Develop Reference

Wait for thread to finish and then move to next position

i am trying to display a Toast on the screen and when Toast fades off then move to the next question. I have tried with Thread but cannot seem to manage.
My code:
next.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (getUserSelection()){
position = position + 3;
if (position < questionsArray.size()) {
curName = questionsArray.get(position).getName();
curArray = questionsArray.get(position).getAnswers();
curIscorrect = questionsArray.get(position).getIscorrect();
setupQuestionView(curName, curArray, curIscorrect);
} else {
StringGenerator.showToast(QuestionsActivity.this, "Your score : " + score + "/" + (questionsArray.size() / 3));
}
}else {
StringGenerator.showToast(QuestionsActivity.this, getString(R.string.noanswerselected));
}
}
});
and the getUserSelectionMethod:
private boolean getUserSelection() {
correct = (RadioButton)findViewById(group.getCheckedRadioButtonId());
if (correct == null){
return false;
}else {
correctAnswerText = correct.getText().toString();
if (map.get(correctAnswerText).equals(Constants.CORRECTANSWER)) {
score++;
setCorrectMessage();
return true;
} else {
setWrongMessage();
return true;
}
}
}
private void setCorrectMessage() {
correctToast = new Toast(QuestionsActivity.this);
correctToastView = getLayoutInflater().inflate(R.layout.correct, (ViewGroup) findViewById(R.id.correctRootLayout));
correctText = (TextView)correctToastView.findViewById(R.id.correctTextView);
correctText.setText(getString(R.string.correctAnswer));
correctToast.setDuration(Toast.LENGTH_SHORT);
correctToast.setView(correctToastView);
correctToast.show();
correctThread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
correctToast.cancel();
}
});
correctThread.start();
}
private void setWrongMessage() {
wrongToast = new Toast(QuestionsActivity.this);
wrongToastView = getLayoutInflater().inflate(R.layout.wrong, (ViewGroup) findViewById(R.id.wrongRootLayout));
wrongText = (TextView)wrongToastView.findViewById(R.id.wrongTextView);
wrongText.setText(getString(R.string.wrongAnswer));
wrongToast.setDuration(Toast.LENGTH_SHORT);
wrongToast.setView(wrongToastView);
wrongToast.show();
wrongThread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
wrongToast.cancel();
}
});
wrongThread.start();
}
Any suggestion on how to do this?

You can determine the toast visibility:
toast.getView().getWindowToken()
If the result is null, than your toast isn't visible anymore, and than you can run any code you want.

as stated in this answer you can start a thread that waits the duration of the Toast:
Thread thread = new Thread(){
#Override
public void run() {
try {
Thread.sleep(3500); // 3.5seconds!
// Do the stuff you want to be done after the Toast disappeared
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
Toast.LENGTH_SHORT and Toast.LENGTH_LONG are only flags so you have to either hard code the duration or keep them in a constant. The durations are 3.5s (long) and 2s (short).
If you want to manipulate some of your views, you cannot do this in another thread than the "main" UI thread. So you have to implement a kind of callback/polling mechanism to get notified when the SleepThread has finished.
Check this answer to read about a couple of ways to do this. Probably the easiest of them to understand and implement is this:
After you started your Thread you can check if it is still alive and running by calling thread.isAlive(). In this way you can do a while loop that runs while the thread is running:
// start your thread
while(thread.isAlive()){}
// continue the work. The other thread has finished.
Please note that this is NOT the most elegant way to do this! Check the other possibilities in the answer I've mentioned above for more elegant solutions (especially the last one with the listeners is very interesting and worth reading!)

That's because the Thread class is purely executed in the background and you need to manipulate the view in the Main thread. To solve your issue just replace the Thread with AsynTask.
AsyncTask<Void,Void,Void> a = new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
correctToast.cancel();
}
};
a.execute();
If you look at my code you can see my onPostExecute, this method is called in the Main Thread.

My Error was because i was trying to acess UI Elements through another Thread so modifying the code like this:
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
QuestionsActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
moveToNextQuestion();
}
});
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
thread.start();
did the trick. I hope my answer helps someone!!!

