this is a piece of code from my project, i need this thread to be over untill the end and only then go to the last Log.i() and finish the function.
public void delay3Seconds(final String txt1, final String txt2, final String s, final Intent i)
{
//keepMoving= false;
counter= 3;
secondsBool= true;
if(!errorMonitor)
{
Log.i("Main.delay3Seconds()", s+" in 3 seconds");
new Thread()
{
public void run()
{
while(secondsBool)
{
try {
Thread.sleep(1500);
}
catch (InterruptedException e){e.printStackTrace();}
if(!errorMonitor)
{
handler.post(new Runnable()
{
public void run()
{
final DialogFragment loadDF= new RecDialog(MainActivity.this, txt1, txt2, s+(counter--)+" שניות", null, false, true, ll.getWidth(), ll.getHeight());
loadDF.show(getSupportFragmentManager(), "RecDialog");
dialog.dismiss();
dialog= loadDF;
if(counter == 0)
secondsBool= false;
}
});
}
else
secondsBool= false;
}
if(!errorMonitor)
{
handler.post(new Runnable()
{
public void run()
{
dialog.dismiss();
if (i.resolveActivity(getPackageManager()) != null)
{
Log.i("Main.delay3Seconds()", "resolveActivity != null");
setResolveNotFail(true);
Log.i("Main.delay3Seconds()", "resolveNotFail = "+resolveNotFail);
startActivity(i);
}
else
{
Log.i("Main.delay3Seconds()", "resolveActivity == null");
setResolveNotFail(false);
Log.i("Main.delay3Seconds()", "resolveNotFail = "+resolveNotFail);
}
}
});
}
}
}.start();
}
Log.i("Main.delay3Seconds()", "(end) resolveNotFail = "+resolveNotFail);
}
i can't figure out how to do that. i tried using synchronized(), but i probably use it wrong because the function finishes itself first and only then the thread works, simultaneously to the activity.
i would appreciate any tips on how to do that..
That's absolutely not how or why you use a Thread. First off, if this is the UI thread you should never pause it for 3 seconds. Second, the entire point of a Thread is to work in parallel. You never want one thread to pause and wait for another. If you need something on Thread A to occur only when Thread B is done, you send a message via a handler, semaphore or other method to Thread A when Thread B is done.
Looking at your code, it seems like you should throw it out and reimplement it with a timer.
https://docs.oracle.com/javase/tutorial/essential/concurrency/join.html
Just call the .join() method after you start your thread so the calling thread will wait until your new thread executes.
Something like this:
Thread t = new Thread(...);
t.start();
t.join();
Related
i want to start Asynchoronous task after some sleep time. For that i am using thread and i start my asynchronous task in that thread finally block. But it gives cant create a handler inside a thread exception.
i am using the following logic.
thread= new Thread()
{
public void run()
{
try
{
int waited = 0;
while (waited < 300)
{
sleep(100);
waited += 100;
}
}
catch (InterruptedException e)
{
// do nothing
}
finally
{
Load ld=new Load();
ld.execute();
}
}
};
thread.start();
Well, first of all, if the final goal is to run AsyncTask after some delay, I would use Handler.postDelayed instead of creating separate Thread and sleeping there:
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
new Load().execute();
}
}, 300); //300ms timeout
But, if you really wanna make fun of Android, you can create HandlerThread - special thread which has looper in it, so your AsyncTask will not be complaining anymore:
thread= new HandlerThread("my_thread")
{
public void run()
{
try
{
int waited = 0;
while (waited < 300)
{
sleep(100);
waited += 100;
}
}
catch (InterruptedException e)
{
// do nothing
}
finally
{
Load ld=new Load();
ld.execute();
}
}
};
thread.start();
Please note that you are responsible for calling quit() on this thread. Also I'm not sure what happens if you quit this thread before AsyncTask is done. I don't remember where AsyncTask posts its results - to the main thread, or to the thread it was called from...
In any case, second option is just a mess, so don't do it:) Use the first one
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
// Do whatever you want.
}
}, SPLASH_TIME_OUT);
}
You can use like above. there SPLASH_TIME_OUT is the millisecond value that u want to make a delay.
Use Handler class, and define Runnable YourAsyncTask that will contain code executed after sleepTime
mHandler.postDelayed(YourAsyncTask, sleepTime);
You must run AsyncTask in UI thread, so you can use something like this:
class YourThread extends Thread{
private Activity _activity;
public YourThread(Activity _activity){
this activity = _activity;}
public void run()
{
try
{
int waited = 0;
while (waited < 300)
{
sleep(100);
waited += 100;
}
}
catch (InterruptedException e)
{
// do nothing
}
finally
{
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
Load ld=new Load();
ld.execute();
}
});
}
}
}
and in your activity call thread like this:
YourThread thread = new YourThread(this);
thread.start();
also note: use soft reference to activity or do not forget kill thred when activity will be destroyed.
just do your like below code:
define a thread globally.
public static Thread thread;
thread= new Thread() {
public void run() {
sleep(time);
Message msg = setTextHandler.obtainMessage(2);
setTextHandler.sendMessage(msg);
}
};
thread.start();
and your handler look like
private final Handler setTextHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
if (thread!= null) {
thread.interrupt();
thread= null;
}
switch (msg.what) {
case 2: //do your work here
Load ld=new Load();
ld.execute();
break;
}
}
};
I want to write a download manager app, in the activity I add a progress bar which show the current progress to the user, now if user touch the back button and re-open the activity again this ProgressBar won't be updated.
