I am using ASyncTask to do simple animation in my app. But it only works on Android 5.0+, below that it just crashes and says that I edit UI from the wrong thread. Here is my code:
private class AlphaCorrect extends AsyncTask<Integer, Integer, Integer> {
float alpha;
#Override
protected Integer doInBackground(Integer[] params) {
Log.i("back","running");
for (float i = 0.0f; i < 0.9; i += 0.02) {
alpha = i;
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
Update();
}
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
for (float i = 0.8f; i > -0.1f; i -= 0.02) {
alpha = i;
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
Update();
}
return null;
}
#Override
protected void onPreExecute() {
Log.i("run", "RUN");
canClick = false;
}
#Override
protected void onPostExecute(Integer result) {
canClick = true;
}
protected void Update() {
correct.setAlpha(alpha);
}
}
I tried Runnable, Thread and some other things already. Any ideas?
You do exactly what the error says - you update UI from another thread. Override onProgressUpdate method of AsyncTask, put Update() inside it and call publishProgress(0) in your doInBackground method
you can not edit any ui of the activity from the do in background of any asynctask. thats why you are getting this error. the values you can edit from the doinbackground is local verables and global veriables.
you can not edit the ui from doInBackground().
the sloution would be to use onProgressUpdate() and do the ui changes in the onpogressupdate() .
let me know if this is what you want.
it just like their say.you cann't update anything in your Update(), you should use the onProgressUpdate()，this method provide by AsynTask.
Related
I'm having trouble with AsyncTask running multiple methods in doInBackground. this is my AsyncTask code:
public class FETCHDATA extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
pdialog = new ProgressDialog(getContext());
pdialog.setTitle("Please Wait");
pdialog.setMessage("Fetching data...");
pdialog.show();
}
#Override
protected Void doInBackground(Void... voids) {
try{
method1();
method2();
method3();
method4();
method5();
method6();
method7();
}catch (Throwable e){
e.printStackTrace();
}
}
#Override
protected void onPostExecute(Void aVoid) {
if (pdialog.isShowing()){
pdialog.dismiss();
}
}
Instead running and waiting the first method is done, the doInBackground proceeds to the next method. and the ProgressDialog dismiss by one second.
Note
Every Method will get data from our API and save it on my SQLiteDatabase .
QUESTION
How can i execute my methods when the first method has finished getting and saving data before moving to the second methods.
Maybe you have to create multiples AsyncTask and whenever the first method finish, communicate it with returning a boolean instead of void instance here ---> extends AsyncTask.
This is weird.
I assume that your methodX() are asynchronous call?
In that case, you can use Thread.join() or CountDownLatch.
You are violating usage of async task. Async task is designed for doing short async operations and update the UI easily before, during and after, It is not for doing 7 network & Sqlite operations at once.
You can read more here, : https://developer.android.com/reference/android/os/AsyncTask
So you need to implement some kind of job for yourself to execute these operations at once or use some popular libraries like Retrofit.
If you insist to use async task, since an async task need to be executed from UI thread, you need to create new async task an execute it from onPostExecute every time when it is done and you of course need to pass a param(a counter or something) to doInBackground to know which method should be called.
You can put a counter with a switch case statment in the doInBackground in wich you choose the methode to execute and then in the onPostExecute call new FETCHDATA().execute() recursively
EDIT : working code ( i forgot break; after case;)
int counter = 1; // global
class Fetchdata extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
}
#Override
protected Void doInBackground(Void... voids) {
try {
switch (counter) {
case 1:
method1();
break;
case 2:
method2();
break;
case 3:
method3();
break;
case 4:
method4();
break;
case 5:
method5();
break;
default:
cancel(true);
counter = 1;
break;
}
} catch (Throwable e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
counter+=1;
Log.d(TAG, "onPostExecute: "+counter);
// cancel(true);
new Fetchdata().execute();
}
}
void method1(){
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Log.d(TAG, "methode1: coucou");
}
void method2(){
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Log.d(TAG, "methode2: ");
}
void method3(){
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Log.d(TAG, "methode3: ");
}
void method4(){
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Log.d(TAG, "methode4: ");
}
void method5(){
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Log.d(TAG, "methode5: ");
}
I think the problem is that your all methods or some methods already runs on a separate thread . So whenever you call a method which already runs on separate thread doInBackground() i.e current thread will not wait for it and continue the execution.