Android runOnUiThread to show progress dialog and to populate views

I usually work on .Net but I need to develop an Android app. So I am new on Android, sorry for mistakes in advance! :)
Here is my story,
I am populating a customer list(creating ui elements in code behind) with views in a button click. I am doing that pulling datas from database. So it takes some time to pull the data and creating views. What I wanna do is showing a progress dialog while customer list is being populated. Currently I am able to make it run. But the problem is it doesn't show the progress dialog immediately, then customerlist and progress dialog are displayed at the same time.
Here is my button click;
public void ShowCustomers(View view){
final ProgressDialog dialog = new ProgressDialog(MainActivity.this);
runOnUiThread(new Runnable() {
#Override
public void run() {
dialog.setTitle("Title");
dialog.setMessage("Loading...");
if(!dialog.isShowing()){
dialog.show();
}
}
});
new Thread() {
public void run() {
try{
runOnUiThread(new Runnable() {
#Override
public void run() {
PopulateRecentGuests(); //Creates customer list dynamically
dialog.dismiss();
}
});
} catch (Exception e) {
Log.e("tag", e.getMessage());
}
}
}.start();
}
And populating the customers;
public void PopulateRecentGuests(){
LinearLayout customers = (LinearLayout)findViewById(R.id.customers);
String query = "SELECT * from Table";
ModelCustomer customerModel = new ModelCustomer();
ArrayList<HashMap<String, String>> recentGuests = customerModel.RetrievingQuery(query);
customersCount = recentGuests.size();
Context context = getApplicationContext();
if(customersCount < 1)
Toast.makeText(context, "There is no available customer in database!", Toast.LENGTH_LONG);
else if(!recentGuests.get(0).containsKey("err")) {
for(int i = 0; i < recentGuests.size(); i++){
HashMap<String, String> guest = recentGuests.get(i);
Button button = new Button(context);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
params.setMargins(0,5,0,5);
button.setLayoutParams(params);
button.setWidth(800);
button.setHeight(93);
button.setTag(guest.get("id"));
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
System.out.println("New button clicked! ID: " + v.getTag());
Intent intent = new Intent(getApplicationContext(), ProductPageActivity.class);
intent.putExtra("CustomerID", v.getTag().toString());
startActivity(intent);
}
});
button.setBackgroundColor(Color.parseColor("#EFEFEF"));
button.setText(guest.get("FirstName") + " " + guest.get("LastName") + " " + guest.get("GuideName"));
button.setTextColor(Color.BLACK);
button.setTextSize(20);
button.setEnabled(false);
customers.addView(button); // customers is a linear layout and button is being added to customers
Button guest_list_btn = (Button)findViewById(R.id.guest_list_btn);
guest_list_btn.setEnabled(true);
}
}
else{
CharSequence text = recentGuests.get(0).get("err");
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
Button guest_list_btn = (Button)findViewById(R.id.guest_list_btn);
Button guest_list_close_btn = (Button)findViewById(R.id.guest_list_close_btn);
customers.setVisibility(View.VISIBLE);
AnimationSet aset = new AnimationSet(true);
aset.setFillEnabled(true);
aset.setInterpolator(new LinearInterpolator());
AlphaAnimation alpha = new AlphaAnimation(0.0F, 1.0F);
alpha.setDuration(400);
aset.addAnimation(alpha);
TranslateAnimation trans = new TranslateAnimation(200, 0, 0, 0);
trans.setDuration(400);
aset.addAnimation(trans);
customers.startAnimation(aset);
guest_list_btn.setEnabled(false);
guest_list_close_btn.setEnabled(true);
for(int i = 0; i < customers.getChildCount(); i++){
View child = customers.getChildAt(i);
child.setEnabled(true);
}
}
After my research, I understand that runonuithread is called after looper. My question is How can I display the progress dialog immediately and then I can populate the customer list (creating ui elements). By the way, I tried to do that with asynctask first but I wasn't able to.
Thans in advance!

But the problem is it doesn't show the progress dialog immediately,
then customerlist and progress dialog are displayed at the same time.
That's because you do the long operation(and closing the dialog sequentially) on the main UI thread. Instead you should separate things between retrieving the data(which takes time) and building the views(along with closing the dialog).
//...
new Thread() {
public void run() {
// do the long operation on this thread
final ArrayList<HashMap<String, String>> recentGuests = customerModel.RetrievingQuery(query);
// after retrieving the data then use it to build the views and close the dialog on the main UI thread
try{
runOnUiThread(new Runnable() {
#Override
public void run() {
// remove the retrieving of data from this method and let it just build the views
PopulateRecentGuests(recentGuests);
dialog.dismiss();
}
});
} catch (Exception e) {
Log.e("tag", e.getMessage());
}
}
}.start();

