How to delay code execution (draw the path) for few seconds? - android

This is the problem about loading.
My application should wait for 3 seconds and then draw path. Now, the loading message box appears within 3 seconds but the application does not wait for 3 seconds and draw immediately . Is there any problem in my coding ?
Many Thanks!!
public void drawpath(){
// first to do some checking
if (sourceLat.equals("22.3366467") && destinationLat.equals("35.68449"))
ShowMsgDialog("Please enter the starting point and destination");
else if (sourceLat.equals("22.3366467") )
ShowMsgDialog("Please enter the starting point by touch");
else if (destinationLat.equals("35.68449") )
ShowMsgDialog("Please enter the destination by touch");
else if (pairs != null ){
// go to loading function
loading();
// Start to draw the path
String[] lngLat = pairs[0].split(",");
GeoPoint startGP = new GeoPoint((int) (Double.parseDouble(lngLat[1]) * 1E6), (int) (Double.parseDouble(lngLat[0]) * 1E6));
mc = mapView.getController();
geoPoint = startGP;
mc.setCenter(geoPoint);
mc.setZoom(15);
mapView.getOverlays().add(new DirectionPathOverlay(startGP, startGP));
......
}
in the loading() function:
private void loading() {
progressDialog = ProgressDialog.show(this, "Showing Data..", "please wait", true, false);
new Thread()
{
public void run()
{
try{
sleep(3000);
}
catch (Exception e){
e.printStackTrace();
}
finally{
progressDialog.dismiss();
}
}
}.start();
}

You can also do it in the following way:
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
drawPath();
}
}, 5000);
This won't display any lint warnings.

A handler would do the job very easily.You won't need a separate thread or AsyncTask(). Use a Handler in your Activity to delay events such as calling the method drawPath() in your case:
private RefreshHandler mRedrawHandler = new RefreshHandler();
private RefreshHandler mRedrawHandler = new RefreshHandler();
class RefreshHandler extends Handler {
#Override
public void handleMessage(Message msg) {
drawPath();
}
public void sleep(long delayMillis) {
this.removeMessages(0);
sendMessageDelayed(obtainMessage(0), delayMillis);
}
};
In your onCreate() of Activity (or In onClick() of any button, whenever you want to start a delay), call mRedrawHandler.sleep(3000); , drawPath(); is a method where you are starting the draw.

After you spawn a new thread your code regains control and continues executing. Your additional thread is waiting not the original one.

for delayer in android activity
import android.os.Handler;
in code main
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
}
}, 5000);
But the above code is obsolete
It is better to use the following code
Use it for Java
new Handler(Looper.getMainLooper()).postDelayed(new Runnable() {
#Override
public void run() {
// Your Code
}
}, 3000);
Use it for Kotlin
Handler(Looper.getMainLooper()).postDelayed({
{
//Your Code
}
}, 3000)

Related

Android: ProgressDialog not progressing inside a Thread

I'm calling several AsyncTasks to do a job. In order to know when they are done. I have an object (synchronized) with a numerator that holds the number of current running AsyncTasks.
After deploying all of them I do the following:
final ProgressDialog pd = new ProgressDialog(this);
pd.setMessage(getString(R.string.please_wait));
pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
pd.setCancelable(false);
pd.setProgress(0);
pd.setMax(Utils.getAsyncs());
pd.show();
new Thread(new Runnable() {
#Override
public void run() {
while (Utils.getAsyncs() > 0)
pd.setProgress(pd.getMax() - Utils.getAsyncs());
runOnUiThread(new Runnable() {
public void run() {
pd.dismiss();
}
});
}
}).start();
When the dialog shows, it starts progressing but at some point it gets stuck til the end of everything and then dismisses (as expected).
I tried to put
pd.setProgress(pd.getMax() - Utils.getAsyncs());
also inside a runOnUiThread but that made things worse and I'm sure I'm missing something else. hence my question. Thanks
edited by request:
public static int getAsyncs() {
return asyncs;
}
edit 2: I did the following based on a comment
while (Utils.getAsyncs() > 0) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {}
runOnUiThread(new Runnable() {
public void run() {
pd.setProgress(pd.getMax() - Utils.getAsyncs());
}
});
}
and it seems to be better
In your class fields
private Handler progressHandler = new Handler();
private Runnable progressRunnable = new Runnable() {
#Override
public void run() {
progressDialog.setProgress(progressValue);
progressHandler.postDelayed(this, 1000);
}
};
When the time consuming thread is started
// Here start time consuming thread
// Here show the ProgressDialog
progressHandler.postDelayed(progressRunnable, 1000);
When the time consuming thread ends
progressHandler.removeCallbacks(progressRunnable);
/// Here dismiss the ProgressDialog.
ADDED:
Instead new Thread(new Runnable) that you probably use for your time consuming code I propose to do this:
To initialize the task :
MyTask task = new MyTask();
task.execute();
// Here show the PorgressDialog
progressHandler.postDelayed(progressRunnable, 1000);
Add this private class inside your main class:
private class MyTask extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... voids) {
//Here do your time consuming work
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
// This will be called on the UI thread after doInBackground returns
progressHandler.removeCallbacks(progressRunnable);
progressDialog.dismiss();
}
}
do something lik this
new Thread(new Runnable() {
public void run() {
while (prStatus < 100) {
prStatus += 1;
handler.post(new Runnable() {
public void run() {
pb_2.setProgress(prStatus);
}
});
try {
Thread.sleep(150);
} catch (InterruptedException e) {
e.printStackTrace();
}
if(prStatus == 100)
prStatus = 0;
}
}
}).start();