Apart from that The way you put try-catch is not a proper way to do it . Also if you want to call several threads one after another you should go with ThreadPoolExecuter.
If you are not using a Network library To make API calls you can use RetroFit.
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!!!
I made Service that runs on the background collecting data from internet using AsyncTask and storing them in Shared Preferences. Even though the work is done in AsyncTask it still freezes my main activity.
Here is the code for Service:
public class GetterService extends Service {
SharedPreferences.Editor editor;
HashMap<Integer,String> links = new HashMap<Integer,String>();
#Override
public void onCreate() {
editor = PreferenceManager.getDefaultSharedPreferences(this).edit();
populateLinks();
}
private void populateLinks(){
// Here I add links to HashMap
}
#Override
public IBinder onBind(Intent intent) {
Toast.makeText(this, "GetterService ON BIND", Toast.LENGTH_LONG).show();
return null;
}
#Override
public void onDestroy() {
super.onDestroy();
Toast.makeText(this, "GetterService ON DESTROY", Toast.LENGTH_LONG).show();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
doTasks();
return super.onStartCommand(intent, flags, startId);
}
#Override
public boolean onUnbind(Intent intent) {
Toast.makeText(this, "GetterService ON UNBIND", Toast.LENGTH_LONG).show();
return super.onUnbind(intent);
}
private void doTasks(){
for (Integer in : links.keySet()) {
Document doc = null;
try {
doc = new NetTask().execute(links.get(in)).get();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (doc != null) {
Elements names = doc.select("strong, li");
if(names != null && names.size() > 0) {
for (int j = 0; j < names.size(); j++) {
editor.putString("header"+j, names.get(j).text().toString());
}
}
editor.commit();
}
}
}
public class NetTask extends AsyncTask<String, Integer, Document>
{
#Override
protected Document doInBackground(String... params)
{
Document doc = null;
try {
doc = Jsoup.connect(params[0]).timeout(5000).get();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return doc;
}
}
}
and here is how I start the service from main activity:
Intent startServiceIntent = new Intent(this, GetterService.class);
this.startService(startServiceIntent);
Even though the work is done in AsyncTask it still freezes my main activity.
You are using get():
doc = new NetTask().execute(links.get(in)).get();
And get() blocks the UI thread until the AsyncTask has completed, to me this method defeats the purpose of using a AsyncTask...
You should move this logic:
if (doc != null) {
Elements names = doc.select("strong, li");
if(names != null && names.size() > 0) {
for (int j = 0; j < names.size(); j++) {
editor.putString("header"+j, names.get(j).text().toString());
}
}
editor.commit();
}
Inside your NetTask's onPostExecute() method and remove get(). Now your AsyncTask won't bind-up the main thread.
It's because of the
new NetTask().execute(links.get(in)).get();
call.
AsyncTask.get() blocks until the async call has been completed. To be asynchronous you need to implement
onPostExecute()
and process the results there.
Don't call get(), just call execute(). Implement and overridden onPostExecute() to take a Document object as a parameter. onPostExecute() is called automatically when doInBackground() returns. Code in onPostExecute() is executed on the UI thread, so you can interact with the UI that way.
I suggest you take a look at the AsyncTask section in this document, http://developer.android.com/guide/components/processes-and-threads.html and the AsyncTask API page here, http://developer.android.com/reference/android/os/AsyncTask.html.
I had the similar problem and figured out what's going on. This code will not freeze UI, but if you put 'for loop' and sleep inside onProgressUpdate, then UI will be frozen during the process.
public class Karaoke extends AsyncTask<Void, Integer, Void> {
private Handler mHandler = new Handler(Looper.getMainLooper());
protected Void doInBackground(Void... urls) {
animating = true;
{
for (int i = 0;i < 6; i++)
{
publishProgress(i);
try
{
Thread.sleep(1000);
publishProgress(i);
}
catch (Exception xx){
}
}
}
animating = false;
return null;
}
#Override
protected void onProgressUpdate(Integer... values) {
if (light)
{
light = false;
iv_array[findview(egtxts[values[0]].getText() + "")].setImageResource(onpress);
}
else
{
light = true;
iv_array[findview(egtxts[values[0]].getText() + "")].setImageResource(onup);
}
}
protected void onPostExecute(Long result) {
//showDialog("Downloaded " + result + " bytes");
}
}
I want to show 1 to 100 in a changeable text. I like to use sleep()function so that it looks like that it is increasing form 1 to 100. my code is
for(int i= 0;i<100;i++) {
scorelevel.setText(String.valueOf(i));
try{
Thread.sleep(1000);
}catch (InterruptedException e) {
e.printStackTrace();
}
}
but it did not show properly. Any help or suggestion is appreciated.