Determine that thread is running or not if using runnable in android

I have created a program in android for multithreading.
When I hit one of the button its thread starts and print value to EditText now I want to determine that thread is running or not so that I can stop the thread on click if it is running and start a new thread if it is not running here is mu code:
public void startProgress(View view) {
final String v;
if(view == b1)
{
v = "b1";
}
else
{
v = "b2";
}
// Do something long
Runnable runnable = new Runnable() {
#Override
public void run() {
//for (int i = 0; i <= 10; i++) {
while(true){
if(v.equals("b1"))
{
i++;
}
else if(v.equals("b2"))
{
j++;
}
try {
if(v.equals("b1"))
{
Thread.sleep(3000);
}
else if(v.equals("b2"))
{
Thread.sleep(1000);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
handler.post(new Runnable() {
#Override
public void run() {
// progress.setProgress(value);
if(v.equals("b1"))
{
String strValue = ""+i;
t1.setText(strValue);
}
else
{
String strValue = ""+j;
t2.setText(strValue);
}
//t1.setText(value);
}
});
}
}
};
new Thread(runnable).start();
}
#Override
public void onClick(View v) {
if(v == b1)
{
startProgress(b1);
}
else if(v == b2)
{
startProgress(b2);
}
}

Instead of that messy code, an AsyncTask would do the job you need with added readability ...
It even has a getStatus() function to tell you if it is still running.
You'll find tons of examples by looking around a bit (not gonna write one more here). I'll simply copy the one from the documentation linked above:
Usage
AsyncTask must be subclassed to be used. The subclass will override at least one method (doInBackground(Params...)), and most often will override a second one (onPostExecute(Result).)
Here is an example of subclassing:
private class DownloadFilesTask extends AsyncTask<URL, Integer, Long> {
protected Long doInBackground(URL... urls) {
int count = urls.length;
long totalSize = 0;
for (int i = 0; i < count; i++) {
totalSize += Downloader.downloadFile(urls[i]);
publishProgress((int) ((i / (float) count) * 100));
// Escape early if cancel() is called
if (isCancelled()) break;
}
return totalSize;
}
protected void onProgressUpdate(Integer... progress) {
setProgressPercent(progress[0]);
}
protected void onPostExecute(Long result) {
showDialog("Downloaded " + result + " bytes");
}
}
Once created, a task is executed very simply:
new DownloadFilesTask().execute(url1, url2, url3);

Use a static AtomicBoolean in your thread and flip its value accordingly. If the value of the boolean is true, your thread is already running. Exit the thread if it is true. Before exiting the thread set the value back to false.

There are some way can check the Thread properties
You able to check Thread is Alive() by
Thread.isAlive() method it return boolean.
You able to found runing thread run by
Thread.currentThread().getName()
Thanks

Progress dialog is not showing while calling a web service

I am new to android. I want to show progress dialog when user click on login button. I tried this but the dialog is not showing
btn_logIn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View view) {
getUserCredentials();
}
}); //end of anonymous class
private void showProgressDialog() {
if (dialog == null) {
dialog = new ProgressDialog(this);
}
dialog.setMessage("Please Wait. Your authentication is in progress");
dialog.setButton("Cancel", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which)
dialog.dismiss();
}
}); //end of anonymous class
dialog.show();
} //end of showProgressDialog()
private void getUserCredentials() {
EditText txt_userName = (EditText) findViewById(R.id.txt_userName);
String userName = txt_userName.getText().toString();
EditText txt_password = (EditText) findViewById(R.id.txt_password);
String password = txt_password.getText().toString();
if (userName != null && !userName.trim().equals("") && password != null && !password.trim().equals("")) {
showProgressDialog();
callWebService(userName, password);
}
} //end of getUserCredentials()
private void callWebService(String userName, String password) {
try {
SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
request.addProperty("userName", userName);
....
Object result = envelope.getResponse();
if (result.equals("true")) {
dialog.dismiss();
Toast.makeText(this, result.toString(), Toast.LENGTH_SHORT).show();
} else {
dialog.dismiss();
Toast.makeText(this, result.toString(), Toast.LENGTH_SHORT).show();
}
} catch (SocketTimeoutException e) {
dialog.dismiss();
Toast.makeText(this, "Service is not connected, Please make sure your server is running", Toast.LENGTH_LONG).show();
} catch(Exception e) {
e.printStackTrace();
dialog.dismiss();
Toast.makeText(this, "Unable to connect, please try again later. Thank you", Toast.LENGTH_LONG).show();
}
} //end of callWebServide()
Am i doing anything wrong. When i click on login button and service is not running then it shows message that Service is not connected, Please make sure your server is running", but the dialog isn't showing...Why? My logic is when user click on login button and fields have values then start showing progress dialog and if anything happens like when result come or server is not running or if any exception happen , then i remove the dialog and show the appropriate message, but dialog isn't showing...Why? What i am doing wrong? Please help..
Thanks

