In your case, you can use the AsycnTask for the fetching data.
class MyAsync extends AsyncTask<Void, Void, Void>{
final String[] resp = new String[1];
JSONObject response;
#Override
protected void onPreExecute() {
super.onPreExecute();
// Show Progress Dialog
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
// Hide Progress Dialog
if (response != null) {
version_code = response.getInt("version_code");
recommended_update = response.getBoolean("recommended_update");
forced_update = response.getBoolean("forced_update");
}
if (recommended_update) {
recomendUpadate();
} else if (forced_update)
onUpdateNeeded(url);
else {
Intent intent = new Intent(SplashActivity.this, LoginActivity.class);
startActivity(intent);
finish();
}
}
#Override
protected Void doInBackground(Void... voids) {
try {
resp[0] = AttemptingUploadCheckList.getJsonObj(url);
response = new JSONObject(resp[0]);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
For executing the above AsynTask
private void networkRequest() {
new MyAsync().execute();
}
Thread does not care about Activity or any other Component's lifecycle Except the Process in which it is Running.
You need to check for state of component yourself.
I can provide some example code but i really do not understand what exactly you are trying to do .
Considering you are making a network request there. Java thread individually is hard to handle in such cases considering the fact that after response we need to move on to Main thread to update the UI. So i highly recommend you should use a Network API Library probably RetroFit .
You can check state of the Component like isFinishing() in Activity .
I'm building a android app that using connection with Java server (on computer).
I have a problem- when I find that there is no connection with the server, I'm trying to reconnect to the server but it doesn't work.
Here is the Client class code:
public class Client extends AsyncTask {
private final int port = 1978;
private final String ip = "192.168.14.22";
private Socket socket;
private DataOutputStream output;
private DataInputStream input;
public Client() {
}
#Override
protected Object doInBackground(Object[] objects) {
try {
socket = new Socket(ip, port);
output = new DataOutputStream(socket.getOutputStream());
input = new DataInputStream(socket.getInputStream());
Log.d("Network c1", "Connected");
} catch (IOException e) {
socket = null;
Log.d("Network c1", "Not connected");
}
return null;
}
public boolean checkConnection() {
if (output == null)
return false;
try {
output.writeUTF("abc");
return true;
} catch (IOException e) {
return false;
}
}
#Override
protected void onProgressUpdate(Object[] values) {
}
}
And the Activity code:
public class LogInActivity extends AppCompatActivity {
Client client;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_log_in);
client = new Client();
client.execute();
//I used timer because it didn't work without it- That saied always 'not connected' message/Toast
new CountDownTimer(5, 0) {
public void onTick(long millisUntilFinished) {
}
public void onFinish() {
check();
}
}.start();
}
private void check() {
boolean isProcess;
isProcess = !checkConnection();
if (isProcess) {
AlertDialog.Builder builder = new AlertDialog.Builder(this, R.style.Theme_AppCompat_Dialog_Alert);
builder.setTitle(getResources().getString(R.string.app_name));
builder.setMessage("Unable connect to the library");
builder.setPositiveButton("Try Again", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
//See note 1.
check();
}
});
builder.setCancelable(false);
builder.show();
}
}
public boolean checkConnection() {
if (client.checkConnection()) {
Toast.makeText(getApplicationContext(), "Connected to the library", Toast.LENGTH_SHORT).show();
return true;
} else {
Toast.makeText(this, "Unable connect to the library", Toast.LENGTH_SHORT).show();
return false;
}
}
}
Note 1:
The problem is here.
This Dialog need to be shown until the server/Library connected.
If the server is on before the app turned on, the check() method works well and says 'Connected successful' and the Dialog doesn't show.
But if when the app started, the server was unreachable, and turned on later (And became reachable)- the check() method don't work and always shows the Dialog.
What is the problem?
By the way, I tried to restart the client AsyncTask Class, but i didn't succeed.
(I tried to do close(true) to it, and after do excute() to it again, but the cancel() method didn't worked, and was a error that said that after a AsyncTask Class excuted, it can't excute again)
Thanks.