how to start Asychoronous task in a thread finally block in android

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;
}
}
};

Run a AsyncTask every 10 seconds until cancelled

In my application, I have a button that starts an AsyncTask that downloads data with coordinates for google maps, then draws a marker on the map at the following coordinates. I want to run this every 10 seconds until the user presses the button again.
Here's my code for the handler:
class handleMap{
Handler mHandler = new Handler();
Runnable mTask = new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
while(btnRefreshPressed == false){
try{
new getGoogleMap().execute();
mHandler.postDelayed(mTask, INTERVAL);
Thread.sleep(INTERVAL);
} catch(Exception e){
System.out.println(e.toString());
}
}
}
};
public void starReapetingClass (){
hMap.starReapetingClass();
}
public void stopDoing(){
mHandler.stopDoing();
}
}
And in the menubutton where it is called:
case R.id.id_Refresh:
handleMap hMap = new handleMap();
if(btnRefreshPressed == true){
menuItem = item;
menuItem.setActionView(R.layout.progressbar);
menuItem.expandActionView();
fRun += 1;
btnRefreshPressed = false;
hMap.run();
}else if(btnRefreshPressed == false){
if(fRun > 0){
menuItem.collapseActionView();
menuItem.setActionView(null);
}
btnRefreshPressed = true;
hMap.stopHandler();
}
This currently causes the application to freeze, and the system outputs a dialog saying that the app isn't responding, and asking if I want to close or wait.
I suspect it has to with the while statement, but I don't get any errors in logcat.
Thanks in advance.
Just use:
private int mSampleDurationTime = 10000;
private boolean continueToRun = true;
mHandler.postDelayed(mRunnable, mSampleDurationTime);
where mRunnable is your task:
private final Runnable mRunnable = new Runnable() {
//...
public void run() {
...
if(continueToRun == true){
mHandler.postDelayed(mRunnable, mSampleDurationTime);
}
}
...
};
First time you call postDelayed and invoke new Runnable(). After, if you want to continue,
call the same method into run()

Update UI from running thread

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.

how to create a thread to refresh data in 3 second interval

I need a thread (it does httppost ,and parse the answer xml and refresh listview to set the changes from parsed xml) in 3 sec interval
I have already tried this code
Timer timer = new Timer();
timer.scheduleAtFixedRate(
new TimerTask() {
public void run() {
try {
httpPostList(url);
saxParseList();
list.invalidateViews();
Thread.sleep(1000);
} catch (Exception ie) {
}
}
}, 1000, 1000 * 30);
I would appreciate you to create a Service with an AsyncTask in it.
Async Tasks are the Android Synonym to normal Java Tasks, Documentation finding here: http://developer.android.com/reference/android/os/AsyncTask.html
Services are Background Processes, seeing this Doc:
http://developer.android.com/reference/android/app/Service.html
Try using handlers:
Handler handler;
#Override
public void onCreate(Bundle savedInstanceState) {
// ...
handler = new Handler() {
#Override
public void handleMessage(Message msg) {
updateUI();
}
};
Thread thread = new Thread() {
#Override
public void run() {
while(true) {
Message msg = new Message();
handler.sendMessage(msg);
try {
sleep(3*1000); // 3 seconds
} catch (InterruptedException e) {
}
}
}
};
thread.start();
}
private synchronized void updateUI() {
// ...
}
Finally I made it using "Async task".

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