Don't block UI thread, use AsyncTask instead
Use Timer and TimerTask to perform any time based task.
You can start counter using runOnUiThread to update textView as:
private boolean mClockRunning=false;
private int millisUntilFinished=0;
public void myThread(){
Thread th=new Thread(){
#Override
public void run(){
try
{
while(mClockRunning)
{
Thread.sleep(1000L);// set time here for refresh time in textview
YourCurrentActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
if(mClockRunning)
{
if(millisUntilFinished==100)
{
mClockRunning=false;
millisUntilFinished=0;
}
else
{
millisUntilFinished++;
scorelevel.setText(String.valueOf(millisUntilFinished));//update textview here
}
}
};
}
}catch (InterruptedException e) {
// TODO: handle exception
}
}
};
th.start();
}
You could use a TimerTask (link), too.
please see my code .. and if you can, tell me why my progressDialog stopped when the function is halfway done in the background, the screen hangs (nothing is displayed, the logcat shows all logs i put in the background function).
Then, right before the end, the progressDialog starts animating again and closes after a couple seconds (the function is finished and the result is displayed normally)
public class changeWall extends AsyncTask<Integer, Integer, Integer> {
protected Integer doInBackground(Integer... urls) {
int totalSize=0;
try {
if(s.loadBoolean() == false)
{
log("IF = false");
log("tempLogin = "+tempLogin);
log("tempPassword = "+tempPassword);
getNewResponse(tempLogin,tempPassword);
if(needSave)
{
s.saveBoolean(true);
}
}
else
{
if(s.loadLogin()==null)
{
getNewResponse(tempLogin,tempPassword);
}else
{
getNewResponse(s.loadLogin(),s.loadPassowrd());
}
}
parser.setLol(0);
parser.startParse(RESULT_STRING);
log("end parse");
} catch (ClientProtocolException e) {
log("internet connection lost");
} catch (IOException e) {
// TODO Auto-generated catch block
log(" connection lost");
}
log("count = "+parser.getFacebookId(1));
publishProgress();
totalSize=1;
log("end of start");
return totalSize;
}
protected void onProgressUpdate(Integer... progress) {
log("wall click ON PROGRESS UPDATE");
wall.setBackgroundResource(R.drawable.tabbuttonon);
messages.setBackgroundResource(0);
activity.setBackgroundResource(0);
profile.setBackgroundResource(0);
l1_1.setBackgroundResource(R.drawable.tabbuttononleft);
l1_2.setBackgroundResource(R.drawable.tabbuttononright);
l2_1.setBackgroundResource(0);
l2_2.setBackgroundResource(0);
l3_1.setBackgroundResource(0);
l3_2.setBackgroundResource(0);
l4_2.setBackgroundResource(0);
l4_2.setBackgroundResource(0);
wall.setTextColor(Color.BLACK);
messages.setTextColor(Color.WHITE);
profile.setTextColor(Color.WHITE);
activity.setTextColor(Color.WHITE);
try {
loadWall();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
wallProgres.dismiss();
}
protected void onPostExecute(Long result) {
if(result==1)
{
log("end WallChange");
}
}
}
simple map as this showed :
----start progress(progress.show())
----start function
--- animation (progressDialog)
---animation(---)
---animation(---)
---FREEZ
---FREEZ(Function steel working normal, progressDialog in freeze mode)
---animation
---end function
---progress.dismis();//
similar problem i found here..(this problem = my problem but without download) Freezing UI Thread with AsyncTask
Regards,Peter.
It may not be correct but place
wallProgres.dismiss();
in onPostExecute rather than in onProgessUpdate method.
beacuse onProgressUpdate calls while running , but onPostExecute calls after execution.
Hope it helps..
place this line "wallProgres.dismiss()" in onPostExecute().
protected void onPostExecute(Long result) {
if(result==1)
{
log("end WallChange");
}
if(wallProgress.isShowing())
wallProgres.dismiss();
}
put this line
wallProgres.dismiss();
in onPostExecute() method
protected void onPostExecute(Long result) {
if(result==1)
{
log("end WallChange");
wallProgres.dismiss();
}
}