To avoid from this problem I create a single thread with unique name for each download that keep progress runnable and check if that thread is running in onResume function, if it is then clone it to the current thread and re-run the new thread again but it won't update my UI either, Any ideas !?
#Override
public void onResume()
{
super.onResume();
Set<Thread> threadSet = Thread.getAllStackTraces().keySet();
Thread[] threadArray = threadSet.toArray(new Thread[threadSet.size()]);
for (int i = 0; i < threadArray.length; i++)
if (threadArray[i].getName().equals(APPLICATION_ID))
{
mBackground = new Thread(threadArray[i]);
mBackground.start();
downloadProgressBar.setVisibility(View.VISIBLE);
Toast.makeText(showcaseActivity.this
, "Find that thread - okay", Toast.LENGTH_LONG).show();
}
}
private void updateProgressBar()
{
Runnable runnable = new updateProgress();
mBackground = new Thread(runnable);
mBackground.setName(APPLICATION_ID);
mBackground.start();
}
private class updateProgress implements Runnable
{
public void run()
{
while (Thread.currentThread() == mBackground)
try
{
Thread.sleep(1000);
Message setMessage = new Message();
setMessage.what = mDownloadReceiver.getProgressPercentage();
mHandler.sendMessage(setMessage);
}
catch (InterruptedException e)
{
Thread.currentThread().interrupt();
}
catch (Exception e)
{/* Do Nothing */}
}
}
private Handler mHandler = new Handler()
{
#Override
public void handleMessage(Message getMessage)
{
downloadProgressBar.setIndeterminate(false);
downloadProgressBar.setProgress(getMessage.what);
if (getMessage.what == 100)
downloadProgressBar.setVisibility(View.GONE);
}
};
Download button code:
downloadBtn.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View arg0)
{
downloadProgressBar.setVisibility(View.VISIBLE);
downloadProgressBar.setIndeterminate(true);
downloadProgressBar.setMax(100);
Intent intent = new Intent(showcaseActivity.this, downloadManagers.class);
intent.putExtra("url", "http://test.com/t.zip");
intent.putExtra("receiver", mDownloadReceiver);
startService(intent);
updateProgressBar();
}
});
I'd strongly recommend reading the Android Developer blog post on Painless Threading. As it states, the easiest way to update your UI from another thread is using Activity.runOnUiThread.
I'm trying to write code to pull a server every second for updated messages. The messages then get displayed in a text view. If I do not change the text in the text view it runs fine. It will crash if I try to change the textview on the thread. IF i change it not on the thread works fine.
I'm assuming the thread cannot access the main threads memory? How can I set the text in the view with the text just loaded over the internet?
In the code below I have a thread that does a endless loop with a sleep. It calls a method called SendMessage. Send Message loads in text over the internet and at the end tries to update the View with it. It causes a exception when this happens.
code:
public class cChat extends cBase implements OnClickListener {
/** Called when the activity is first created. */
TextView mUsers;
TextView mComments;
int i=0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.chat);
mUsers=( TextView) findViewById(R.id.viewusers);;
mComments=( TextView) findViewById(R.id.viewchats);;
Thread thread = new Thread()
{
#Override
public void run() {
try {
int t=0;
while(true)
{
SendMessage();
sleep(1000*5);
t++;
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
thread.start();
}
public void onClick(View v) {
} // end function
// send a uypdate message to chat server
// return reply in string
void SendMessage()
{
try {
URL url = new URL("http://50.63.66.138:1044/update");
System.out.println("make connection");
URLConnection conn = url.openConnection();
// set timeouts to 5 seconds
conn.setConnectTimeout(1000*5);
conn.setReadTimeout(5*1000);
conn.setDoOutput(true);
BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
// String line;
String strUsers=new String("");
String strComments=new String("");
String line=new String();
int state=0;
while ((line= rd.readLine() ) != null) {
switch(state){
case 0:
if ( line.contains("START USER"))
state=1;
if ( line.contains("START COMMENTS"))
state=2;
break;
case 1:
if ( line.contains("END USER"))
state=0;
else
{
strUsers+=line;
strUsers+="\n";
}
break;
case 2:
if ( line.contains("END COMMENTS"))
state=0;
else {
strComments+=line;
strComments+="\n";
}
break;
} // end switch
} // end loop
// the next line will cause a exception
mUsers.setText(strUsers);
mComments.setText(strComments);
} catch (Exception e) {
i++; // use this to see if it goes here in debugger
// System.out.println("exception");
// System.out.println(e.getMessage());
}
} // end methed
}
use runOnUiThread as
YOUR_CURRENT_ACTIVITY.this.runOnUiThread(new Runnable() {
#Override
public void run() {
// the next line will cause a exception
mUsers.setText(strUsers);
mComments.setText(strComments);
//....YOUR UI ELEMENTS
}
});
EDIT :
see doc runOnUiThread
You can use a handler to post tasks (Runnables) to the UI/Main Thread:
private Handler handler = new Handler();
//...