You should not check for connectivity periodically (every couple of seconds like you do in this code).
Instead you should let the OS do this for you, it will be more reliable and more efficient in terms of battery and CPU.
Take a look at this answer
I have a fragment that contains a Button btn_connect that when it is pressed a WiFi Direct connection is established between 2 devices. This fragment implements ConnectionInfoListener. So it has onConnectionInfoAvailable function where I want to execute an AsyncTask class. The problem that I have is that in one Activity, I am doing:
fragment.mContentView.findViewById(R.id.btn_connect).performClick();
And the button is being clicked and the connection is established so the code goes into the onConnectionInfoAvailable function but the AsyncTask is not being executed.
#Override
public void onConnectionInfoAvailable(final WifiP2pInfo info) {
//..code..
Log.d("Test 1", "Test 1");
new MasterServerTask().execute();
}
public class MasterServerTask extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... arg0) {
//**************
Log.d("IM INSIDE ASYNCTASK CLASS", "SOCKET");
try {
serverSocket = new ServerSocket(8090);
} catch (IOException e) {
e.printStackTrace();
}
while (true) {//wait for clients
Socket socket = null;
try {
socket = serverSocket.accept();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.d("ACCEPTED A SLAVE DEVICE "+num_clients, "ACCEPTED A SLAVE DEVICE "+num_clients);
num_clients++;
OutputStream os=null;
try {
os = socket.getOutputStream();
} catch (IOException e) {
e.printStackTrace();
}
proxy.addSlaveOutputStream(os);
}
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
}
}
mContentView.findViewById(R.id.btn_connect).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {//Phone that connects first is NOT the group owner
// port = Integer.parseInt(editTextPort.getText().toString());
Log.d("IM IN THE OTHER FRAGMENT", "Connect");
WifiP2pConfig config = new WifiP2pConfig();
config.groupOwnerIntent = 0;
config.deviceAddress = device.deviceAddress;
config.wps.setup = WpsInfo.PBC;
if (progressDialog != null && progressDialog.isShowing()) {
progressDialog.dismiss();
}
progressDialog = ProgressDialog.show(getActivity(), "Press back to cancel",
"Connecting to :" + device.deviceAddress, true, true
);
((DeviceActionListener) getActivity()).connect(config);
}
});
Is there an easy workaround solution for this?
Check how/where you are calling WifiP2pManager.initialize() to create the WifiP2pManager.Channel object. The Looper you provide it is the one which will receive all callbacks for your instance of WifiP2pManager.ConnectionInfoListener. If you are giving it a background thread then the AsyncTask will not execute - it must be started from the main (UI) thread.
The comments on the question were really helpful. The reason why the AsyncTask was not getting executed is because it was called from another task that is currently being executed. So in order for it to work, I replaced the AsyncTask with Thread classes. All the code in the doInBackground() was placed inside the thread's run() function. Now the performClick() executes a Thread, not an AsyncTask and it worked.
I have a problem on android. I have an application that asks the user for the local Ip address (from the device's interface) and another remote address. The application has to bind to the specified local address and connect to the remote address. Quite simple, but, indeed, bind does not work ass i expected..