Try this,
Change your getUserCredentials() like this,
private void getUserCredentials() {
EditText txt_userName = (EditText) findViewById(R.id.txt_userName);
String userName = txt_userName.getText().toString();
EditText txt_password = (EditText) findViewById(R.id.txt_password);
String password = txt_password.getText().toString();
if (userName != null && !userName.trim().equals("") && password != null && !password.trim().equals("")) {
showProgressDialog();
Thread t=new Thread(new Runnable() {
public void run() {
callWebService(userName, password);
}
}); t.start();
}
}
And your callWebService method like this,
private void callWebService(String userName, String password) {
try {
SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
request.addProperty("userName", userName);
....
Object result = envelope.getResponse();
if (result.equals("true")) {
dialog.dismiss();
Toast.makeText(this, result.toString(), Toast.LENGTH_SHORT).show();
} else {
ActivityName.this.runOnUiThread(new Runnable() {
public void run() {
dialog.dismiss();
Toast.makeText(this, result.toString(), Toast.LENGTH_SHORT).show();
}
});
}
} catch (SocketTimeoutException e) {
ActivityName.this.runOnUiThread(new Runnable() {
public void run() {
dialog.dismiss();
Toast.makeText(this, "Service is not connected, Please make sure your server is running", Toast.LENGTH_LONG).show();
}
});
} catch(Exception e) {
e.printStackTrace();
ActivityName.this.runOnUiThread(new Runnable() {
public void run() {
dialog.dismiss();
Toast.makeText(this, "Unable to connect, please try again later. Thank you", Toast.LENGTH_LONG).show();
}
});
}
}
Update 1
To answer your questions from your comments,
1)Yes Async Task is more efficient. It has its own methods to do the same task what I have described here.
AsyncTask has the following methods,
i)onPreExecute()-which can be used to start your Dialog
ii)doInBackground()-which acts as the background thread.
iii)onPostExecute()-which gets called at the end where you can dismiss the dialog.
The reason why I didn't mention is that, there are possibilities that you might have to change your working code's structure to adapt to Async task.
2)runonUiThread- as the name indicates, anything inside this will be considered as it is running in the main UI thread. So basically to update the screen you have to use this. There are also other methods available, like Handlers which can also do the same task.

Use AsyncTask for it when ever task started at that time initialise your widget and then call your webservice from run method and close your progress bar on stop method.

thread not running in background

i am calling this function from the menu and calls the upload(item) function to pass the index of the selected priority.
public void showPriorityDialog()
{
final CharSequence[] priority = {"1 Hour", "12 Hours", "24 Hours", "Cancel"};
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Select Priority");
builder.setItems(priority, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int item) {
if(item != 3)
upload(item);
}
});
AlertDialog alert = builder.create();
alert.show();
}
however, whenever i call the upload function, the thread doesn't run in background, and the OS thinks that the app is not responding due to executing timeout.
public void upload(int priority)
{
final int _priority = priority;
uploadThread = new Thread()
{
#Override
public void run()
{
try
{
super.run();
mHandler.post(new Runnable() {
#Override
public void run() {
try
{
//ftp commands...
}
catch (Exception e)
{
Toast.makeText(getApplicationContext(), e.toString() , Toast.LENGTH_SHORT).show();
}
}
});
}
catch (Exception e)
{
Toast.makeText(getApplicationContext(), e.toString() , Toast.LENGTH_SHORT).show();
}
}
};
uploadThread.start();
}
am i doing something wrong? TIA

When you do mHandler.post(), your entire Runnable executes on UI thread and your background thread just exits. To fix, do FTP before posting to handler. Then do mHandler.post() to have Toast appear. Note that you catch also need to display Toast via post.