Thread thread = new Thread()
{
#Override
public void run() {
try {
int t=0;
while(true)
{
handler.post(new Runnable() {
#Override
public void run() {
SendMessage();
}
});
sleep(1000*5);
t++;
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
You can't touch an UI widget from a thread different than the one used to create it (the UI thread). But if you have a reference to the Activity, you can simply do:
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
mUsers.setText(strUsers);
mComments.setText(strComments);
}
});
which would require strUsers to be accessible by the anonymous class. For that you can simply do:
final String finalUseres = strUsers;
and use finalUsers within run().
Try using a Service to continuously pull/send data to server. This will reduce the load on your UI-Thread.
the Andoid UI toolkit is not thread-safe. So, you
must not manipulate your UI from a worker thread
To fix this problem, Android offers several ways to access the UI thread from other threads. Here is a list of methods that can help:
Activity.runOnUiThread(Runnable)
View.post(Runnable)
View.postDelayed(Runnable, long)
you can also use AsyncTask.
see this tutorial on process and threads in android.
hi i am working on custom toast , and i am able to do that, but after when i move to next activity the thread is running or active of back activity , so what should i do for removing that thread or stop this thread.
my code is given below :
public void customToast(int x, int y, String str) {
if (Util.tipson == true) {
toast = new Toast(getApplicationContext());
toast.setDuration(Toast.LENGTH_SHORT);
toast.setGravity(Gravity.TOP, x, y);
LayoutInflater li = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
toastView = li.inflate(R.layout.toastlayout, null);
toast.setView(toastView);
TextView text = (TextView) toastView.findViewById(R.id.text);
text.setText(str);
// toast.show();
fireLongToast();
}
}
private void fireLongToast() {
t = new Thread() {
public void run() {
int count = 0;
try {
while (true && count < 40) {
try {
toast.show();
sleep(100);
count++;
} catch (Exception e) {
// TODO: handle exception
}
// do some logic that breaks out of the while loop
}
toast = null;
toastView = null;
} catch (Exception e) {
Log.e("LongToast", "", e);
}
}
};
t.start();
}
You Need to stop your thread by yourself. Since java doesn't allow you to use stop() function.
Write class for your Thread as this
public class YourThread extends Thread {
private volatile boolean stopped = false;
public void run() {
int count = 0;
try {
while (true && count < 40 && !stopped) {
try {
toast.show();
sleep(100);
count++;
} catch (Exception e) {
// TODO: handle exception
}
// do some logic that breaks out of the while loop
}
toast = null;
toastView = null;
} catch (Exception e) {
Log.e("LongToast", "", e);
}
}
public void stopThread() {
stopped = true;
}
}
Now when your Activity which has the Thread Finishes stop Your thread
#Override
protected void onDestroy() {
if(isFinishing())
yourThreadVariable.stopThread();
}
Dont know for sure, but you can call the function join of thread in onDestroy of your activity.
To stop the thread you can just use interrupt(). But for better solution I would say not to use Thread. Just create a Handler with Runnable and manage your Runnable using Handler, that would be a nice way as Android has given Handler for managing one or more Runnables.
Creating a Runnable
Runnable runnable = new Runnable() {
#Override
public void run() {
// put your code stuff here
}
};
To start Runnable use
handler.postDelayed(runnable, your_time_in_millis);
To stop Runnable use
handler.removeCallbacks(runnable);
Does finishing the activity have any effect?
I would like to suggest Lalit Poptani method too and implement this:
protected void onStop(){
handler.removeCallbacks(runnable);
super.onStop();
}
The documentation for the method:
onStop,Called when the activity is no longer visible to the user, because another activity has been resumed and is covering this one. This may happen either because a new activity is being started, an existing one is being brought in front of this one, or this one is being destroyed.
http://developer.android.com/reference/android/app/Activity.html
I would like to create a popup after a splashscreen.
But A have a crash. I think, because the popup is create in a thread (but terminated).
So crash..
I don't find a good code :(
Code:
Thread splashTread = new Thread() {
#Override
public void run() {
boolean error = true;
try {
int waited = 0;
Parser parser= Parser();
error = parser.init();
while (waited < _splashTime) {
sleep(100);
waited += 100;
}
} finally {
if(!error){
startActivity(new Intent(getApplicationContext(),
Main.class));
finish();
}else{
createPopup(context);
}
}
}
};
You would have much better luck with a Handler and a Runnable for this type of thing. The contents of the Runnable will still execute on the main thread even though you are posting from a different thread. The Handler class executes in whatever thread it is created in.
Runnable splashRunnable = new Runnable(){
public void run(){
if(!error){
StartActivity(new Intent(getApplicationContext(), Main.class));
finish();
}else createPopup(context);
}
};
//in your thread
mHandler.postDelayed(splashRunnable, _splashTime);