I added the following permissions on the manifest file:
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
The source code is the following one:
public class MainActivity extends Activity
{
String Tag = "TAG";
private int LOCAL_PORT = 4444;
private int REMOTE_PORT = 80;
private EditText LOCAL;
private EditText REMOTE;
private Button Connect;
private TextView STATUS;
private Context context = this;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LOCAL = (EditText) findViewById(R.id.editText1);
REMOTE = (EditText) findViewById(R.id.editText2);
Connect = (Button) findViewById(R.id.button1);
Connect.setOnClickListener(new View.OnClickListener() {
public void onClick(View v)
{
BotleneckHandle WORK;
Toast.makeText(getApplicationContext(), "Proceeding to connect",
Toast.LENGTH_SHORT).show();
/*
if(LOCAL.getText().toString() == null || REMOTE.getText().toString() == null || LOCAL.getText().toString().equals(" ") || REMOTE.getText().toString().equals(" ") || LOCAL.getText().toString().equals("") || REMOTE.getText().toString().equals(""))
Toast.makeText(context, "Wrong parameters", 2000);
else
{
Toast.makeText(getApplicationContext(), "Proceeding to connect",Toast.LENGTH_SHORT).show();
}*/
WORK = new BotleneckHandle();
WORK.execute();
}
});
STATUS = (TextView) findViewById(R.id.textView1);
}
private class BotleneckHandle extends AsyncTask <Void , Void , String>
{
Socket Skt = null;
String ReturnStatemente = new String();
SocketAddress localAddr = new InetSocketAddress(LOCAL.getText().toString(), LOCAL_PORT);
protected void onPreExecute(){ }
protected String doInBackground(Void... params)
{
try
{
String s=new String();
s+= "Local="+LOCAL.getText().toString()+":"+LOCAL_PORT+" Remote="+REMOTE.getText().toString()+":"+REMOTE_PORT; //so far so good, Confirmed by debug
Toast.makeText(getApplicationContext(), s,Toast.LENGTH_SHORT).show(); //Does not show anything due the fact that i didn't published it as an assync task update..
//binding to a local address
Skt.bind(localAddr); //cannot make the bind :-/
//connecting to remote host
Skt=new Socket(REMOTE.getText().toString(), REMOTE_PORT); //if bind is comment, still does not work.. I bet
ReturnStatemente = "Connected";
}
catch (UnknownHostException e)
{
e.printStackTrace();
Toast.makeText(context, "Unknown remote host", 2000);
ReturnStatemente = "Not Connected";
}
catch (IOException e)
{
e.printStackTrace();
Toast.makeText(context, "Connection fail", 2000);
ReturnStatemente = "Not Connected";
}
finally{try {
Skt.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}}
return ReturnStatemente;
}
protected void onPostExecute(String result) { STATUS.setText(" CONECTION STATUS == " + result); }
}
}
What am i doing wrong on bind? As far as i see, and as i searched for its good.. Did i miss something?
kind regards
You're trying to call bind on a variable before you assigned anything to it. So its still null. That isn't going to work. You need to create an instance of Socket before you can call methods on it.
progressDialog = ProgressDialog.show(GetResponse.this, "", "Loading...");
new Thread()
{
public void run()
{
try
{
// inside i have written code for making connection to the server using SSL connection.
}catch (Exception e)
{
progressDialog.dismiss();
exception(e.getMessage())
}.start();
}
private void exception(String msg)
{
Toast.makeText(this, msg, Toast.LENGTH_LONG).show();
this.finish();
Intent i = new Intent(getBaseContext(), LoginPage.class);
startActivity(i);
}
my LoginPage.java is previous activity.
If the connection is successfull it goes to the next activity ot doesnt give any error,
But if der is any prob with connection then i want progress bar should be stopped and go back to the LoginPage activity and also i want the error msg to be displayed.
From the above im getting some error.. Please help me out on this
Pass in and use the context from LoginPage. Also, use the 101010 button to format your code as code in your posts.
you can go up by using try catch mechanism where in your catch place your toast message and u can do it also by asynchronous task,
here simple code
private class Task_News_ArticleView extends AsyncTask<Void, Void, Void> {
private final ProgressDialog dialog = new ProgressDialog(
Bru_Sports_View.this);
// can use UI thread here
protected void onPreExecute() {
this.dialog.setMessage("Loading...");
this.dialog.setCancelable(false);
this.dialog.show();
}
#Override
protected Void doInBackground(Void... params) {
try {
//here the condition to check login details
}
} catch (Exception e) {
}
return null;
}
protected void onPostExecute(Void result) {
if (this.dialog.isShowing()) {
this.dialog.dismiss();
}
}
}
and u can also use try,catch in catch block you can place your toast message
with finsih() method